Amplifier headroom matters
Fact or fiction: an amplifier with 10 times more power than the speaker needs sounds better than one more closely matched?
The short answer is often yes, but it's worth looking into the why of this statement.
First, let's get some facts sorted out. Most listeners have no clue how much power their speakers are actually consuming. And this is true even for those that on occasion have had their amplifier shut down. Relying on the speaker manufacturer's estimate of power handling is pretty much useless information. The fact that a speaker can handle 300 watts doesn't mean it's ever going to see that much power.
In fact, most amplifier power spent driving speakers under musical conditions is typically below 50 watts, with an average of around half that. Where peak power gets big is on low frequencies and large transients. Which is why equipment manufacturers once attempted to rate amplifiers with Musical Power rather than their RMS power. (This happened at a time when we were obsessed with big watts).
When music demands power the last thing you want is to run out, or even get close to the system's limitations. On those peaks and crescendos, we hope for unfettered performance whose sonic qualities match those of softer passages. Unfortunately, this is a rare achievement because of too little headroom.
Headroom is the secret sauce for reproducing effortless music. Headroom maintains an amplifier (or speaker's) linear performance region—an area we hope to keep sacred. Once we exceed an instrument's linear region, its sweet spot, sound changes and not for the better. The closer we get to a device's limits the less free and open the music will sound.
Here's a good way to calculate this. Most amplifiers and speakers are comfortable at about 20% of their rated output. Exceed that and you venture into areas of strain, struggle, and compression.
Headroom matters when music matters.
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