Damping to exitation of parasitic modes of

Hey Geoff,

A good friend is encouraging me to try Mad Scientist Black Discus. Looks like a unappetizing Reese Cup to me. Have at it if you will.

The DIY power purifier on their website looks interesting...

Dave

Ok, If you can tell me these things dont have a half-life of 3 months I'll probably bite. So whatever this is works in conjunction with a variable density medium, is very small, and passive, hmm. Battery operated? Very small field generator? So Shun Mook 'IS" from the 9th dimension which evolves through the center "Torus" per string theory! Ok where do I pick mine up? Or do they simply appear, but only for us whom are enlightened? Is there a currency exchange involved? I still believe in the barter system. Here, hold this duck whist I..........
                 But seriously folks, Can I buy used? Scratch and dent clearance?

I Have never heard anything negative about Shun Mook, so there "should" be something to it. At least I hope so if he's getting my ducky!

As Acoustic engineer my advice is first to determine what frequency range you want to dampen (for example 20Hz -100Hz) and then find a material that is suitable. I know that sounds trivial but most people just start throwing names before even analyzing the problem. To find the suitable material I would check the transmissibility curves of different materials. A transmissibility graph is basically an input/output graph; everything above "1" means that you get amplification and below "1" means damping. Obviously you don’t want any resonance peaks in the region that you want to improve, otherwise you can end up making things worse. By comparing the graphs of different materials you can select the one that provides the most damping in the frequency region of interest. Those transmissibility measurements are really basic and any serious company should be able to provide you with those graphs. If they don’t I would question their seriousness.

I kind of doubt any manufacturer provides transmissibility curves for either damping materials or for components. Vibration Isolation manufacturers sometimes provide transmissibility curves, but only for structureborne vibration, including vibration below 20 Hz, which is significant because below 20 Hz is not only below the standard audio band of 20 Hz to 20 kHz but also because the spectrum below 20 Hz is very detrimental to the sound and by and large not addressable by damping techniques per se. Finally transmissibility curves probably do not apply to induced vibration such as that produced by Transformers, capacitors, motors, CD transports, etc.