Hello everyone, I just made this diffusor using wood 40x40mm.
measurements of colums are:
I' am planing to make ~10 of those ant put them on the wall, behind drums in my rehersal/recording studio. I would realy like some advice, am I making a horrible mistake, or it would be ok?
Thank you all in advance!
I agree, and I will recommend polycylindrical diffusers instead of phase grating type for recording, IF there is a enough space for them to work... if not....then, no diffusers at all is the best.
I guess we agree on the basics, but possibly disagree on the details. I would personally avoid polys due to the minimal temporal scattering they offer unless a large number (and of different size) are in use, but maybe that’s what you mean. The room in the pics does however look way too small for this though.
I would personally consider diffusers ("real" diffusers ...) as long as the ISD (or ITD) is larger than about 12 ms or so (in a recording room, a tad longer if control room) but possibly also add a way to alter the acoustics (heavy drape or other way of changing the acoustics).
Probably not worse, but not as good as absorption, esp. thick absorption. There are a few reasons for this. One is that we have to be a certain distance away from a diffusor for it to work optimally, and the drums are quite close to those walls. Second is that a diffusor like what you built works only at a relatively narrow frequency range compared to absorption (especially thick absorption).
Room is used mainly for rehersals. Will diffusers make drums sound worse?
Phase grating diffusers directly audible effect is great for drummers and drums playing/practicing.
The phase grating diffusers influence of recorded sound doesn't justify investments for them.
If someone doesn't have a large room for drums, phase grating diffusers won't make it acoustically larger for sound recorded in it, because it is mostly a directly audible effect (increasing virtual/acoustical size) for people's ears.
EDIT: E.g. Strong diffusive reflections can cheat our brain, but not the microphone... in short.
Drum sounds are blasts of surprisingly full range noise. The Kit can readily cover the full audible spectrum. Being noise, what sounds 'good' would be very hard to quantify either scientifically or aesthetically. Then there is the issue of what sounds (and feels) good to the drummer versus the mics.
Drums are typically miced closely, often within centimetres of source. I doubt very much that reflections from nearby surfaces be they specular or somewhat diffused will have any effect at all on the signal from the mic. I would add these mics are also directional, particularly at HF.
Drums are often placed close to walls or even in corners to achieve an LF tonal boost. In addition to this boost the kick drum and toms will feel quite different under the foot or stick, due to this "room load". Again, due to close micing, I don't think it matters whether these walls are treated or not. But some great drum rooms have used stone walls, a la Newell.
This probably sounds better to the drummer, before the cans go on. Probably sounds nice in the room, certainly prevents flutter.
Note, sheets of ply or such slightly angled to the walls around the drums creates a nice woody effect, while also preventing flutter echo.
Overhead mics are a special case. Despite being directional it is best that they are well away from walls and most importantly, the ceiling. A full absorbent ceiling/cloud is a great friend to the engineer recording drums.
There is a cheap to free lunch here. PZMs or even regular mics, particularly but not exclusively omni, can be mounted on the ceiling or walls behind or in front of the drummer. This eliminates those boundary reflections entirely, resulting in very clear imaging.