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Subwoofers, Bass, and Transducers > Your Home Theater ULF Score
dominguez1's Avatar dominguez1 06:08 AM 10-23-2013
Quote:
Originally Posted by nfraso View Post

Your Cap S2 estimate is having the 18" drivers each moving 27mm. Based on what we know about the driver, this seems reasonable.

We don't know much about the Triax drivers, but there are claimed CEA-2010 numbers. Because they are averaged (20-31.5Hz), and because he uses the goofy pascal conversion which shifts the weighting, it's hard to nail down exactly what is claimed. It seems though, with what is given, that you'd need right around the same amount of throw from each driver to hit those numbers.

So 3 x 15's each with 27mm clean throw would yield 98.5dB, identical to the Cap S2 for our purposes.

That's my best guess with what's available.
Nfraso, curious. How do you calculate that it would take 27mm for the s2?

ZivkoF's Avatar ZivkoF 08:21 AM 10-23-2013
Quote:
Originally Posted by dominguez1 View Post

Nfraso, curious. How do you calculate that it would take 27mm for the s2?

It is NOT 27mm, from JTR site it IS 30mm smile.gif

The Captivator S2 is a sealed subwoofer with two 18″ driver that is for applications needing tremendous output.
Two massive excursion 18″ subwoofer (30mm xmax each way)
Sealed design for in room single digit frequency reproduction.
Heavily braced cabinet
completely front firing for versatility
Built in 2400 watt RMS, up to 95% efficient, DSP optimised, class D amplifier with balanced XLR inputs
magnetically attached grill
The 4000 watts amplifier is equipped with a full digital sound processor that has been optimised to the smoothest frequence response and highest possible output with minimal distortions (input overload protection and high pass filter).
nfraso's Avatar nfraso 10:48 AM 10-23-2013
Specs don't matter much in this context. This thread is using CEA-2010 ("relatively" distortion limited output) numbers for the SI-18, and everything is being compared to that standard. So it's not about an xmax rating for the woofer, it's about distortion limited excursion. Of course it's also about actually measured distortion limited output- but many things have not been measured.

It's all a wild guess.

SI-18 is rated at 23.5mm xmax from the manufacturer, and to hit 89.2dB at 10Hz using the CEA-2010 standard, it was moving 19.3mm.

That's what we're talking about here. If we went by specs, the output at 23.5mm would have the SI-18's numbers go up, and the Cap S2 would still just be X relative to those numbers. Not much different. It's why we can get away with guesstimations.

Now in room, you'll have gain down low supplementing, Josh said it (SI-18) was relatively quiet through the first 25mm, and of course xmech is somewhere 30-35mm. So depending on variables, everyone is going to be using this thing (or any other driver in any system) differently, pushing it more or less depending on headroom, and so the whole nature of this thread is really just about getting you into the ballpark of where your displacement ranks relative to your room size.

As for how you calculate that number, it's just piston excursion.

SPL = 112 + 10 * log(4 * pi^3 * Ro / c * (num * Vd)^2 * f^4)

density of air = Ro = 1.18 kg/m^3
speed of sound = c = 1130 ft/sec, 345 m/s

And of course Vd (displacement) = Sd (surface area of the driver) * xmax*2 (for full stroke)
ironhead1230's Avatar ironhead1230 11:17 AM 10-23-2013
Quote:
Originally Posted by nfraso View Post

Specs don't matter much in this context. This thread is using CEA-2010 ("relatively" distortion limited output) numbers for the SI-18, and everything is being compared to that standard. So it's not about an xmax rating for the woofer, it's about distortion limited excursion. Of course it's also about actually measured distortion limited output- but many things have not been measured.

It's all a wild guess.

SI-18 is rated at 23.5mm xmax from the manufacturer, and to hit 89.2dB at 10Hz using the CEA-2010 standard, it was moving 19.3mm.

That's what we're talking about here. If we went by specs, the output at 23.5mm would have the SI-18's numbers go up, and the Cap S2 would still just be X relative to those numbers. Not much different. It's why we can get away with guesstimations.

Now in room, you'll have gain down low supplementing, Josh said it (SI-18) was relatively quiet through the first 25mm, and of course xmech is somewhere 30-35mm. So depending on variables, everyone is going to be using this thing (or any other driver in any system) differently, pushing it more or less depending on headroom, and so the whole nature of this thread is really just about getting you into the ballpark of where your displacement ranks relative to your room size.

As for how you calculate that number, it's just piston excursion.

SPL = 112 + 10 * log(4 * pi^3 * Ro / c * (num * Vd)^2 * f^4)

density of air = Ro = 1.18 kg/m^3
speed of sound = c = 1130 ft/sec, 345 m/s

And of course Vd (displacement) = Sd (surface area of the driver) * xmax*2 (for full stroke)

If you are lazy you can also use this site. It makes an assumption of Sd based on diameter so will not be as accurate as using the actual Sd of the driver, but it will get you in the ballpark

http://www.baudline.com/erik/bass/xmaxer.html
nfraso's Avatar nfraso 11:27 AM 10-23-2013
Yes, you can just convert actual Sd into that .83 * diam estimate it uses so it comes out the same in the end.
MKtheater's Avatar MKtheater 12:28 PM 10-23-2013
The reason I don't use the CEA numbers is because all the drivers are not at DB. Also in room the THD comes way down so clean output becomes a mot point with the sealed systems. Look at the 190v2 test, it did not pass at 10hz but in my room my multiple system hit 122 dBs at 10hz without compression.
nfraso's Avatar nfraso 12:45 PM 10-23-2013
Quote:
Originally Posted by MKtheater View Post

The reason I don't use the CEA numbers is because all the drivers are not at DB. Also in room the THD comes way down so clean output becomes a mot point with the sealed systems. Look at the 190v2 test, it did not pass at 10hz but in my room my multiple system hit 122 dBs at 10hz without compression.

Which is fine, but you're comparing against an SI-18 which was measured CEA-2010. So you can only do it one way or the other. If we're just using full rated xmax excursion then you have to use a "multiplier" against the SI-18 with 23.5mm output.
MKtheater's Avatar MKtheater 01:17 PM 10-23-2013
Quote:
Originally Posted by nfraso View Post

Which is fine, but you're comparing against an SI-18 which was measured CEA-2010. So you can only do it one way or the other. If we're just using full rated xmax excursion then you have to use a "multiplier" against the SI-18 with 23.5mm output.

I did. I kept everything equal and let everyone know what the SI did on winisd as well. I posted the chart of many drivers with the SI included. Of course in typical fashion the more displacement the higher the spl's. BY comparison the Fi car system I am putting together show about 5dBs at 10hz more than what I had. 30 liters to 57.8 liters. I will measure in room to see how close this gets with 10-12% THD as the limit, or compression.
MKtheater's Avatar MKtheater 01:31 PM 10-23-2013
Now having said all that in Winisd the eD 18 is just below the SI at 10hz but look at the long term graph on DB, the eD is 7.1 dBs down. Now this is either driver rolloff, too small of an enclosure for the eD, or both. On Data-bass the eD's rolloff at 17 dBs and I measured and in my room they rolled off at 15 dBs(20-10hz). The CHT's rolled off at 16 dBs in room and the 13Av2 rolled off at 11 dBs. So even though they have less displacement they need less power to reach 10hz. Sop based off this the SI-18 should be down about 2 dBs in room like the eD 13av2's. Now the Fi car audio Q 18 is down 11.7 dBs on DB so if the IB3 with slightly more x-max is like it than I should be down 1.5 dBs, also like the 13av2's or SI-18. Now with only one sub the SI will be cleaner but with multiples in room they are all super clean. People need to realize that if they have one or two subs the cleaner sub might be better.
dominguez1's Avatar dominguez1 05:59 PM 10-23-2013
Quote:
Originally Posted by nfraso View Post

Specs don't matter much in this context. This thread is using CEA-2010 ("relatively" distortion limited output) numbers for the SI-18, and everything is being compared to that standard. So it's not about an xmax rating for the woofer, it's about distortion limited excursion. Of course it's also about actually measured distortion limited output- but many things have not been measured.

It's all a wild guess.

SI-18 is rated at 23.5mm xmax from the manufacturer, and to hit 89.2dB at 10Hz using the CEA-2010 standard, it was moving 19.3mm.

That's what we're talking about here. If we went by specs, the output at 23.5mm would have the SI-18's numbers go up, and the Cap S2 would still just be X relative to those numbers. Not much different. It's why we can get away with guesstimations.

Now in room, you'll have gain down low supplementing, Josh said it (SI-18) was relatively quiet through the first 25mm, and of course xmech is somewhere 30-35mm. So depending on variables, everyone is going to be using this thing (or any other driver in any system) differently, pushing it more or less depending on headroom, and so the whole nature of this thread is really just about getting you into the ballpark of where your displacement ranks relative to your room size.

As for how you calculate that number, it's just piston excursion.

SPL = 112 + 10 * log(4 * pi^3 * Ro / c * (num * Vd)^2 * f^4)

density of air = Ro = 1.18 kg/m^3
speed of sound = c = 1130 ft/sec, 345 m/s

And of course Vd (displacement) = Sd (surface area of the driver) * xmax*2 (for full stroke)

Good stuff nfraso, thanks!


dominguez1's Avatar dominguez1 09:32 PM 10-30-2013

New Estimated SI Conversions in Yellow

 

 

 

PSA Triax added; Equals Cap S2

 

Chase Sealed Subs revised estimated output based on recent findings of 11mm xmax

4 Chase 18.1's = ~1 LMS-U

Chase 18.1 = ~1/2 an SI 

Chase 18.2 = ~1 SI

 

 

Quote:
Originally Posted by laugsbach View Post

I am a Tweak City Audio & Chase Home Theater customer and still have (5) PRO-10 speakers and (4) 18" sealed subs using the Eminence driver. My first experience with the subs was the CS-18.T with the Dayton amp...two 18" sealed subs wired for a 4 ohm load to the amp. My initial impression was very positive but I was not impressed with the under 20Hz performance with the Dayton amp and traded it to CHT for a EP-4000 amp that was head and shoulders better and never shutdown while running demanding LFE demos. I used my DCX-2496 EQ to create a LP filter to help boost the low end and the subs started to sound very poorly when playing demanding scenes (20Hz and under) at reference levels.

I added another (2) SS-18.1 subs to the mix along with another EP-4000 amp and noticed a big improvement as well as a HUGE boost to the look of the sub. I placed the four subs around my room to even out the response and dialed them in with OmniMic to be level with my main speakers. I could still find the limit of the system quite easily and had to dial back the LP filter to keep the sound quality high and not worry about the subs sounding bad when a new, hot LFE movie showed up. At this point, I sent an e-mail with the spec # to Eminence requesting the T/S parameters and they replied with the following:

Re: 6.82 Ohms
Le: 2.07 mH
QM: 8.25
QE: 0.28
QT: 0.27
Xmax: 11.11 mm
Pmax: 300 Watts
Bl: 21.12 Tm
Coil Diameter: 3.00 Inches
Gap Height: 0.375 Inches
Efficiency: 2.61 %
fs: 21.4 Hz
Mms: 137.8 grams
Mmd: 114.8 grams
Cms: 0.401 mm/N
Rms: 2.247 N*sec/m
Vas: 777.9 liters
SD: 1169.0 cm^2
VD: 1299.1 cm^3
EBP: 75.4
Magnet Weight: 120 ounces
Winding Width: 1.250 inches
SPL: 96.2 dB 1W-1m

Three things jumped out at me. First was the SPL showing a very sensitive driver but I was concerned about the Xmax at 11.11mm and the Power Max of 300 watts. At this point, I stopped trying to push for better extension in my 3000 cubic feet room on a cement floor and dialed things back on the amp and ditched the LP filter on the DCX to keep the subs well within their limits. IMHO, this driver is better suited for a ported design for home theater but I love the sound of the sealed box running in the 40Hz to 150Hz range. I added a HUGE ported sub designed by Josh Ricci to handle from 10Hz to 40Hz and let the CHT subs pound away from 40Hz to the 150Hz crossover.

I finally caught the DIY/AIY bug and ordered (3) Fusion 12 speakers and (4) SI 18" subs along with the 4 cubic feet flat packs from Erich at DIY Sound Group. I moved the entire CHT system to a separate area (4000 cubic feet on a suspended floor) that my wife uses for Yoga, Meditation and Trance Dance and it POUNDS the music out for her clients...she even likes the wood "feet" from the CS-18.T! biggrin.gif

As always...IMHO, YMMV.
 
LL
 
Quote:
Originally Posted by bossobass View Post

The piston excursion calculators prediction of output at 10 Hz using 8 of the CS subs vs 2 MAL-21" and vs 2 LMS5400-18", each at rated X-max, should say all there needs to be said of this absurd comparison. Of course, there are many more variables to consider, but the excursion displacement capability below 20 Hz is pretty much where to begin if one is really using a MAL-21 as a model "…in terms of achieving performance…".
 

MKtheater's Avatar MKtheater 10:41 PM 10-30-2013
I modeled the chase sub and at 10 hz it is like the Dayton. Maybe 1 dB down. Just like the Dayton is might have a rated lower X-max but can play more than the rated X-max.
nfraso's Avatar nfraso 10:46 AM 10-31-2013
Quote:
Originally Posted by MKtheater View Post

I modeled the chase sub and at 10 hz it is like the Dayton. Maybe 1 dB down. Just like the Dayton is might have a rated lower X-max but can play more than the rated X-max.

Only for output and only if we take Chase at his word that it's actually 19mm xmax. Since he's embellished other specs of the same line, this can't really be done with a straight face.

One thing we do know, regardless of rated geometric xmax on these two drivers, Ricci found the Dayton to reach physical limits (xmech) just past 30mm and the Chase Eminence 18 right at 20mm.

Between that apples to apples information and knowing the stark response difference between the two, it's fair to assume the vast majority of CHT users are seeing less ULF than those with Daytons:



(I took Ricci's FR measurement of the Dayton and exported the data into REW to align with my close-mic of the CHT-18.)

Besides, we've already seen how they fare in ULF vs others at GTGs and they either don't have enough throw to compete or they don't have enough power or they don't have enough signal shaping. One, any combination, or all of the above at any given point in time. Furthermore with the supplied Dayton SA1000 most users have, not only does it not have enough power after you let Audyssey run wild on that response (or chop the top end of the response of with PEQ/LPF) but your amp shuts down and you have to get up and restart it. At this point in time I'd say you have 0 ULF. wink.gif
dominguez1's Avatar dominguez1 11:22 AM 10-31-2013
Quote:
Originally Posted by MKtheater View Post

I modeled the chase sub and at 10 hz it is like the Dayton. Maybe 1 dB down. Just like the Dayton is might have a rated lower X-max but can play more than the rated X-max.
Mk, can you run the sim with the t/s specs given by eminence for this driver and compare like you did with the other drivers?
MKtheater's Avatar MKtheater 11:37 AM 10-31-2013
Quote:
Originally Posted by nfraso View Post

Only for output and only if we take Chase at his word that it's actually 19mm xmax. Since he's embellished other specs of the same line, this can't really be done with a straight face.

One thing we do know, regardless of rated geometric xmax on these two drivers, Ricci found the Dayton to reach physical limits (xmech) just past 30mm and the Chase Eminence 18 right at 20mm.

Between that apples to apples information and knowing the stark response difference between the two, it's fair to assume the vast majority of CHT users are seeing less ULF than those with Daytons:



(I took Ricci's FR measurement of the Dayton and exported the data into REW to align with my close-mic of the CHT-18.)

Besides, we've already seen how they fare in ULF vs others at GTGs and they either don't have enough throw to compete or they don't have enough power or they don't have enough signal shaping. One, any combination, or all of the above at any given point in time. Furthermore with the supplied Dayton SA1000 most users have, not only does it not have enough power after you let Audyssey run wild on that response (or chop the top end of the response of with PEQ/LPF) but your amp shuts down and you have to get up and restart it. At this point in time I'd say you have 0 ULF. wink.gif

Again, they were your T/S parameters. I am pretty sure there are others who have heard the Daytons and ordered the CHT's and are happy. I guess they don't count.
MKtheater's Avatar MKtheater 12:01 PM 10-31-2013
Quote:
Originally Posted by dominguez1 View Post

Mk, can you run the sim with the t/s specs given by eminence for this driver and compare like you did with the other drivers?

Well sure, but why use x-max from eminence and not from Dayton. I know Ricci said we could use more but we need to test the Chase sealed to be sure, no?

Here it is


MKtheater's Avatar MKtheater 12:13 PM 10-31-2013
oops, that was 19mm of x-max, new one coming.


ironhead1230's Avatar ironhead1230 12:14 PM 10-31-2013
Quote:
Originally Posted by dominguez1 View Post

New Estimated SI Conversions in Yellow





PSA Triax added; Equals Cap S2

Chase Sealed Subs revised estimated output based on recent findings of 11mm xmax
4 Chase 18.1's = ~1 LMS-U
Chase 18.1 = ~1/2 an SI 
Chase 18.2 = ~1 SI
 

Going by displacement alone, a triax would be close to an S2, but looking at the measurements from PSA, it may be less. PSA shows the triax 20-31.5hz CEA average is 117.8db which is 7.8db higher than the SI. That would put it at about 2.45 times a single SI. However, comparing compression sweeps shows the Triax compressing at 10hz around 97-99db and the SI around 91-93db. This would put the triax at about 2.0 SI. My WAG would have the triax slightly lower than the S2, 2.4-2.6.

Quote:
Originally Posted by MKtheater View Post

I modeled the chase sub and at 10 hz it is like the Dayton. Maybe 1 dB down. Just like the Dayton is might have a rated lower X-max but can play more than the rated X-max.

I agree with MK, I think you are underestimating the CHT. A lot of the estimates are not limited to the XMax rating of the driver or limited by distortion.

Ricci mentions that for the Dayton "a value of about 20 mm seeming like a good value for "useful" excursion. The coil contacts the backplate at just past 30 mm inward." For the CHT, "The xmax of the driver is listed as about 19mm one way ... In use the driver would produce this much stroke but the xmech seems to be at almost the same point as the useful excursion."

If you want to keep the CHT below xmech, that would put it a couple mm less excursion than the dayton.
nfraso's Avatar nfraso 12:19 PM 10-31-2013
Quote:
Originally Posted by MKtheater View Post

Again, they were your T/S parameters. I am pretty sure there are others who have heard the Daytons and ordered the CHT's and are happy. I guess they don't count.

Not sure what this means. "Happy" means nothing versus objective data.
Quote:
Originally Posted by MKtheater View Post

Well sure, but why use x-max from eminence and not from Dayton. I know Ricci said we could use more but we need to test the Chase sealed to be sure, no?

Here it is


Again, you're modeling with an assumed xmax. You have no idea what the clean throw is of that driver other than taking Chase's word for it (which is a joke). What we do know:

By geometric xmax rating from each driver's source, the Dayton has a 15% advantage.

By physical limitations (xmech) Ricci found the Dayton to have a 50% advantage.

There's zero data indicating these drivers are equal, there is hard data indicating the Dayton has anywhere from a significant to substantial advantage.

Compound that with, again, hard data indicating due to FR and supplied power users of the Chase system are far less likely to see ULF... it all adds up very neatly.

Do we need Chase sealed subs to be tested? Of course, that's been asked of Chase for what, 3 years now? There's a reason why this has been avoided at all costs. We're looking at it ^.
MKtheater's Avatar MKtheater 12:30 PM 10-31-2013
Quote:
Originally Posted by nfraso View Post

Not sure what this means. "Happy" means nothing versus objective data.
Again, you're modeling with an assumed xmax. You have no idea what the clean throw is of that driver other than taking Chase's word for it (which is a joke). What we do know:

By geometric xmax rating from each driver's source, the Dayton has a 15% advantage.

By physical limitations (xmech) Ricci found the Dayton to have a 50% advantage.

There's zero data indicating these drivers are equal, there is hard data indicating the Dayton has anywhere from a significant to substantial advantage.

Compound that with, again, hard data indicating due to FR and supplied power users of the Chase system are far less likely to see ULF... it all adds up very neatly.

Do we need Chase sealed subs to be tested? Of course, that's been asked of Chase for what, 3 years now? There's a reason why this has been avoided at all costs. We're looking at it ^.

Happy means a member wanted the Dayton DIY performance and bought CHT subs and loves them. I have measured my CHT subs and ULF existed.
ironhead1230's Avatar ironhead1230 12:38 PM 10-31-2013
Quote:
Originally Posted by MKtheater View Post

Well sure, but why use x-max from eminence and not from Dayton. I know Ricci said we could use more but we need to test the Chase sealed to be sure, no?

Here it is


Quote:
Originally Posted by MKtheater View Post

oops, that was 19mm of x-max, new one coming.


Are you using Dayton's T/S specs or Ricci's?
MKtheater's Avatar MKtheater 12:48 PM 10-31-2013
Quote:
Originally Posted by ironhead1230 View Post


Are you using Dayton's T/S specs or Ricci's?

Ricci's
nfraso's Avatar nfraso 12:51 PM 10-31-2013
Quote:
Originally Posted by MKtheater View Post

Happy means a member wanted the Dayton DIY performance and bought CHT subs and loves them. I have measured my CHT subs and ULF existed.

Neither of these observations have any bearing towards objectivity. Happy could very well mean they enjoy 2/3 or half of the displacement just fine. Good for them, but it doesn't add anything here. ULF "exists" on 12" pro mids- again, it doesn't really tell us anything.

Let's put this another way. We've got the Chase driver at 11.1mm geometric rated xmax vs the Dayton's 12.8mm. Like I noted, 15% advantage. Outdoors, we slowly crank excursion to find the CEA-2010 distortion limited output and find the Dayton moving further than that, say 20mm in the low end on average cleanly. Not having been tested, we don't know where the Chase is, but can it do 15% less at this point like it's geometric rating says? Maybe, so let's say 17mm here.

Now, back to the context of this thread. We take each driver inside the typical room and add gain in the ULF region. The drivers have some more freedom to run lose with distortion lowered. We no longer have a CEA-2010 standard, but what the average joe finds to be "reasonable" levels of distortion. So turn up the gain a bit and let's see where we're at.

The Chase 18 starts tapping out at 20mm, game over. You're going to have to back off to 19mm at a minimum. Now, adding +3dB to that the Dayton is at 27mm and hasn't yet reached it's physical limits!

So the Dayton in-room could very well hold a 50% advantage in ULF for users. And that's giving the Chase unit the benefit of the doubt with proper signal shaping and juice that you and I both know most users don't have.

Again, the Chase is going to have nearly an 8dB disadvantage in ULF to be overcome assuming the user even has the tools necessary, and the majority of owners with the SA1000 do not:


MKtheater's Avatar MKtheater 01:03 PM 10-31-2013
You see I never really care for all this as I will buy a Dayton and test it myself. I have all my data for my other systems saved so I will know for sure how it will behave in my room in comparison and show the results.
MKtheater's Avatar MKtheater 01:05 PM 10-31-2013
I will run compression and THD tests and then add 18 dBs. I will make sure it is a great spot for a nice response too.
nfraso's Avatar nfraso 01:15 PM 10-31-2013
If it's something you've wanted to do out of your own curiosity, go for it. If you're trying to prove something to me, I'll save you the hassle. Your measurements, though you may have corrected issues and found a reasonably accurate procedure now, have already had a myriad of issues and inconsistencies ranging years, equipment and systems. Your own nearfield responses of the system in question are wildly out of line with known T/S parameters and other measured responses. There's nothing that can be compared with any certainty save anything going forward. It would be far easier for Chase to send one of his clearance units to Ricci for testing.
MKtheater's Avatar MKtheater 01:23 PM 10-31-2013
I know, all my experiences in my room means nothing. All my compression sweeps and THD tests done with the same gear mean nothing. Now you are trying to discredit me? So of course now if someone actually tests sweeps and THD on both subs with the same gear is wrong but GTG's are OK without any of those tests? Your personal bias is showing too much now Matt.
nfraso's Avatar nfraso 02:03 PM 10-31-2013
We're veering a bit off track here, but since you brought it up... This isn't about discrediting you, you've had a hell of a run with more configurations than most people will hear in their lifetime. But you've admitted yourself the measurements, especially with this Chase systems have their issues:
Quote:
Originally Posted by MKtheater View Post

Here was my near field response:



I am showing about a 28hz -6 dBs point without EQ.

eD 13Av2 near field response:



This shows about a 19hz -6 dB point without EQ and why it had more low end.
Quote:
Originally Posted by MKtheater View Post

I never bothered measuring for the top end at that time. I don't have the subs to test anymore so these are old graphs. I said that they did rolloff more than others.

Here was a graph of my second CHT system using the Clone and near field. I don't know why it was so different as I did the same thing as before.


Quote:
Originally Posted by MKtheater View Post

I said a long time ago that second nearfield was wrong somehow as room gain seemed to be added, it looked awesome though! Back then everyone knew it was off but I used it to show room gain anyways because it is still about the same in my room.

Again, there are people getting 7hz, 10hz, 15hz, and 20hz response with their sealed CHT subs. There is no way in hell for that to be possible if the -6 dBs point was 36 Hz. I used to use the cal files for my meter and when I just used C-weighting the flat response without EQ became -7 dBs at 10hz. I measured with two different calibrated mics and guess what, the same. 6-7 dBs of boost I was flat to 5-6hz. The eD system required 1-2 dBs of boost to do the same. That is not 25 dBs down at 10hz or I would need 15 dBs of boost and that did not happen.

We've already covered this elsewhere, you've got one graph with an 18dB/octave slope from 20Hz to 10Hz which can't be accurate. The other where the nearfield response is -6dB somewhere under 20Hz! That's obviously not accurate. Two close-mics, even with different amps should not yield wildly different results where both results have serious issues with some basic common sense observations.

Then you say there's no way in hell my graph is accurate (-6dB at 36Hz with boost) because of all of the supporting measurements you have, yet we know from published T/S parameters that my nearfield response is more the likely reality than either or any response you've offered up for those subs.

So how can you use any of your Chase sub measurements as a viable benchmark of any kind?
MKtheater's Avatar MKtheater 02:35 PM 10-31-2013
Quote:
Originally Posted by nfraso View Post

We're veering a bit off track here, but since you brought it up... This isn't about discrediting you, you've had a hell of a run with more configurations than most people will hear in their lifetime. But you've admitted yourself the measurements, especially with this Chase systems have their issues:


We've already covered this elsewhere, you've got one graph with an 18dB/octave slope from 20Hz to 10Hz which can't be accurate. The other where the nearfield response is -6dB somewhere under 20Hz! That's obviously not accurate. Two close-mics, even with different amps should not yield wildly different results where both results have serious issues with some basic common sense observations.

Then you say there's no way in hell my graph is accurate (-6dB at 36Hz with boost) because of all of the supporting measurements you have, yet we know from published T/S parameters that my nearfield response is more the likely reality than either or any response you've offered up for those subs.

So how can you use any of your Chase sub measurements as a viable benchmark of any kind?

Why keep showing an incorrect graph I made when you know that Bosso has shown my in room response of my eD and CHT systems to be correct compared to my eD nearfiled and your CHT nearfield? Trying to prove something? wink.gif So you mention that any data I collect won't mean anything to you(it means something to me and others) based on a couple nearfield measurements(again that proving a point thing) but will gladly bring up GTG's opinions that compared speakers and subs that did not even have a flat response, nice!eek.gif

Just because you covered it does mean anything, all this about CHT has been covered.

Common Matt, this is getting stupid. BTW, why won't you answer what you are using now? Don't we all share or are you here for a purpose.
nfraso's Avatar nfraso 02:52 PM 10-31-2013
That wasn't your eD nearfield, it was a WinISD sim. tongue.gif Yes, you have two graphs at your LP that when overlaid vs accurate nearfield responses (IE, not yours) give us a pretty good picture of how the room is affecting the response. Is there any level of precision to be had there? It doesn't really seem so. After all, your room isn't going to be slightly different on different days. rolleyes.gif

How many measurement rigs have you used for all of your different systems? Has your signal chain changed since the 190v2s up until now?

You have measurements of the Chase 18 with the FP14000 (or the 10000Q?), but how many people use this? Vast majority have the Dayton SA1000- do you have output data for that configuration?

You want to throw the KC GTG results out the window because the Chase subs placed dead last- and I'm the one with some sort of bias here?

I agree that this is getting stupid, I just don't understand why you keep pressing it. To better keep this on topic can you try to respond to the discussion about the excursion capabilities of the Eminence driver vs the Dayton given all of the actual facts available to us.
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