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Discussion Starter #1
Hi all,

I just finished building a modified martysub and I'm having some equalization problems. I ran REW, plugged its computed EQ values into an FBQ 2496 feedback destroyer, and came up with what I thought was a great looking reponse curve. However, once I ran Audyssey MultiEQ XT on my AV receiver it added some really odd peaks and valleys in the 40-70 Hz range. Anyone know what's going on? Is it just an artifact of having my sub gain set too high and Audyssey running out of overall gain?

My bass components:
Marantz SR6007 SW1-> Powered NHT SubOne
Marantz SR6007 SW2-> FBQ 2496 -> EP4000 -> Martysub

In the first attached photo:
Yellow is full range 5.2 system with Audyssey off in Multi-Channel Stereo mode
Green is full range 5.2 system with Audyssey on in Multi-Channel Stereo mode

In the second attached photo the blue line is the Martysub alone, without the Marantz in the chain at all.

I'd really appreciate any help, the system as a whole sounds much better with Audyssey on but I feel like I'm short changing my low end with such a weird response.
 

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First a few questions, you said Auddysee is running out of gain, what is the value in the avr? Also, are you boosting the low bass because most subs natural curve get's lower under 30-40 Hz? Try 1/6 smoothing the graphs.
 

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Discussion Starter #3
Good call on the 1/6th smoothing, much easier to look at now. I've attached it below.

Some EQ's will have a limit on the sum of all gains they apply, I just wondered if it was expending all of this budget to try to bring the level down and having none left for actual EQ'ing. Audyssey wants to set the sub level at -12dB, which I increased because I felt it was too conservative.

The overall low boost is only because I haven't gotten the sub amplifier's gain lined up with the rest of the system yet. Because this gain is so high it appears as a boost when I do a full range sweep. I'm attaching what I have plugged into the FBQ 2496 for an EQ as well, if that clears anything up.
 

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The -12 setting mean the gain is turn way to high on the sub/s. How large is the room and what is the XO in the avr? What are the PEQ settings for frequency, bandwidth and gain? Also the graph only needs to go to 200 Hz. We are not overly concerned with what is going on above the XO since Auddysee is taking care of that.
 

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@derrickdj1 is correct, you need to turn down the gain on the sub and re-run Audyssey until you get in the "acceptable" range on the sub trim (acceptable is anywhere between -11.5 and +11.5, although I prefer to get it right around -8 to allow for plenty of room to run the sub hot without going over 0). You only need to run a single mic position until you get the sub trim where you want it (by adjusting the gain on the sub up/down), only then do you run the full Audyssey calibration.

The issues you are having in your OP are exactly the reasons why I EQ post-Audyssey. ;)


Oh, sorry @derrickdj1, sub graphs should be un-smoothed.
 

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75" Samsung Q80R QLED, Denon AVR3300, Revel F36, C25, W263, FV15HP x 2, ATV4K, Sony Blu Ray, Harmony
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Yeah you have the sub 20-25 dB hot :eek: Audysey is setting the sub as low as it can to try to get it to the proper level. No way this could possibly sound anywhere close to good or correct. Turn the sub gain down until your AVR sets the sub level around -6. Then feel free to adjust your sub up by 3-6 dB to taste.

Also, scale your sub graph 10-200 Hz, 45-105 dB for easy reading.
 

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It looks like your two subs are out of phase, and/or all of the PEQ filters have introduced phase problems that Audyssey then tries to correct. Try disabling all of the PEQ on the Marty and removing the NHT sub entirely, then adjust the input sensitivity and see what the measurement looks like after re-ruunning Audyssey.
 

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Discussion Starter #8
Wow, thanks for all the tips, this is so helpful.

Sounds like I put the cart before the horse by not setting my levels before anything else. I'll get my levels set right and rerun Audyssey until it comes up with a sane subwoofer level.

I didn't consider phasing, that's a good point. Things get a little confusing running in mono bridged mode, I should go back and make sure I didn't roll the wires anywhere. I'll also run tests without any PEQ or other subs to see if they're introducing any phase problems.

Again, thanks for the help, I'll post an update when I've done all this and have some results.
 

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Don't forget that the goal is to get both subs set up with REW in such a way that you have the smoothest response possible before any eq is applied. Actually, peaks or are ok, even big ones. The goal is to eliminate any nulls. So experiment a bit with placement, gain, phase etc before applying eq.
 
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