Bass Traps - 703 vs Mineral Wool

[redrue]

Owens Corning 703 seems to be a favorite for
building traps but I've seen that, for broadband
absorption, 4" mineral wool has better (the best?) numbers.

I've built my own traps using the 4" mineral wool and
have realized a much better sounding room. BUT... I still
have some issues around a couple frequencies under
300 hz. (My understanding from reading Ethan Winer's
ample work on the subject is that the solution is more
broadband absorption)

But for the aforementioned two frequencies, I'm within 6db
across the spectrum when doing a room analysis. (It's a small, carpeted
study in my house).

I've built these traps making certain assumptions based solely on
the specs given on the Auralex website without any corroboration
or pro advice. It would be nice to hear from an authority
if adding more of my traps with the mineral wool is heading in
the right direction towards taming these problematic frequencies.

I'm almost 'there'

thanks!

[Glenn Kuras]

6db window is pretty damn good if not awesome. How many traps do you have straddling corners now and how bad was it before you started? You will find that adding more will help, but you are talking 1 to 3 db at this point.

Glenn

[redrue]

Well.. it's within 6db across the spectrum ABOVE 300hz.

I didn't test before placing the traps so I can't quote
any numbers of 'improvement' but the room is about
12X14 so you know there's a bit of challenge.

I've got one big peak and one big dip below
300hz.. question is: am I on the right track with
my self-made traps of mineral fiber? Can I kill those
peaks and null points? Just add more?

grazie

[Glenn Kuras]

Originally Posted by redrue

Well.. it's within 6db across the spectrum ABOVE 300hz.

I didn't test before placing the traps so I can't quote
any numbers of 'improvement' but the room is about
12X14 so you know there's a bit of challenge.

I've got one big peak and one big dip below
300hz.. question is: am I on the right track with
my self-made traps of mineral fiber? Can I kill those
peaks and null points? Just add more?

grazie

Oh below 300hz ok now I get it.

I am not sure how you made your panels but if you only want to work on below 300hz and just a little above then I would put some FRK or FSK on the fronts of them to act as a membrane. It will absorb more low end and reflect a little more high end.

Glenn

[Ethan Winer]

Originally Posted by redrue

I've got one big peak and one big dip below
300hz

In a room that size I expect you have five or six (or even more) peak/null pairs all below 300 Hz. How are you measuring? The correct way to measure bass frequency response in a small room is at a very high resolution - like 1 Hz or 1/24th octave.

--Ethan