Jump to content
Electrodynamic

SI 4" coil DS4-18 info and discussion

Recommended Posts

I understand your point and here's the counterpoint.  People are simulating "max spl" WinISD comparisons all the time using the published xmax or power handling as the limit and treating the sims like gospel truth even though the large signal parameters may have been derived in very different ways and are not comparable.

 

The effect of high power on drivers is pretty well known and you can get a crude estimation of power compression by adding some Re to the sim.  It's not totally accurate of course but it works as an educated guess.  And there are ways to simulate the inductance effects of this type of high excursion driver too, Ricci was doing it long before I did my study although I don't think he published much (if anything) about the method he was using to estimate the effects.

 

If you ignore all these things - the differences in how large signal parameters are derived, the power compression effects, the inductance effects - you end up with meaningless sims that get plastered all over the internet and treated as though they are meaningful ways to compare different drivers.  But if you make some educated guesses in the sim work the sims are MUCH more realistic, this includes knowing how the large signal parameters were derived..

 

When most people do a simple sim they won't be able to make their sim match a data-bass measurement even at very small signal levels like the 1 watt measurement.  On the other hand, with my educated sim tweaks (even the generic version of the tweaks) I can make a pretty good match to the 1 watt measurement AND the max spl measurement.

 

Sims can be pretty realistic if you feed them the right information, which sometimes includes tweaking the specs in ways that have been shown to have predictable and repeatable accurate results.  (Not accurate in the sense of perfectly accurate but a lot more accurate than a simple sim.)

 

I put a lot of time into figuring out how to sim things accurately compared to reliable real world measurements.  And my sims are very accurate.  When they vary from measurements I usually know why - there's only so much information a sim can account for.  High power sims add some variability into the mix but it's not like it's a complete unknown what's going to happen.  You can get a pretty accurate estimate from a sim even under high power conditions.  Especially with the simpler designs like sealed box data-bass measurements.

Share this post


Link to post
Share on other sites
When most people do a simple sim they won't be able to make their sim match a data-bass measurement even at very small signal levels like the 1 watt measurement.  On the other hand, with my educated sim tweaks (even the generic version of the tweaks) I can make a pretty good match to the 1 watt measurement AND the max spl measurement.

 

Sims can be pretty realistic if you feed them the right information, which sometimes includes tweaking the specs in ways that have been shown to have predictable and repeatable accurate results.  (Not accurate in the sense of perfectly accurate but a lot more accurate than a simple sim.)

 

I put a lot of time into figuring out how to sim things accurately compared to reliable real world measurements.  And my sims are very accurate.  When they vary from measurements I usually know why - there's only so much information a sim can account for.  High power sims add some variability into the mix but it's not like it's a complete unknown what's going to happen.  You can get a pretty accurate estimate from a sim even under high power conditions.  Especially with the simpler designs like sealed box data-bass measurements.

 

I wonder how tweaking sims of sine sweeps relates to HT reproduction. In my experience, not so much... especially power compression projections. As I've attempted to point out elsewhere on these boards, we've fed >8KW to a pair of 15s playing soundtrack clips where a sine sweep at anywhere near that would easily have created a new asshole in the drivers. The 2 metrics have virtually no correlation.

 

To your earlier stuff about the HS24 and it's usable throw being 50% less than what Nick estimated from proto to production versions, if that were a correct estimate, I doubt the CEA 2010 burst numbers Josh posted resulting from testing an actual driver would be correct. In fact, they seem perfectly in line with >30 mm, THD-limited @ 10 Hz and far more when the THD limit was tossed. Certainly not 20 mm, Jacob and Klippel notwithstanding.

 

The HS drivers Nick brought to our G2G gave a measured 45 mm outward throw. Yes, the inward motion was less, limited by the air spring and predictably so. We much prefer the added 2HD to driver destruction. The point I'm trying to make is that the driver displayed remarkable composure despite the violence that accompanies 45 mm one-way throw. It's certainly the most excursion without incident of any of the 100s of 15" drivers we've used over the years. That has nothing to do with claims of Klippel verified Xmax, which isn't a priority on my criteria list, but was very close to Nick's claims to me before he arrived with the drivers. We ran a battery of real world tests using 2 other very good drivers for comparison and found the driver to be all that. We had also seen the HS24 being pounded at a G2G and my considered opinion is that 20 mm is not the drivers one way Xmax, regardless of which metric you might use to arrive at the hallowed number.

 

The other point of interest to me is the asymmetry that every driver displays when in a sealed box vs a free air test of any sort. When using a standard formula as a starting point for using the air spring of a sealed enclosure to limit excursion, the inward half of the cycle of motion is always less than the outward half. Siegfried discussed this phenomenon years ago and included a formula to predict the increase in 2HD caused by the asymmetrical motion. No manner of sim tweaking will show this phenomenon or its results.

 

For the record, I'm a huge fan of Dan Wiggins and an official SI fanboi (just ask any member of this forum). I think WinISD is a scourge and much prefer to discuss actual subwoofer hardware and their actual performance using actual movie soundtrack as source. No dis, just adding opinions to the fray.

Share this post


Link to post
Share on other sites
 



I wonder how tweaking sims of sine sweeps relates to HT reproduction. In my experience, not so much... especially power compression projections. As I've attempted to point out elsewhere on these boards, we've fed >8KW to a pair of 15s playing soundtrack clips where a sine sweep at anywhere near that would easily have created a new asshole in the drivers. The 2 metrics have virtually no correlation.

 

 

Your point here seems to be that the signal is different between the dynamic soundtrack clips and a sine sweep, the latter being a much more demanding signal that will cause more power compression and at some point thermal failure.  Point taken and this is very true.  That doesn't mean that either of those signals don't produce power compression, and that the power compression that does show up will cause the same heating effects (although at different heat levels).  And those power compression effects can be crudely simulated.  Just because the dynamic soundtrack clips are less intense than a sine sweep doesn't mean they don't produce heat in the coil, or that the heat in the coil or that the effect can't be crudely simulated.

 

I've spent a lot of time on various forums talking about how the signal itself, crest factor (dynamics), duty cycle (length) and frequency (vs impedance) have a lot to do with power compression and thermal failure.  Different signals cause wildly different amounts of heat, even at the same amp voltage setting, this is known.

 

To your earlier stuff about the HS24 and it's usable throw being 50% less than what Nick estimated from proto to production versions, if that were a correct estimate, I doubt the CEA 2010 burst numbers Josh posted resulting from testing an actual driver would be correct. In fact, they seem perfectly in line with >30 mm, THD-limited @ 10 Hz and far more when the THD limit was tossed. Certainly not 20 mm, Jacob and Klippel notwithstanding.
 
I never said the part in bold, it's actually a gross misrepresentation of what I did say.  This is why this topic gets so heated, my point is being completely missed.
 
Usable throw and klippel verified xmax are two VERY different things.  I don't doubt the SI 24 has 36 mm and maybe more usable throw.
 
That DOES NOT negate the fact that a klippel verified test will show closer to 20 mm xmax.  That's not a guess, the actual klippel graph that shows it was posted by Jacob and he outright stated xmax was limited to 20 mm because of Le.
 
I understand that in these circles the usable throw number is MUCH more important and the klippel verified number means nothing at all.
 
The point here is that Nick specifically has stated on a number of occasions that the SI drivers are klippel verified.  It's stated so specifically in the SI 18 data-bass write up even with the subsequent subtle wording change.  The Bl curve may have been verified with the klippel system, that is a VERY different thing than the xmax being klippel verified.
 
So why is this so important?
 
2q385lc.png
 
Top graph is data-bass measured max output for Dayton HO 18 overlaid with SI 18 max output.
Bottom graph is UM 18 vs SI 18.
For these three drivers the published xmax is 12.75 mm (HO), 22 mm (UM) and 22.5 mm (SI).
 
It's hard to guess how much of the compression measured was due to power compression and how much was due to excursion limits, but the data-bass commentary for all three states there was excursion noises, so we can probably assume they were all at their limits.
 
Let's look at 10 hz specifically, where the drivers are all presumably excursion limited.  If the drivers were all rated in the same way we would expect the UM and the SI to be head to head, as they are rated within .5 mm of each other in xmax.  And both the UM and the SI should be almost 3 db ahead of the HO because they are rated to have almost twice the xmax, which equates to 3 db more output.
 
But that is not the case, the HO and the SI are within about 1.5 db of each other and the UM is a full db ahead of the SI.  
 
The UM is almost 3 db ahead of the HO, which means the Dayton specs are directly comparable with each other.  The fact that the SI is not head to head with the UM and not 3 db ahead of the HO means the xmax specs between the two companies are NOT comparable.
 
So what's the big deal when we are only talking about 1, 1.5, 3 db difference?  The big deal is that it takes twice the excursion to produce 3 db more.  So a difference of 1 db, while barely audible, means a difference in excursion of about 1/3, which is huge.
 
And my main point is that you can't compare these different drivers in sims and expect any reasonable accuracy when the xmax is not comparable.
 
If this stuff wasn't important we wouldn't always constantly be waiting with baited breath for the new product data-bass measurements to see which driver can outdo the others by 1 db at 10 hz.  There is a big faction that believes the published specs don't mean much, which is why the measurements are important.  My point is that the specs COULD have meaning if they were standardized or if we at least knew how they were derived.

 

 

The HS drivers Nick brought to our G2G gave a measured 45 mm outward throw. Yes, the inward motion was less, limited by the air spring and predictably so. We much prefer the added 2HD to driver destruction. The point I'm trying to make is that the driver displayed remarkable composure despite the violence that accompanies 45 mm one-way throw. It's certainly the most excursion without incident of any of the 100s of 15" drivers we've used over the years. That has nothing to do with claims of Klippel verified Xmax, which isn't a priority on my criteria list, but was very close to Nick's claims to me before he arrived with the drivers. We ran a battery of real world tests using 2 other very good drivers for comparison and found the driver to be all that. We had also seen the HS24 being pounded at a G2G and my considered opinion is that 20 mm is not the drivers one way Xmax, regardless of which metric you might use to arrive at the hallowed number.
 
I understand these drivers perform well, all of them.  And I know you beat the living hell out of the 24 and it did well with huge usable excursion.  That doesn't negate the fact that this usable excursion has nothing at all to do with distortion percentages,  klippel tests, klippel verification or the fact that different companies use different methods to spec xmax.
 

 

The other point of interest to me is the asymmetry that every driver displays when in a sealed box vs a free air test of any sort. When using a standard formula as a starting point for using the air spring of a sealed enclosure to limit excursion, the inward half of the cycle of motion is always less than the outward half. Siegfried discussed this phenomenon years ago and included a formula to predict the increase in 2HD caused by the asymmetrical motion. No manner of sim tweaking will show this phenomenon or its results.
 
This may be true but it's not really a factor here.  Data-bass measured all the of the above drivers in the same box so they were all seeing the same air load.  Ideally there would also be measurements in IB where the air load was not a factor (and then it would also be a lot more clear in the distinction between power compression losses and excursion limits) but there's only so much we can reasonably ask data-bass to measure.
 

 

For the record, I'm a huge fan of Dan Wiggins and an official SI fanboi (just ask any member of this forum). I think WinISD is a scourge and much prefer to discuss actual subwoofer hardware and their actual performance using actual movie soundtrack as source. No dis, just adding opinions to the fray.
 
I use Hornresp, not WinISD, Hornresp is more accurate and better in many ways.  Still, if you want accurate sims of these high excursion drivers at high power levels you need to know which parameters to tweak.
 
I don't like the fact that people that can barely enter t/s parameters into WinISD think the max spl comparisons between drivers have any kind of meaningful information but you see these comparisons plastered all over the internet daily.
 
Dan Wiggins is a good designer and SI makes good products.  I'm especially attracted to Sundown products though.  The fact that these people all make great stuff doesn't mean they are immune to posting accurate specs, especially when they go on open forums for marketing purposes and say the products are klippel verified when they are not.  Dan and Nick have both done that, Jacob has done the opposite, he actually posted the graph that showed the SI 24 was NOT klippel verified and explained in detail why it wasn't.
 
Presumably Jacob specs xmax in the same fashion as SI.  And that's fine with me.  The big difference is that Jacob is not claiming klippel verification while Nick has on many occasions for many of his drivers.

Share this post


Link to post
Share on other sites

Lots of stuff, little time...

 

How can a driver exhibit full output potential at all frequencies in-band with a sine sweep (or a model of a sine sweep, tweaks notwithstanding)?

 

It can't.

 

The power compression curves do not relate to conditions seen with playback of dynamic source. A better metric is the multi-signal Spectral Contamination test that I suggested to Ed & Ilkka a long while back and that Josh used a couple of times and stopped using. Ilkka stopped including the test because he said he was only looking for non-linear distortions of the harmonic and intermod variety and that the SC test was close enough in line with the other THD tests he used for him to consider the SC test redundant.

 

I disagreed then and do still. Simultaneous playback of multiple frequency tones is a much better sim of some program source than a sine sweep. To our point here, the compression curve for the SC input would be a flat line vs the radically curved compression curve derived from the sweeps. This is what you expect (and will see) when using dynamic source as input, 'x' dB of compression, in-band.

 

Another important point is that all, as in ALL of the commercial HT subs tested with the progressive sine sweeps display compression that is induced by aggressive limiting (which is basically using an electronic compressor with slightly different parameters). This is not power compression and thus has little to do with the driver.

 

Another important point is that Josh uses the same box for every driver. As an example, take the case of his recent purchase of an extremely low 'Q' 19" driver in the same box as he tested the RE XXX-18" in. In the HD-limited "Max Burst" test, the box "compressed" the low end of the high Q, high Vas XXX, which prefers 20-25 cubes, by -10dB vs the low Q, low Vas driver, which was right at home in 4-5 cubes. No excursion driver parameter was involved in that compression, but the comparisons of max output @ 10 Hz are made as though they are the final actual result regardless of other considerations.

 

So, no... excursion limits cannot be assumed in Josh's or anyone's results.

 

"Dan Wiggins is a good designer". OK, ya think? He's a pioneer who took Xmax to a whole 'nuther universe. He touts XBl^2 because he owns it and makes a living from it. Duh. He's also gone further to expanding general knowledge of overhung, underhung and LMS tech than anyone I'm aware of in his numerous discussions of comparisons of the 4 motor topologies. Specsmanship a problem? Far less so with Dan than the ocean of audio bullshit we swim in.

 

Usable excursion is what you discover it to be when using the driver as part of a designed system.

 

The problem with fashioning your own star, pinning it on and strutting into these forums as an admitted self-appointed specs police officer is that it comes with a certain amount of heat that should not surprise you. Nor should Nick's defensive reactions.

Share this post


Link to post
Share on other sites

Lots of stuff, little time...

 

How can a driver exhibit full output potential at all frequencies in-band with a sine sweep (or a model of a sine sweep, tweaks notwithstanding)?

 

It can't.

 

The power compression curves do not relate to conditions seen with playback of dynamic source. A better metric is the multi-signal Spectral Contamination test that I suggested to Ed & Ilkka a long while back and that Josh used a couple of times and stopped using. Ilkka stopped including the test because he said he was only looking for non-linear distortions of the harmonic and intermod variety and that the SC test was close enough in line with the other THD tests he used for him to consider the SC test redundant.

 

I disagreed then and do still. Simultaneous playback of multiple frequency tones is a much better sim of some program source than a sine sweep. To our point here, the compression curve for the SC input would be a flat line vs the radically curved compression curve derived from the sweeps. This is what you expect (and will see) when using dynamic source as input, 'x' dB of compression, in-band.

 

Just because your preferred test signal does a better job with the media content you prefer (dynamic movie soundtracks) doesn't mean the sine sweep method isn't useful and better represents other media content.  There is increasingly more MUSIC content that has a low crest factor constant duty cycle single frequency bass lines  comparable to pure sine waves.  The sine sweep test is MUCH closer to simulating those conditions than your proposed test.

 

So yeah, your test is better to simulate the dynamic content you listen to, while sine sweeps are better to simulate certain electronic music that's much closer to a constant sine wave.  There's no perfect test because the media signals are wildly different and there's nothing you can do about that.

 

Another important point is that all, as in ALL of the commercial HT subs tested with the progressive sine sweeps display compression that is induced by aggressive limiting (which is basically using an electronic compressor with slightly different parameters). This is not power compression and thus has little to do with the driver.

 

Again, this may be true but it's not relevant.  If a diy'er chooses to use a limiter he's going to see different results than if he didn't.  That's common sense.  And the fact that you can't directly compare commercial products that are heavily limited to data-bass measurements that are not is also common sense.  But it has nothing at all to do with comparing data-bass measurements to each other.

 

 

 

Another important point is that Josh uses the same box for every driver. As an example, take the case of his recent purchase of an extremely low 'Q' 19" driver in the same box as he tested the RE XXX-18" in. In the HD-limited "Max Burst" test, the box "compressed" the low end of the high Q, high Vas XXX, which prefers 20-25 cubes, by -10dB vs the low Q, low Vas driver, which was right at home in 4-5 cubes. No excursion driver parameter was involved in that compression, but the comparisons of max output @ 10 Hz are made as though they are the final actual result regardless of other considerations.

 

As I mentioned it would be awesome to see data-bass measure all drivers in IB which would negate a lot of these issues.  Even so, the 3 drivers I showed in comparisons don't have dramatically different box requirements, at least not like the extreme example you are talking about.  And the data-bass commentary specifically says that all 3 of those drivers exhibited mechanical excursion noise in the high power test, so we KNOW they were at or near their mechanical excursion limits, or at least into heavy distortion due to excursion.

 

 

 

So, no... excursion limits cannot be assumed in Josh's or anyone's results.

 

You can make some pretty educated guesses based on the measurements themselves, the measured t/s parameters and the text commentary that accompanies the measurements.  All 3 drivers I showed were at or near their mechanical excursion limits in the high power tests.  You don't have to assume anything.  It's not a perfect way to test for max excursion limits but there's a lot of data there, enough that we have a pretty good picture that they were at or near mechanical excursion limits in the high power testing.

 

 

 

"Dan Wiggins is a good designer". OK, ya think? He's a pioneer who took Xmax to a whole 'nuther universe. He touts XBl^2 because he owns it and makes a living from it. Duh. He's also gone further to expanding general knowledge of overhung, underhung and LMS tech than anyone I'm aware of in his numerous discussions of comparisons of the 4 motor topologies. Specsmanship a problem? Far less so with Dan than the ocean of audio bullshit we swim in.

 

Let's be realistic.  He patented a certain coil topology.  His topology isn't that different than other examples that came before.  He's responsible for designing a lot of drivers for himself and for other companies.  He has a lot of knowledge.  But he's not a god.  And he has been shown to cheat in specs, up to 2x more "klippel verified" xmax than a 3rd party (and even his own) klippel measurements show.  And yes, he did claim it was klippel verified.

 

 

 

Usable excursion is what you discover it to be when using the driver as part of a designed system.

 

The problem with fashioning your own star, pinning it on and strutting into these forums as an admitted self-appointed specs police officer is that it comes with a certain amount of heat that should not surprise you. Nor should Nick's defensive reactions.

 

I'm not a police officer, I'm pointing out the difference between usable excursion and klippel verified xmax, a distinction that has been completely lost on almost everyone.  Klippel verified has a very specific meaning and Si is throwing the term around for marketing purposes. 

 

I'm not surprised by Nick's defensive reactions but I am surprised that they are completely and totally devoid of any technical information at all.  They are all completely emotion based attacks on character and do not even hint at any technical information.  His high school level emotional outbursts are completely opposite of what you might expect from an industry leader.  Look at forum posts from people like Danley, almost completely technical in nature with no emotion whatsoever.

 

His most technical posts by far are when he posts t/s parameters.  And from the description he gave of how he got the t/s parameters it sound like they were actually measured at the factory (probably fresh out of the box and not broken in) and printed on a page that he received with the shipment of drivers.  Then it's likely that he added the xmax parameter based on a simulated Bl curve, based the power handling spec on what you can reasonably get away with for warranty claim purposes, and that's the new driver spec.  And that's the extent of Nick's technical postings, basically.  Other than that it's mostly emotionally based character attacks.  And note that he is quite critical of Mach 5, he frequently "interrupts" Mach 5 threads in the same way he accuses me of doing to his.  And then he specifically asks that no one derail his own product threads with talk of Mach 5 products.  This behavior is a bit surprising, to be honest.  I'm not surprised that he's mad at me but the way he deals with it is surprising.

Share this post


Link to post
Share on other sites

So what's the big deal when we are only talking about 1, 1.5, 3 db difference?  The big deal is that it takes twice the excursion to produce 3 db more.  So a difference of 1 db, while barely audible, means a difference in excursion of about 1/3, which is huge.

 

Actually it's 6dB for twice the displacement. But yeah, still takes quite a bit more excursion for an additional 2dB over another driver.

 

Lots I'd like to respond to in the recent discussion when I get a chance.

Share this post


Link to post
Share on other sites

Err, forgive the nitpicking here, diy speaker guy, but doubling excursion gives a 6 dB increase in output, not a 3 dB increase.  I don't think it really changes your arguments either way though.

 

Also, I really don't like the term "usable excursion".  What this actually means depends entire on who's doing the evaluation, and more importantly, it says nothing about how the system behaves between the "true linear Xmax" (i.e., the minimum Xmax reported by a Klippel analysis) and this "usable excursion" limit.  The Xmech spec is of limited use for similar reasons.  Once you pass true linear Xmax, BL is usually dropping and/or Kms is increasing.  But how quickly do these parameters change beyond true linear Xmax?  It depends entirely on the driver and to some extent the box volume.  Either way, the greater the deviation of BL and Kms from their small signal values, the more distortion and compression that will be observed.  As such, "usable excursion" pretty much depends on how much distortion and compression is considered acceptable by the designer, and as a consequence, the question of whether driver A or driver B has more useful excursion may even flip-flop from one evaluator to another.

 

One other note is that I don't think Josh's tests adequately reveal problems with low Le Xmax versus Kms or BL Xmax.  The trouble is that Le effects are much stronger for high frequencies, but sine sweep tests can't induce the high excursion at high frequencies necessary for these effects to appear.  OTOH in real world use, a very low Le Xmax will manifest itself when high frequency and low frequency signals are reproduced simultaneously.  The low frequency signal induces the high excursions and oscillating Le, which in turn modulates the high frequency response.  There's simply no way to see these effects when testing with low frequencies and high frequencies separately.

Share this post


Link to post
Share on other sites

Hey DIYSG,

 

It's obvious that you'll have an answer to whatever is posted by whomever posts it regardless of the point being made. This is typical of posts in recent years. It's non-productive and pretty boring.

 

You called out Dan Wiggins for 3 mm of Klippel throw. You busted Nick for "Klippel verified". Awesome.

 

Do you have anything else? A subwoofer you're proud of with irrefutable data? If so, please start a thread for those who may be interested.

 

Is there any news on the DS-4-18" Is there a 15" version? Any builds with in-room response graphs, SpecLab graphs, etc.?

  • Like 1

Share this post


Link to post
Share on other sites

Err, forgive the nitpicking here, diy speaker guy, but doubling excursion gives a 6 dB increase in output, not a 3 dB increase.  I don't think it really changes your arguments either way though.

 

Yes, sorry, sometimes I get so ahead of myself that I'm not thinking enough about what I'm currently writing.

Share this post


Link to post
Share on other sites

Hey DIYSG,

 

It's obvious that you'll have an answer to whatever is posted by whomever posts it regardless of the point being made. This is typical of posts in recent years. It's non-productive and pretty boring.

 

 

 

There is no "regardless of the point being made".  i directly respond to stuff.  If I'm missing the point let me know.  

 

But yeah, I do have an answer to "whatever".  This isn't something I haven't put any thought into.  And if I couldn't respond and hold up a technical conversation I wouldn't post in the first place.  If you find a technical discussion non productive and boring you can put me on your ignore list.

 

 

 

You called out Dan Wiggins for 3 mm of Klippel throw. You busted Nick for "Klippel verified". Awesome.

 

Remember, I wasn't the one that called him out.  It was a 3rd party klippel measurement that called him out.  The reviewer was Erin H of diymobileaudio and Medley's Musings fame.  His klippel assessment of the CSS VWR126X clearly showed a Bl limit of 2.4 mm, whereas the driver product sheet specifically said "Xmax (Klippel) 5.9 mm".

 

That's a difference of 3.5 mm.  3.5 mm might not seem like much until you consider the published "klippel xmax" is something like 2.5 times more than klippel tests show.  That's pretty significant.

 

So how did this happen?  Here's the measured Bl graph.

 

x2nrfa.png

 

See that huge massive offset that was designed into the driver on purpose?  Well that massive offset also limits the Bl xmax to a very low number.

 

When Dan was specifically questioned about the published xmax he said this.

 

So the tradeoff: center the BL curve, give it a few mm "more" stroke for bottom end use, or purposefully set the voice coil off center and make the inductance more linear over frequency. For a woofer, the choice is obvious - more stroke please! For a wideband midrange (which is what this is), the choice is a bit less clear, but was made to prefer inductance over raw stroke.

 

...

 

In other words, you more or less confirm ErinH's results give or take a mm or so. Is that correct?

Give or take a mm PLUS the offset, yes. Say you have a driver that is -8/+4 for its curve. It's offset by 2mm. Klippel will report that driver as 4mm of "linear" throw, therefore many people assume the driver has 8mm of linear excursion. Well, not really - it has 12mm, but with an offset added in. And if in normal operation that offset is desired, then you really DO have 12mm of linear stroke to use, not the 8mm you would think from a Klippel rating of 4mm.

 

This explanation of the offset is complete garbage, it's just not how klippel testing works.  If you offset to one side and that makes the other side of the curve terrible it obviously isn't linear stroke on both sides - in this case one side has lots of linear stroke and the other side has very little.  You can't just add the two sides together, you have to limit to the side that has the worse linearity..

 

So he fully admitted that he sacrificed the Bl curve to give better Le performance.  But that means that the Bl curve is now screwed and the driver now has a very low xmax from Klippel standards because of that.  The way he was interpreting the klippel data and the subsequent published klippel based xmax spec are completely contrary to klippel standards.  It's nice that he used the machine to design the driver but it's inappropriate to use the klippel name in the product data sheet when you so clearly abuse the intent of klippel verified testing definitions.  Instead of admitting that klippel does have a definition for it's tests Dan and the CSS product manager instead attacked the 3rd party measurement and the guy that did it.

 

This was posted by someone else as a response to Dan's numerous posts on the matter. 

 

The facts are clear for anybody with an ounce of logic, CSS xmax specs are overrated (proven by SDX7 3rd party testing). What we know from this round of testing is that CSS willingly post false xmax specs and defends them with a dose of slander. We know this because for the 4" midrange Klippel methodology is revealed as the measuring stick (per whitesheet), and we even know the distortion threshold used, 80% (per designer). 

 

The results are simple, a third party tester used the same tool with the same testing thresholds and arrived at a much smaller value than advertisedThere is no supporting evidence that the difference can be accounted for in any reasonable way. In the world of speaker testing this is as close as we have gotten to verify a spec. 

 

Unreasonable Claims:

1. .82 down on the BL does not correspond to 10% distortion 

This is of no consequence. Nobody is testing W.Klippel's assumptions on why .82 down corresponds to 10%, this has nothing to do with the thread's turn of events. In fact, the distortion limits .8 as picked by the speaker designer reflects the contrary belief. 

 

2. The Klippel machine is not perfect (uses fitting, and has some margin of error)

This is of no consequence because CSS themselves picked the Klippel machine as a measuring stick. Now that the results haven't panned out, the Klippel is a bad machine. This is slander against the Klippel itself, not because we can't discuss it but due to the manner in which these discussions arose. If it tested at 9mm xmax I'm sure we'd hear all sorts of great things about the Klippel. 

 

3. Erin is not a professional

This is actually the worst imo. This is 3rd party testing and the best way to do this is to have an unbiased user that knows what he is doing. His method hasn't been disproved so it's personal bashing at the core. 

 

4. There is some error in the fitting

True, but not enough to ever make the stated xmax in the whitesheet possible. Come up with a way 2.4 xmax turns into 5.9mm, or better said 150% fitting error. 

 

5. 5.9mm is included in 2.4mm spec's margin of error. 

There is no evidence to this either. At one point it was argued that tests were run, results were averaged, then a new 2% margin of error was added on that. That is not how you give a point estimate. 5.9mm Klippel is a point estimate unless claimed otherwise. It should not be the upper bound estimate of another upperbound estimate. This is a statistical mess, you are erroneously expressing an upper bound as a point estimate based on several standard errors that are not combined in any way. You might as well claim 20mm xmax. All you have to do is send it through enough testing to combine their errors in an unusable fashion. 

 

6. 5.9mm is a Klippel spec if the speaker is centered.

This is baloney. If you make a pure midrange, and your technique (using nonlinearities to linearize some 3rd parameter) requires that you butcher up the xmax, your spec sheet should show it. This is not a spec sheet for a theoretical unicorn driver, that can be optimized as a bass driver or midrange. It is what it is. Why import xmax as derived under some imaginary implementation? Lastly, this is not how Klippel xmax ratings are given, xmax is picked based on the worst performing parameter in any direction. In the past, when manufacuturer's tried to defend overrating relied on dropping suspension or inductance nonlinearities out of problem. But you can't do that here can you? BL is the core parameter and it is also the weakest link. It is what it is.

 

It was also in that thread that it was revealed that the CSS product rep didn't even know how to read a klippel graph.  He tried to "educate" the guy that did the measurements and got found out.

 

So yeah, this is a pretty big deal, IMO at least.

 

The implication of this is that Dan believes it's ok to use the side of the curve that shows more linear extension instead of Klippel's standard of using the side of the curve that shows the least excursion.  The logical extension of this is that you could offset the driver 20 mm and claim 40 mm stroke in one direction  (and publish 40 mm as klippel verified xmax) even if the offset means you have 1 mm of linear stroke in the other direction, in which case the xmax would be defined as 1 mm by the klippel definition.  This is just pure cheating and he got caught.  If he had had the foresight to leave the work "klippel" off the product data sheet at least he could have explained this stuff away.  His explanations are pretty weak but it would then be considered  a very creative and brand new definition of xmax as opposed to outright cheating.  Instead, the plan of attack was to attack the messenger (the guy that did the measurements),and try to bog down the conversation with technical details that have nothing to do with anything (which were roundly countered in italics above) which is all too common.

Share this post


Link to post
Share on other sites

Hey DIYSG,

 

It's obvious that you'll have an answer to whatever is posted by whomever posts it regardless of the point being made. This is typical of posts in recent years. It's non-productive and pretty boring.

 

You called out Dan Wiggins for 3 mm of Klippel throw. You busted Nick for "Klippel verified". Awesome.

 

Do you have anything else? A subwoofer you're proud of with irrefutable data? If so, please start a thread for those who may be interested.

 

Is there any news on the DS-4-18" Is there a 15" version? Any builds with in-room response graphs, SpecLab graphs, etc.?

 

 

You're right Dave, I would just like to see an industry-wide acceptance of measuring standards. So everyone is on the exact same playing field. Subs, amps, speaker wire, the whole Kit and Kaboodle so they say. Maybe when the cows come home  :rolleyes:

 

Dave, as well as myself and many others have seen many of the drivers in question here and the truth behind the matter is they are all excellent performers, with limited distortion...very limited in fact. I could hang around and keyboard jockey a little more but I need to check myself before I set audio science back another decade with a post or another g2g :D

Share this post


Link to post
Share on other sites

You're right Dave, I would just like to see an industry-wide acceptance of measuring standards. So everyone is on the exact same playing field. Subs, amps, speaker wire, the whole Kit and Kaboodle so they say. Maybe when the cows come home  :rolleyes:

 

Dave, as well as myself and many others have seen many of the drivers in question here and the truth behind the matter is they are all excellent performers, with limited distortion...very limited in fact. I could hang around and keyboard jockey a little more but I need to check myself before I set audio science back another decade with a post or another g2g :D

 

Completely missing the point, as usual.  It would be nice to have an industry standard but it's not absolutely necessary.  What you are NOT allowed to do is make verifiably false claims.  I JUST SHOWED an example of a driver that said "Xmax (Klippel) 5.9 mm" when in fact klippel says it's 2.4 mm.  This is not a problem?  

 

Of course not, if all you care about is completely subjective assessments and never measure anything.  As I've pointed out, huge amounts of 2nd order distortion can sound more pleasant, fuller, better than clean reproduction.  And you can't measure this distortion by ear.  So where's the proof of distortion in your GTG subjective assessments?  Just because you don't care doesn't mean it's not an issue.

 

This discussion is about the blatant abuse of a known standard (klippel).  If you don't want to be held to klippel standards don't put that word in your ad copy, forum posts or data sheets. If you use the klippel machine to assess only one aspect of a driver's performance, make that clearly known instead of saying the driver is "klippel verified".  Abusing the standard is all about marketing, not science.  This is pretty simple, and I get it, you just don't care.  I do.  Sarcasm and subjectivity won't change anything on either side.

 

This is the root of the problem in one simple image.  When the general public and especially the manufacturer doesn't care what the specs are there's a big problem.  That thorough test wasn't published until a couple years after the specs were published and 2 years worth of false claims had been made and repeated by many people including the manufacturer.  Some of those false claims (like the single SI 24 = four LMS 18s) came directly from your GTG and were repeated endlessly until the day the SI 24 data-bass measurements came out.  Who knew the claims would turn out to be untrue?  I did, I was saying it all along even before the measurements said it.  And I got a lot of harassment from you and others for saying it.  Turns out there is some value in science and common sense.

 

2je5nk2.png

Share this post


Link to post
Share on other sites

Completely missing the point, as usual.  It would be nice to have an industry standard but it's not absolutely necessary.  What you are NOT allowed to do is make verifiably false claims.  I JUST SHOWED an example of a driver that said "Xmax (Klippel) 5.9 mm" when in fact klippel says it's 2.4 mm.  This is not a problem?  

 

Of course not, if all you care about is completely subjective assessments and never measure anything.  As I've pointed out, huge amounts of 2nd order distortion can sound more pleasant, fuller, better than clean reproduction.  And you can't measure this distortion by ear.  So where's the proof of distortion in your GTG subjective assessments?  Just because you don't care doesn't mean it's not an issue.

 

This discussion is about the blatant abuse of a known standard (klippel).  If you don't want to be held to klippel standards don't put that word in your ad copy, forum posts or data sheets. If you use the klippel machine to assess only one aspect of a driver's performance, make that clearly known instead of saying the driver is "klippel verified".  Abusing the standard is all about marketing, not science.  This is pretty simple, and I get it, you just don't care.  I do.  Sarcasm and subjectivity won't change anything on either side.

 

This is the root of the problem in one simple image.  When the general public and especially the manufacturer doesn't care what the specs are there's a big problem.  That thorough test wasn't published until a couple years after the specs were published and 2 years worth of false claims had been made and repeated by many people including the manufacturer.  Some of those false claims (like the single SI 24 = four LMS 18s) came directly from your GTG and were repeated endlessly until the day the SI 24 data-bass measurements came out.  Who knew the claims would turn out to be untrue?  I did, I was saying it all along even before the measurements said it.  And I got a lot of harassment from you and others for saying it.  Turns out there is some value in science and common sense.

 

2je5nk2.png

 

[sarcasm]You are very cute [/sarcasm]. At least you took the time to use MS Paint to circle my name out of context.  B)

Share this post


Link to post
Share on other sites

Completely missing the point, as usual.  It would be nice to have an industry standard but it's not absolutely necessary.  What you are NOT allowed to do is make verifiably false claims.  I JUST SHOWED an example of a driver that said "Xmax (Klippel) 5.9 mm" when in fact klippel says it's 2.4 mm.  This is not a problem?  

 

 

 

I get the point.  It is a problem.  But is it a big enough problem that you need to get on multiple forums to 'expose' it at every opportunity?  Do you write scathing reviews on Amazon.com for anything 'not up to claimed standards'?  Do you call/write to Kraft Foods and tell them that the claim 'The Cheesiest' is not accurate for their mac and cheese, as another product is obviously 'cheesier' and millions of consumers are being robbed of 'cheesiness' on a visceral level?  Is there going to be a "60 minutes" segment on how audio specs are not truthful?

 

You must realize most consumers of audio have no idea what Xmax even means, and they listen and purchase with their eyes, not their ears.  They just know that 'my four 12's kick ass' or 'check out the veneer on my speakers' or some such.  Make no mistake.  We (collective multi-sub high output HT enthusiasts) are lunatic fringe at best, and make for some of the most demanding customers on the planet.  Most folks do not even have 1/10th the capability of most of the systems here, so I can absolutely see some benefit in calling out manufacturers for specmanship given the costs involved in a high-output HT LF system.  

 

I have no stake in any company that posts here nor do I own their products.  Do you?  By the way you write, I could infer as much, or at least that you have felt cheated at some point by purchasing something that didn't perform as well as advertised, as you spend significant amounts of time policing these things on forums.  Just curious, what kind of audio system do you run?  I am interested to find out what you picked out for yourself since you are definitely aware of published standards vs reality.

 

You must understand, no negative tone here, just curiosity.  I just don't get the significant time expenditure if there is no direct benefit from it other than an iron-clad claim to 'I'm right...see, I told you so'.

 

 

JSS 

  • Like 3

Share this post


Link to post
Share on other sites

So much for one post and gone. Perhaps he should become a media watchdog, much more important impacts on our lives than audio.

 

People have issues with tone. As with the poster above, I have no dog in the fight as all my drivers are JBL, B&C, and Eminence. None of which are known for awesome Xmax.

Share this post


Link to post
Share on other sites

I get the point.  It is a problem.  But is it a big enough problem that you need to get on multiple forums to 'expose' it at every opportunity?  Do you write scathing reviews on Amazon.com for anything 'not up to claimed standards'?  Do you call/write to Kraft Foods and tell them that the claim 'The Cheesiest' is not accurate for their mac and cheese, as another product is obviously 'cheesier' and millions of consumers are being robbed of 'cheesiness' on a visceral level?  Is there going to be a "60 minutes" segment on how audio specs are not truthful?

 

You must realize most consumers of audio have no idea what Xmax even means, and they listen and purchase with their eyes, not their ears.  They just know that 'my four 12's kick ass' or 'check out the veneer on my speakers' or some such.  Make no mistake.  We (collective multi-sub high output HT enthusiasts) are lunatic fringe at best, and make for some of the most demanding customers on the planet.  Most folks do not even have 1/10th the capability of most of the systems here, so I can absolutely see some benefit in calling out manufacturers for specmanship given the costs involved in a high-output HT LF system.  

 

I have no stake in any company that posts here nor do I own their products.  Do you?  By the way you write, I could infer as much, or at least that you have felt cheated at some point by purchasing something that didn't perform as well as advertised, as you spend significant amounts of time policing these things on forums.  Just curious, what kind of audio system do you run?  I am interested to find out what you picked out for yourself since you are definitely aware of published standards vs reality.

 

You must understand, no negative tone here, just curiosity.  I just don't get the significant time expenditure if there is no direct benefit from it other than an iron-clad claim to 'I'm right...see, I told you so'.

 

 

JSS 

 

Expose it at every opportunity?  If you check back at the last few times this issue came up you will see that I was provoked into saying something.  i don't bring this up for fun.  I'm either provoked into responding to something or directly responding to misinformation.  Nobody seems to have a problem with the misinformation but there's a huge problem if I respond to it.  Can't you see that this thread is five pages of people mocking me?  But then I show up and respond and people want to know why.  Really?  i never start this, I just respond and people question my motivations.

 

Just a few weeks ago Nick was telling a customer one SI 24 = 3 HST 18s.  Not even sure why, he's selling product either way.  This just isn't true.

 

That fact that some people don't even know what xmax is, is exactly why I'm doing this.  People run WinISD comparisons all the time with no idea that their sims are not accurate.

 

If there's something in the information I posted that's wrong, please correct me.  (Anyone, not just you.)  But if there's not, why is there such an extreme backlash to being presented with information? 

 

Again it comes to questioning my motivations.  I have no financial stake and my current system is irrelevant.  I would very much like a few Sundown products.  But does that really matter?

Share this post


Link to post
Share on other sites

So much for one post and gone. Perhaps he should become a media watchdog, much more important impacts on our lives than audio.

 

People have issues with tone. As with the poster above, I have no dog in the fight as all my drivers are JBL, B&C, and Eminence. None of which are known for awesome Xmax.

 

Yeah, I was prepared to leave after one post.  But there's just something about Nick's passive aggressive sarcastic pokes that I can't resist.  This has happened SEVERAL times now.  I prove my point and Nick escalates things way out of proportion and then we end up here.  If people are going to mock me and question my motivations I am going to answer.  

 

As far as being a watchdog, we really shouldn't need one.  If manufacturers are going to market aggressively on open forums they should be held to a certain standard of truth in advertising.  SI has displayed a pattern of behavior with making false claims.  That's why I respond.

Share this post


Link to post
Share on other sites

Completely missing the point, as usual.  It would be nice to have an industry standard but it's not absolutely necessary.  What you are NOT allowed to do is make verifiably false claims.  I JUST SHOWED an example of a driver that said "Xmax (Klippel) 5.9 mm" when in fact klippel says it's 2.4 mm.  This is not a problem?  

 

Of course not, if all you care about is completely subjective assessments and never measure anything.  As I've pointed out, huge amounts of 2nd order distortion can sound more pleasant, fuller, better than clean reproduction.  And you can't measure this distortion by ear.  So where's the proof of distortion in your GTG subjective assessments?  Just because you don't care doesn't mean it's not an issue.

 

This discussion is about the blatant abuse of a known standard (klippel).  If you don't want to be held to klippel standards don't put that word in your ad copy, forum posts or data sheets. If you use the klippel machine to assess only one aspect of a driver's performance, make that clearly known instead of saying the driver is "klippel verified".  Abusing the standard is all about marketing, not science.  This is pretty simple, and I get it, you just don't care.  I do.  Sarcasm and subjectivity won't change anything on either side.

 

This is the root of the problem in one simple image.  When the general public and especially the manufacturer doesn't care what the specs are there's a big problem.  That thorough test wasn't published until a couple years after the specs were published and 2 years worth of false claims had been made and repeated by many people including the manufacturer.  Some of those false claims (like the single SI 24 = four LMS 18s) came directly from your GTG and were repeated endlessly until the day the SI 24 data-bass measurements came out.  Who knew the claims would turn out to be untrue?  I did, I was saying it all along even before the measurements said it.  And I got a lot of harassment from you and others for saying it.  Turns out there is some value in science and common sense.

 

2je5nk2.png

 

I'd love to indulge you... again, but I simply don't have the patience to deal with you anymore. We had a $3,000 measurement rig running which we captured all kinds of great information on, including distortion (or lack thereof) in broadband content. I won't even look it all up as I am sure it wouldn't live up to your standards anyways...

 

 If people are going to mock me and question my motivations I am going to answer.  

 

As far as being a watchdog, we really shouldn't need one.

 

Answer this, are you willing to accept your true identity, and at least change your profile picture?

 

captws_captainamerica_avatar.jpg

Share this post


Link to post
Share on other sites

Expose it at every opportunity? If you check back at the last few times this issue came up you will see that I was provoked into saying something. i don't bring this up for fun. I'm either provoked into responding to something or directly responding to misinformation. Nobody seems to have a problem with the misinformation but there's a huge problem if I respond to it. Can't you see that this thread is five pages of people mocking me? But then I show up and respond and people want to know why. Really? i never start this, I just respond and people question my motivations.

 

Just a few weeks ago Nick was telling a customer one SI 24 = 3 HST 18s. Not even sure why, he's selling product either way. This just isn't true.

 

That fact that some people don't even know what xmax is, is exactly why I'm doing this. People run WinISD comparisons all the time with no idea that their sims are not accurate.

 

If there's something in the information I posted that's wrong, please correct me. (Anyone, not just you.) But if there's not, why is there such an extreme backlash to being presented with information?

 

Again it comes to questioning my motivations. I have no financial stake and my current system is irrelevant. I would very much like a few Sundown products. But does that really matter?

Like I said, I was just curious. The significant time expenditure and multiple forums made me wonder what the stakes were.

 

Your system IS relevant, especially if you have been cheated by manufacturer 'specmanship' in the past.

 

In my case, I felt cheated by Sherbourn/Emotiva, as well as Outlaw Audio when I pointed out the PT-7030 and model 975 shortcomings. They will never get another dollar from me. Lesson learned.

 

Like I said, just curious what would motivate someone to be the loudpeaker driver chief of police other than it just being a hobby, or some crusade for truth in audio. If the latter, you need to go talk to the magic speaker cable and interconnect people. That stuff is not just fudged numbers, but pure lies.

 

I have nothing against people caling folks out. If the manufacturer cleans up their act and modifies their claims, no need for further call-out, though.

 

JSS

Share this post


Link to post
Share on other sites

Like I said, I was just curious. The significant time expenditure and multiple forums made me wonder what the stakes were.

 

Your system IS relevant, especially if you have been cheated by manufacturer 'specmanship' in the past.

 

In my case, I felt cheated by Sherbourn/Emotiva, as well as Outlaw Audio when I pointed out the PT-7030 and model 975 shortcomings. They will never get another dollar from me. Lesson learned.

 

Like I said, just curious what would motivate someone to be the loudpeaker driver chief of police other than it just being a hobby, or some crusade for truth in audio. If the latter, you need to go talk to the magic speaker cable and interconnect people. That stuff is not just fudged numbers, but pure lies.

 

I have nothing against people caling folks out. If the manufacturer cleans up their act and modifies their claims, no need for further call-out, though.

 

JSS

 

I haven't been cheated financially, and by definition, if I know the truth and make the purchase I haven't been cheated.  I have recommended others purchase SI products but I haven't purchased any myself.  If I was to purchase this type of driver it would be a Sundown or Mach 5 product, but probably Sundown as one of their products sims really well in a project I've been thinking about for years.

 

I don't have to talk about the magic cable people, if they showed up in any of the forums I'm a member of they would be slaughtered by other members.  I wouldn't have to say a word.  I'm not sure why it's not like that with driver specs.

 

If by "the manufacturer clean up their act and modifies their claims" you mean the manufacturer continues to repeat the claims despite being proven false and defends these claims with personal attacks and [sarcasm][/sarcasm], then that's pretty accurately what's going on.

 

If Nick was really worried about the specs he would have addressed this comment I posted, not the one he actually did respond to.  This comment is a pretty serious question of whether he actually measured the driver himself at all and whether the specs were measured broken in or fresh out of the box.  This is pretty important stuff, he just doesn't care about the specs, he cares a lot more about me.

 

 

 

And from the description he gave of how he got the t/s parameters it sound like they were actually measured at the factory (probably fresh out of the box and not broken in) and printed on a page that he received with the shipment of drivers.

 

Once again, this discussion is turning into a confrontational mess because Nick and Beast have no interest at all in the technical aspect of the conversation, only in bullying, mocking and poking.  If it was possible to have an actual technical discussion this could have been cleared up two years ago.  

 

I don't think anyone is rebutting any of the technical information I posted but there's a huge backlash against the fact that I'm saying it at all.  This backlash is what keeps the discussion going in increasingly malicious directions.

Share this post


Link to post
Share on other sites

Nick and Beast are just tired of your tirade, and wasting time indulging you with additional posts and rewriting countless times the technical information that you still feel is flawed. The info is all out there for you. Klippel is no longer mentioned, except in jokes that basically align to these previous conversations. This has been beat to death so much there isn't even a horse left. It's like a pile of goop now.

 

I will be the first to admit I don't cruise around all the forums as much as I used to, but I just find it terribly ironic that every time a new SI product hits the shelves, you magically appear and start your endless tirade again. The Capt. America things was meant for a good laugh, not a mocking gesture. I rarely if ever take these forums that seriously, and while I respect your need for justice in online marketing, you've simply taken it to the edge and you should expect it to rub people the wrong way. We are now AGAIN two pages deep talking about something that has ABSOLUTELY NOTHING TO DO WITH THE DRIVER this thread is even about.

 

While through all this I still understand your basic problem and even agree with you for the most part, you are also disgustingly incorrigible.

Share this post


Link to post
Share on other sites

We are now AGAIN two pages deep talking about something that has ABSOLUTELY NOTHING TO DO WITH THE DRIVER this thread is even about.

 

While through all this I still understand your basic problem and even agree with you for the most part, you are also disgustingly incorrigible.

 

WHO STARTED THAT?  There was 4 pages of klippel jokes in this thread before I even became a member to address that fact.  There's a few pages of the same (but even more malicious) pokes in the SI 24 thread.  If you really wanted an end to this you would stop endlessly posting about it even when I'm not around, even when I'm not even a member of the forum.  You guys derail your own threads to talk about me and then blame me for it.  WTF!?!

 

I DON'T EVER START THESE THINGS.  I only respond to provocation or misinformation and YOU GUYS drag the discussion along with more provocations and no technical input whatsoever.  To this day there's never been a real technical discussion about any of this.

 

In an ideal world, if no one was allowed to post anything that was not technical in nature, there would be maybe 50 total posts about all these issues combined.  So whose fault is it really?

Share this post


Link to post
Share on other sites

Wiggins wasn't called out. He thoroughly explained that the little mid-bass driver in question does indeed have the rated Xmax, but he chose to offset the coil for better performance.

 

DIYSG is just another one of those few guys over the years who just loves to read himself talk.

 

I tried to explain, but it always falls on deaf ears with someone who just wants to be right. If, for example (and, all of my references will be to drivers of the large diameter, long throw type because 6", 5 mm Xmax drivers are irrelevant) , you have a driver Xmax spec that satisfies the DIYSG type to perfection, as soon as you load the driver into a small sealed box, the VC is offset by the air spring. So, should a manufacturer provide a formula for how Klippel verified Xmax will change according to box size?

 

If the free air Klippel Xmax is so crucial to modeling and actual performance, why would the Air Spring offset not be just as crucial, or, as DIYSG put it: "This may be true but it's not really a factor here..." Like hell it isn't. It's THE factor here.

 

The Klippel verified Xmax spec is all but irrelevant. Dan attempted to explain that to DIYSG. The discussion is actually kinda funny. Dan explained in technical terms while to every explanation DIYSG just kept yelling "Change the spec!", "When ya gonna change the spec?" "Did you change the spec yet?", "Hey, everyone, he didn't change the spec!", "Did everyone see me tell him to change the spec?", "Well, don't worry, I'll re-post it in every forum on the planet until every living being sees that I called out He Who Isn't A god!!!"

 

As a manufacturer, I say that a Raptor System 3 has 40 liters of displacement capability, that spec is not based on any driver spec in free air. That would be a bullshit spec, although it seems that, according to DIYSG, the free air driver Klippel verified Xmax spec would be the legally mandated spec. WOO-HOO, make that 43 liters!!!

 

I'm positively certain that DIYSG had no idea what Air Spring Asymmetrical Throw was, that it causes a rise in 2HD or what the formula is to calculate the result of the phenomenon. I'm also positively certain that he will say that he knows everything and that the information is irrelevant to him adding a notch on his pistol handle.

Share this post


Link to post
Share on other sites

You're right Dave, I would just like to see an industry-wide acceptance of measuring standards. So everyone is on the exact same playing field. Subs, amps, speaker wire, the whole Kit and Kaboodle so they say. Maybe when the cows come home  :rolleyes:

 

Dave, as well as myself and many others have seen many of the drivers in question here and the truth behind the matter is they are all excellent performers, with limited distortion...very limited in fact. I could hang around and keyboard jockey a little more but I need to check myself before I set audio science back another decade with a post or another g2g :D

 

Like I always say...

 

ALLLLLLLL YOURRRRRR FAULLLLLLLLLLLT!!!

 

BTW, as an aside to the DIYSG showthread:

 

As always, I thoroughly enjoyed myself at your very cool abode in them thar hills above beautiful downtown Asheville, NC, my friend. I love the sound in your HT space. The low end is excruciatingly powerful @ +15dBRL, although I prefer a flat-to-+6dBRL. The guest list was a pleasure to be around and engage with, the food and libation were top shelf and it's one of my favorite things to check out a half-sloshed Rowdy Roddy Piper say stuff like "Go ahead, Dave... crank it. It's only a chopper scene. No sweat."

  • Like 3

Share this post


Link to post
Share on other sites

Wiggins wasn't called out. He thoroughly explained that the little mid-bass driver in question does indeed have the rated Xmax, but he chose to offset the coil for better performance.

 

DIYSG is just another one of those few guys over the years who just loves to read himself talk.

 

I tried to explain, but it always falls on deaf ears with someone who just wants to be right. If, for example (and, all of my references will be to drivers of the large diameter, long throw type because 6", 5 mm Xmax drivers are irrelevant) , you have a driver Xmax spec that satisfies the DIYSG type to perfection, as soon as you load the driver into a small sealed box, the VC is offset by the air spring. So, should a manufacturer provide a formula for how Klippel verified Xmax will change according to box size?

 

If the free air Klippel Xmax is so crucial to modeling and actual performance, why would the Air Spring offset not be just as crucial, or, as DIYSG put it: "This may be true but it's not really a factor here..." Like hell it isn't. It's THE factor here.

 

The Klippel verified Xmax spec is all but irrelevant. Dan attempted to explain that to DIYSG. The discussion is actually kinda funny. Dan explained in technical terms while to every explanation DIYSG just kept yelling "Change the spec!", "When ya gonna change the spec?" "Did you change the spec yet?", "Hey, everyone, he didn't change the spec!", "Did everyone see me tell him to change the spec?", "Well, don't worry, I'll re-post it in every forum on the planet until every living being sees that I called out He Who Isn't A god!!!"

 
Again, completely missing the point.  Dan and CSS chose to write Klippel on the data sheet and a 3rd party reviewer used the same system with the same klippel defined distortion points and came up with a very different number for klippel xmax.  Dan did not once mention air spring offset, he specifically offset to improve Le performance.  Maybe you should read it again.  You can't put Klippel on the spec sheet when the klippel system shows 2.5 times less xmax than claimed.  The klippel test shows VERY CLEARLY that the driver doesn't have the specified xmax.  One side of the Bl curve is incredibly unlinear.  The fact that Dan specifically said if it was a subwoofer driver he would have chosen a nice Bl curve (instead of a nice Le curve) indicates that he DOES NOT think this sorts itself out because of box air spring asymmetry.
 
IF THE KLIPPEL VERIFIED XMAX SPEC IS ALL BUT IRRELEVANT IT SHOULDN'T SAY KLIPPEL ON THE SPEC SHEET AND THEY SHOULDN'T HAVE SPECIFICALLY CHOSEN KLIPPEL AS THEIR MEASUREMENT STANDARD.  Is this really that hard to understand?
 
When I said air spring asymmetry was irrelevant I clearly pointed out it was irrelevant in the data-bass measurement comparisons of the 3 drivers I showed.  They were all in the same box, they all had the same air spring to push against.  In that comparison it absolutely was irrelevant, they were all measured under exactly the same conditions in the same box.

 

 

 

As a manufacturer, I say that a Raptor System 3 has 40 liters of displacement capability, that spec is not based on any driver spec in free air. That would be a bullshit spec, although it seems that, according to DIYSG, the free air driver Klippel verified Xmax spec would be the legally mandated spec. WOO-HOO, make that 43 liters!!!

 

I'm positively certain that DIYSG had no idea what Air Spring Asymmetrical Throw was, that it causes a rise in 2HD or what the formula is to calculate the result of the phenomenon. I'm also positively certain that he will say that he knows everything and that the information is irrelevant to him adding a notch on his pistol handle.

 

What does air spring asymmetrical throw have to do with this?  This is a discussion of using the klippel name in inappropriate ways.  If you want to claim a driver is klippel verified it has to pass klippel tests at the published xmax spec.

 

I NEVER SAID klippel verified xmax should be legally mandated, in fact I said no standard was absolutely necessary.  What you CANNOT do is claim klippel verified status if the driver can't pass a klippel test at the published spec.

 

If you want to have a detailed conversation about air spring asymmetry or the reasons why coil offset can be a good thing that's fine but it doesn't have anything to do with THIS discussion.

 

It's a bit amusing that you think I'm trying to earn a notch on my handle when you are arguing just as vocally as I am but in a much more confrontational and emotional manner (and unfortunately missing the point completely).

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...