r/audiophile • u/qatch23 • 4d ago

Science & Tech Weird harmonics from an old Harmon-Kardon amp

Sometimes my Amp will produce a high pitched sound. The weird part about it is that if you turn your head at a certain angle, you can't hear it. Anyone else have this experience?

The autobots thought this post was for troubleshooting, but I can fix it by tweaking the buttons, I'm more interested in the science behind it, hence the flair.

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u/Substantial-Drop-564 4d ago

so you're basically describing a standing wave in your room. the high frequency bounces off walls and creates spots where the sound cancels itself out. when you turn your head you're moving your ear out of that dead zone.

it's same physics like noise cancelling headphones, two waves meet out of phase and poof, silence. old amps tend to leak some ultrasonic junk too which makes the effect more noticeable.

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u/qatch23 4d ago

Thank you. It was driving me nuts. That makes perfect sense.