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For background, I am not a musician, but I know a few things from physics. Physics tells us that we should perhaps expect that if your room changes, then you might need to tune your instruments differently - is this something that you can experience in real life? For instance, in a larger room, are notes more 'flat' than usual? (or the other way around perhaps?)

As another consideration, the characteristic wavelengths of some notes will be on the order of human scales (for instance, in usual conditions you can expect middle C to have a wavelength of around a meter and a half). In this situation, it seems that you might even have a phenomena where if people in the audience are all seated approximately this far apart from each other, you would hear a boost at this wavelength(?) Is this something that is ever observed? Do noise-cancelling materials pasted onto the walls largely mitigate both of these effects?

QCD_IS_GOOD
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    Perhaps you're considering the 'Doppler' effect. That does alter pitch, but only by virtue of fairly swift movement. That of course won't happen in any room. – Tim May 25 '21 at 06:10
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    Could you explain the physics principles that led you to these ideas? – ojs May 25 '21 at 08:01
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    Physics does not tell us these things. – Strawberry May 25 '21 at 10:51
  • In large concert halls and cathedrals sound might achieve harmonic resonance with the room. In this case the frequencies can reverberate sometimes making the noise or tones dramatically louder. As it relates to an orchestra or band, the conductor should direct players to play softer or louder to accommodate room acoustics. As it relates to a rock band, sound engineers should level instruments and equipment to conform to audio room physics. – Stereomac May 25 '21 at 15:08
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    Noise-canceling and sound dampening material have been used in performance arenas and studios for years. Auditorium designed specifically for sound have been engineered for many millennia. Sound dampening foam, panels, and curtains are used when designed room physics are incapable of controlling sound. – Stereomac May 25 '21 at 15:08

3 Answers3

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Room layouts don't affect the pitch of notes (unless the walls are moving).

There could theoretically be some strange beating effects if the room had a very narrow resonance near a note, or perhaps you are thinking about avoiding a room mode by tuning so that the room mode lands in between notes instead of on a note. In reality, room resonances are not that narrow and precise, so there is no practical reason to consider the room when tuning your instrument.

Edward
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    Room temperature on the other hand... I've played few cold, empty rehearsal venues only to have to reconsider my tuning when the warm audience shows up and heats the room. More to do with the temperature than the layout, though. – Pam May 25 '21 at 12:32
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    @Pam That's more to do with the instrument though isn't it? – Neil May 25 '21 at 13:46
  • @Neil Air temperature matters, irrespective of the instrument. Sound has a higher speed in cold air than in warm air, and the speed of sound directly influences the frequencies. – CamilB May 25 '21 at 13:58
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    @CamilB Depending on the instrument, the effects of temperature go in opposite directions. Wind instruments get sharper as the temperature rises, string instruments get flatter (the strings expand and loosen). – PiedPiper May 25 '21 at 14:50
  • @CamilB, that's interesting, I always thought the impact of temperature was mostly on the instrument dimensions. But I play flute and the temperature-induced change in dimensions (and therefore pitch) in a relatively small metal tube are probably (proportionately) one of the more variable. High pitched instruments probably suffer more. – Pam May 25 '21 at 14:52
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    Temperature may change the frequency of the sound produced by the instrument but it won't change sound frequency as it propagates in the room. Temperature (or temperature gradient) may change sound propagation direction, and thus range of the sound. It matters for setting up PA for outdoor concerts, but not for the sound frequency. – user1079505 May 25 '21 at 15:21
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    @Pam The impact of temperature on wind instruments is not so much on the dimensions of the instrument, but on the speed of sound inside the instrument. – Rob May 25 '21 at 15:21
  • @Pam - we all need to re-tune after temperature changes, but that's down to the instrument changing pitch, not the fact that the temperature of the room has varied, in itself. – Tim May 25 '21 at 16:21
  • @CamilB - interesting. Could you expand that into an answer? Although, I'm sceptical, as (OP's question) the size of a room has little bearing on the temperature. And - all instruments will be creating sound at the same time, so are you saying that the listener hears in a different key? – Tim May 25 '21 at 16:25
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    @CamilB That's not true. For a simple counterexample, consider a loudspeaker, which can produce a 440Hz tone accurately regardless of the temperature. This tone will still be 440Hz when it reaches the listener, whether you're in a 0 degree room, 100 degree room, or even underwater. The speed of sound doesn't actually affect the frequencies. – Edward May 25 '21 at 16:37
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    My understanding is this: if the material through which the sound propagates requires less energy to move (higher speed of sound), then the same instrument will produce different notes. I might be mistaking the direction though (warm / hot air vs high / low speed). Example: your voice sounds different when breathing in helium, which is far lighter than normal air, but your vocal tract is the same. – CamilB May 26 '21 at 07:23
  • I've asked the question: https://music.stackexchange.com/questions/114738/how-does-temperature-affect-tuning because I honestly thought I knew the answer to this but it turns out I didn't. – Pam May 26 '21 at 08:40
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Sound waves reflect from walls; they may form resonances or standing waves, which is perceived by certain notes being louder than others. This is a very important factor in design of rooms meant for listening music (in particular recording and mixing rooms in a studio). Large resonances should be avoided, and frequencies of the resonances should be uniformly distributed. This is achieved by choosing room geometry as well as placing acoustic treatment devices such as diffusion panels or bass traps.

In larger rooms, like concert halls, standing waves are less of a problem, while the concern is making sure the sound from the stage is delivered uniformly to the audience, and the reverberation amount is appropriate. Concert halls often feature fanciful shapes and structures on the walls and the ceiling; they are exactly for this purpose.

user1079505
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Different frequencies are affected by room dimensions and content. Rows of seats (especially if hardback) then each row reflects a different frequency. People and clothing an curtains and upholstery can absorb a lot of sound energy. However, as instruments (like pianos, accordions, etc.) are difficult to retune for various venues, the rooms are generally set up to work well. Some venues are "live" and sound bounces back loudly and others are "dead" and you cannot hear the music from the other side of the room.

https://physicsworld.com/a/acoustics-in-architecture/

ttw
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    Different frequencies are affected differently yes, but only attenuated or boosted differently. There is no frequency change so even when it is easy why would you need to retune ? – Tom May 25 '21 at 05:38
  • If you retune, you will be playing different frequencies. The only things I have noticed that works nicely are slight tempo changes, – ttw May 25 '21 at 06:35
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    I don't understand your last comment. Do you think there would be a percentage correlation between say, tuning up and playing faster? Sounds bizarre to me. – Tim May 25 '21 at 10:18
  • If one plays an A at 440, reflection will occur at some multiple of the wavelength of the 440 sound. An A at 435 will reflect at slightly different spots leading to a different sounding reverb. I have heard this (in a bowling alley that was converted to a dance hall) in that there were "muddy" spots in the hall where the music sounded blurry. These spots moved a bit (a few inches) depending on the pitch being played. It's more important in concert halls with rows of seats. – ttw May 25 '21 at 13:19
  • Playing softer or louder to meet a balanced sound requirement may also be considered tuning, however, changing an instruments pitch will only sound out of tune. – Stereomac May 25 '21 at 15:11
  • @Stereomac - that comment needs some explaining. – Tim May 26 '21 at 09:48