Bass traps... how to use?

[Manning]

OK, so I snagged a mountain of Primacoustic foam panels off eBay. (As a bonus I scored seven extra panels he had forgotten about).

So now I have four big bass traps (about 900 high with a 300 x 300 x 400 mm triangular profile). They are going into my booth (internal rectangle dims are 2100 long by 1450 wide. Ceiling is 2100 high).

The door is at one of the short sides, and the recording position is at the opposite short wall (ie. singer's back to the door).

I'm at a loss as to where to place the bass traps (or if I even need them). Anyone got some ideas as to the best starting approach?

[Wiz]

traditionally, the best place for bass trapping, is to cover any corners...

wall wall floor(tri corner)

wall wall ceiling (tri corner)

ceiling wall

floor wall

[Manning]

Hmmm... I would need 8 traps to completely wedge off all four corners.

As I have four traps, would I be better off with one trap in each corner, or should I do two corners floor to ceiling (presumably at the "dead" end).

[Sammas]

Hey Manning, I suspect experimenting and taking some measurements is the only way you will find out.

Room Eq Wizard is free, and I think there is a pretty decent shareware/trial version of fuzz measure pro if you are on mac.

[Wiz]

Honestly.


whack em in, listen, move em around.. .listen...


its really the only useful way.

But, if you put bass traps, in corners, it is where they are the most effective (you know, generally)


cheers

[Hookemeister]

if you put bass traps, in corners, it is where they are the most effective

+1 on Wiz's advice. Low frequency always accumulates in the corners of the room

Put them up in the 4 upper corners of the room.

As a bonus I scored seven extra panels he had forgotten about

Place these around the walls so that you have a live area facing an absorptive area but keep them about 600mm away from the corners.

(internal rectangle dims are 2100 long by 1450 wide. Ceiling is 2100 high)

Now Manning, I hate to be the bearer of bad news. but your going to have serious peaks and dips in the area of 82Hz, 164Hz and particularly around 237 - 246Hz as a result of those coincident dimensions.

Acoustics 101: Avoid building rooms with 2 or more equal dimensions or multiples of a dimension.

82Hz is basically the low E on a guitar, 164Hz, the octave above and 246Hz is close enough to the B string,
so you'll have some problems if you use it as a cab room.

What you need is some tuned absorbers in the corners below your triangular foam sections.

I'm pretty busy at the moment with an installation but it should be completed in a couple of weeks.

If you can wait that long I'll design some panel absorbers for you to help tame those problems.

Hope this helps

Greg

[Manning]

Greg - some good news: it will NEVER be a cab room.

This is a booth just for my wife (who has 130 songs she has written). Hence 99% will be her, and 1% acoustic guitar.

I always knew the rectangular shape would be an issue, however my complete lack of carpentry skills dictated the design to a degree. (I have since acquired some skill... not much but a little).

Having said that, I'll gladly take any help or advice, as always. I'm still amazed I even finished the damn thing**.

(**OK, it's not *quite* finished yet, the outer shell for the ventilation ducting is not quite done)