How to diagnose the need for room treatment?


I have my stereo setup in the family living room (30x14x8 ft). I have done some work around speaker placement, and treating 1st reflection points, but don't know if I need to do more. I often read room treatment being crucial. So while my system sounds good to me (I'm new at this), it might be able to sound a lot better.

How can I come up with a diagnose, short of trial and error of every posibility?

Thanks!
lewinskih01

Showing 2 responses by sbank

I beg to differ with the last couple of responses. If you'd really like to get the best sound possible from your setup, you really need to make an attempt to gain a solid understanding of how your gear, room acoustics, speaker placement and seating placement are interacting.

Get a cheap spl meter from Radio Shack and a cd with test tones from either rives.com, a website or a Stereophile test cd. Place the meter on a camera tripod where your head is when you sit in the sweetspot. Measure the response using the test tones (search archives here on how to do this exactly), and graph them on the chart you can download from rives.com.

If you play with speaker and seating placement & remeasure, you will be able to significantly affect in room bass performance. Often you will have peaks at some frequencies and troughs at other frequencies. Offer, you have to live with tradeoffs to get the best overall balance. Bass traps in the corners behind the speakers offer the biggest improvement in most situations. the room acoustics forum on audioasylum is the best place I've read up on this topic.
Good room treatment doesn't have to cost tons or look like hell. Natural fibre rugs, velvet curtains, upholstery and bookshelves can all contribute to improved sonics if diy or commercial room treatments aren't in your budget or to your liking.
Don't let anybody fool you. The room is probably your most important component. Cheers,

Spencer
Nice work, freak!

The peaks @ 31.5hz & 80hz are probably the biggest concerns I see. In room high frequency plots tend to drop off steeply as you see, so not as surprising(at highest frequencies) as you might expect. However your overall picture of bass all + and treble all - doesn't seem like it would sound very natural. Do you get the sense that your "bass is turned up, and treble down?" Speaker placement & seating changes could affect this greatly. Since you are already far out from back wall, I'm guessing that current placement is exciting some room nodes. Experiment in small increments(i.e. 6in).
Lastly, not a big problem, but by definition, shouldn't 1000hz = 0? Cheers,
Spencer