newbie, please help out,

[heb]

Okay, after endlessly surfing this forum and the web, I've come to the conclusion I need help.
I have a small project studio in Bermuda in a house that I rent. I have THE worst time mixing, because I really am not sure what to do to get my room in tune.
The dimensions of my room are 14' Long, 8.5' wide and 9.75' tall. There's two windows and a permanent closet (see attached)
I've downloaded the modelcalc program and worked out that I have issues at around 200hz, 280hz, 405hz and 460hz.

obviously i need to do some low end trapping but i'm quite confused on how to go about building bass traps (dimension wise) to cover these frequencies.

Can someone please guide me in what I can do to improve the sound of my room? I'm not in love with the layout, so if there's anything anyone might suggest for rearranging to perhaps improve the sound/layout that would be great.
and advice on building traps or other acoustic treatment.

now, i rent this house, so i can't build anything permanent. The walls are 8" thick limestone (quite soft and don't support a great deal of weight).
It's impossible to get any auralex panels here (well, you can, but it's $50 US for a rip off brand 1' x 1' square) And i have yet to find any company willing to sell relatively small amounts of insulation. The only people that seem to bring it in, use it for large corporate projects and aren't willing to part with small amounts (don't ask me why) The other shame of it is, wood is relatively expensive too, it's about $10 US for an 8' 2x4. Obviously i'm going to have to bite the bullet on building materials, and i may have a line on some pink panther insulation from a friends jobsite. (I just thought i'd give an idea on material costs here, it makes me quite jealous when i see people building out rooms from scratch, when i couldn't even imagine the overall costs of doing that here)

The drawing i've included is the current layout
One dimension i didn't list in the drawing is the desk, it's about 7' long, it can be trimmed, but only by about a foot (2 ' max), oh and the couch is about 3.5' high (it's currently blocking the closet doors, which i hate)

Thanks in advane for your help

oops almost forgot, it's all hardwood floor

[Ethan Winer]

heb,

> I've downloaded the modelcalc program and worked out that I have issues at around 200hz, 280hz, 405hz and 460hz. <

Actually, you have problems at all frequencies.

> i'm quite confused on how to go about building bass traps <

For a room like that I prefer broadband bass traps rather than trying to target numerous specific frequencies. The basic idea is rigid fiberglass four inches thick, mounted across as many corners as you can manage. There's a lot of information here if you take the time to look around, and you'll find lots of specifics in my Acoustics FAQ:

www.ethanwiner.com/acoustics.html

> I'm not in love with the layout <

The way you have it now is fine.

--Ethan

[heb]

Thanks for the reply, I'll take another look at your acoustics faq page. Obviously i was interpreting the modelcalc results incorrectly.
Can you please help me to understand them? I thought that the problem frequencies would be only those that were really close together.

[heb]

Ethan, should I be looking at doing something like this?

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4581

If I am unable to find rigid insulation, what is my next best option?

and lastly, obviously, it would be better if i could cover the full height of my corners, is it worth it though, if i can only cover say, the upper half of the height?

[Ethan Winer]

heb,

> Obviously i was interpreting the modelcalc results incorrectly. <

No, you did fine. But...

1) A mode calculator is useful mainly when designing a room, to know if you have "good" dimensions. For a room that's already built it's moot.

2) No matter what is predicted, the exact mode frequencies you actually get will vary for various reasons. I've seen modes measured in a room be as much as 20 percent off from what was predicted.

3) I said you'll have problems at all bass frequencies because comb filtering is also a cause of peaks and nulls. The exact frequency depends on the distance between the speakers and each room boundary, and also between your ears and each boundary. The result is a mess of peaks and deep nulls that exist all over the place.

> should I be looking at doing something like this? <

Sure.

> If I am unable to find rigid insulation, what is my next best option? <

Fluffy fiberglass can be packed to be more dense. But it's more effort to make look nice.

> only cover say, the upper half of the height? <

The more you cover, the best the results.

--Ethan

[myfipie]

One thing you could do is stack fluffy fiber glass in the rolls, floor to ceiling in all covers of the room. You can then put a fabric wall in fron to it to cover it up.
Glenn