[music-dsp] underwater sound

James Chandler Jr jchandjr at bellsouth.net
Tue Jun 15 12:30:41 EDT 2004


----- Original Message ----- 
From: "Dave Gamble" <signalzerodb at yahoo.co.uk>
To: "a list for musical digital signal processing"
<music-dsp at ceait.calarts.edu>; "Martin Eisenberg" <martin.eisenberg at udo.edu>
Sent: Tuesday, June 15, 2004 12:17 PM
Subject: Re: [music-dsp] underwater sound


>
> On 15 Jun 2004, at 17:21, Martin Eisenberg wrote:
>
> > From: "Dave Gamble" <signalzerodb at yahoo.co.uk>
> >
> >> I like the idea of an electronics<->biology analogy; a capacitor
> >> (with resistor to ground) acts as a high pass filter, because
> >> there's no direct connection between the two sides of the
> >> capacitor.
> >> Likewise, unless the bones are directly connected to your
> >> skeleton (which they're not, iirc; they float), you have a
> >> capacitor made of bones (no idea about the resistor to ground!),
> >> which means you'll get a high pass effect.
> >
> > Hmm. Why should bones act as series capacitors? Though it does evoke
> > some nice, bizarre imagery. Do you love Giger? ;)
>
> My theory was that if stuff transmits through the bones ok, then
> they're like the wires;
> a break in the wire [i.e. a gap between two bones] is therefore like a
> capacitor!
> More sensibly, if the bone is vibrating into some material with a fixed
> compressibility,
> then it's almost 'charging' the material like a capacitor....

Interesting factoid-- the Etymotics 'musicians hifi earplug' hearing protectors,
use the equivalent of an acoustic capacitor to linearize the frequency response.

A solid rubber earplug drastically cuts high-freq response, making the plug
practically unusable for music. Not only can't you hear proper tone balance, but
for some reason solid plugs (at least for me) cause disorientation and a 'spaced
out' feeling, not good onstage.

The Etymotics hifi plugs have a tube-channel, with a little plastic gizmo
plugged in. The gizmo contains a tiny stiff diaphram, which acts like an
acoustic capacitor to allow a proper hi-freq balance to get thru. They work
great!

JCJR





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