Metric Lumber Sizes in Inside Out Wall

John's Inside-out wall plan is in Metric.. I'm assuming that these dimensions (especially with the slat sizes & gaps) should be adhered to closely. http://www.sae.edu/reference_material/audio/pages/Walls.htm So I was wondering what the imperial equivalents are? his slats are listed as 100mm, 50mm and 25mm. Am i correct in assuming my slats should be exactly 4", 2" and 1"? What about width? And what about the 75mm x 35mm frame? does this really mean i should trim my 2"x4"s down to exactly 3" ? Any insight greatly appreciated. -Gregor

Hi, slat sizes are dependent on Freq. You need to download the hemholtz excel doc. find what frequency you need to affect and have your slats that size. Or just what looks good, gap size can control the freq you want. Wall depth is: Go with the thickest you can afford and fit in the room. If your utilising the wall cavity as a bass trap the bigger is better. However 35x70, 45x 90, 120x 35, 120x45, will all work fine. get what ever you can fit and afford. You will still need to add corner traps in all corner and then some..... lil

Gregor Smith wrote:

So I was wondering what the imperial equivalents are?

A Windows metric>Imperial conversion app. http://joshmadison.com/software/convert-for-windows/

slat sizes are dependent on Freq. You need to download the hemholtz excel doc. find what frequency you need to affect and have your slats that size

ok, so with the helmholtz calculator I have control over my range of broadband absorption. So what should my strategy be? should i wait to test my room before committing to the placement of the slats? assuming i'll have superchunks in all corners, and some membrane traps if necessary, where should my broadband absorption begin and end, frequency wise?

A Windows metric>Imperial conversion app.

Thanks for this. But i'm still confused about John's plan- is he referring to exact sizes? if so they are far from standard lumber sizes, at least here in Canada. thanks, Gregor

You may require a >table saw<...there isn't a app for that yet ;)

Xspace- :D You can wait to test the room or you can punch the dimenstions into a room mode calculator. The angled slat walls are a broadband trap anyway so you can just aim for 200-300hz as a middle freq. Any bass trapping is good!

Any bass trapping is good!

Yup! And more is even better! :lol: - Stuart -