Our system’s power amplifier is almost always bigger than needed. Or is it?
We know that headroom, the reserve amplifier power we hope not to use, is important. But how much is enough? Do we have to acquire a scope and meter and dust off our engineering degrees to measure the peak power our system demands? I think there might be an easier way.
With the understanding it’s not hard amplifier clipping we’re talking about I think we can safely make a few observations about the amount of headroom we have by simply listening.
The need for headroom has to do with perceived compression of music’s dynamics. The more headroom the lower the compression we experience.
For listening evaluations of peak power, I prefer orchestral music for several reasons: its acoustic instruments and fixed proportions. We know what those instruments should sound like and we can imagine the proportions of an orchestra easier than we can a rock band or jazz ensemble.
What we’re hoping for is a lack of compression when the entire orchestra’s playing loudly. It’s rare, but with enough headroom and the right speakers, an orchestra’s loudest crescendos should scale in image size and tonal qualities to it’s quietest levels. Anyone that’s ever heard our Infinity IRSV system knows exactly what I am referring to. Scale without compression.
Most speakers don’t scale all that well so separating out the headroom issue of the amplifier chain vs. the speakers can be problematic, but easier than trying different loudspeaker combinations. A friend’s higher power amplifier is a relatively easy swap to see where your system stands on dynamic compression.
Amplifier power is almost never enough when we consider headroom in the hopes of reducing compression.