Bossobass Mini GTG Thread

[Shredhead]

I don't think your testing is thorough enough.

Who said I was finished testing sme? Keep your pants on.

[chrapladm]

WOW.....I dont know how I missed this thread. Emotions going from extreme excitement to sadness. Huge thanks Bosso for doing this GTG and posting about it.

 

As you all know I am very slowly trying to build my D.O 15HST D2 with obvious inspiration coming from the Raptors. As we kept talking about volume needed for the pair I am wanting to know what volume did you end up with Bosso?

 

I have many other questions but for now this will do. I have been looking at getting started on my enclosure build soon and wanted to know.

[chrapladm]

Never mind @BossoBass Dave I see that the Raptors are 4.5cuft. Are there any other options other than the WM-8 to use for a L/T and EQ?

 

I only ask because I know yours is not for sale  and I am not really a big fan of the MiniDSP's. I have always wanted a WM-8 and wished I could have bought MK's but just a timing thing I guess. I wish could add the phase option also to the WM-8 but oh well. BUT seeing now that you have already "built," what I am going to build I figured best to ask you about this also.

 

Thanks a bunch and when can we see more info on your upcoming amps?

 

AND what height or distance would you recommend  from the frame lip to a sheet of glass?

 

I normally would use 50mm from the top of the surround and that is usually plenty but I was amazed how much further the cone does move past the resting height position in your super slow motion of the HST.

[Bossobass Dave]

Ha! I was wondering where you went to and when you's notice we built and tested your sub for you.

 

The excursion doesn't happen from the top of the surround, it happens from the top of the cone edge. IOW, the cone may move outward for 35 mm while the top of the surround will only move outward for 5 mm at the same time. With all of the different choices for surround these days, it pays to measure first and design later.

 

For example, the 3 drivers in the shootout all have different surround shapes and materials.

 

I prefer to measure the throw distances before deciding the safe distance and then experimenting with the distance from top plate to surround. That's because the distance changes the driver loading and therefore affects performance. That's all I'm saying on that subject... do your own homework and report back.

 

We're still testing the amps. A new prospect is on its way. You'll just have to wait.

 

More testing on the shootout subs is forthcoming as well.

[Ricci]

I haven't been keeping up for a while so I am getting a refresher on what's been discussed lately. I've missed some good discussion and data.

 

 

(Bolded part by me)

 

I intend to show the results of part of the tests Paul and I have conducted that show a result contrary to what Josh posted here and that others have agreed with in comparing results of the standard CEA tone burst and sine sweep tests. The missing piece is that max excursion plus multi-octave spreads of additional simultaneous playback requirement, without additional excursion extremes, requires additional amplification for an accurate result at the seats.

 

I've mentioned, ever since Josh began testing with a K-10 connected to mains of a dedicated 220V-50A line, that the results, especially the max short term burst and max short term burst averages, should not be expected by DIYers who connect similar systems to a Behringer iNuke connected to shared 120V-20A mains, or similar popular choices +/- a couple of dB.

 

Taking Josh's example of the LMS-Ultra-18 only requiring 120V @ 10 Hz to achieve maximum excursion, working out to 3600W, and reasoning that a K-10 amplifier is not needed, we take a soundtrack effect and input that into a system and find that it will require a good bit more than 3600W because the input signal is a full spread IN ADDITION TO the requirement at 10 Hz.

 

Here's a SL cap of that last punch, followed by a CEA 2010 shaped tone burst at 10 Hz.

 

Here it is again with the level of the soundtrack effect unchanged from the first SL cap but with the CEA burst increased by more than 10dB to show the difference in requirement to reproduce the shaped tone burst vs the soundtrack effect:

 

The point is that, although it may take 'X' watts to drive the HST-15 to X-max, or maximum excursion, at <10 Hz, it will always take 'X' +'Y' watts to reach that point at <10 Hz when adding the wide spread of additional frequencies all the way up to crossover, or as much as 5 additional octaves of content that typically comprises a world class ULF effect.

 

You say that you disagree with me but we seem to be talking about different things or just have different views on what is a safe power level for drivers in a sealed app.

 

I am saying that if 120 volts of a 10Hz sine wave is close to bottoming a driver, that is all that I would recommend running or would run myself on that particular driver / cab combo. What others decide to do is no concern of mine. Your data and Shred's that has been posted here support that a sub 20Hz sine wave requires more excursion from the driver than a complex signal composed of a spread of frequencies if the maximum voltage of the signal for both is held constant. As you say this is really common sense stuff. Nothing new there. 

 

Your tests with the Abomination scene versus a 10Hz sine illustrate exactly the point I was making and why I don't recommend more than the sine wave power. It takes a significant increase in voltage to get the driver to xmax or xmech with a wide bandwidth signal  versus the sine wave so if you provide enough amplifier to push the driver to a realistic safe stopping point with the wide band signal what happens if a single frequency sine wave down low does come along? The amplifier doesn't care much about what signal it is and has the extra voltage available for the wide band scene, now being utilized for the single frequency sine and the driver excursion demands are increased greatly which could lead to a damaged driver or at the least bad noises. 

 

A single frequency sine is close to the worst case scenario for driver excursion and if you limit the amplifier capability to a point that it cannot bottom the driver with this signal all other signals should be safe from driver over excursion. Granted those types of signals are very rare so it is unlikely and a lot of people do run more power than this without issue. However there is no possibility of over excursion in scenario 1 where there is a possibility if more amplifier capability is used, even if it is a remote chance.  Commercial powered systems like SVS and HSU could never allow even that slight chance as it would result in some percentage of damaged drivers and warranty claims. You said that more power is required to accurately reproduce the upper octaves at the seats. That isn't true. The upper frequencies are the easy part. If the sub system can't accurately track the wide band or upper end stuff with an amplifier system that keeps it safe from potential bottoming then more sub system is needed. Plain and simple.

 

 

The short answer is, yes... not 120V.

 

First, there's no 10 Hz content in pink noise, unless you create it yourself. The point of Josh's post is power requirement to push whatever driver to "full displacement".

 

Drive the sub to maximum excursion using a 10 Hz sine wave. Drive the same sub to maximum excursion using pink noise from 10 Hz to 80 Hz and yes, of course, you will measure higher voltage from the amplifier.

 

It's really just common sense that it will require more power to drive a sub to full displacement plus a full spread of content above that point than it would to drive the sub to full displacement with only a single frequency sine wave.

 

 

You're crossing into other ares of sub design here^^^, one of which at least you've addressed yourself, that being the displacement disadvantage of a higher sensitive driver.

 

Most subwoofers have to employ limiters to inadequately reproduce the total wide bandwidth effect because the sum of power is always higher for the frequency spread than it is for the single frequency that will overdrive the excursion limits of the driver or drivers in the system because they are displacement limited, where the headroom certainly always is (and as you've mentioned that I have said more than once in the past).

 

That's not the crux of the discussion.

 

Ilkka's short-lived multi-tone test shows that several sine waves of 90dB sum to 110dB. There's no way you get higher output from same input power. Josh did a few himself, so you can ask him how he calculated total power in dBSPL.

 

 

In the graph above of the spectral contamination test of the LMS-U-18,  just imagine for the sake of discussion that the first tone at 20 Hz drives the sub to max excursion. If so, the reading with a single tone at 20 Hz would be 92dB. Adding the additional tones doesn't drive the sub beyond max excursion, but the total is 110dB and certainly more power is required to achieve that than was required to generate the 20 Hz tone alone.

 

I'm curious to know why you believe it would not require more power to reproduce the multi-tone spread than it would to reproduce only the single tone at 20 Hz?

 

 

 

The REW SPL meter in Z weight mode can auto-calculate the total from a spread of infinite separate simultaneous frequencies in dBSPL. To measure volts and amps and watts is a simple matter of having a high quality DMM and a calculator.

 

Yep agreed on the above points.

 

If you haven't ever heard a system reproduce this type of signal it's interesting to say the least. I'd call it ugly. Even with the driver nowhere near xmax it sounds like the sub is going to die badly. Just a brutal brutal signal. It'll put some heat into a voice coil with quickness. If the signal was a burst instead of steady state that would probably help but I never set that up. We both quit using it for those reasons I'd imagine. But yeah if you ever get the chance to try it it's an interesting test just for how taxing it seems to be.

[Ricci]

I tend to stay away from RMS figures when measuring stuff because I'm uninterested in averages and the average point varies too much from a sine to a real life source to be useful to me.  I also tend to stay away from posting peak to peak values because it confuses the folks who don't understand what that means.  I stick with the peak values either positive or negative.  Here is what the waveform from Hulk looks like (scaled properly):

 

Here is the scene (properly scaled to the above numbers in post #426) next to the 10Hz sine:

 

So yeah, for sure the hulk scene "places a more sustained load (lower crest factor) on the amp."  -I completely agree.  That's one of the reasons that I just stick to peak values for measuring power, voltage, and current. 

 

To my eyes the 10Hz sine clearly has more sustained draw from the amplifier and lower crest factor. Is that what you meant?  If you move the Hulk peak over to line up with the 10Hz crest they have close to the same total shape however while the 10Hz cycle is a continuous curve through the entire peak of the signal the Hulk part has only momentary peaks and a lot of breaks for the amplifier in between.

 

 

 

Anyway thanks to you and Dave both for posting all of the data you have been in the last couple of months. Good stuff. The amplifier / speaker wiring scheme especially.

 

[Shredhead]

To my eyes the 10Hz sine clearly has more sustained draw from the amplifier and lower crest factor. Is that what you meant?  If you move the Hulk peak over to line up with the 10Hz crest they have close to the same total shape however while the 10Hz cycle is a continuous curve through the entire peak of the signal the Hulk part has only momentary peaks and a lot of breaks for the amplifier in between.

 

I understand what you are saying but I don't know that it is necessarily true because the hulk's waveform is squeezed down to fit.  The time scales are not even close to the same, I was just showing the comparison to view the peaks.  Either way I don't think crest factor is an important consideration because like I said before, I only deal in peaks whether that be a positive or negative value. 

 

 

 

I am saying that if 120 volts of a 10Hz sine wave is close to bottoming a driver, that is all that I would recommend running or would run myself on that particular driver / cab combo.

 

I think the hulk vs. 10Hz experiment shows that if you planned for 120V WCS for amp power, you wouldn't be able to power the driver to it's fullest potential with a scene like this one. 

 

Yes, if you plan on 150V WCS for scenes and a 10Hz reference sine wave with re-directed channels adding to the level gets played then it would be bad.  That's a good reason not to listen to an unknown source at full amp output.  Or for the users who want to crank it dangerously every time and not care about tweaking the system, maybe an "idiot proof" commercial sub system would be better or dumbing down the power they throw at their drivers so they don't make a mistake and damage them. 

 

Hope you don't take all this as a diss to the way you test drivers.  I appreciate what you do and I understand how complicated things get when using source material to test with instead of sine waves. 

[Infrasonic]

Not to dismiss this excellent discussion but this ^^^^^ issue seems rather irrelevant with an over-the-top subwoofer system with multiples of excellent drivers. Definitely not the "norm" but around here, it's rather ordinary to have this kind of capability.

[Ricci]

I understand what you are saying but I don't know that it is necessarily true because the hulk's waveform is squeezed down to fit.  The time scales are not even close to the same, I was just showing the comparison to view the peaks.  Either way I don't think crest factor is an important consideration because like I said before, I only deal in peaks whether that be a positive or negative value. 

 

 

I think the hulk vs. 10Hz experiment shows that if you planned for 120V WCS for amp power, you wouldn't be able to power the driver to it's fullest potential with a scene like this one. 

 

Yes, if you plan on 150V WCS for scenes and a 10Hz reference sine wave with re-directed channels adding to the level gets played then it would be bad.  That's a good reason not to listen to an unknown source at full amp output.  Or for the users who want to crank it dangerously every time and not care about tweaking the system, maybe an "idiot proof" commercial sub system would be better or dumbing down the power they throw at their drivers so they don't make a mistake and damage them. 

 

Hope you don't take all this as a diss to the way you test drivers.  I appreciate what you do and I understand how complicated things get when using source material to test with instead of sine waves. 

 

Nah...We are just having a discussion. You are correct that you might not be able to realize the maximum potential for some movies when limiting to 120v as in the example, but really since source material is so unpredictable it is difficult to do that. What would you pick for your reference signal? Is it HTTYD, or the Hulk, or maybe EOT? Either way as Scott said we are splitting hairs a bit as everyone around here knows that the last 2-3dB out of a driver are what you want to avoid using and with everyone's systems having multiple 18's or 15's, or horns or whatever I bet most of us are well under 50% headroom utilization the vast majority of the time.

 

I had missed the fact that the hulk scene was squashed in your pic. Should have realized that.

[Bossobass Dave]

The short answer is, yes... not 120V.

 

First, there's no 10 Hz content in pink noise, unless you create it yourself. The point of Josh's post is power requirement to push whatever driver to "full displacement".

 

Drive the sub to maximum excursion using a 10 Hz sine wave. Drive the same sub to maximum excursion using pink noise from 10 Hz to 80 Hz and yes, of course, you will measure higher voltage from the amplifier.

 

It's really just common sense that it will require more power to drive a sub to full displacement plus a full spread of content above that point than it would to drive the sub to full displacement with only a single frequency sine wave.

 

This ^^^ was the premise and the test proved it.

 

The Hulk required 22% more power. As you mentioned, other soundtracks, many soundtracks at that, require even more, with no harm to the driver. And, we all know (or should know) that a system with zero amplifier headroom is a no-no. Transients require even more power with less harm to the drivers.

 

The question came up as I matched LMS-Us vs the HST-24, adding 3dB for each doubling of drivers and not 6dB. The comment then was that a single K-10 is sufficient to drive a quad of LMS-U because the max voltage at 10 Hz was the max the driver could take.

 

I agree.

 

So, what is the decibel addition then?

[Bossobass Dave]

Watched X-men 1st class the other night. Had forgotten what a ULF monster this flick is. I ran SL through the entire movie and capped the missile scene:

 

 

Paul and I visited Nick last weekend and had a great visit. Swapped out his iNuke6K with a real Lab clone FP14000. In the process we found he was running the inuke at 2 ohms per channel. Since the inuke is dual full bridge configuration (it can't be bridged because each channel is already full bridge), he was, in effect, running 2 bridged amps at 2 ohms each.

 

No bueno.

 

We heard bad sounds during playback of a scene from Pacific Rim. Swapped the amps, checked the resistance and let the same scene rip. The FP14000 clone bridged into a nominal 4 ohms is in charge now.   The only bad sounds he'll hear now will be from the dual opposed dual HST-12 sub he built and uses in the small HT room.

 

I hear Nick's taking heat at AVS. I wonder why you post there at all Nick? Masochist?

 

Anyway, the news about the new driver is welcomed with props and curiosity for more details. Please post what ya got here and let them come over here to read all about it.

 

Someone pinged me about a thread bump over there. Someone asked Qs, including why I use 15s and not 18s. It's always been about size. Years ago we polled women by placing several sized subs in our living room and asking what the absolutely largest enclosure was acceptable to them. We used box sizes from 2 cubes to 8 cubes.

 

4.5 cubes was the statistical limit.

 

We designed the 15s to that size. You can fit more multiples for even soundscaping and stacking is far more doable for even more concentration of power per cubic inch. Here's a scaled pic giving an idea of the difference between Raptor 15s and 18s:

 

Obvious difference. Easier to place 4 x 15 loaded enclosures than 2 x 18 loaded enclosures, easier to finish to make look good, etc.

 

I also saw the thread asking what's the cheapest way to get ULF or something like that. To me, it's like asking what's the cheapest car that will win at Nascar or what's the cheapest rocket that will fly me to the space station. Smoke a joint and use the power of suggestion, it seems to have worked for the ID sub companies for more than a decade.

 

Been busy. More as I have time...

[chrapladm]

Ya no surprise that he is getting some flack for posting a thread. BUT thats what I expect from AVS.

 

Amazed the Inuke even lasted as long as it did. And those new prototype 18's looks beautiful.

 

ANd glad you answered those questions on AVS over here. It was irritating to me that a LOT of the same questions keep getting asked and new members dont use the search function or even read the whole thread. SO I ignore most new member threads and posts if answers have been stated already.

[BeastAudio]

Where are yall getting the new proto pics? NICK!!! WHY HAVE YOU FORSAKEN ME!?!?!?!

[3ll3d00d]

Where are yall getting the new proto pics? NICK!!! WHY HAVE YOU FORSAKEN ME!?!?!?!

 

 

 

post 46 in http://www.avsforum.com/forum/155-diy-speakers-subs/2137370-big-stereo-integrity-news-2.html#post37408514

[Electrodynamic]

Haha. Yes I am catching a lot of flack for posting the pictures of the DS4 in that thread but like I said in the other forum, I simply don't care if anti-SI groupies were lurking around for something to go crazy about and then have misconstrued the reality of the situation into "LOOK AT THIS SALES TACTIC!!!!"

 

The HT line is going away. There simply isn't enough profit in them to continue making them. The DS4 (that's the driver pictured above) is something that I want to come out with even if only for one small production run. Even though I'm stepping down from direct sales Sundown Audio will still be able to take and process orders for the DS4. If it doesn't sell it will be eliminated from future sales. 

 

I'll post the T/S parameters of the DS4 this weekend. I don't have them on this laptop but I have them at work. Pretty neat driver with lots of potential.

 

Sorry Beast, nothing personal. I just forget to send texts or emails or love letters because so many things are happening so quickly.

 

 

About the Inuke6k and clone swap: I initially planned on using an Inuke 3000 but then went for the 6000. I had already built the drivers so I hooked them up and saw if the amp would last or not. It surprisingly did not go into protect at all but rather clipped but not until a reasonable decibel level. I have massive line sag in my upstairs media room so the Lab Gruppen clone's fan cycles quite a bit upon initial startup. But after I get a dedicated 20 amp line installed up there I think/hope that problem will go away. And yes the LG clone is a monster compared to the Inuke in every way. Size, weight, power, power beyond power in comparison. The clone laughs at supplying the power when the Inuke was screaming for mercy. But then again I was running the Inuke at half its rated impedance. The LG clone is at 4 Ohm  mono (same load as 2 Ohm stereo). 

 

Last but not least it was a pleasure having Dave (Bossobass) and his on, Paul, over for the evening. Even my 3 year old son Tyler, who is fairly shy around new people, had no problem having fun playing games with Dave and Paul. I need to have a few more people over here once a dedicated line is installed to feed the power-hungry clone upon initial startup, haha. 

[MemX]

Haha. Yes I am catching a lot of flack for posting the pictures of the DS4 in that thread but like I said in the other forum, I simply don't care if anti-SI groupies were lurking around for something to go crazy about and then have misconstrued the reality of the situation into "LOOK AT THIS SALES TACTIC!!!!"

 

The HT line is going away. There simply isn't enough profit in them to continue making them. The DS4 (that's the driver pictured above) is something that I want to come out with even if only for one small production run. Even though I'm stepping down from direct sales Sundown Audio will still be able to take and process orders for the DS4. If it doesn't sell it will be eliminated from future sales. 

 

I'll post the T/S parameters of the DS4 this weekend. I don't have them on this laptop but I have them at work. Pretty neat driver with lots of potential.

 

Sorry Beast, nothing personal. I just forget to send texts or emails or love letters because so many things are happening so quickly.

 

 

About the Inuke6k and clone swap: I initially planned on using an Inuke 3000 but then went for the 6000. I had already built the drivers so I hooked them up and saw if the amp would last or not. It surprisingly did not go into protect at all but rather clipped but not until a reasonable decibel level. I have massive line sag in my upstairs media room so the Lab Gruppen clone's fan cycles quite a bit upon initial startup. But after I get a dedicated 20 amp line installed up there I think/hope that problem will go away. And yes the LG clone is a monster compared to the Inuke in every way. Size, weight, power, power beyond power in comparison. The clone laughs at supplying the power when the Inuke was screaming for mercy. But then again I was running the Inuke at half its rated impedance. The LG clone is at 4 Ohm  mono (same load as 2 Ohm stereo). 

 

Last but not least it was a pleasure having Dave (Bossobass) and his on, Paul, over for the evening. Even my 3 year old son Tyler, who is fairly shy around new people, had no problem having fun playing games with Dave and Paul. I need to have a few more people over here once a dedicated line is installed to feed the power-hungry clone upon initial startup, haha. 

 

I am sad that the HT line is going away because they are amazing VFM (even with shipping and tax they are still about half the price of a good 18" driver over here in the UK, I think) while also being excellent quality, and planning for when I am rich (haha...) I wanted to get four more so I could run an 8x18 setup, but I can't afford any at the moment and have nowhere to store them, so I will have to pick up something else whenever I eventually get the cash together (and move house!).

 

I fear I will inadvertantly break one of my current drivers somehow so four more would be spares until fitted into something else, but it's not going to happen!  Boooooo!    lol

 

 

Anyway, my appalling budgeting issues aside, thanks for bringing the HTs to the market as long as you have   I think they will be well missed as they are pretty much the 'go to' 18" driver now for many people!

[chrapladm]

I am very curious what the weight of this driver will be also. Because that could mean 200 dollars or 350 dollars shipping for me. Funny that a 15HST is almost as expensive as shipping a single 24". I hate shipping

 

BUT do what you need Nick. After chatting with you it makes perfect sense to me about not continuing the HT lineup. I look forward to this weekend and doing some modeling. Hopefully it will be TH friendly but more importantly for me it will be FLH friendly.

[MemX]

I am very curious what the weight of this driver will be also. Because that could mean 200 dollars or 350 dollars shipping for me. Funny that a 15HST is almost as expensive as shipping a single 24". I hate shipping

 

Well, you know which one you need to order, then...

[chrapladm]

Well, you know which one you need to order, then...

LOL Well if I only had to pay the shipping then I would have a pair of SI24's already:) BUT I keep saving because the exchange rate also when way south for me also.

[Infrasonic]

I'm starting to think it would be easier on your wallet if you were to move back to the States.

[chrapladm]

LOL. It would but then I would go more extreme with everything. IPAL's for everything. The one good thing I have going for me is that I can get the BC products for about the same price as USA. Just normal USA pricing not one off deals or anything. Good enough for me. Plywood is ridiculous. Could build everything out of MDF but it doesnt sit well in my mind. LOL. Hate to see how much a Othorn would weigh out of MDF. .

 

Anyways ply for me always.

[EndersShadow]

Reading this thread makes me wish I lived closer to NC.  I'd love to get my ears on either of those setups.

 

Right now I'm still going through some upgrades to my AVR but then I'm likely back to shooting for dual subs of some sort and if the HT-18 is around I will shoot for 2 of those, otherwise looks like the HST series for me.  Maybe a couple 11's because of their small box size so I could fit maybe 4 in the room spaced appropriately...

 

but thats off topic.

 

Regardless if I'm ever in the area I may have to make some time to do some visiting......

[BeastAudio]

Reading this thread makes me wish I lived closer to NC.  I'd love to get my ears on either of those setups.

 

Right now I'm still going through some upgrades to my AVR but then I'm likely back to shooting for dual subs of some sort and if the HT-18 is around I will shoot for 2 of those, otherwise looks like the HST series for me.  Maybe a couple 11's because of their small box size so I could fit maybe 4 in the room spaced appropriately...

 

but thats off topic.

 

Regardless if I'm ever in the area I may have to make some time to do some visiting......

Totally do it. You're welcome to my place any time! 

[Electrodynamic]

Reading this thread makes me wish I lived closer to NC.  I'd love to get my ears on either of those setups.

 

Right now I'm still going through some upgrades to my AVR but then I'm likely back to shooting for dual subs of some sort and if the HT-18 is around I will shoot for 2 of those, otherwise looks like the HST series for me.  Maybe a couple 11's because of their small box size so I could fit maybe 4 in the room spaced appropriately...

 

but thats off topic.

 

Regardless if I'm ever in the area I may have to make some time to do some visiting......

 

If you came over this direction you would have to make the 2 hour trip to my house to listen to my DO HST-11 setup in my small room because I'm not bringing the DO HST-11 setup to Brandon's theater room. Doing so would be like throwing a hotdog down a hallway. Totally not fair, haha. 

[Shredhead]

because I'm not bringing the DO HST-11 setup to Brandon's theater room. Doing so would be like throwing a hotdog down a hallway. Totally not fair, haha. 

Yeah, plus it's roughly the weight of a neutron star.