Posted by Mark in Ohio on August 18, 2000 at 00:02:49:
In Reply to: Re: Kleenex and Spit posted by Matt G on August 17, 2000 at 12:24:07:
Sorry folks;
Ceiling tile, carpet, eggcrate, & foam are NOT going to address this problem. I'm not trying to be being arrogant here; I was simply an architectural acoustical consultant for a few years. I had tried the same shortcuts myself, & wondered why it wasn't working.
Someone above mentioned a book by "Everest", and I recommend it highly for gaining a better understanding of how sound propigation and transmission occurs.
The book referrred to is THE MASTER HANDBOOK OF ACOUSTICS by F. Alton Everest (TAB books)
Another text I recommend even more highly, however, is ARCHITECTURAL ACOUSTICS by M. David Egan (McGraw-Hill Inc.) Amazon.com has 'em both. Interlibrary loan is another option- lotsa copies out there.
Be aware folks that stuff we're dealing with here (transmission thru a structure) has hardly anything to do with interior reflections. By throwing up a bunch of high frequency absorption, you only make it harder for Rick to hear his overtones & thus work on his Tone Jones.
I have the absorption specifications for a zillion (almost) different materials that are commonly used in construction and home brewed acoustic "treatment". Just as a quick example, below are the absorption coefficients for HEAVY Carpet mounted on a concrete wall or floor:
125 Hz - 2%
250 Hz - 6%
500 Hz - 14%
1000Hz - 37%
2000Hz - 60%
4000Hz - 65%
For reference, the FUNDAMENTAL of Bb, 2nd line in the bass clef staff, is close to 125 Hz. That means only 2% of fundamental is absorbed IF ALL surfaces (floor, ceiling and walls) of your room are carpeted!!! (the ceiling being wood actually changes things somewhat, but the illustration is still valid). Meanwhile, your overtones dissapear in succession. Such a room would be both "tubby" and "dead" at the same time. Pitch is also difficult to discern in such an environment (tests have proven this).
A totally dead (absorptive) ceiling is death to the Tubist.
Sorry to burst any of the well-intentioned ideas that some have put forth here in this thread, but I had once pursued these things full-time, and have seen (heard) them all in practice. Sound Transmission is Rick's first problem here. The sill plate may be the culprit.
I would like to publish a practice room construction primer someday. Alas, leisure time is a precious commodity!
Mark in Ohio