Playing the modular through my home stereo

harrybissell at prodigy.net harrybissell at prodigy.net
Thu Mar 2 16:00:05 CET 2000


Not too traumatic unless the speaker is driven outside of the normal excursion range...
The major failure modes for cone speakers are

1) Mechanical limit of cone travel reached. This "hammers" over the bottom of the voice coil form, then it rubs. Pushing the cone gently with the hand will let you feel this type of damage.

2)Electrical overload... usually due to excess heating of the voice coil... which either expands and causes rubbing (damage 1), or melts the glue, or worst case frys the copper (or aluminum) voice coil.

If you are outside of these limits you are probably OK.
Speaker Manufacturers solve these by allowing lots of overtravel in the voice coil magnetic gap... using aluminum voice coil formers that can dissipate heat, using ferrofluids for heat transfer and lubrication,
big "fins" on the magnet structures, and even (no sh!t)
using Teflon coating on the voice coil so that if it does rub during an overload the damage is minimized.

Note that almost all "home" speakers do not use ANY of these protection methods. They expect the usual FM maybe 50db dynamic range... the 1812 overture cannons on CD will blow them every time !!!

H^) harry


 ---- On Mar  1 JWBarlow at aol.com wrote: 
> 
> In a message dated 3/1/2000 3:47:11 PM, pfperry at melbpc.org.au writes:
> 
> >Only time I blew the speakers out, I was using a r*land
> >D*gital soundcanvas card & running a midi file shifted
> >down 4 octaves.
> >This gave very low freq square waves.. I couldn't hear 
> >anything except this 'clicking' sound.. thought the gain was
> >too low.. turned out what I was hearing was the cones bottoming
> >out on squarewaves at 5 Hz or so.
> 
> What I've wondered about for a long time is the effect of instantaneous 
> transitions on speakers (even in the audio range). It seems hard enough to 
> get electrons to move like saw and square waves, let alone speaker cones. 
> Anyone know how traumatic this is for speakers?
> 
> John Barlow






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