multiples notes in dsp and in reality ?

[Tepeix]

A little maybe stupid question

I press 32 notes at the same time with a real piano.
The sound is louder than one, but not so much.

Now i play it with a naive dsp synth.
Well, it will clip so the sound is not so much louder if i play at a volume close to the limit.
But i feel like the raise in volume is bigger than with a real instrument.

Is it true ?
if yes, why ?
Is it because in a real piano every note come from different sources ?
Or the resonance inside it ?
Or a natural overdrive or compression of the sound in real world ?

Thanks for any response !)

Here's a little test that send 32 midi note in once.

[tulamide]

I am not that much into sound waves, but I remember that one of our members, Martin Vicanek, once explained it. It is something with the way the sound waves add up, which differs from a synth.

[Tepeix]

Thanks !
I find that topic : viewtopic.php?f=4&t=75814&start=10
And will continue my research !

Interesting thing i find in, is that in nature note will not be send at the same time,
so the phase is not the same for all, also different vibrato could help.

I suppose that in real world the phase could start up or down. Or maybe it could be any phase start ?
But maybe air itself act also as a special compressor ?)

[HughBanton]

Glad you found that thread, we covered a lot of interesting stuff about this subject.

I confess that I still haven't completed the 4-speaker test I promised last year. My plan, when I get round to it, is to establish whether uncorrelated noise sources fed through separate speakers will appear to add up differently (better?) when the speakers are distanced from each other, because if placed together I discover it's much the same as when you simply mix four sources into one, which does sound over-added.

One thing I can definitely confirm, however, is that 'pitched-noise' sources produced by keyboard-controlled comb-filtering add up much more realisticallly than broad band or more simply filtered noise. Interesting. Since I've mostly switched to that method I've been much more content with note addition.

Something else to consider with real acoustic instruments: when two sound waves meet in mid-air, portions of their waves can actually anihalate each other. Terminally. Once a pressure wave is killed off it can't then miraculously reappear. However two or more electronically generated sound sources mixed together can't affect each other in this way, they'll just merrily continue to oscillate exactly as instructed. Likely to appear louder.

On a real piano sound board the vibrations of one string are bound to influence those of all the others, so multiple anihalations will take place as the sounds decay; you don't naturally get this interaction in electronic instruments.

One last thing - take a look at 'Acoustic Shadows' .. https://en.wikipedia.org/wiki/Acoustic_shadow . I've definitely experienced this effect when standing, say, a mile from a motorway - I could hear loud traffic noise from my left and from my right, but in the center ... silence! Most odd.

H

[Tepeix]

Thanks for all those precision's. Very interesting !

That inspire me this wrong synth
The idea is to shufle the channel of the pitch poly and add them together.
When more than one note are played (by group of four) it add a vibrato.
But the result seams unstable.
Finally it's even more fun to add the other note with a fixed multiplied amount.

The more fast or chords the player do the more is it punished with wrong notes lol