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post #1 of 42 Old 02-19-2014, 12:43 AM - Thread Starter
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Ok, I have been trying to determine where the max and/or continuous spl calculation is located at on some if not most of our preferred manufacturer's products is located.

When I say our preferred I'm referring to Jtr, danley, seaton, and seos designs.

Most accurate FR ratings normally say something along the lines of +3/-3 db thru "x" hz-"x"hz. Well that leaves 6 dbs on the table and gives the consumer no idea where the variations occur.

The manufacturers that I mentioned use pro-audio bass drivers in their designs and sometimes in multiples. So where is this max continuous db mark located in most loudspeakers? Is it in the bass drivers FR, MR FR, or in the cd/horn FR?

I'm "just" educated enough to understand that a smooth/flat FR is better suited for most speakers but there has to be a point where the FR is either up 6db or down 6 db if the stats show a sweep from say 60hz-18khz is +3db/-3dbrated for max/continuous output of 133db within said FR.

So since none of these full range speakers use terminals for each seperate section, how does one know where that max/continuous spl lies upon the total FR without a "max" spl graph?

I was first thinking that the speakers that used multi 10"-12/15" drivers, the max/continuous numbers came from the bass drivers, but is that a realistic assumption? I know a flat FR is what is most desirable but the numbers have to come from somewhere.

This leads me to my next point of emphasis. +3/-3 db might not seem like much but when the spl levels are reaching 130-135db, each 3 db is truly a huge step up in loudness so have wanted to learn a little more about the general ratings. From some quick googlings I found data that seemed to suggest the ratings are in the 2k-3khz range. Does this seem realistic?

All this stems from ipgraditus which many of you understand. The main point in general is the danley SH-50 vs the other two higher output loudspeakers: SH-64 or SH96HO. Really trying to understand what the difference in spl will be throughout the entire spectrum. I have well over 140db of bass that will need to be matched and would hate a speaker that is rated at say 142db max to only be in one octave.

Back in my car audio days I was hitting 155+dbs at idle but I also had 18+ mids/highs that could "clearly" be heard and felt with all the subs. I know car audio and ht are completely different but not only did I set KY spl records back in the 90's, I was also the only one that had the mids/highs to make it sound superdupperiffic! And that was a serious statement. I had about as much money invested in my door panels/mids/highs/EQ/etc as I did in my batteries/amps/subs/caps/altinators/power wire distribution etc...

I just want to do better than keep up with 145+db bass in my ht!!!

A total overhaul is in store!
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post #2 of 42 Old 02-19-2014, 01:49 AM
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wow...

your observation is astute. most manufacturers don't provide that data. what you want, of course, is a simple request: frequency response every 5db until the speakers crap out. this way you could see where and how that happens.

even better would be response and distortion every 5db until the speakers crap out.

BUT, what company in their right mind would provide such information? answer: none.

so what to do?

short of actual measurements, the best you can do is probably model it up, make some assumptions, and...guess.

the good driver manufacturers can actually give a pretty good idea. such will often show frequency response, then a power rating with a description of the conditions, such as 18sound does for the 15nd930

"Program power rating is measured in 125 lt enclosure tuned at 50Hz using a 40-400Hz band limited pink noise test signal with 50% duty cycle applied for 2 hours."

combined with the power compression numbers and, well, you get the idea.

it at least that helps with the guess. :-)

it isn't completely surprising, as raw pro-audio drivers are marketed to engineers or quasi-engineers, while the speakers themselves are marketed to the g.p.

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post #3 of 42 Old 02-19-2014, 04:37 AM
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Well....you could make a reasonable assumption that the -3 dB points are going to be at the ends of the FR curve since the woofer and tweeter eventually give up. The +3 dB point may be much harder to find since a 3 dB peak might might sound quite nasty depending on where you find it...like horn honk. So the better designs probably focus on getting rid of the annoying peaks which is why you might see +1dB/-3dB used as a specification. So the peak SPL should be over a broad range and not just one octave...and active equalization would be used to maximize the range.

If you really are looking at trying to hit >145 dB then you'll probably have to bypass the off-the-shelf solutions HT solutions anyway...
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post #4 of 42 Old 02-19-2014, 05:49 AM
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Quote:
Originally Posted by audiovideoholic View Post

Ok, I have been trying to determine where the max and/or continuous spl calculation is located at on some if not most of our preferred manufacturer's products is located.
Sadly, wherever the marketing department decides. mad.gif
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Back in my car audio days I was hitting 155+dbs at idle
In a car, maybe, though chances are not really, as what you're reading in a car is as much compression of the air in the small enclosed space as actual SPL. Anyone can take an SPL meter and get an off the scale reading by blowing into the mic. Continuous exposure to an actual SPL level of 155dB would render you deaf in short order.
As for manufacturer max SPL numbers, all are fantasy. They calculate the max SPL by linear extrapolation of the driver thermal limit versus base sensitivity. But SPL increase over base sensitivity for more power applied is not linear. Between thermal and mechanical power compression and the displacement limits of the drivers calculated max SPL can be 6dB higher than actual.

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post #5 of 42 Old 02-19-2014, 06:40 AM
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Don't forget that extra 3dB for converting to peak SPL either Bill.

Another problem is that in many designs the drivers cannot even handle the maximum power used for the calculated SPL over the full intended bandwidth without damage or serious over excursion.
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post #6 of 42 Old 02-19-2014, 07:37 AM
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Actually the real answer is that it doesn't matter unless you are setting up a 1000 seat theater and even then it isn't that hard to figure out. The point is that max SPL for mains speakers is basically a moot point with any of these speakers in even the craziest home setting with the craziest user.

Why don't they publish it? Because there is no "it" defined for Max SPL. Max SPL before it fails? How long? Max SPL before it sounds bad? Define "bad". Compression? Distortion benchmarks?

The issue is minimally about the fact that most speakers measure within +/-3db. Sure, that would impact how the speaker is tested, but less than the fact that a speaker will "run out of steam" at different spots.

Now, Ricci does this testing with subwoofers because subwoofers need to output far more SPL and reaching the maximum SPL of a subwoofer, especially at very low frequencies is a realistic issue.

It is easy to estimate the thermal maximums on main speakers though based on what the driver manufacturers publish (if you believe the specs of course). Will the speaker sound good at those levels? Like I mentioned before, how do you want to quantify that and test it?

We've gone over much of this in the other thread but I think you lack an actual understanding of 130db+ at higher frequencies...or you are deaf. Bill is right, you weren't actually producing 155db in your car. You also probably weren't doing more than 110db at higher frequencies unless you were using horns and you certainly weren't in the car without ear protection.

What are the details of this 145db HT sub setup you have right now? Over what bandwidth? What have you used to measure that SPL level or are you just simming that you have 145db max SPL? What mains are you using now?
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post #7 of 42 Old 02-19-2014, 01:53 PM - Thread Starter
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Quote:
Originally Posted by mobeer4don View Post

Well....you could make a reasonable assumption that the -3 dB points are going to be at the ends of the FR curve since the woofer and tweeter eventually give up. The +3 dB point may be much harder to find since a 3 dB peak might might sound quite nasty depending on where you find it...like horn honk. So the better designs probably focus on getting rid of the annoying peaks which is why you might see +1dB/-3dB used as a specification. So the peak SPL should be over a broad range and not just one octave...and active equalization would be used to maximize the range.

If you really are looking at trying to hit >145 dB then you'll probably have to bypass the off-the-shelf solutions HT solutions anyway...

Thanks LTD and thank you.

I was mainly curious about if the numbers where coming from the bass drivers down say under 100hz as the difference between a speaker that will play down to say 60hz and that +3db number did indeed come near that end of the FR for the bass driver it wouldn't be better/louder than another speaker that is rated 3db louder if the sub system was covering it up.

I was just curious like stated above and am sure any 13(x) db speaker will do just fine if there is headroom once pushed to 12(x)db at the seats.

I'm not trying to have 140+db from say 200hz and up but rather have loudspeakers that keep up with 145+db from the subs. I boost the low end by about 15-20db (depends on content) like most so would need "guessing" aprox 125ish db at seats in order to still sound right/keep up with subs.

Does that make sense?
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post #8 of 42 Old 02-19-2014, 01:58 PM - Thread Starter
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Quote:
Originally Posted by Bill Fitzmaurice View Post

Sadly, wherever the marketing department decides. mad.gif
In a car, maybe, though chances are not really, as what you're reading in a car is as much compression of the air in the small enclosed space as actual SPL. Anyone can take an SPL meter and get an off the scale reading by blowing into the mic. Continuous exposure to an actual SPL level of 155dB would render you deaf in short order.
As for manufacturer max SPL numbers, all are fantasy. They calculate the max SPL by linear extrapolation of the driver thermal limit versus base sensitivity. But SPL increase over base sensitivity for more power applied is not linear. Between thermal and mechanical power compression and the displacement limits of the drivers calculated max SPL can be 6dB higher than actual.

No need to accuse for false accusations.

If want to call someone a liar then just say it.

Term lab isn't affected by wind like other mics is my understanding. I could be wrong but that would imply that all these people that are putting hundreds of thousands of dollars into an "SPL" vehicle aren't truly setting "SPL" records.
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post #9 of 42 Old 02-19-2014, 02:08 PM - Thread Starter
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Originally Posted by coctostan View Post

Actually the real answer is that it doesn't matter unless you are setting up a 1000 seat theater and even then it isn't that hard to figure out. The point is that max SPL for mains speakers is basically a moot point with any of these speakers in even the craziest home setting with the craziest user.

Why don't they publish it? Because there is no "it" defined for Max SPL. Max SPL before it fails? How long? Max SPL before it sounds bad? Define "bad". Compression? Distortion benchmarks?

The issue is minimally about the fact that most speakers measure within +/-3db. Sure, that would impact how the speaker is tested, but less than the fact that a speaker will "run out of steam" at different spots.

Now, Ricci does this testing with subwoofers because subwoofers need to output far more SPL and reaching the maximum SPL of a subwoofer, especially at very low frequencies is a realistic issue.

It is easy to estimate the thermal maximums on main speakers though based on what the driver manufacturers publish (if you believe the specs of course). Will the speaker sound good at those levels? Like I mentioned before, how do you want to quantify that and test it?

We've gone over much of this in the other thread but I think you lack an actual understanding of 130db+ at higher frequencies...or you are deaf. Bill is right, you weren't actually producing 155db in your car. You also probably weren't doing more than 110db at higher frequencies unless you were using horns and you certainly weren't in the car without ear protection.

What are the details of this 145db HT sub setup you have right now? Over what bandwidth? What have you used to measure that SPL level or are you just simming that you have 145db max SPL? What mains are you using now?


I'm not arguing about spl numbers taken by a term lab meter at sanctioned events. If all the spl contests are just conducted to give owners a sense of false hope then glad I got out of pouring all my money into it. I do know I never quoted any number metered by mids/highs. I plainly said they were extremely loud.

I have measured my room with omnimic and told you that in the last thread. I also told you I didn't think the measurement was accurate with the levels measured. It deffinately sims over 140db and there is room gain. 10 ftw/mal 21s with fp10k clones and qsc amps. Jtr 888s.

Here is screen shot with headroom still left in all of system. Just a hip hop track at LP

[URL=http://TooShort.jpg]TooShort.jpg[/URL]
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post #10 of 42 Old 02-19-2014, 03:35 PM
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I guess I'm not really adding anything, but there's not really an answer unless you precisely define what signal you want SPL for, as different spectral content will change what combination of overexcursion/thermal capacity/distortion limits are exceeded.

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post #11 of 42 Old 02-19-2014, 03:36 PM
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AVH, not sure if this has been mentioned yet, but think about the equal loudness contour when putting 145db in perspective. We are so much less sensitive to bass that 145db flat would sound WAYYY bright...

Back in your car audio days I'd put money done that you weren't coming anywhere close to 150db from your components in your kick panels

biggrin.gif

I bet if you ran a moderate house curve down to 5Hz or so, that the SH-50's or the "neos" would hang with your lowend without a problem.

Now if you are looking to find your physical limit, I'd have to say that you are pissing in the wind my friend. I thought I would be able to get close with my setup, but I don't even think doubling up my subs in my space would get me to "that" level...

Just sayin'...

tongue.gif

 

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post #12 of 42 Old 02-19-2014, 03:47 PM
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I'm not sure how those measurements were taken, but it goes to my point that you aren't listening to frequencies above 100hz at 140db (assuming those SPL levels are accurate). Whether by the design of your system's EQ or simply that the content has extremely recessed highs relative to lows.

Now find a movie where there is confirmed content from 10hz to 20khz where the highs are no more recessed than -10db from the lows. EQ your system perfectly flat. Then turn it up until you either see 140db peaks or you can no longer stand it without ear protection. Your JTR 888's should get you to 129db with full rated power.

There are basically 3 reasons why this all a moot point:

1. Your content is already bass heavy so you don't need as much 100hz+ capability
2. You will EQ it even more bass heavy
3. You cannot withstand SPL at high frequencies like you can at low frequencies

Once you account for those three things, you likely need 15-30db less capacity above 100hz than you need below it when listening to the type of bass heavy content that you would with 140db bass peaks. That would put you around 125db needed capacity for the mains which is frankly generous. Nobody would enjoy higher frequencies at those levels.

Post a full range sweep measurement of your system. If you aren't running your subwoofers extremely hot I'll be shocked.

If you post a sweep and you are flat across the whole bandwidth AND you have some content you enjoy that has peaks above 100hz that equal to the peaks below 100hz and you like this content at 140db THEN maybe you need some mains capable of more SPL than JTR T8's. In fact, I think Jericho's are your only choice.
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post #13 of 42 Old 02-19-2014, 04:00 PM - Thread Starter
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Quote:
Originally Posted by popalock View Post

AVH, not sure if this has been mentioned yet, but think about the equal loudness contour when putting 145db in perspective. We are so much less sensitive to bass that 145db flat would sound WAYYY bright...

Back in your car audio days I'd put money done that you weren't coming anywhere close to 150db from your components in your kick panels

biggrin.gif

I bet if you ran a moderate house curve down to 5Hz or so, that the SH-50's or the "neos" would hang with your lowend without a problem.

Now if you are looking to find your physical limit, I'd have to say that you are pissing in the wind my friend. I thought I would be able to get close with my setup, but I don't even think doubling up my subs in my space would get me to "that" level...

Just sayin'...

tongue.gif

No, nowhere near that from mids/highs. I've never implied that. Thats why I said I've never experienced full range at levels above 12(x)ish but would like FR to be equal to "minus my bass boost" of anywhere between 10-20db at my LP. If subs play at let's just say 140db even then if listening to hip hop I'd like the LCR to output right around 120db at my seats (14-15') away from baffle. If listening to rock then the boost/curve would be less so would need about 5db more so 125db at LP.

Does that make sense? Movies are always around reference with 10-15db curve so my current LCR keep up fine.
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post #14 of 42 Old 02-19-2014, 04:08 PM
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Originally Posted by LTD02 View Post

wow...

your observation is astute. most manufacturers don't provide that data. what you want, of course, is a simple request: frequency response every 5db until the speakers crap out. this way you could see where and how that happens.

even better would be response and distortion every 5db until the speakers crap out.

BUT, what company in their right mind would provide such information? answer: none.

so what to do?

short of actual measurements, the best you can do is probably model it up, make some assumptions, and...guess.

As others have stated, there is no simple number. It's akin to asking for a single number to represent how loud a sealed subwoofer can play... (qualifications intentionally not included)

Different marketeers use all sorts of different numbers. Those that aren't just using pie-in-the-sky calculations often use pink noise measurements, sometimes band limited, sometimes not. While the 5dB increasing curves are very interesting and telling of certain behavior, it is important to understand that they might also grossly underestimate the useful loudness of a wide bandwidth loudspeaker. A swept sine wave delivers full power at every frequency individually. With pink noise the power and excursion requirements at each frequency can be 1/6th to 1/20th that of a sine wave of the same total power. Particularly in cases where significant compression is seen in the increasing level curves before maximum amplifier power is reached, useful music and pink noise playback will be a good deal higher than what those curves indicate.

Active designs also are at a disadvantage when only looking at swept sine measurements. Consider a theoretical 2 way speaker powered by a 1kW amp showing a maximum output with a swept sine wave that is amplifier limited. If you had the same speaker which was bi-amplified using 2 1kW amplifiers, the swept sine wave measurements would max out at the same maximum curves, but the Bi-amplified box would likely produce 3dB more with pink noise or music.
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post #15 of 42 Old 02-19-2014, 04:30 PM
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" A swept sine wave delivers full power at every frequency individually. With pink noise the power and excursion requirements at each frequency can be 1/6th to 1/20th that of a sine wave of the same total power."

peaks tend to look a lot more like sine waves than pink noise. just say'n...

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post #16 of 42 Old 02-19-2014, 04:54 PM
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Quote:
Originally Posted by popalock View Post

AVH, not sure if this has been mentioned yet, but think about the equal loudness contour when putting 145db in perspective. We are so much less sensitive to bass that 145db flat would sound WAYYY bright...

Depending on which of these sets of curves you go by, we would perceive the bass as becoming relatively louder or keeping up with the rest of the spectrum

https://www.google.com/search?q=equal+loudness+curves&client=firefox-a&hs=5Te&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=CVYFU9WqK9TyyAG7ooHwCQ&ved=0CDMQsAQ&biw=1331&bih=616&dpr=1.25

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post #17 of 42 Old 02-19-2014, 05:36 PM
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Quote:
Originally Posted by LTD02 View Post

" A swept sine wave delivers full power at every frequency individually. With pink noise the power and excursion requirements at each frequency can be 1/6th to 1/20th that of a sine wave of the same total power."

peaks tend to look a lot more like sine waves than pink noise. just say'n...

That depends greatly on what is making that peak noise. That might be the case with some examples in the subwoofer range (certainly not all), but that doesn't follow what I've observed in full range situations. The content and time average which dictates perceived loudness tends to lean more toward shaped pink noise than just sine waves. All music and movie soundtracks we listen to fall somewhere on the spectrum between a sine wave and white noise but never quite reaching those extremes. As such it only makes sense that examining/considering behavior of both extremes will give good insight as to the behavior with content falling in between.

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post #18 of 42 Old 02-19-2014, 05:59 PM
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Originally Posted by audiovideoholic View Post

I just want to do better than keep up with 145+db bass in my ht!!!
A total overhaul is in store!

haha, Like a boss! eek.gif

I'd hazard a guess (without measuring or anything) that the max spl is between 100hz to 4khz in 99% of the cases... and for subwoofers about 50hz. All depending on the tuning/XO/overall-design of course.

That said, things are starting to look flatter above 90db.








So far I've logged somewhere around 17,000 to 30,000 hours at (or well above) 90db. (and I'm only 30 and my system keeps getting beefier each year)
I guess I'm done-for... redface.gifeek.gif
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post #19 of 42 Old 02-19-2014, 06:41 PM
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Originally Posted by audiovideoholic View Post

Term lab isn't affected by wind like other mics is my understanding.

TermLab is affected by wind, but only in Nasa-mode, in the comp-mode (i.e >10hz) I can't remember... I'd have to double check.

I could believe that 10 Mal's powered by two clones and a QSC would be definitely 120 to 150 depending on distance and room-modes, and a few other things.

Will you be buying a TermLab?

Here is 1 sealed LMS-18 with 1ch of a 10kQ @ 6inches on the TL. The Mal's are probably very similar.



So 2 LMS = 129db, 4 LMS = 135db, 8 LMS = 141db, 10 LMS = 142db
@ 6 inches


hmmm... cool.gif 117db never looked so serious in TermLab-land, at a distance, in free-space eek.gif (Now you have me curious, I'll have to try some music with it at a distance, stand-by smile.gif )

Note: The noisefloor of a TL is roughly 105db, they recommend 115db+ measurements ONLY.
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post #20 of 42 Old 02-19-2014, 07:38 PM
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Ok here we go. Blowing into it gave me this, clearly not a sinewave and in the infrasonic range.
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post #21 of 42 Old 02-19-2014, 07:45 PM - Thread Starter
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Originally Posted by BassThatHz View Post

Ok here we go. Blowing into it gave me this, clearly not a sinewave and in the infrasonic range.

Was that NASA mode or does air movement from the subs in the space indeed affect the spl reading during competitions/everyday applications?

Since I'm not educated on most of the sciences I'm going to throw this out there while on the subject.

During the comps I participated in we had to keep the windows up. I could get a higher reading by letting the passenger window down aprox 3". Would that mean more moving air was being generated which in turn raised the reading? I remember a couple of threads talking about opening doors in HTs and windows in HTs but they really didnt materialize into much.

Just noticed the frequency which you got the max reading. So would air movement ever get to the higher numbers that we see in comps? Nobody is going to win a comp with a (x)db rating at a frequency over 60-70 in the oddest of scenarios.
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post #22 of 42 Old 02-19-2014, 07:50 PM
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"That depends greatly on what is making that peak noise. That might be the case with some examples in the subwoofer range (certainly not all), but that doesn't follow what I've observed in full range situations."

we will just have to agree to disagree this time. :-)

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post #23 of 42 Old 02-19-2014, 08:07 PM
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Here's the TL music results SPL at the LP with 8 18's and 30kW.

Woofer-Cooker, one of my favorite bass tracks. haha

Note: The update speed is only 1hz at an FFT of 512, so it's more like a randomly sampled scrolling, clearly there are a few SPL bursts that were short enough (yet powerful) there that it didn't even detect LOL
(Can be set to a max update speed of 4hz @ FFT128)

So there you have it.

and yeah I know... I need more jigowatts (working on it biggrin.gif)


and just for comparison, here's what my CM-140 has to say at the throat of the SEOS-12 and LMS-18 (note: 2100watts on each of the tweeters).

I don't have any problems hearing that. hehe biggrin.gif
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post #24 of 42 Old 02-19-2014, 08:16 PM
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why don't you get set up with spectrumlab? great analysis tool.

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post #25 of 42 Old 02-19-2014, 08:34 PM
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Quote:
Originally Posted by audiovideoholic View Post

Was that NASA mode or does air movement from the subs in the space indeed affect the spl reading during competitions/everyday applications?

Since I'm not educated on most of the sciences I'm going to throw this out there while on the subject.

During the comps I participated in we had to keep the windows up. I could get a higher reading by letting the passenger window down aprox 3". Would that mean more moving air was being generated which in turn raised the reading? I remember a couple of threads talking about opening doors in HTs and windows in HTs but they really didnt materialize into much.

Just noticed the frequency which you got the max reading. So would air movement ever get to the higher numbers that we see in comps? Nobody is going to win a comp with a (x)db rating at a frequency over 60-70 in the oddest of scenarios.

This is all competition-mode.

If you are driving around with the windows down and doing hair-tricks there is gonna be lots of wind.


That said, I attached a piece of glass to it, like it would be in a car comp and blew on it, and I only got 109db that time, and blowing on the case gave nothing.
I don't have any ported subs so I couldn't tell you what it would do in a port.
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post #26 of 42 Old 02-19-2014, 08:39 PM
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Quote:
Originally Posted by LTD02 View Post

why don't you get set up with spectrumlab? great analysis tool.
I have that already, plus others as well. No worries.

I've been using analysis software for 13 years now wink.gif I have 5 different ones. speclab goes the deepest.
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post #27 of 42 Old 02-19-2014, 08:52 PM - Thread Starter
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Quote:
Originally Posted by BassThatHz View Post

This is all competition-mode.

If you are driving around with the windows down and doing hair-tricks there is gonna be lots of wind.


That said, I attached a piece of glass to it, like it would be in a car comp and blew on it, and I only got 109db that time, and blowing on the case gave nothing.

I don't have any ported subs so I couldn't tell you what it would do in a port.

Ok so air movement isn't going to affect the measurement realistically? I remember the shop owner getting a kick out of placing the meter in what could have been a location that acted like a port or some other type of enhancer when it read like 10-15dbs higher. There was a section right between the two sets of 4 drivers that acted like a vortex which would cause objects to basically stay elevated in one spot.

So, what is the science behind what bill and Coc stated above about if it metered at 155db it was more likely around 130 or whatever? Their statements just don't make any sense to "me" as I know air is moving but pressure is also building. When your chest is tight, hard to breath, ears feeling full, eyes bouncing around in their sockets it just seems like an odd statement which I obviously don't understand if any truth to it.
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post #28 of 42 Old 02-20-2014, 02:01 AM
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How often have you driven your 888's to clipping?

You said yourself that when one starts to approach 130db territory that every 3db increase is SUBSTANTIAL. So would another 3db do it for you?

Are the 888's the most capable HT speaker you've been exposed to?

 

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post #29 of 42 Old 02-20-2014, 07:25 AM
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Here is the thing about car SPL competitions as I understand it. Extremely high car SPL works by compressing the air in small volume and that it can be loosely described as "Sound" pressure level and is rather difficult to measure accurately even with a device like a TermLab. It is almost like infinite boundary gain. The reality is that building a SPL competition vehicle is as much about the pressure chamber as it is about the subs and amps. If you really wanted to find out how loud the subs in a competition vehicle can get you would take them out of the car. smile.gif

As far as the windows up rule, I'd guess that a cracked window can create a port resonance in the car causing pressure to spike enough to show higher SPL. For competitions it just measures a broad SPL figure right?

Now, an interesting experiment would be to take two TermLabs. Take a subwoofer outside. Position one 6 inches in front of the cone and place one sealed inside the box. Measure. This is similar to measuring a car sub both in and out of the car (not exact, but similar).

So BassThatHz you are estimating 142db max SPL from 8 5400's @ 6 inches? That equates to about 125db at 1m. Of course it isn't that simple because it assumes perfect summation. If that is the case then there is no way AVH's system is capable of 145db @ 1m. It is important to talk in terms of 1m. The JTR T8 can do 145db at 6" based on its 129db max SPL spec.

Out of curiosity, in those SPL competitions, can you win with say 160db @ 1khz instead of at 50hz? Clearly that is not bass, but I could build something that could probably do 160db easily at those frequencies using Danley's layered combiners and 30-40 compression drivers. It wouldn't take all that much power either.

The fact that Danley's Jericho speakers can produce ~150db @ 1m over a broad band with a flat response says it wouldn't be hard to go higher while only focusing on a narrow band and with in a car.
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post #30 of 42 Old 02-20-2014, 09:08 AM - Thread Starter
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Quote:
Originally Posted by popalock View Post

How often have you driven your 888's to clipping?

You said yourself that when one starts to approach 130db territory that every 3db increase is SUBSTANTIAL. So would another 3db do it for you?

Are the 888's the most capable HT speaker you've been exposed to?

I've pushed them to distortion and backed the volume down I don't know 10-20 times. I don't know as I got used to the settings and knew better than to go any louder.

Yeah 3db increments are loud. But I sit at closest 15' and middle row (which is not concrete so get better tactile effects) is 22' so they are loud but not screaming in your ear loud.

Yea, the 888 is loudest speaker I've heard in a ht for sure. When I had them in my office (aprox 6' away) they were about right but a tad soft on low end. I'd say if they were 3-6bd louder it would be close but that's assuming running without headroom and second/third row would be questionable. I don't care for third row at all though but second row is different. All scope formatted material requires second row seating but then again that would only be for demos/music/concerts (10% or less of the time).

All this is just for very random moments of fun. I don't listen to music like I used to or like BassThthz does anymore. The noticeable difference in movies will be minimal with any upgrade. But hey we all like to get crazy with the volume at some point and having ability to crank it would be great.
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