[time-nuts] 5060A question

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Jan 8 05:58:30 UTC 2008


Magnus Danielson wrote:
>> Hej Magnus
>>
>> Do you mean an active noise cancellation system??
>>     
>
> No, you could do that too, but I was basically refering to a simple box tuned
> in size to cancel at 2 kHz. Toss in a thick cloth for additional resistive
> damping.
>
> You could even go Helmholtz if you want.
>
> Simple passive cancelation. Classical acoustical approach. For 2 kHz it is in
> reasnoble sizes.
>
> Another thing is to put heavy lead-rubber on the metal faces to make them less
> of a resonator/radiator. That mod can be done inside the box.
>
> There are a whole bunch of other tricks. Pressing on the surfaces of the
> whining chamber will make it stiffer and provide a higher acoustical impedance.
> Pressing using rubber blocks, from say silicon rubber, is known to work.
>
> Cheers,
> Magnus
>
>   
Hej Magnus

Its a pity that the old  rho-c impedance matched high dissipation rubber
method only works under water.

Bruce






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