# My PEQed dual sub graphs



## morik (Mar 15, 2011)

So I've been playing around with both Audyssey (MultiEQ XT 32) & a DSP 1124p and various house curves & such, and I ended up with the following. (Should I make the REW window smaller before capturing graphs, so the scale isn't so stretched out?)

(3 filters in the DSP prior to running audyssey to knock out some bigger peaks, 3 filters post-audyssey to get that house curve, which is a 9db rise from 63 to 20)

My setup:
2 Rythmik F15HPs, in separate locations (one near front speakers, one behind listening area)
2 Mirage OMD-15s as mains, crossed over at 60hz
(And then 4 OMD-5s for surround/rear, and an OMD-C1 for center, but those aren't active in any of these graphs. The surrounds & rears cross at 80hz, the center at a disappointing 150hz according to Audyssey (was 120hz when the center was on the floor, but once I put together the TV stand and put it up on there, Audyssey puts it at 150hz)

I'm happy with the low-end bass. I'm not happy with the 100-150ish region. I'm not sure what I can do about it though... would room treatments help this? Similarly that area from 300-550hz is a little crazy, and I don't like that the high end is spiking before dropping off.

Right now I have no treatments, no rugs, no carpet. Concrete floor basement with tile on top, half the walls are concrete with drywall, other half are drywall with a concrete walled & floored room on the other side. There is an opening in a corner of the room for the staircase.


The first graph is response from 5 - 100, unsmoothed.
The second graph is response from 15-200, also unsmoothed
The third graph is the 15-200 response with the my target house curve superimposed.
The fourth graph is the waterfall for the 15-200 response.
The fifth is a full sweep, 1/12th smoothing


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## robbo266317 (Sep 22, 2008)

The dips may be room modes. What are the dimensions of your room?

It sounds like you will benefit considerably from room treatment as well with all those hard surfaces.


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## morik (Mar 15, 2011)

My room is 25.5' long. The room has a column in the middle. On one side it is 16' wide (not the HT side), and on the other 18'. The stairs opening is behind the home theater area. The ceilings are generally 7'8", but are about 6'10" for a 4' strip down the middle of the room:



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(The 6'10" ceiling actually extends all the way to the other side of the room, doesn't stop at the column)



In terms of room treatments, any way I can get an idea of what to expect? (I have to sell my wife on letting me put what she considers a bunch of "ugly " up on the walls... she doesn't like the fabric covered acoustic panels.)

I'm also not sure of where I would put them... the OMDs are omni-directional, and the manual states not to use treatments at the first point of reflection. I am eventually going to end up with the surrounds & rears ceiling mounted (they are wall mounted right now), so I assume putting down a big rug might be considered treating their first point of reflection... would adding a lot of treatments, along with large rugs, to the areas outside the HT listening area be better?


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## morik (Mar 15, 2011)

So in an attempt to fix a few of the issues I mentioned above, as well as the oddness around 80hz, I moved the main speakers out about 4' from the back wall (from 1.5'), and re-ran audyssey with my listening position further back.

I got the following results (crossed at 80 instead of 60 this time--with the prior attempts, crossing at 80 introduced a huge null at 77hz). This is with 5 filters on my PEQ, all post-audyssey--I decided not to try to knock out peaks pre-audyssey after all.

So one thing I did beforehand was when running audyssey, instead of setting the subs to 75db as they suggest, I did 81db to give me room to up the trim prior to EQing to the house curve. (I then bumped them 9db each, to the level the DSP 1124p still doesn't clip at for the depth charges in U571, but gets some yellow flickering)

So for some reason, with the speakers further out from the wall, I'm getting that big spike from 77 to 125.

At lower volumes, with dynamic EQ on, its fine--the balance of 100hz vs 80hz vs 60hz vs 28hz is pretty good. But at higher volumes, where dynamic EQ isn't bumping the low end as much, the difference is much more noticable. I couldn't do a listen test tonight at my usual volume (my usual volume wakes the wife up), but listening at lower volumes, I like the way it sounds (at low volume) better than it did with the settings in the first post (at low volume).

(By "low" I mean probably around 70-75db... I normally listen around 85-95db)


I'll give it a listen tomorrow and see what I think, but I'm wondering whether a reasonable solution would be to rerun audyssey with the subs even hotter, and then bump them up such that they are about 5db hotter than they are in the graphs below, so that they match up better with the spike from 77 to 125.

(All in all, I'd rather run with 77-125 a little hot vs the dips around 80, 90, and 100-125 that I saw in my first post)

Anyone have any opinions on all bass 5db hot vs having that big hot area from 77 to 125?


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## robbo266317 (Sep 22, 2008)

So moving them out from 4 feet as opposed to 1 1/2 feet changed the dip into a peak. 
I would try moving them back 15 inches and remeasure since it is obviously room interactions (Or try measuring them at 6 inch intervals from 1 1/2 through to 4 feet).
There are several guides on speaker location vs room size to get approximate speaker and listening positions. I will check it out over the weekend.


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## morik (Mar 15, 2011)

I wish I didn't have to run audyssey to get an idea of where they are at :-/

That makes each position I want to measure take a lot longer 

I'll do that this weekend and see where it gets me.


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## morik (Mar 15, 2011)

So I fiddled some more and the best I could come up with is below.

I don't know which I prefer... and I didn't really give the other setup a good long listen... :-/

I'm leaning towards the one with the big hot area from 77 to 125. One thing I didn't try on those (that I did do on these) is an additional wide cut around 100hz on the subs, to offset the gain I put on prior to the house curve. That may cut down on some of the big area.

Thoughts?


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## morik (Mar 15, 2011)

So I went back to the positions where 100hz had that hot zone, and reapplied my house curve with a filter up at 100hz or so. I was unable to reproduce the results from before where I seemed to greatly mitigate the null at 80hz, even though I put the speakers in pretty much the same place... maybe off by a few inches at most.

I have 3 house filter sets now: One is a 2 filter set. The second is a 7 filter set that has a better looking waterfall, but my guess is that it won't sound any better than the 2 filter set. I'll do a blind test of the two sets tomorrow.

I took the low-end up a lot more than my previous set. When I was figuring out how much of a boost I needed, I had my receiver set in PC mode (I use my PC as a media center), and ran REW test tones with the receiver volume structure set up as I have it for music, at my normal volume. I decided I needed a 6db boost from 60 to 28. I use REW in non-PC mode (auxiliary mode with analog inputs). When I did a house curve boosting by 6 or so up to 28 (as measured by REW, such as in post #7), measuring the SPL of 28 vs 60 back in PC mode with my usual music volume setup showed 28 was lower than 60 by a decibel or two (C-weighted). With the REW SPL that is (using calibrated Behringer ECM-8000). So i don't know why it didn't work out (when deciding to boost 6 db, that was by listening to the 60hz tone, measuring the SPL with the ECM-8000, playing the 28hz tone, manually raising volume until it sounded as loud, and then measuring the SPL, and taking the difference). I tested the new boosts by ear and now 28hz sounds about as loud as 60. I have no idea why the REW measured boost didn't translate to the same boost with my usual music settings... but it looks like boosting by 10-14db is good.


I also made a movie set with 2 filters which puts everything basically back to the Audyssey base settings, with the exception that the very low end (2-15hz) is still boosted by 4-6db... one of the filters is a max bandwidth cut at 20hz, but still didn't get the low end back down sufficiently. I'm not sure if the movie set is necessary or not... I'll test that out tomorrow too.


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## morik (Mar 15, 2011)

So I did a blind test between my 3 filter sets:
- 7 filters house curved
- 2 filters house curved
- 2 filters no house curve (filters needed to bring boosted volume back down to baseline audyssey levels)

My wife did the switching, and put it in order of: 7 filters curved, no curve, 2 filters curved

I greatly prefered the 2 filters curved, but I think that is because of the contrast between it and the no curve.

I did a second blind test between the 7 filter curve and the 2 filter curve. I liked both.
- The 2 filter curve sounded just a tad heavier. Perhaps due to the peaks at 45 & 51? When I put the two graphs side by side those are the only areas that are much bigger in the 2 filter graph... maybe I'll try another filter or two to bring those down.
- The 7 filter curve seemed to blend a bit better

I then went back and forth between the two and listened to the same bass-heavy parts of a few songs over and over, and couldn't really tell a difference.


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## ISLAND1000 (May 2, 2007)

You sure have played around trying to get those humps and dips down to . . . . what 3-5 db?
When you do a listening test, can you identify when a sound or musical note is over emphasized or lost?
I have problems running a "best flat" curve for the sub and trying to join it with MCACC curve (Pioneer AVR) of the mains. It helps me to get some separation between the two systems, IE: crossover sub @ 80Hz Crossover mains @ 100Hz. It seems I get some doubling (boost) if I cross-over both @ 80Hz.
Your having room modes from the floor to ceiling height and another from the 12 foot wall length. The third room dimension is distributed because of the connecting room space.
Trying to EQ your room with subs in the corners is difficult BUT even with all your problems, your curve looks acceptably good to me.
You've got to get some acoustic absorption on the walls and the floor. I'll bet once you've got the reflections dimmed and under some control, you'll like the way your system sounds.
How does it sound?


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## morik (Mar 15, 2011)

I think it sounds pretty good actually. I would not have expected it to sound as good as it does given the bare walls and bare floor.

I'm happy with the bass as well now. I went with the 2 filter set, but tweaked it a bit. With 3 filters, I got the graph below.

My wife is amenable to putting down a big rug or two, but much less amenable to wall treatments. I guess I'll get a few rugs as my next step, and see how they do.

I enjoy tweaking things, which is why I'm spending all this time .


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## ISLAND1000 (May 2, 2007)

Your wife is such a cutie . . . . . she gave you rugs to cover the concrete floor. Excellent.
Now you have to convince her she really needs to express her inner mogul with some flowered drapes placed at those spots only YOU know are correct to relieve her inner stress. onder:


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## morik (Mar 15, 2011)

Well, it is a finished basement, so the concrete is hidden by nice large tiles & drywall.
She thinks putting "a bunch of <censored>" on the walls would look tacky.


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## ISLAND1000 (May 2, 2007)

Under THOSE acoustic circumstances, your system can only sound "kinda" good.
It's best to keep the boss happy and the family together.


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## morik (Mar 15, 2011)

Well I'm slowly working her around. She's pretty chill actually. Talked to her more last night and she said she would at least look at some of the wall stuff I'm thinking about. Acoustic panels would be best, I imagine? Better than say a tapestry?


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## ISLAND1000 (May 2, 2007)

For myself, I would opt for the tapestry. It would serve two functions 1) please the wife, 2) cut the mid to high frequency reflections and reveal that all too frequently forgotten "detail" that is so important to music and dialogue.
My own personal favorite "tapestry" would be a heavy wine colored floor to ceiling piece folded luxuriously against some pieces of dark-walnut framed art work from the Renaissance period, reminiscent of King James throne room.
What I'm suggesting is not going to be found at your local Walmart or even Joanne Fabrics. Maybe the price of these items would serve to impress your wife.


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