"Pooh Bear" wrote in message
...
A low damping factor means that an amplifier cannot adequately control
speaker
resonances or the back emf caused by transients.

From the aspect of resonances - a 'poor' i.e. low damping factor will tend
to
result in a possibly initially flattering bass rise around speaker
resonance
with typical ported enclosures. This is well documented. The resulting
bass is
also poorly controlled though leading to 'farty bass'.

The inability of an amplifier to control the back emf from the motor coil
will
also result in signal degradation.

Note that the resistance of the cabling between amp and speaker affects
damping
factor too. That's one reason why damping factor *in isolation* is
misleading
perhaps. The resistance of the speaker cable appears in series with the
amplifier output impedance. This is why speaker wiring should be of the
largest
practical gauge in order to reduce its resistance.

Having said that..... it was IME rare for tube amps to have better damping
factor than say ~ 15-20. Translating to an output impedance of maybe a few
hundred milliohms to an ohm. Likely the cable resistance made little
difference.

Modern SS amps can have output impedances easily as low as in the tens of
milliohm region. This makes cable resistance much more critical in
comparing one
with another ( along with bi-wiring etc... ).

Graham

Yes. That's as I understand it.
The valve amp designer who interests me the most, Arthur Radford,
produced during the 1960s a 100W amp for studio use with a DF of 60.
He did state however that above a figure or 15 or so, the increase in
DF had negligible effect. I have also seen this stated by Norman Cowhurst
and by Howard Tremaine in his broadcast industry training manual from
the 1970s, the Audio Cyclopedia.

Iain