TromboneChat

If I take my trombone to a local park, and play some long tones, the echo that comes back (from the hills & trees) sounds a few cents higher than what I played. What's going on?

AtomicClock wrote: ↑Sat Oct 19, 2024 9:13 pm If I take my trombone to a local park, and play some long tones, the echo that comes back (from the hills & trees) sounds a few cents higher than what I played. What's going on?

The pitch is most likely being affected by the wind. The coriolis force also produces a weak Doppler effect.

It can also be hard to hear your own pitch via feedback outside. You may just be playing that high but it doesn't sound like it behind the bell.

Also, not every part of your sound will reverberate back to you at the same volume, i.e. The environment is filtering frequencies. Two examples of things that might be happening here. 1) the higher overtones of your sound are being reverberated more/filtered out less than the low ones in that environment, which can give a perception of a slightly higher pitch. 2) the attack phase of your sound, where the pitch is not yet clearly defined and contains a ton more higher frequencies than the sustain phase, is being reverberated and heard more (and longer) than you normally would hear it, bleeding into the reverberated sustain phase, and combining with the previous point to make the echo higher than what you played.

There's a church I've often rehearsed and performed in that has the opposite problem. An extremely long and sustained reverb, but that comes back just slightly lower because more of the low frequencies are being reverberated. When the music is slow and sustained enough that the ear stops tuning out the reverb as just reverb, we'll hear ourselves being out of tune with the reverb coming back to us.

AtomicClock wrote: ↑Sat Oct 19, 2024 9:13 pm If I take my trombone to a local park, and play some long tones, the echo that comes back (from the hills & trees) sounds a few cents higher than what I played. What's going on?

Don't assume that sound heading out from your bell to a reflective surface takes the same path back to your ears.

Also your perception of your own pitch (and sound) is not always the same as what's coming out of the bell.

I've been through that in recording studios. Listening back I have sometimes been sharp and other times flat, when I thought I was playing in tune.

The same could happen with an echo.

LeTromboniste wrote: ↑Sun Oct 20, 2024 10:13 am Also, not every part of your sound will reverberate back to you at the same volume, i.e. The environment is filtering frequencies. Two examples of things that might be happening here. 1) the higher overtones of your sound are being reverberated more/filtered out less than the low ones in that environment, which can give a perception of a slightly higher pitch. 2) the attack phase of your sound, where the pitch is not yet clearly defined and contains a ton more higher frequencies than the sustain phase, is being reverberated and heard more (and longer) than you normally would hear it, bleeding into the reverberated sustain phase, and combining with the previous point to make the echo higher than what you played.

There's a church I've often rehearsed and performed in that has the opposite problem. An extremely long and sustained reverb, but that comes back just slightly lower because more of the low frequencies are being reverberated. When the music is slow and sustained enough that the ear stops tuning out the reverb as just reverb, we'll hear ourselves being out of tune with the reverb coming back to us.

This is really interesting!!!
It must depend on the environment/acoustic space.
Over distances though, the higher frequencies are transmitted across smaller area than the lower. But maybe it's not a general rule, plus other already mentioned factors coming into play...


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And the apparent pitch shift, just guessing now — could be a quirk of reflection/reverberation, and/or effect of blending with other/ambient noises...
Or it could be purely psychoacoustic (whatever that means). Or some kind of aural illusion, or sonic illusion: do these even exist?
Also there is the possible discrepancy between the thing as thought and that same thing perceived. "Seeing is believing" only literally: seeing IS believing (hearing, not seeing, obviously), or "i'll believe it when i see it" but in reverse, if that makes any sense. Or, to use a well-known quote: "I've heard a thing or two because i know a thing or two". Or that experiment where majority of participants start to say a black object is white https://en.wikipedia.org/wiki/Asch_conf ... xperiments
In the echo example the mind may just be taking precedence over the ear. And who knows what's on IT'S mind. : )
ok i think my own mind just broke. I'll correct this tomorro