Nomenclature (411) Q&A

What do under-driven speakers sound like? edit

When an amplifier is too small, when it does not have enough power to drive the speakers it is attached to, what does it sound like?
1 Answer
Michael Davis, I work here
Unfortunately people label several rather different amplifier-speaker combinations as under-powered and speakers as under-driven.

In the most innocuous case people will call a speaker under-driven, and an amp under-powered, if the bass is not loud and forceful and punchy. Typically the kind of bass that is desired in these circumstances is bass that can only be generated by solid-state amps. The type of people who label these kinds of amps under-powered and the speaker under-driven are almost always people who prefer a sound that can only be generated by solid-state (transistor-based) gear. Others are of the opinion that bass generated by large solid-state amps is not like that generated by most musical instruments in the real world and that a little softer, rounder bass is natural and that these kinds of speaker / amp combinations are not under-driven at all.

Another situation often occurs with very hard to drive speakers driven by large amplifiers that are still not up to the job. Sound for these pairings is often slightly compressed, the major notes of the music petering out before the get to their full loudness that we would naturally expect to hear and the minor notes hardly showing up at all, especially when the major notes are still being generated - the amp just plain runs out of steam trying to keep up with the major notes. The sound then appears to have a lack of resolution (subtleties and micro-dynamics are near non-existent) and notes just decay off over-quickly, the amp not up to the task on controlling the speaker in such a very sensitive and delicate manner.

In the average case, the sound just does not have a lot of dynamics. It is dull sounding and you may want to keep turning it up louder and louder to try and get it to have more dynamics and be more exciting to listen to.

In the worst case, the harmonics will be off, the dynamics will be OK for some frequency ranges and awful for others, some frequencies will be much louder than others, and turning the volume up just makes it worse.

The opposite of an under-driven, under-powered sound is 'well controlled' sound.

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