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Stereo Integrity HS-24 Measurements & General Discussion


Ricci

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I haven't had any time to look at or get the measurements ready for upload yet. Things are BUSY right now. I should be able to get my head above water next week. No the driver did not die. It's good to go. I did give it everything it wanted though. ;) As soon as I can get this stuff ready to upload I will.

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I haven't had any time to look at or get the measurements ready for upload yet. Things are BUSY right now. I should be able to get my head above water next week. No the driver did not die. It's good to go. I did give it everything it wanted though. ;) As soon as I can get this stuff ready to upload I will.

Sounds like a bunch of poppycock to me but we'll let it slide since that avatar is hilarious.

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Just laying around by the pool all month, getting fed grapes by a couple of tall Scandinavians. C'mon guys I'm sure you can understand. Priorities...

Plus Nick's driver pulled a gun on me, beat up my neighbors Bose Lifetyle system then called the cops on itself last week. I'm waiting for it to get out of jail so I can wrap things up.

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Just laying around by the pool all month, getting fed grapes by a couple of tall Scandinavians. C'mon guys I'm sure you can understand. Priorities...

Plus Nick's driver pulled a gun on me, beat up my neighbors Bose Lifetyle system then called the cops on itself last week. I'm waiting for it to get out of jail so I can wrap things up.

You knew that woofer was up to no good when it started buying black market weapons and posed for your avatar.

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Just laying around by the pool all month, getting fed grapes by a couple of tall Scandinavians. C'mon guys I'm sure you can understand. Priorities...

Plus Nick's driver pulled a gun on me, beat up my neighbors Bose Lifetyle system then called the cops on itself last week. I'm waiting for it to get out of jail so I can wrap things up.

 

LMAO!!! That's awesome! :D

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Just laying around by the pool all month, getting fed grapes by a couple of tall Scandinavians. C'mon guys I'm sure you can understand. Priorities...

Plus Nick's driver pulled a gun on me, beat up my neighbors Bose Lifetyle system then called the cops on itself last week. I'm waiting for it to get out of jail so I can wrap things up.

 

You using all that PA shit to do stand up? :P This ^^^ was FUNNY.

 

Just saw the HS-24 results. Nice, but honestly, predictable. It has just under double the rated displacement of the rated displacement of the HST-18. Box them more to parity and  that's what the results will yield. Displacement is what it's all about <20 Hz. If I had a single vote, I'd suggest inclusion of $/Liter in the list. It's simple to calculate and it really is the bottom line.

 

But, that's comparing Nick driver to Nick driver, which says a lot about Nick. His stuff is extremely high quality, regardless of the price point and target parameters. Not to mention he's as cool as ice. Congrats to him on a job well done. :)

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I loved the whole review but especially the last two lines of the first paragraph...yes, we indeed need to see such a test. :)  And can't wait for more reviews of this in-room to show what some room reinforcement will yield.  Great stuff as usual Josh!

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This driver/enclosure combo did better than I thought!  I was actually shocked that it had better performance than two top tier 18's together.  The box is huge and that is the only issue with me and the deal breaker.  Hard to hide that thing and that is what I would want to do.

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1 HS-24 >  2 HST 18 for output, even below 20 Hz, but the more striking difference to me is the reduced distortion in the HS-24.  How much does that reduced distortion have to do with the larger box versus differences between drivers?  Anyone with sub design experience care to comment?  Otherwise, I'll have to wait and see how the smaller box DSS designs measure.

 

Oh, if only I could make 24s work in my room, but I think I'll still be happy if I can hook up 4 x HST-18s.

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This driver/enclosure combo did better than I thought!  I was actually shocked that it had better performance than two top tier 18's together.  The box is huge and that is the only issue with me and the deal breaker.  Hard to hide that thing and that is what I would want to do.

 

 

There's this new company that builds the 24" into an end table or coffee table so you don't even have to hide it. :D

 

A big thanks to Josh for getting the results posted. Definitely not trying to sound cocky I'm not surprised by the results at all - very pleased and proud to see the data up on Data-Bass.com. :D

 

And yeah I seem to remember a new company that is providing a turn-key solution using the 24 complete with a 4,000 watt plate-amp complete with EQ and DSP built-in providing a flat response down below 20 Hz. Hrmm....who was that again:P

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1 HS-24 >  2 HST 18 for output, even below 20 Hz, but the more striking difference to me is the reduced distortion in the HS-24.  How much does that reduced distortion have to do with the larger box versus differences between drivers?  Anyone with sub design experience care to comment?  Otherwise, I'll have to wait and see how the smaller box DSS designs measure.

 

Oh, if only I could make 24s work in my room, but I think I'll still be happy if I can hook up 4 x HST-18s.

 

I've been commenting on that a lot on AVS but my posts get burried by people finding every last nit pick thing to comment on and try to steer the thread towards negative town. The size and weight of the diaphragm has a lot to do with it. Keep in mind one crutial element - the 24 has to move a LOT less to produce the same output as one 18. Less cone movement for the same SPL using the same motor and coil for both drivers = less distortion. 

 

Kevin Morton made a comment about my DO HST-11's saying that I wasn't going to need the full output of the iNuke6k because he doesn't hardly ever reach it with his DO HS-24's. I reminded him that his drivers have over 91 dB of output with one watt, the HST-11's don't quite have 84 dB of output with one watt. Lets make the comparison easier and say the HST-11 is rated at 81 dB (it's not 81 dB but lets just say it is) and the HS-24 is rated at 91 dB (it actually is 91 dB). That's a ten dB advantage for the 24. TEN decibels!  Huge advantage for the 24 requiring over 3x less amplifier power to supply the same output. Now I am assuming the correct box size for both drivers, etc, only trying to focus on one thing here for this example. The 24 also has a hefty amount of mass available to swing around making it play low in any sized sealed box. It's not only fairly efficient considering the stroke it is capable of but it also has high mass which are not usually found together. 

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1 HS-24 >  2 HST 18 for output, even below 20 Hz, but the more striking difference to me is the reduced distortion in the HS-24.  How much does that reduced distortion have to do with the larger box versus differences between drivers?  Anyone with sub design experience care to comment?  Otherwise, I'll have to wait and see how the smaller box DSS designs measure.

 

Oh, if only I could make 24s work in my room, but I think I'll still be happy if I can hook up 4 x HST-18s.

 

There are 2 factors at work here. One is the Vb (box size) and the other is the K20 vs the K10.

 

Credit to Siegfried Linkwitz for the Air Spring Distortion formula, which calculates the increase in (mostly) 2HD as Vb decreases, with excursion at full rated Xmax. Basically, of course, 2HD will double as you halve the box volume and, also obviously, more clean amp gives higher output with lower THD.

 

bb847a320f4bd4da501ae36c539f756b.gif

 

And, I'll say this again for the heck of it... Pretty much no one will drive any of these subwoofer drivers with a K20 on a dedicated 220V 50A line, so knock 5dB to 7dB off those max numbers for any driver tested with e K20 fed by those mains.

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I've been commenting on that a lot on AVS but my posts get burried by people finding every last nit pick thing to comment on and try to steer the thread towards negative town. The size and weight of the diaphragm has a lot to do with it. Keep in mind one crutial element - the 24 has to move a LOT less to produce the same output as one 18. Less cone movement for the same SPL using the same motor and coil for both drivers = less distortion.

 

The air displacement for a given excursion depends on the size of the diaphragm.  This much is clear.  We expect the 24" to move about 2X more air than the 18" on its own.  That is clear in the results showing 10 Hz CEA of the 24" being 7 dB higher than the 18".  (So perhaps the 24" has a little more than 2X as much surface area since the Xmax is about the same.)  As such, it makes sense to compare the performance of 2 X 18" to 1 X 24".  Even doing this, it looks like the single 24" has a lot less distortion than the dual 18s.

 

To see what I'm saying, note that for low frequencies, the 24" in-a-box measured about 7 dB more sensitive than the 18" in-a-box.  So if we were running two 18" in twice the size of Ricci's box, we'd expect to get a sub only 1-2 dB less sensitive than the 24".  Now, look at the distortion curves for each as posted by Ricci.  Note the voltages used.  Note that that the corresponding curves for the 18" used about 1-2 dBV more than for the 24" (e.g., 25V vs. 20 V).  As such, these curves (except the one for the highest level) should be close enough to compare directly to see how distortion of 2 X 18" compare to 1 X 24" at the same output level.  The HS-24 beats the pants off the dual HST-18s in this comparison, even though it only gets 1 dB more (than dual 18") at 10 Hz on CEA.

 

Does this has to do with the mass of the diaphragm?  I'm wonder if the difference in distortion performance is due to the resonant frequency of the system, which would be influenced by the diaphragm mass only indirectly?  Perhaps, the more the system is in resonance, the more it resists the non-linear contribution of the suspension?  If so, then the lower resonant frequency of the HS-24 system that Ricci tested (25 Hz) versus the HST-18 he tested (32 Hz) could account for the improved performance.  It might also explain why it is > 1 dB compared to dual HST-18 above 10 Hz.  Looking at the pictures though, the patterns don't speak of resonance frequency being all that big of a big factor.  If resonance is not important here, then the HS-24 may distort less for a different reason.  Could it be the non-linearity of the air box spring?

 

There are 2 factors at work here. One is the Vb (box size) and the other is the K20 vs the K10.

 

Credit to Siegfried Linkwitz for the Air Spring Distortion formula, which calculates the increase in (mostly) 2HD as Vb decreases, with excursion at full rated Xmax. Basically, of course, 2HD will double as you halve the box volume and, also obviously, more clean amp gives higher output with lower THD.

 

Thanks for the formula.  This assumes an adiabatic process for compression and rarefaction, which may actually be a "worst case scenario" for air box spring distortion.  Using the published specs and the formula above for the 2nd harmonic distortion, I get 2.0% for the HS-24 and 4.9% for the HST-18 at the same 35 mm excursion.  The box size is definitely significant at higher frequencies, but this overwhelmed by 3HD and higher below 20 Hz.  Also, the HST-18 shows way more 2HD than is predicted here, so air box spring doesn't look like the big contributor here.

 

I'm ignoring amp distortion for the K-10 versus K-20 amp because I'm mostly interested in distortion at low frequencies, and in both situations, the Xmax was hit well before the amp ran out of power.

 

All of this does suggest that the HS-24 is a superior performing driver, not just because of its displacement capability but because of its superior linearity compared to the HST-18 in the ~15 dB leading up to each drivers' Xmax.

 

Edit: The distortion curves at the highest level depicted are not comparable because the level was increased 5 dBV for the HST-18 versus 2 dBV for the HS-24.

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The formula predicts increase/decrease as Vb changes for a given driver. It does not predict THD from a sub nor is it a tool for comparison of different drivers.

 

There are 2 factors at work... Vb and amplifier.

 

Looking at Ilkka's test results of the LMS-Ultra vs Josh's test of same, the only apparent variable was the amplifier used. Josh got +3dB more output at 10 Hz with magnitudes less THD using a sine sweep. All other variables (air temperature, humidity, calibration, driver parameter tolerance difference, etc) cannot explain the difference in result.

 

504df9406716526ca526b77f56273bc7.png

 

Amplifiers act very differently <20 Hz and without data little can be assumed.

 

Josh knows my position on THD results from progressive sine sweeps. ;)  It is essentially much ado about nothing. If you look at the comparison using CEA shaped tone bursts, where the THD limits determine the results, you see better evidence that the difference is Vb and amplifier.

 

b06242b16c33cf10738ac7ef5551a5cb.png

 

You can use the ASD formula and the CEA results to predict Dave Gage's version of the HS24, subtracting for plugging the amp into a typical 110V/15A shared outlet or a 110V/20A dedicated outlet, factoring in line sag as well. B)

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