Finally measuring time! 8 FTWs and 2 Mal 21s. Need help - Page 4

Can you knock down that 37hz peak by about 5db's?
Edited by JapanDave - 3/5/13 at 1:22am

Are you not using some form of shelving filter below 30hz?

I realize it can be frustrating, but this will work out and it'll sound fantastic.

Can you either link to, or show an un-EQ'd response at the LP?

The comment above where you say you made 10-15 adjustments, kinda concerns me. You want to be methodical, and make some simple but effective steps. This will work out.

What Scott was referring to is sealed subs roll-off naturally, and require some boosting in the lower octaves to compensate for the big wavelengths fighting the smaller box. This EQ'ing is somewhat different in purpose than the "room" EQ'ing ... dealing with the constructive and destructive and standing waves.

I'm guessing with merely three bands of adjustment, you could get a decent response.

Perhaps at this point, I'd suggest you bring up the bottom end roll-off with your EQ, and then knock down a couple of peaks, you want to use as few filters as is nessesary. Then turn Audyssey loose, and see the result, .. you may be closer than you think.

BTW; what's your room's dimensions?

holic, you are still -12db @ 10hz. Do you have a room-null there?

Assuming not and with that much displacement, 0db@10hz should be a reasonable goal.
I'd say solve that first and worry about the room dips afterward.

145db that's insane. Are you sure that's accurate?
I have yet to hit 130db-C on my CM-140 with 9 subs at the LP, most of the time it is around 117db-C.

I have found that lately that most cheap SPL meters (Under $200) are not very accurate in the base region. I prfere to measure SPL in REW after it has been correctly calibrated in a frequency where the SPL meter is known to be be reasonably accurate.

holic has 1100sq inches more cone surface than I have (a 33% increase).

I use mostly 18's, and most of them don't have anywhere near as much excursion either. So I only have the equivalent of 4 21's worth of displacement for ULF.

So that could explain why he could hit numbers that my system could only dream of.

The response you're getting at the top of post #94 looks great! All it needs is a shelving filter below 30hz. Bam!

Yeah, the response isn't bad.

I'm thinking there's a few too many filters being used, but wth.

Were you using that many filters before you started over? TBQH, I thought you had it right the first time. Don't know what you did differently this time around, but your first round of measurements seemed to hit it right on the head...

You're using a MiniDSP 10x10 or something right?

There should be a PEQ mode for each filter. Just one of them should be set to a 'low shelf' filter set it ~30hz or so and give yourself 6-12dB boost of that. You probably won't need any of those PEQ's below 30hz if that works correctly.

do you have room in the back corners for a pair of massive corner bass traps to try to absorb much of the modal effects?

There you go!!!!!




How many dB is the shelf filter set for? Add more.

Similar to a studio, with flush mounted/soffited mains, any system with such flush mounted sources in the front wall, the need for rear wall attenuation/absorption is magnified.

We discussed this some time ago, but yes, ... you'll benefit a great deal from as much effective trapping as you can employ. Either huge traps in the corners, or both the corners and the rear wall. There's easily implemented measures to retain the precious spaciousness characteristics that many covet, if you wish.

It's almost impossible to possess too much bass damping. Wonderfully, the subjective effect of properly damped LF is so, so nice. The superbly delineated transients, the leading edge impact, and the overall bass clarity is fully exposed when the decay of the previous energy is properly disposed of.

When a nicely damped LF decay is combined with a properly executed time/phase alignment between the subs and mains, the clarity and resolution can be stunning. "Speed" is the primary adjective one encounters when exposed to such ideal time domain conditions.


Anyway, the response looks like it's getting pretty good, ... how do you think it sounds?

Yea yea!!! How much are you using right now? Are you seeing a lot more amplifier pull now that you have it in? I am starting on my dcx2496 with a LP@20hz starting with 5dB and measuring that tonight, I will then bring it up as I run sweeps to see what it gets me I have all my mics now so I will be measuring like crazy over the next few nights

How much excursion do you have left after all that boost down low when running 0db 10-20hz sinewaves as input?
If you do have tonnes of amp headroom and excursion to spare... might as well maximize the use of it (like at least 85% or so). 15% safety margin.

^^^^^^^

Lol!!! At 95dB from 10hz and below with ten 21" subs I think he has plenty on tap, my friend.

I meant the full 16bit/24bit 0db digital input signal sinewaves, not the THX-certified in-room Reference SPL rating.

Oh.... Yeah, that would be pretty loud with ten 21's.