A recording captures the precise back-and-forth motion of air at the microphone.
The loudspeaker should precisely reproduce that back-and-forth motion. But what happens if you reverse the plus and minus of the cables? The wave physically pushes when it should pull.
Can you hear the difference?
I want to draw a clear line here between two things that get conflated all the time in our HiFi Family conversations. The first is relative polarity, which is simply whether your two speakers are wired in phase with each other. The second is absolute polarity, which is whether the signal reaching the speakers matches the polarity of the original waveform captured by the microphone. These two get treated as one issue and they are completely different. One is a setup mistake.
The other is a debate that's been going on for decades.
Relative polarity is the easy one. Wire one speaker backward and the result is immediately and dramatically wrong. The center image collapses, bass cancels because the two drivers are working against each other, and the entire soundstage becomes unstable and small. Every careful listener I know catches this within seconds, and it's one of the simplest things to verify when setting up a new system.
Absolute polarity is the controversial one. With both speakers wired identically — but identically inverted relative to the original recording — the soundstage remains intact, the bass behaves normally, and to most listeners on most material the difference is small or imperceptible. On some recordings, particularly direct-to-disc or simply-mic'd acoustic music, careful listeners reliably claim to hear a difference.
Real or imagined?
The complication is that nearly every recording passes through multiple amplification stages during production, each of which may invert the signal, and the resulting absolute polarity at the listener's speaker is genuinely unknown for most catalog material. So, suggesting the ultimate measure of truth is found at the speaker terminals...
All that logical gobblydeygook aside, I have known more than a few critical listeners who can accurately spot the difference between in and out on many a recording.
Golden eared, indeed.
0 comments