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  3. 989972365

Room Acoustics Problem?

By Audiogon standards, I have a mid-level system with Brystons (BP-25, 7B-STs), Thiel CS6's and the Perpetual Technology DACs (posted not too long ago on Virtual Systems). I'm annoyed by a saturated sounding mid-range and was exploring some options with the help of fellow Agoners on other posts. Then, I ran into Sean's March 3 post on how to run a more accurate frequency distribution reading with the Radio Shack SPL meter and the Stereophile CD. Here goes: At an 80db base, 20-25 Hz is OK, 32-50 drops off to -6db, 3db spike at 63, 80-315 OK, 3db drop at 400, 500-4000 OK, 4-6 db spike at 5000 & 6300, 10000 OK, 12500 and over drops off like crazy (3 moving to 10 db). OK is defined as plus or minus 2db. Does this sound like a room acoustics problem? Big room, lots of cushy furniture, hard wood floor. Is there something else I should be looking at? Help! Thanks in advance.
ozfly
onhwy61's avatar
onhwy61
5,141 posts
 
I'm assuming your measurement were at the listening position, if true, then your system measures quite well. The 4-6 dB spikes in the upper midrange could be sonically objectionable, but they could simply be measurement artifacts. Playing with toe-in might eliminate them. You might also consider one of the DSP room correction products from Perpetual Tech, TACT or Sigtech.
edle
235 posts
 
A piece of carpet in the hardwood floor will help to improve sound.....
joeabrams
132 posts
 
While I agree with the previous two folks, I also think that the combination of Bryston and Thiel can sound bright and forward under some conditions. If this system does sound "bright" to you, DO NOT toe the speakers in unless they are wider apart than their distance from your listening seat -- keep then parallel to each other. Also, this system can be VERY cable-sensitive. What speaker cable are you using?

Best of luck,
Joe
nilthepill
842 posts
 
OZfly, I assume that you already have corrected for the ERROR added by the measuring device. If not here are the corrections. ADD the error value to measured value and review the results to see where the problem is.
Freq error
20 6.2
25 4.4
31.5 3
40 2
50 1.3
63 0.8
80 0.5
100 0.3
125 0.2
160 0.1
200 0
250 0
315 0
400 0
500 0
630 0
800 0
1000 0
1250 0
1600 0.1
2000 0.2
2500 0.3
3150 0.5
4000 0.8
5000 1.3
6300 2
8000 3
10000 4.4
12500 6.2
16000 8.5
20000 11.2

Of course this may make your upper mid-range, low treble problem worse. In that case room acaustics would not cause big boost unless you have highly reflective surface-mirror, cabinet glass or big picture frame between you and speakers. If not, thiels are known to on brightet side in low treble range. Joe suggestion in combination with near field listening, verified by trial and error re-measurements should do the trick or try different IC between Pre amp and amp.
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