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In computer music one usually says that the audio latency of the system should ideally be less than 10ms…

On the other hand, as the speed of sound is around 340 m/s in the air it means that whenever you are away of more than 4m from an audio source, you perceive the sound emitted by this source with a latency which is greater than 10ms. Does it means that someone performing should be this close to his amplifier? Also, when several musicians are performing together (let's say a march band, which farthest musicians are way farther than that) I guess there is a kind of "closest neighbor synchronization" so that the whole band is in synced, but still… (Obviously,this does not apply for amplified bands as the speed of sound in cable is close to the speed of light, or when a director a synchronizing everybody by visual signals, they go at the speed of light too…).

Are we overthinking this latency problem when doing computer music?

(Not much of a real question, but this has puzzled me for quite a long time…)

  • @CarlWitthoft by that I refer to the amount of time between the action on the instrument and the reception of the sound at the ear. Not even talking about recording, but just to have the feeling that the instrument is not sloppy (see musicproductiontips.net/audio-latency-optimize-your-buffer-size ) – Tom Jun 30 at 13:58
  • Sound from Guitar to Amplifier doesn't go as Sound but as Electromagnetic pulses (Pulses or Audio-forms depends on the type of input - Analog and Digital). In other words Speed of sound in Wire = Lights speed. So latency in Computer music is not caused by 340m/s but your Computer hardware. – RishiNandha Vanchi Jul 1 at 5:14
  • @RishiNandha_M Yes, I agree. I am just comparing this value with the latency you can expect for air vehiculated sound in a live environment. I did not talk about the speed of sound in the paragraph on computer music... – Tom Jul 1 at 6:16
  • @CarlWitthoft 60 / 120 / 16 = 0.125s, a bit more than 2ms :D – moonwave99 Jul 1 at 15:02
  • @moonwave99 dammit I calculated bps :-( which will teach me to type without thinking – Carl Witthoft Jul 1 at 18:48
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If you ever have a chance to play a very large pipe organ, give it a try. You will have difficulty playing until you get used to the latency of several tenths of a second.

The 10ms figure was determined about 50 years ago when a new keyboard design was invented. In this design, currently used for computer keyboards and most music keyboards, the keys are scanned one-by-one. But if it took 100 ms or more to scan all the keys, the timing could sound off by any amount from zero to 100 ms and the performer lost a sense of "feel" of the keyboard. When the cycle was made faster so that it took only 10 ms, none of the performers had this problem.

It's likely that the variance in the latency is more of a problem than the latency. If every note is late by exactly 100 ms, as when you are far away from your guitar amplifier, you quickly adjust. Organ pipes are at varying distances from the organist.

How large groups of performers stay in sync is a very interesting question. I don't know if it's been studied with marching bands, but it has been studied in basketball fans.

In 1995 Cherrill P. Heaton determined that when a basketball player's shot goes into the basket without touching the rim or the backboard, the crowd chants "Air Ball!" always in unison, and always on the notes F for Air and D for Ball. His study was published in the journal Popular Music And Society. Here is a link to a newspaper article about it:

https://www.latimes.com/archives/la-xpm-1995-09-24-mn-49383-story.html

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  • Thanks for your answer! I guess the orchestra is working a bit like your basketball example: as everybody is following the same "object" (the ball or the director) and as the speed of light is so big, everyone is synced with that object… But without director I still wonder… – Tom Jun 30 at 11:54
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    i've been in large marching bands, and yes the sections farthest from the home-crowd side of the field are taught to "lead" the beat so there sound will be in sync with the closest portion of the band from the point of view of the audience. – Carl Witthoft Jun 30 at 13:23
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    I played piano-and-organ duets in a church with the piano up front and the organ in the gallery in the back, maybe 40 feet apart. It worked fine, But I have seen performances of pieces in very large churches, for instance the Berlioz Te Deum, where the organist had to anticipate the beat. It sounded OK in some places in the seats; not quite so OK in others. – Mark Lutton Jun 30 at 22:57
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When you stop to realize a rock and roll or country music stage is often 40, 50 or 60 feet across the front of the stage, you might expect that latency between performers might become a real problem, but when every instrument is miked up or D.I.ed into the sound system and mixed the resulting sound has no noticeable latency between instruments because everything is close miked, blended together and presented back to the performers in a monitor system of one sort or another. The same process happens for the audience and the only latency problem for the audience happens as the audience member is situated further away from the speaker arrays and the sound arrives later at their seating area. Even so, the instruments have already been blended into one main sound picture so the latency between instruments is rarely problematic. The room acoustics are where most of the problems really occur.

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  • Yes, obviously I am expecting this kind of problems when the sound is traveling a great path in the air: for big acoustic bands (or for instance of the monitors are too far away)... – Tom Jul 1 at 6:18

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