You know that grey/black foam that is mostly used for lining tool mallets or computer cases?
I happened to get my hands on two 4" x 8" x 11" blocks of the stuff for free.
Being easily distracted and my current speaker project not going too well, I got sidetracked into cutting cavities into those blocks to insert small 4" JVC fullrange drivers and hotglued cheap pressure terminals on the back. I made the cavities just big enough to accomodate the basket/magnet assembly.
I had tried those drivers in pretty big (24" x 40") OB's before and although they had nice midrange and highs, there was of course no bass. In the foam blocks, things all sound much better. The bass is nowhere near strong mind you, but usable down to ~100Hz subjectively w/o any measurement (driver Fs = 115Hz) which is much better than in the OB's.
I have them on top of my floorstanders ~2' from side and back walls. With the speakers facing me, I get a very forward sound. If I aim them at the corners with their backs facing me, it's more diffused, I lose imaging some but the room-filling effect is nice and highs don't sound "lost" or muffled. Adding a small subwoofer would make that a nice system on it's own and I would not shame having them as rears in a HT setup either.
I think what I'm getting here is some kind of aperiodic damping with the foam block and a dipole-esque response although with lesser nulls at the sides and bigger lobe at the front.
I'll try to take some measurements for fun if I have time.
How would you describe what I built there in terms of acoustic loading and polar response?
Thanks!
IG
I happened to get my hands on two 4" x 8" x 11" blocks of the stuff for free.
Being easily distracted and my current speaker project not going too well, I got sidetracked into cutting cavities into those blocks to insert small 4" JVC fullrange drivers and hotglued cheap pressure terminals on the back. I made the cavities just big enough to accomodate the basket/magnet assembly.
I had tried those drivers in pretty big (24" x 40") OB's before and although they had nice midrange and highs, there was of course no bass. In the foam blocks, things all sound much better. The bass is nowhere near strong mind you, but usable down to ~100Hz subjectively w/o any measurement (driver Fs = 115Hz) which is much better than in the OB's.
I have them on top of my floorstanders ~2' from side and back walls. With the speakers facing me, I get a very forward sound. If I aim them at the corners with their backs facing me, it's more diffused, I lose imaging some but the room-filling effect is nice and highs don't sound "lost" or muffled. Adding a small subwoofer would make that a nice system on it's own and I would not shame having them as rears in a HT setup either.
I think what I'm getting here is some kind of aperiodic damping with the foam block and a dipole-esque response although with lesser nulls at the sides and bigger lobe at the front.
I'll try to take some measurements for fun if I have time.
How would you describe what I built there in terms of acoustic loading and polar response?
Thanks!
IG