Been playing around with aluminum ribbons (9 microns) for some time and was struck by how awfull they sound played full range. Sizzle at the top and raspy down low (below 1000hz). Tinkered and tinkered with all manner of damping metheds and then hit upon something that seemed to work perfectly...
Stretched out some very sheer pantyhose sprayed a little 3M Super 77 (I mean a little) on it, applied my ribbon to that, detensioned the hose, and BAM!!! Beautiful sound. Alison Krauss' voice brought tears, as it should have.
You heard it here first!!!!
Stretched out some very sheer pantyhose sprayed a little 3M Super 77 (I mean a little) on it, applied my ribbon to that, detensioned the hose, and BAM!!! Beautiful sound. Alison Krauss' voice brought tears, as it should have.
You heard it here first!!!!
I first tried corragated ribbon onto the stretched hose, but there was still some extraneous noise. So I then tried it flat. That's when the magic occured. The advantage of very sheer pantyhose is that it is so light and the amount of glue needed to attach it is so small. Since the glue is sprayed on, what doesn't adhere to the very fine fibers passes on through the openings in the weave. The amount of added mass is so small that I noticed NO reduction in output.
No rattling or buzzing down low (even at 50hz) and the top is smooth as silk.
No rattling or buzzing down low (even at 50hz) and the top is smooth as silk.
Cheap Walmart stuff is all I've tried so far (I'm back in the US). It's extremely sheer. You don't want anything "supportive". Anything heavier would likely hurt efficiency and I suspect something even more sheer would damp resonances just as well without excess mass.
Got me thinking about spider webs now!
Got me thinking about spider webs now!
My magnet design allows my ribbon to move > +/- 5mm without a change in flux density. So my goal was to elimate a separate midrange driver. It's clean as a whistle with no drop-off at 200-300 hz so that goal has been met. I'll just cross-over there to a woofer.
Well, I also I glued the corrugated ribbon edgewise on both sides to stretched hose, such that the ribbon was 'normal' to the hose. That worked very well, but there was still some extraneous high frequency stuff. I haven't given up on that concept.
But what gave startling results was when I just flattened the ribbon out and fixed it flat against the stretched hose, like bologne on a piece of bread. Just a little spritz of Super 77.
But what gave startling results was when I just flattened the ribbon out and fixed it flat against the stretched hose, like bologne on a piece of bread. Just a little spritz of Super 77.
I tend to agree. The small amount of glue evenly distributed helps good bit, I'm sure. But the pantyhose has damping properties as well, because of friction where the fibers interconnect. Any movement within the weave, caused by extraneous vibrations within the ribbon, results in energy being scrubbed off.
As for the primary resonance of the ribbon; that just depends on the tension I put on it. When I pull it tight, frequency rolls off below 1khz. With no tension (i.e., no centering force), the resonant frequency is probably close to 0 hz. Afterall, a spring/mass system with a super weak spring gives a super low resonance. With no tension, I can hear rather deep base.
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