Why all-channels-driven ratings matter

Why published numbers differ

An amplifier may be tested with one channel at 1 kHz, two channels across the audio band, or every channel using a continuous signal. Distortion threshold, duration, load impedance and mains voltage may also change. All can be legitimate specifications, but they cannot be compared as if they were identical.

Shared resources inside the chassis

Multichannel amplifiers often share a transformer or switch-mode supply, capacitors, cooling path and mains inlet. When many channels demand sustained power, supply voltage or thermal limits can reduce output relative to the one-channel result.

That does not automatically make the design unsuitable. Real film sound rarely drives every channel with the same continuous sine wave, and efficient allocation can reduce cost, size and idle consumption.

Continuous versus burst output

All-channels continuous data shows worst-case sustained capability under stated conditions. Burst or dynamic data shows how the amplifier handles brief peaks using supply reserve. Cinema needs both perspectives: dialogue and music create sustained demand while effects create high crest-factor transients.

Use the channel map

Estimate which channels are likely to work hardest. Dedicated LCR amplification can reduce demand on a shared surround/height chassis. Compare realistic programme capability, impedance, protection and cooling rather than insisting on one laboratory test as the only truth.