Drilled holes in the basstrap-frame?

[elmolemon]

Hi,

i already have superchunks in the corners of my room and i plan building some basstraps (20cm deep - rockwool) for the wall behind my speakers and for the side walls (early reflections).

I love the ideas from the "how i build my basstrap"-thread!

But how important are the holes in the wodden frame of the bass-traps?

That's a lot of work and i'm unsure if it's worth it..

I think about using ikea-book-shelves as frames (without the back), instead of building them on my own..

[Ethan Winer]

Holes simply increase the absorbing surface area. If all four edges on a 2'x4' by 4-inch thick panel are totally exposed, that gives 50 percent more absorbing surface than the front surface alone. A bunch of large holes might be more like 25 percent more surface.

--Ethan

[elmolemon]

Thank you Ethan!

I get that, but are the sides really important?

Isn't the absorption dependent from the "sound-pressure"?

If i imagine the absorption-panels behind my monitors and on the sides (early reflection points) i'm unsure if i benefit from the additional work..

[Jaques Beraques]

It wont hurt!
It´s just a bunch of extr work!

[Ethan Winer]

Originally Posted by elmolemon

If i imagine the absorption-panels behind my monitors and on the sides (early reflection points) i'm unsure if i benefit from the additional work..

I agree that for reflection points anyway, the extra absorbing surface is probably not worth the effort. Note that the front wall behind your speakers is not a particularly important place for absorption. It's not a reflection point unless your speakers face that way!

--Ethan

[elmolemon]

Originally Posted by Jaques Beraques

It wont hurt!
It´s just a bunch of extr work!

Originally Posted by Ethan Winer

I agree that for reflection points anyway, the extra absorbing surface is probably not worth the effort. Note that the front wall behind your speakers is not a particularly important place for absorption. It's not a reflection point unless your speakers face that way!

--Ethan

Thanks again Ethan!

But isn't the bass response of monitors omnidirectional??? My K&H O300 go quite deep (40hz)..

Isn't there the problem of comb-filtering?

I thought that it would be consensus to add absorption on the front wall behind the speaker..

But i must add, that i have to place the monitors quite close to the wall. That is also the reason why in my case i planed to treat the area behind my speakers.

[Jaques Beraques]

Originally Posted by elmolemon

Thanks again Ethan!

But isn't the bass response of monitors omnidirectional??? My K&H O300 go quite deep (40hz)..

Isn't there the problem of comb-filtering?

I thought that it would be consensus to add absorption on the front wall behind the speaker..

Thats what I thought , too.

[Glenn Kuras]

Originally Posted by elmolemon

Thanks again Ethan!

But isn't the bass response of monitors omnidirectional??? My K&H O300 go quite deep (40hz)..

Isn't there the problem of comb-filtering?

I thought that it would be consensus to add absorption on the front wall behind the speaker..

But i must add, that i have to place the monitors quite close to the wall. That is also the reason why in my case i planed to treat the area behind my speakers.

See the following.
Learn what is SBIR (Speaker Boundary Interface Response).

[elmolemon]

Originally Posted by Glenn Kuras

See the following.
Learn what is SBIR (Speaker Boundary Interface Response).

Thank you Glenn!

That's exactly the reason why i plan to treat the wall behind my speakers!

And as my speakers go quite low (40Hz) there should be nothing wrong about it, right?

[Glenn Kuras]

Originally Posted by elmolemon

Thank you Glenn!

That's exactly the reason why i plan to treat the wall behind my speakers!

And as my speakers go quite low (40Hz) there should be nothing wrong about it, right?

nothing wrong at all.

Glenn

[Ethan Winer]

Originally Posted by elmolemon

But isn't the bass response of monitors omnidirectional??? ... I thought that it would be consensus to add absorption on the front wall behind the speaker.

Most people treat the front wall with thin material that affects mids and highs only. That will do nothing for bass. Treating the front wall for bass is very useful! But that requires many bass traps, not 1-inch thick foam as you often see.

--Ethan

[elmolemon]

Originally Posted by Ethan Winer

Most people treat the front wall with thin material that affects mids and highs only. That will do nothing for bass. Treating the front wall for bass is very useful! But that requires many bass traps, not 1-inch thick foam as you often see.

--Ethan

Thanks Ethan!

As i plan to build my absorption panels 25cm (=10") deep, that shouldn't be a problem, right?

I plan to use the ikea kilby bookshelf as frame, just like in the pic. Will the heavy frame in my case (behind the speakers and early reflection points left&right) be a problem?

I plan to build 4 and put one behind each of my monitors on the front-wall, then there is a superchunk left and right in the corners of the front-wall, and anonther kilby trap left and right on the side-walls against early reflections.

Good? Or is the frame a problem?

Example kilbys:

[Ethan Winer]

I'm sure that's fine.

[elmolemon]

Originally Posted by Ethan Winer

I'm sure that's fine.

Thanks Ethan! thumbsup