Room Acoustics


Suggestions for this annoying problem appreciated.I get an annoying room resonance in the low mid bass that just excites the hell out of the room in spite of speaker placement, different amps, and corner treatments( 4 corners with ASC super 16's to the ceiling), curtains over sidewall windows etc. Speakers are Eidolons, room is 15wX22dX9h. Short shag carpet, speakers on apex couplers. Sound is 99% stunning with that occasional Dave Holland bass note that just won't quit. I think it's possibly the floor, pier and beam over a finished rec room in basement. I'm considering putting the Edolons on granite and maybe having someone professionally check the room acoustics. Is this related in any way to the downfiring port of the Eidolon?. Thoughts appreciated including any suggestions as to someone coming out to test the room. Thanx in advance.
mes
With the Eidolons, you may want to move them slightly away from or closer to the wall. This shouldn't substitute for troubleshooting the source of the noise. I have a pair of Avalons, and they are very picky of room position. I had a similar phenomenon, and I found that some loose flooring / rafter bracing in my house was the cause. There was a weekend when we were replacing carpet that I went around my living room, sinking a 5lb box of decking screws every 3 in in the subfloor; Went down stairs while the wife was jumping on the floor and marked all of the locations where I heard noise, and secured all of the bracing with glue and screws. I put R25 insulation in the floor joists with 5/8 drywall below the listening room. All of this including the carpet cost less than my interconnects, and made the whole room much more quiet. After I was done, I heard more noise, which turned out to be a bush on aluminum siding, rattling soffet, and some tin lamps on the wall. I would guess that the addition of granite slabs under the speaker will not fix your problem, but it is not a bad thing to try... Good luck!!
J K
I have a very funny graphic idea of that day in your house with your wife jumping up and down and you drilling screws into nearly annything that moved o rmade noise....sort of right out of bugs bunny or something
jd
$4700 retail in ASC traps and still a bass problem? Is there something wrong with that picture?

....some good suggestions though from those up above...good luck.
JDWEK -- It was kind of a funny scene... I am also a fan of Bugs and it could have been good 'toon material. I also caught the business from more than one that saw a screw every 3 inches... My floor doesn't make any noise any more...

Mes -- One thing I forgot -- are these Eidolons new, or not played often, or have been disconnected, moved, ect?? If so, let them break in for 500 hours and not worry about it(unless the bass sounds distorted or is breaking up). Avalons are by far the worst speaker to break in, requiring a lot of power and time. They will also get "cold" if not played at least once a week for a good listening session.
Agree that an active EQ trim at the problematic frequency can be an effective fix, if you've covered the other fundamentals (speaker placement, securing vibrating room elements, etc..

Rooms all have their own resonance, and few approach near neutrality, while many are simply problematic even when you do all the dirty work, spend a bunch on tube traps, etc..

Sometimes just a little trim at a problem frequency is so much more of an easy fix than infinately fussing and frustrating yourself...or, lighten your bass tone control slightly, if you have one. Yes, it's not purist to use tone controls, but you are looking for the overall best effect, and if improves things more than worsens them (hopefully much more), don't be too religiously against it.

Digital EQ should have the least negative effect, especially on phasing, but also a high quality analog EQ is not something to rule out. Used sparingly, mostly for cutting peaks (dips are often hard to add gain to, as they often are due to out of phase signals). Try to use it very sparingly, and only on the bands where it truly sounds good to use. Try keeping your adjustments to about 3db or less for least negative effects. I picked up a beautiful and really quite transparent Rane EQ at the Flea Market for $60. Rane makes alot of pro gear, and their analog EQs are quite nice.

Alternatively, try some different interconnects and maybe speaker cables. Some are lighter on bass than others, and the right one might just rid you of the bass bloat you are getting. If all else fails, remember that 99% there isn't so bad, and think of all the people putting up with all the pops, ticks, and warbles they get with their vinyl, and they still find the ability to love the heck out of it.

Jeff