high level differences between foam/bass traps/absoption panels/etc

[localhost127]

^^^^

[tINY]

Foam is almost worthless in most studios. It only absorbs high frequencies well and most problems are in the mid and low frequency ranges in rooms smaller than a 250 seat theater.

The rest of the traps you mention are more of a continuum and in smaller rooms, you really should just use the 4" everywhere unless you have a good reason to use thinner.




-tINY

[localhost127]

^^^^

[gremmy]

1) broadband absorber: The term "broadband" is used to denote that the panel absorbs "many" frequencies and is not tuned to a particular frequency. Generally, the term applies to panels made of an absorbant material (such as mineral wool, fiberglass insulation, etc.) that absorbs 100% of sound above a certain frequency. For example, a fiberglass panel of a particular thickness might absorb 100% of the sound above 500 hz and less energy at lower frequencies.

2) Bass Trap: a "broadband" absorber that is thick enough to absorb sufficient energy at low frequencies (generally below 250 hz).

3) Mid-High frequency absorber: The way you're using the term, this implies a "broadband" absorber that is *not* thick/dense enough to absorb sufficient energy at low frequencies.

The difference between #2 and #3 is generally thickness/density. For example, 2 inches of OC703 would make a good #3, but for #2 you'd want 4 inches or more.

4) a Tuned Absorber: the opposite of a broadband absorber. An absorber that is "tuned" to a particular set of frequencies. For example, a helmholtz resonator.

[TheEqualizer]

Originally Posted by tINY

Foam is almost worthless in most studios. It only absorbs high frequencies well and most problems are in the mid and low frequency ranges in rooms smaller than a 250 seat theater.

-tINY

Does foam only absorb high frequencies if it is, say, 15" thick?

[tINY]

I'm pretty sure that you can stack foam deep enough to get some absorbtion at lower frequencies.

But why not use mineral fiber? It won't need to be nearly as deep to get good performance at lower frequencies....

...of course, if you have a lot of room to spare, you probably don't have as many acoustical problems to start with...



-tINY

[nosebleedaudio]

Originally Posted by localhost127

hi - ive bookmarked and read most of the common "starting point" links (e.g. ethan's) in this forum...

quick question that i may have missed or that i just need a basic/simple understanding of.

the primary differences and key attributes of different types of applications ... from a high level perspective.

-bass traps - geared more towards low end
-absorption panels (e.g. fiberglass/oc703 4" -6" thick) - to absorb "mid-high" bass
-absorption panels (fiberglass 1"-2" thick) - to absorb mid/high reflections

now what about the auralex and other types of foams i see out there...

the design approach from bass traps to the foam is quite radically different (bass traps generally much larger in size, in corners) - and i see the foam as smaller pieces that are applied to the wall/ceiling/reflection points etc.

if im mostly concerned for my listening room for mild treatment (every little bit helps), and im focusing on 4" traps in the corners and 2" panels on the rear wall/reflection points etc...is there any use for the foam?

a lot of material and sometimes it just takes a bit of time before all the pieces fall into place / completely understood.

thank you-

For foam to absorb the upper bass (150Hz) it needs to be in the 4" thickness, where it gets kinda high($$)..
I use foam in some places, its a done deal in some respects, glue it and go..
It all depends on the room, use, how long you plan on being there ect..
I prefer different thickness, 2" minimum, 4" and 8" in some areas..ALL depends.
All 2" is a mistake, IMHO.