In article , Jo
wrote:
In , harrogate2
typed:

It is nothing to do with the speaker load impedence, rather the amp
output impedence.

When the loudspeaker cone is extended by signal, if the signal is
removed then it is down to the mechanics of the cone mount to return
it to its rest position - except that it won't, it will follow a
decaying oscillation path. During this time, as the voicecoil is now
being moved mechanically in a magnetic field it becomes a generator,
so the lower the load that it sees - in this case the output impedence
of the amp plus cable resistance - the quicker the energy will be
dissipated. As an amp output impedence is typically around 0.1R (or
less sometimes) then the resistance of a thinner cable can become
significant, hence why thick is better.


I don't see that. In addition to the output stage of amp and cable the
same current is *also* flowing through the speaker coil itself, they
are all in series. Therefore it is in the speaker coil where most of
the energy is dissipated, assuming that the output impedance of the amp
is, indeed, low.

That is correct. The problem with 'cable impedances' for speakers isn't
really due to need for 'damping' the mechanical resonance of the driver,
for the reason you explain. The electrical losses tend to be dominated by
the actual speaker resistance.

The problem is that most loudspeakers have an impedance that varies with
frequency. The amp+cable impedances then act with the speaker impedance to
make a frequency-dependent attenuator, and may alter the frequency response
- usually by a slight amount.

Slainte,

Jim

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