RoomEQ help

**JohnM** · **01-03-07, 05:18 PM**

The subwoofer volume alters where the gain trim for the sub ends up when you calibrate, as the higher the volume the more the processor has to reduce the gain of the output signal to get back to the desired level. Best thing is to set the processor sub trim to 0dB, then adjust the sub volume control to get 75dB from the sub calibration signal.

For maximum low frequency extension turn the subsonic filter off.

If the sub's high pass cannot be defeated then leave it set as high as it goes.

Running speakers as bass limited reduces their distortion by reducing cone excursion and even modest subwoofers have better LF than good speakers, however your 802's have very good low frequency extension and you may find they sound better set as full range, that also removes the problem of getting them to integrate well with the sub as the best crossover setting for one speaker may not be the best for the other. Try running them full range and bass limited and see what you like best. If you do run them bass limited then you can experiment with crossover settings from 80Hz downwards to see which setting gives you the smoothest response before you apply any EQ.

**Moez** · **01-03-07, 10:51 PM**

thanks for the advice John ..I'll check these ideas out...also wanted to ask you if changing the phase on a speaker is ok if it gets a better result in the measurement? Also wanted to know if I should use my centre which is an B&W HTM as full range or bass limited?

**JohnM** · **01-04-07, 02:44 AM**

Don't change the phase on the main speakers, but changing phase on the sub(s) is OK. The centre speaker should be set as bass limited.

**Moez** · **01-04-07, 07:56 AM**

my left main only out of phase looked soooo much better , flatter, but if you think it's not a good idea I'll switch it back....the problem with my setup in the front is right main is less than a meter from the sidewall and my left is two meters away

**brucek** · **01-04-07, 08:18 AM**

Quote:

my left main only out of phase looked soooo much better

You'll kill your soundstage if you put them out of phase............

brucek

**Moez** · **01-04-07, 01:34 PM**

John is it OK if I put my center out of phase? It just sounds so much better that way...also flatter resonse on EQ.

**JohnM** · **01-04-07, 03:31 PM**

If it sounds better, then that can't be a bad thing

but keep an ear out for odd effects as things pan across the soundstage from side to side. I guess you have tried inverting the phase of the subs?

**Moez** · **01-04-07, 04:02 PM**

I did and that worked out great....thanks.

**Moez** · **01-05-07, 12:45 PM**

John do you have any good places to look for info on treating the room? I've got some canyons/nulls on these measurements I'd like to address if I could. I've noticed that when I play a constant frequency that I'm seeing as a big null and crawl around the room and see where it's the most quiet, what am I to do to treat it? Just wondering how much control I have over it?

**JohnM** · **01-05-07, 02:18 PM**

Try here: http://www.realtraps.com/

**DrWho** · **01-06-07, 02:31 PM**

Just a few more you might consider:
http://www.ethanwiner.com/acoustics.html
http://forums.klipsch.com/forums/thread/796165.aspx
http://www.acoustics101.com/default.asp
http://www.prosoundweb.com/install/s...t1/mesp2.shtml
http://www.prosoundweb.com/install/s...part2/ppam.php

Never hurts to have too much info

**Moez** · **01-08-07, 09:35 AM**

thanks Mike..

**Moez** · **01-09-07, 02:49 PM**

corrected subs 1 9 2007.jpg

left front with subs 1092007.jpgHi John, I'm posting a measurement of my two subs...I think it looks pretty good but when I take a measurement of my subs along with the left front speaker(set as bass limited) I get a measure,ent that looks like the second post. I've set the crossover in the AV at 80...any idea why it's so much higher than the keft speaker?

**JohnM** · **01-09-07, 05:10 PM**

Do you mean why is the bass higher in the measurement with left+subs than with left alone? That's because the bass management filters for a main speaker only roll off at 12dB/octave (i.e. with the crossover at 80Hz, the level at 40Hz will be 12dB lower than without a crossover and at 20Hz it will be 24dB lower). Your speakers have very good bass extension so even with the crossover filter in place there is still significant low frequency output which adds to that produced by the subs. What does the left speaker measurement alone look like, when run as full range?

**Moez** · **01-09-07, 07:21 PM**

This is the left speaker at full range....that's a of a null at 60hzleft Full Range.jpg

**JohnM** · **01-10-07, 03:16 AM**

That certainly is quite a dip, worth seeing whether it is still there if you test both left and right speakers playing at the same time. Also try measuring with the mic a foot or two to either side and forwards and backwards of the listening position to see how localised that dip is. The speaker does have a LOT of low frequency output though, they really don't need any help from a sub at the bottom end.

**Moez** · **01-10-07, 08:27 AM**

This may be a dumb question John but how do I test both left and right at the same time. Do I chose either left or right in RoomEQ? I know the sub works with either left or right when I chose it as bass limited but not sure how to test both fronts at the same time...Oh I will try moving the mic around...great idea since I can move my sofa around to work...thanks.

**brucek** · **01-10-07, 09:00 AM**

Quote:

Do I chose either left or right in RoomEQ?

Those are simply convenient tabs in REW. The program outputs an analog mono signal on one channel from your computer. Any speaker selection must be done at the receiver itself.

If you want to test your main speakers, simply turn them on with the sub..

brucek

**DrWho** · **01-10-07, 02:38 PM**

Hey Moez, I think a lot of what you're seeing is the result of changing the scales of the graphs...your sub and left+sub are both essentially 84dB peak throughout the band below the crossover region. And the output at 60Hz hasn't changed either. The peak at 24Hz makes sense in light of the huge peak of the left speaker.

Did the mic move at all between the different measurements? Even as much as an inch inadvertantly?

It looks to me like you've got some destructive interference in the 55-90Hz region which has led you to boosting the output of the subwoofer for a flatter crossover transition. Did you smooth the graphs? Unsmoothed is more informative.

Anyways, try dropping the output of your sub 12dB (for when measuring just the left + subs) and then take some more measurements (and keep it unsmoothed). You should notice much more dramatic dips in the crossover region. When you've got both mains playing, you should probably drop the subwoofer 6dB (since there should be a 6dB rise in the higher frequencies compared to just the left main).

**Moez** · **01-12-07, 07:51 AM**

Hey Mike.....are you familiar with the MATT TEST (musical articulation test tones)? I have the test tones to try in my system but was wondering if could analyze the result?

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