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Old 4th September 2019
Gear Addict

Originally Posted by Soundman2020 View Post
There is a simple principle in acoustics: sound waves are only reflected by solid objects that are similar in size to the wavelength of the sound, or larger. In other words, if the object is 5 cm wide/high, it will only affect waves that are 5cm long, or shorter (shorter wave=higher frequency). That would mean waves with a frequency of about 7,000 Hertz, or higher. If the object is 10cm wide/high, then it would reflect frequencies above 3400 Hz. For an object 1 meter wide/high, that would reflect down to much lower frequencies: around 340 Hertz and higher.
Hi Stuart, So I really was talking about the thickness of the slat being 1cm. The width of the slats are 9cm and the space between the slats are 1cm too. The slats go all the way to the ceiling. i basically have a room that is bass trapped with a lot of absorption and am looking at fixing slats over the walls so the room isn't dead. I found slats with these dimensions and wanted to use them and wanted to know above what frequency will be reflected back into the room. Obviously a 100hz sound wave will pass right through that. Hope that helps.

There's also the issue that very thin, flexible objects might act like membranes or foils, in which case they could absorb some sound at the frequencies related to that, and there's the issue that the mass of the object itself will attenuate sound above certain frequencies (prevent i from passing through).
Ok I didn't know that.

And finally, if you place wood slats over some type of cavity, such as the interior of a wall, then you have created a Helmholtz resonator, which will resonate at some frequency governed by the Helmholtz equations, and will therefore absorb that frequency very well, while reflecting higher frequencies, and perhaps somewhat absorbing lower frequencies, depending on mass, etc.
I am aware of this but in this case my main concern was low end control so I used thick superchunk treatment on all walls and ceiling to give me a dead environment down to 60hz then was looking at how to bring back the high end. I was recommended slats and now am looking at material. Can you make a suggestion here?
So there's lots of stuff to take into account. Its not really a simply as just nailing up some slats to get the high end back into the room. That's the general concept, yes, but there's a lot to take into account when you decide how to implement that in practice.
great could you lay it down for me please? I was just told to use random slat sequence so if it is more complex than that please tell me so I can do it right.