low frequencies look good, how do I fix the uppers?

[jholzbauer]

Little bit of background. I purchased 3 SHOs for my fronts, a CS18.1 sub, and 2 Emotiva ERD-1s about a year ago. I have a small dedicated room about 1700 cu ft. The main area is 12x13, but the room is L shaped with another section about 5x6. The 1 sub provided plenty of bass, but because of room issues, the results were very different based on seating position. So, I've been looking for another sub to balance out the results (and because I've been bitten by the "need more bass" bug also). I came across 2 dual opposed DIY MFW15 subs for an outstanding price, so I picked them up and an EP2500 amp. After finally buying a Radio Shack SPL and downloading some test tones, I started working on it the last week or so. I've got the low frequencies dialed in nicely having the 2 dual opposed up front and the CS18.1 next to my couch. I can post a graph later, but basically is 85 dB +/- 3 from 10 Hz - 62 Hz. I have a low spot of 78.5 at 65 Hz, I think due to the crossover point at 70 Hz. I originally crossed at 80 Hz, but that caused too much gain around 90 Hz. No EQ done except Audessey XT through an Onkyo 805.

Here's the deal though... Audessey has always crossed my mains over at 150 and my rears at 120 and I finally figured out why. Here are my readings from 120-160:

120 76
130 66
140 79
150 63
160 79

With the Audessey test tones, all 5 speakers were measured at 80dB... but I'm getting some huge swings around 130 and 150. I guess Audessey saw the big dip at 150 and tried to crossover there.

So, what are my next steps? I'm wondering if I need to put up some room treatments. I've got curtains on the front, a big sectional couch, and carpeted floor.

I appreciate all the knowledge this group has shared which has helped me immensely. Please help me take the next step in understanding this other part of the curve! :salute:

[HopefulFred]

That frequency range looks like a good candidate for SBIR. http://www.realtraps.com/sbirlbir.htm

Try moving the speakers toward and away from the walls (both side and back) and remeasure. If that's the problem, some thickish absorption on those nearby surfaces should fix it (4 inches or so).

(I just realized this was bumped from 18 months ago. I hope you got it sorted already.)

[tesseract]

Bumped up by a pesky spammer, so I swung the hammer.

Thanks for your helpful advice, HopefulFred. :salute:

[derrickdj1]

Are those number including the correction for the spl meter? With PEQ you could boost up the dip around 70. I don't use Audddyssey so I am not sure how easy it is to tweak.

[jholzbauer]

Yeah an old thread but one I should update. Turns out Fred was right. A year or so ago I built some DIY bass traps. I've got a chunk one in the back corner, some side panels, and some stuffing behind my main speakers. Once I got them installed audyssey started setting the crossover at 80 and everything looked a lot better.

That frequency range looks like a good candidate for SBIR. http://www.realtraps.com/sbirlbir.htm

Try moving the speakers toward and away from the walls (both side and back) and remeasure. If that's the problem, some thickish absorption on those nearby surfaces should fix it (4 inches or so).

(I just realized this was bumped from 18 months ago. I hope you got it sorted already.)