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"Mark Zarella" pam wrote:

What differences do you expect to see? Power compression, of course, will
be different between the two cases simply due to the increase in power of
the clipped wave. The high-frequency content of the clipped signal could
be causing breakup. I'm not entirely sure there's a mystery here. Assuming
the loudspeaker is operating linearly, and that the mere difference in
excursion isn't generating a significant increase in distortion content
(possibly not a safe assumption), what other effects would you expect?

Well the operating conventional wisdom is that nominally competent power
amplifiers working in their linear range will sound the same. I agree. But when
the ampliifers sound "different" I don't mean the differences they suffer from
when they are operating in a linear fashion; bt how do they sound different
from each other.

If amplifiers have the same flaws when driven into overload then they will
still sound the same as each other. I'm just looking for a more specific look
at 'audibility'; what is it?, how is it caused?, what does it sound like? And,
most importantly how does of this vary amp-to-amp?

I realize that if you adequate power for the load at hand this is not an issue.
But that's not too helpful to those with limited resources or a given set of
currently owned equipment.

How does one "know" whether he needs a bigger amplifier or perhaps a better
speaker? The smell of melting voice coil glue tells you something is wrong; but
was that running your amplifier full out for a long time and building up hear
OR is your amplifier just too large for the speaker?

Many popular music recordings are so radically compressed that power
compression and mild minor amp clipping may be hard to detect by ear; so how
does the end-user figure out what to listen for?

How do amplifiers driven into overload actually "sound". A crunching protection
circuit may be obvious; but much of the character of overload, electronically
or electro-mechanically is NOT well known or we wouldn't be having these
discussions and wouldn't burn out speakers (except on purpose.)

I'll start first; a common distortion element on subwoofers is "suspension
distortion" where when the suspension is being pulled tight mid-upper bass
hardens into a "pock-pock". "motor suspension" (where the motor runs of of
travel or has uneven BL) manifests itself as a modulation of mid and upper
range sounds (burbling voice or gargling trumpets). What Klippel calls
inductive distortion sounds much the same as motor distortion. The latter two
types are typically handled with a low pass filter.

So how does a current amplifer driven into 6,10 and 20 dB of clipping sound
different from when it's operating in it's linear range and how might it sound
different from a competing model?

"Nousaine" wrote in message
...

wrote:

nousaine write; You know it's funny buut I don't know anyone who has
actively investigated
even
this situation. What I mean it seem to me that the most common "sound"
of
amplifiers driven into overload may not be the "clipping" but the
action
of
overload protection circuitry or the behavior of loudspeakers driven
into
excess distortion.

That may be the case, Tom. But the whole point of the thread was not
really
what causes the sound differences, because we all hear them, just that
when
operating linearly thay all sound the same.

Paul Vina

Sure but I'm wondering who has actually investigated cause, effect and
exactly
what it is that "sounds" different a little more precisely.

I always 'turn it down' when I hear some kind of distortion that seems
related
to overload such as woofer bottoming, tinsel lead snap the odor of voice
coil
glue softening up and the like.

But some types of distortion have specific characteristics such as the
kind
that Klipple calls "suspension" distortion which is a hardening of upper
bass
which can be isolated and related to cause (suspension pulling tight, in
that
case.)

As far as I know no one has specifically investigated this with amplifiers
and
assigned specific types and causal mechanisms. I'm think that some of the
"sound" assigned to amplifiers may actually be related to loudspeaker
distortion, electronic overload protection mechansims and such which make
not
be simple clipping of the signal.

The reason I bring this up now is that a few years ago Floyd Toole told me
of
an experiment conducted at the Canadian NRC where they tapped a clipped
signal
off the speaker terminals being driven a shard as the amplifier could go
and
then played that back in an acoustically separated room on a different
system
so they could "hear" the clipping more sensitively. His comment was the
6-dB of
clipping didn't sound "all that bad".

Si I'm just wondering who else may have examined the phenomenon more
specifically and whether they had useful information to add.