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The effect of splaying walls on first reflection points
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Author:  Leland2 [ Sun Jul 21, 2019 11:15 pm ]
Post subject:  The effect of splaying walls on first reflection points

Whilst idly thinking of room layouts for a particular problem, I started looking at splaying walls. The main reason for splaying walls in this situation is not to solve acoustic issues, but for architectural and access reasons.

Splaying wall the side walls of a room outwards from the speaker wall has the effect of moving the first reflection point further along the side wall towards the speaker wall end of the room. If the room has wall mounted speaker construction with the speaker walls angled, it is posible to move the theoreticall first reflection point behind the speaker wall – ie no first reflection point at the listener position on the side wall.

As one changes the wall splay angle, (keeping other variables the same), there comes a point where the first reflection point is actually in the corner of the side wall/speaker wall boundary. What are the consequences of this? Some thoughts:

1. Would it lead to a very strong image at the listener position if the time delay between the direct sound and the reflected sound was less than the Haas masking time?
2. How much would the comb filtering would affect the frequency response at the listener position?
3. A reflection point in a corner might detrimentally affect the modal response of the room
4. The reflection point in a corner makes it hard to apply treatments. Would putting absorbers in this corner start affect the functionality of the speaker wall (which is supposed to be a reflecting surface)?
5. In practical terms, as one increases the angle of the wall splay, at what point do these effects start to reduce? i.e. How far behind the speaker wall/side wall boundary does the first reflection point have to be before these effects are reduced to negligible?

As it is a bit of an abstracte question, here is sequence of pics based on a particular case to illustrate the effect follows. Any thoughts or comments?

Author:  DanDan [ Tue Aug 27, 2019 12:04 am ]
Post subject:  Re: The effect of splaying walls on first reflection points

Radiation from a speaker generally becomes more and more directional as frequency increases.
Imaging etc. only occurs at higher frequencies.
DD

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