Angling side panel 1st reflection absorbers inwardly...

Hi all I know that in some studio set ups the side walls are angled/splayed outward to reflect MF and HF away from the listener and toward the back of the room. But in most cases where absorption is used (from what I've seen) the absorbers tend to be flush - or at least parallel - to the walls. In such a scenario - if the speakers are toed in at a standard angle of around 30 degrees, sound will therefore reach the absorber at an angle of around 120 degrees. I appreciate that sound does not travel in a straight line and that this is therefore a vast over-simplification - but is it fair to also say that the absorber will not be as effective as it could be because of the high grazing angle? Which leads me onto my point...... I plan to angle my side panels inward (i.e. in the opposite direction to the way walls are splayed in pro studios), reducing the angle from 120 degrees to something more like 90 degrees. I wondered whether other people are doing this in their studios and whether it is generally a good idea or not? Cheers Max PS - I will soon be measuring my room in more detail and will compare ETC measurements to see what differences there are. But as I won't have time to do that very soon, I just wanted to get a few ideas together first....

I'm having difficulty visualizing what you are suggesting, but to answer your question:

is it fair to also say that the absorber will not be as effective as it could be because of the high grazing angle?

In fact, I understand the opposite to be true. The greater the angle of incidence, the better the performance. Take a 4" thick piece of absorption: * If you intersect at 90degrees , the ray intersects the absorption over 4" of its length. * If you intersect at 120degrees, the ray intersects the absorption over 4.6", meaning that a greater wavelength of sound can be absorbed (lower frequency), and I think meaning better performance at any given frequency. Cheers, Dave

Hi Dave and thanks for the input. Sorry - I shouldn't have been lazy and should have included an illustration in the first post! Well, better late than never: Hope that clears things up. With regard your point - I understand the same to be true at LFs. As you say, the sound has more material to pass through (forward and backward) which increases LF absorption. However, I don't think it is the case at all frequencies. As I understand things, the higher incident angle makes the panel more reflective and therefore less effective the higher the frequency. It's in the same way a stone is more "skim-able" on water the greater the angle at which you throw it. Whealy's Porous Absorber Calculator would suggest the same: Any further thoughts (or examples of people angling their side reflectors) would be great. Cheers Max

some additional angles - noting this doesn't take into account the average wider air gap plus the incidence from behind where the corner resonances pass out from behind where the absorption (based solely on the calculator) jump even higher. same for your clouds overhead.

Hi Glenn Many thanks for the repsonse. I must admit though, I don't quite follow what you are saying...... Would you mind - if you have the time - elaborating a little? I'm also confused by the use of -60 and -75 degrees in the PAC., as well as the angles you've listed in the picture. As I understand things, the panel marked 75 degrees in the picture would actually be at an angle more like 130-140, whilst the one marked 60 degrees would be around 170 degrees. That's because I thought the angle should be measured in relation to the actual sound emitting from the speaker (in a straight line, although obviously this is not how it really behaves - just for the purposes of measurement and discussion). So, what are the thoughts on this? Cheers Max

the calculator doesn't work over 100° so the -75 and -60 are really 135 and 150 relative to your alignments (and really the + or - is ignored by the calculator).