Toed in baffle wall

[Mindsource]

Hello

A baffle wall approx. 8 feet from the listening position would look like this

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5 sections of equal size wall approx. 4 feet wide each, all seamlessly joined. The two angled walls are anywhere from 10-30 degrees in. A center channel on the middle wall and left and right on the angled walls, flush mounted. The angled walls are toed in to be on axis with the listening position.

Can anyone see possible benefits or drawbacks?

Thanks!
Shawn

P.S. sorry for the 'image' I am not on my usual computer so no sketchup. The walls would be seamlessly connected, unlike in that image.

 

[AllenB]

It will work if you use speakers that don't direct toward the sides of the angled walls. Any speaker could work with some effort. The centre wall will reflect and the outer walls diffract.

Sounds like you're setting the wall up for this reason?

 

[TBTL]

Control rooms use angled walls with flush mount speakers to avoid the first reflection. Maybe you could get inspiration from that.

 

[picowallspeaker]

ESB 7/07 II - AudioReview

 

[Mindsource]

Thanks for the replies

Allen, I don't exactly get what you mean when you say the center wall will reflect while the angled walls will diffract. I think it is along the lines of my main concern though.

If the wall was flat then well... it's flat, kinda like an infinite baffle. But the edges where the angled walls meeting the center wall is where I am concerned. Is it going to fill the center panel with diffraction? Is there a line in the sand between the wave acting nicely and diffracting?

Also this baffle wall is against a shared wall. Will the distance between it and the actual wall create a triple leaf? The cabinets can be built quite shallow probably 10-15...20cm if need be.

Thanks for any replies
Shawn

 

[AllenB]

Sound that travels along the angled baffle toward the middle of the wall is going to bounce of that panel, because the join between those wall panels doesn't occur in the middle of the speaker.

A baffle wall can be a good thing, but the closer a speaker to walls, the more potential for issues when the wavefront doesn't match the walls.

 

[Mindsource]

What do you mean when the wave front doesn't match the walls? Do you mean diffraction and waves too big for the wall?

Is there a way to build an angled wall where the wave will not diffract? Do sound waves have a 'threshold' before they diffract?

Aaaaalso. What if the baffle wall were absorptive, say the front face had a layer of felt on it. Benefits? Drawbacks?

I guess I should add. I am looking to make a very directional system. Basically sweet spot on my couch and that's about it. As much sound that can be avoided hitting the floor, ceiling, side walls is desired.

 

[AllenB]

What do you mean when the wave front doesn't match the walls?

Consider this crude drawing. Waves (of a smaller wavelength) travelling along the baffle reflect off the angled wall like it was a mirror and change direction.

Then, the edges which were once supported by the baffle (shown where the red lines begin) will diffract into the open space.

Wavelengths larger than the region of this drawing would tend more to fill the space as a whole and behave differently.

 

[AllenB]

Is there a way to build an angled wall where the wave will not diffract? Do sound waves have a 'threshold' before they diffract?

A couple of things, at lower frequencies diffraction happens but it doesn't have the same sonic impact beyond changing the frequency response.

At any frequency, if you can see the need for diffraction you can control it by performing it slowly.

Aaaaalso. What if the baffle wall were absorptive, say the front face had a layer of felt on it. Benefits? Drawbacks?

On one hand it can help to reduce issues emanating from the baffle, on the other hand absorption that makes the baffle disappear can be the cause of diffraction similar to not having the baffle.

In reality a little wont hurt, but where you use it is probably the important point, and sometimes it needs to be the right amount.

I guess I should add. I am looking to make a very directional system. Basically sweet spot on my couch and that's about it. As much sound that can be avoided hitting the floor, ceiling, side walls is desired.

Very narrow is difficult to do well, but may not be necessary. You just want to hold off the early reflections. 90 degrees is easier and you can still hold the wavefront off the walls across the room.

 

[picowallspeaker]

I guess I should add. I am looking to make a very directional system. Basically sweet spot on my couch and that's about it. As much sound that can be avoided hitting the floor, ceiling, side walls is desired.

Place the woofer at equal distance from floor and ceiling