More than 4 subs is completly pointless :) - Page 10 - AVS Forum
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post #271 of 277 Old 06-12-2012, 12:33 PM
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Quote:
Originally Posted by Scott Simonian View Post

It's pretty crazy and has been around for a long time. People were posting it as "hey, check out this crazy sub!" back when I got into DIY audio about 10 years ago. tongue.gif

Even today, isn't it still the same old pissing contest? When one asks for meaningful measurements then people suddenly become very, very quiet.

And I always thought audio is about good sound - silly me.

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
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post #272 of 277 Old 06-12-2012, 08:33 PM
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Quote:
Originally Posted by markus767 View Post

Thanks for the graph but this is spatial averaged, right? Can you show the single data points in one graph? Something like this:
310
I'd love to see graphs 1 vs 2 vs 4 vs 8. I have no doubt that there was improvement with each iteration as you probably didn't choose optimal locations for each configuration.
With the number of subs you have, you should try a double bass array. The result would be much better (if your room has a rectangular layout).

I only have one row of seats, and this was a single-point measure at ear position in the central seat.
It is quasi-L-shaped, and placement options are fairly limited. I thought I picked the best location for each sub given the limited layout.

I have a feeling that I could now be getting additional phase issues that I wasn't before because of the complete differences between the types of woofers and types of amps I use.
4 different types of subs and 2 different brands of amps (soon to be 3 types YAY).

If I did it all over again, I'd probablly just stick with all LMS-18's and FP14K's. With perhaps 1 FP10K for the kick bins. But I haven't heard either amp yet, but I have heard "mostly" good things about them. I not sure yet...

My room has massive modal issues, peaks at 28 to 45hz, and dips at 50-80hz. and a mix of dips and peaks between 110-200hz.
I hate it, it sucks. and this is WITH 100 cubic feet of acoustical foam treatments. YIKES
I'm fairly sure the dips at 10-15hz are woofer/amp mis-match phase issues, as I said already.

Here is the measurement retaken with mains on, CM-140 mic c-weighted, no other mic/soundcard corrections, no smoothing
Green is 4 subs uneq'd, yellow is 7 subs uneq'd, red is 9 subs uneq'd and blue is 9 subs eq'd
37037689.jpg
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post #273 of 277 Old 06-13-2012, 12:01 AM
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BassThatHz,

thanks for the graphs.

Some comments:

Is the mic calibrated? Did you switch on C-weighting compensation?

Even if you optimize for a single seat, you would need to take more measurements at points close to the main listening position to verify response smoothness. Our ears are about 17cm apart and we tend to move while listening.

Did you try different sub locations? The goal is to find locations where the spatial variance is low while the frequency response doesn't show non-minimum phase behavior. Such a situation can be EQ'd sufficiently flat (e.g. with MultEQ XT32).
Here's an example how important sub location is:
http://mehlau.net/audio/multisub_multeq_xt32/

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
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post #274 of 277 Old 06-13-2012, 12:37 PM
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So, can we agree there are more than two theories, But multiples are the way to go.
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post #275 of 277 Old 06-14-2012, 03:20 AM
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I'd say so. Measurement trumps all. The theories are both great jump off points.

JSS
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post #276 of 277 Old 06-14-2012, 11:32 AM
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I'd say so. Measurement trumps all. The theories are both great jump off points.
JSS

I like that, a jumping off point.....
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post #277 of 277 Old 06-14-2012, 11:43 AM
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Yup. Multiples is a good way to get smoother bass, imo.

Check out this graph Josh Ricci did in a test to see how multiple subs combine in output. Notice the more subs added the overall +/- is narrowed.

T_G%2031510addingsubsto4%20548pix.JPG

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