MultEQ and REW

[blekenbleu]

I spent awhile getting comfortable with V3.29, then V4.00 happens just as I want to get serious, sigh.
I hope MultEQ will improve overall room response (and it does seem to clean up surround localization)
and BFD will improve bass response, so wanted to know whether BFD before MultEQ works better than after.
Since I'm still searching for cables that minimize BFD hum to subs without balanced inputs,
I decided to preview MultEQ with REW, without BFD. Here are plots for "direct" 2-channel:
direct.jpg
Audyssey is red, Flat is green and Off (no MultEQ) is blue.
Audyssey appears to mostly affect frequencies above 8kHz, down about 3dB by 15kHz.
Those plots are "unfair", since MultEQ calibration was run for 7.2,
so following are corresponding plots for 7.2 (driven by a monaural REW signal):
7chan.jpg
Audyssey is gold, Flat is maroon and Off is cyan.
Same observations for Audyssey vs Flat above 8kHz,
but they now differ for low frequencies, which no doubt has to do
with allowing multiple crossover values (instead of fixed 80Hz)
from surround speakers.

More to the point, in no case are lower frequencies particularly flat,
and in some case MultEQ introduces dips, suggesting that BFD before MultEQ is indicated.
Following is a straight comparison of MultEQ Flat responses:
flat.jpg
Green is 2-channel and maroon is 7.2; maroon may be flatter for
higher frequencies simply because more drivers mitigate cancellations,
but I probably should recalibrate MultEQ for stereo listening.

I'll probably also want to retweak BFD after MultEQ as well as before.

[brucek]

Here are plots

The standard we use here for graphs is a vertical axis from 45dB to 105dB. When everyone uses the same axis, it makes it easier to evaluate and compare graphs.

If you're using a Radio Shack meter, it is only valid to about 5KHz............

brucek

[Sonnie]

One thing I did not like about the MultEQ in my previous Denon receiver was the fact it effected my bass response in a negative way. Even with the x-over set it affected the low-end.

I've always thought MultEQ worked pretty well for the mid to upper frequencies and I'm looking at another Denon receiver now. I wonder if I unplug the subs if it would leave off trying to adjust the sub pre-out response? Something to experiment with anyway.

[intelonetwo]

Sonnie, was it a subwoofer phase thing....That's interesting that it had such as effect on your subwoofer.

[Sonnie]

I don't believe it was related to phase since simply triggering the MultEQ caused the variances. Here's more info with a graph.