Violins at unison...

[Externet]

A group of violins playing unison the same note on an orchestra... The particular vibrating string emitting the sound cannot be perfectly synchronized from one instrument to another and another.

 

Why there is no perception of tone nodes/antinodes constructive/destructive interference/interaction, but a smooth equal pleasant sound ?

 

When the string is moving 'upwards' in instrument 1, the string in instrument 2 can be moving downwards. Plus any tiny-tiny deviation in tuning the instruments should create noticeable interference.

 

Or the distance from the ear to one or another instrument... Reinforcement or cancellation is not perceived. It sounds just as a majestic sound purity. Why ?

 

I can understand that if the unison instruments heard are from playing a recording, such interference effect should be not perceived as the microphone had a fixed location and picked whatever picked. But live performances sound just superb for a group of equal instruments. For violins or saxophones or whatever at unison.

 

It is like having independent electronic tone generators at unison and their speakers at different spots. Their propagated waves do interfere.

Or, is it only perceived if the listener is in motion in the performing room ?

[imatfaal]

Frequencies are close but not exact.

Frequencies waver and have seriously complicated natural harmonics (the timbre of the instrument)

Even a pure sound is not a single frequency but a large spectrum with a dominant peak

You do get nodes and antinodes but they are a tiny fraction of the overall sound

[StringJunky]

I think you hear what you want hear and ignore the rest. What we perceive is a construct. It seems from what I've read over the years our senses are not faithful passive recorders; the brain will reject and accept information as it sees fit.

[studiot]

 

A group of violins playing unison the same note on an orchestra... The particular vibrating string emitting the sound cannot be perfectly synchronized from one instrument to another and another.

 

Whyever not?

 

Frequency (actually phase) pulling into sync of linked oscillators is a well observed and documented phenomenon.

 

The flashing of fireflies is one classic example.

 

https://www.google.co.uk/search?hl=en-GB&source=hp&biw=&bih=&q=frequency+pulling+of+linked+oscillators&gbv=2&oq=frequency+pulling+of+linked+oscillators&gs_l=heirloom-hp.3...1875.13860.0.14391.41.17.1.23.5.0.219.2032.1j14j1.16.0....0...1ac.1.34.heirloom-hp..22.19.1827.6S54l699au8

[overtone]

The sound heard is not only very complex from each instrument, but modified by the room. Any cancellations and nodes are overwhelmed by the larger volume of these resonances, as well as by fluctuations in the exact position and direction of the instruments (the sounding surface of each instrument is not a point source, either).

 

In some rooms you can hear such cancellation etc - they have "dead spots". In a carefully designed anechoic chamber, the instruments sound much different - I would not be surprised to discover such interference patterns to be audible in an anechoic chamber, the effect being a noticeable change in timbre on certain notes in certain places in the room.

 

 

 

Frequency (actually phase) pulling into sync of linked oscillators is a well observed and documented phenomenon.

You'd have to fix the position of the instruments and extend the duration of the tone unrealistically. Edited February 7, 2016 by overtone

[John Cuthber]

 

 

The flashing of fireflies is one classic example.

 

 

An example of fireflies being able to deliberately synchronise because their reaction times are much faster than the flashing rate.

It's got nothing to do with the issue.

 

A more practical way to look at this would be to have something like an electric organ driving two loudspeakers with identical signals.

 

If you do that then yes, you can observe "dead spots" where the signals cancel out.

[studiot]

An example of fireflies being able to deliberately synchronise because their reaction times are much faster than the flashing rate.

It's got nothing to do with the issue.

 

A more practical way to look at this would be to have something like an electric organ driving two loudspeakers with identical signals.

 

If you do that then yes, you can observe "dead spots" where the signals cancel out.

 

It is you that does not understand resonance.

 

The soundbox in a violin is a resonant structure and the pulling into synchronisation of multiple oscillators is a resonance phenomenon.

 

You example is an example of forced not resonant oscillation.

[John Cuthber]

 

It is you that does not understand resonance.

 

The soundbox in a violin is a resonant structure and the pulling into synchronisation of multiple oscillators is a resonance phenomenon.

 

You example is an example of forced not resonant oscillation.

Violins are, as you say, resonant, and they will exhibit "frequency pulling" effects.

And fireflies don't, and won't.

That's why I said they were different.

The (firefly) phenomenon I referred to isn't anything to do with resonance.

So there's no way you could use it to judge whether I understand resonance or not.

 

Why did you pretend that you could?

 

Since there's, at best, some difficulty getting the two violins exactly in synchronisation- if nothing else because the players will move and the Doppler shift will change the observed frequency- it makes sense to eliminate that and feed the same signal to two loudspeakers.