On 7/23/2013 1:05 AM, chrisatupw@....... wrote:
> From: Tiago A. 
> To: psnlist 
> Sent: Mon, 22 Jul 2013 2:13
> Subject: Subwoofer to reproduce sine waves at low frequencies?
>
> Hi.
> After searching a bit about subwoofers at low frequencies, i put the
> cheapest subwoofer i have (90mm) near (2/3mm) from a L15B 4.5Hz
> horizontal geophone. Using a sine wave tone, it recorded very well at
> 10Hz, <10Hz was a bit tricky but managed to get good results.
> Then i tried at 10s, at first i was only getting a very weak noise at
> 5s from the subwoofer
>
> Hi Tiago,
>
>      The sensitivity of a geophone falls off as f^2 below the resonant
> frequency, so the output at 0.2 Hz will be (4.5/0.2)^2 down on that
> above 4.5 Hz = 506 ! At 10 seconds, it will be over 2,000 down.....
>
>      Regards,
>
>      Chris Chapman
>
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>

If you were to suspend a mass on a spring then
glue some kind of solid connection between the mass
and speaker cone, would that then make the
speaker more responsive at low frequencies ?

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Entropy is the seeking of equilibrium.
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