help with a sometimes boomy sounding room..


Well, here's my low down.

my listening room size: 10'6" wide x 13'length x 7'2" Hi.

my gear: Classe CA-201 w/ reference XLO power cord,
Classe CP-60 w/ Classe reference power cord, MIT Z center w/ Z cord, Sony SCD-1 w/ cardas gold reference power cord,
Monitor Audio GR(gold reference)'20's
MIT MI-350 reference balanced 1 meter from SCD-1 to CP-60,
transparent balanced musinlink-plus 1 meter from CP-60 to CA-201, 10' transparent bi-wire musiclink-plus speaker cables.
I have acoustic treatments on (both) back 10'6" walls , also have treatment behind listening chair at ear level, treatments centered on 13' walls, floor is carpeted with 3/4" padding.

The boomyness on seems to exist during certain songs with heavy bass tracks..., have not had any boomyness when playing SACD's...

The monitor audio's have a great soundstage, good depth and image great.

The speakers are 33.5" off the back wall and 16".5" off the side walls.

OK, tha't's it. Any thoughts.....for improvement?

thank you so much for the long read!
campylver
I'm going to back up the speaker/listening chair position theory. I too have a very small room (9x12x10) and have found that listening in a near field position helps eliminate many room anomilies. A good starting point is the "rule of thirds" in which the speakers are 1/3 into the room and the listening position is 1/3 into the room. Good luck.
Here's my constant recommendation for this and many other room acoustics issues: buy F. Alton Everest's "Sound Studio Construction on a Budget" or his "Master Handbook of Acoustics, 4th Edition". You'll learn how to analyze your room quantitatively, and learn what you can do about room resonant modes that give you boomy bass. If you read most of it, you'll learn how to deal with problems arising above 300 Hz too, with absorption and diffusion.
Sounds like the bass drivers on your speakers are unable to handle lower frequencies. Use an amplified sub-woofer and carefully "dial-in" the bass response using a CD that has a lot of bass cords or scales. The object is to get a continuation of bass response where the speakers stop responding, i.e., a natural unbroken progression of bass notes down the scale.

The sub-woofer should be connected directly to the pre-amp. Hopefully your pre-amp has two sets of analog outputs. If not, you need to try a pre-amp that does.

From your description it sounds as though you are sitting 6' from the speakers, is that correct? Is that the alignment the manufacturer suggests?
I had a similar problem in a similar room. I didn't want to give up my full range speakers for smaller monitors because I wanted to have a stronger bottom than monitors offered. I bought large ASC cube traps for the back corners, but they made little noticeable difference.Finally I bought the Accuphase DG-28 eq, and that corrected the problem completely. I had real bass, without it overtaking the rest of the spectrum. The Tact works equally well on standing wave problems.
Good Luck
Carl
You don't specify what type of acoustic treatment you have on the back walls, but as Audiofile9 points out, only bass traps will address the problem you describe. Most surface treatments only tame reflections above 300 Hz or so. I use ASC Tower Traps and am very satisfied with the improvement they made in a small room....much cleaner, more articulate bass.