In article , The Old
Fogey wrote:
Can anyone define 'Slam' in the context of audio power amps?

First, some other people's "definitions" in the general sense (I will
come to the amplifier context) from the only two audio glossaries I can
find online and some related material.

* A Stereophile magazine glossary defines slam as "British for impact."
(July 1993)

* The GoodSound! Glossary: "Slam: An audio reviewers description of
a systems ability to portray bass notes with visceral impact and
weight."

* B&W: "bass attack."

The general context for most uses of "slam" is of visceral impact (in
the listener) created by an audio system. As such I guess the sensation
to be caused by pressure waves with a large change in pressure across
a small distance. So I assume it is generated by a system's ability
to accelerate air. That is, in response to a transient input of large
amplitude the loudspeaker cones must respond rapidly to create the
pressure wave.

The loudspeaker will have a large role in this (e.g. low cone mass will
probably help). As for cables, B&W say "Too much cable impedance and
you begin to lose bass attack or "slam"."

As for the amplifier I assume its role in "slam" is to cause the bass
driver cones to accelerate rapidly in response to a good transient input
of large magnitude. I do not know how to express this. Especialy as
the article which I thought did got an unexplained "**Nope" in response
which I don't understand as I thought that article was spot on in the
amplifier context.

"Slam" is an effect I have never actually felt in the concert hall even
with big bass percussion so it may only be an artificial effect which
occurs in "small" listening rooms. It happens in mine on all kinds
of music. Perhaps it is an effect which gets created at large rock
concerts but I only listen to rock at home.

It is certainly used as reviewer jargon and as a marketing term. The
differences of opinion here belie statements to the effect that it is
a well understood term.

--
John Phillips