Good looking diffusers! =)
Originally Posted by G. E.
To further enhance the diffusion-qualities (probably for sound-waves coming from a bigger angle as is the case in a ceiling application) at least in one direction I may put thin panels of acrylic glas in between the rows of wells as shown in the 3D-modell. This is different from other designs that use either no panels at all or panels in both directions. Comments?
Hmm.. That's an interesting idea! Don't really know this stuff, but it does seem intuitively wrong to my limited understanding. The single directional well dividers seems like they would transform it into a 1D diffuser..?
Especially when thinking about it with Huygens principle
in mind. Normally, each well (or the inverse, as in the usual case with well-less 2D diffusers, protrusions) acts as a wave source that radiates into the room. The superposition of all the small wave sources in the array creates the desired diffuse sound field at a distance from the array. With the glass wells in there, the waves would bounce back and forth between the glass walls instead of propagating into space, doing weird things to the intended scattering and recombination of waves.
It seems the bigger wells will be the new wave source that emits into the room. With the effective depth of each of the wells between the glass plates being a complex sum of the various smaller depths within the bigger wells. If your design is random (with a flat spectra frequency transform) across all direction, each complex-sum-well will also be random in respect to each other. If I'm not totally mistaken about those devices, the end result should still be wide area scattering, but not as spatially uniform as a full 2D grid would give. It also seems that the scattering will be better without a grid..?
Lastly, if the sides/ends of the glass plate wells are left open, as shown in your drawing, impedance in the bigger well will probably also be quite strongly affected by the size of the wooden pieces at the ends. The variations in size there will probably skew the impedance response of each well, changing the frequency and spatial response of the array. Enclosing the ends would probably give more uniform response if you go for the dividers.
My brain doesn't like raytracing.. Have a bit of a hard time imagining what the response would actually be from your array. Have read Cox and D'Antonio "diffuser bible" but haven't done the hard math or built any of these devices. It may very well be that I'm all wrong about this! Would love to learn more about this subject. Looking forward to responses!