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Mander Organs
davidh

Synchronising organ and singer

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davidh    0

Folo Paril told me of a problem that he has just solved. He often has to accompany the church’s favourite soprano, but, as he is high up in the organ loft and she is almost at the other end of the church, it is difficult to provide a sensitive and responsive accompaniment. There is a perceptible delay before the sounds of the organ reach her and the same delay before her voice is heard back in the organ loft.

His first attempted solution was CCTV and the almost instaneous response of an old analogue system might have helped, but modern digital systems respond too slowly. Folo eliminated the return time from the singer by placing a radio microphone near the singer to relay her sound back to his headphones, but there was still the delay before the organ sound reached her.

He then had a new idea. He has a digital reverberation system attached to the electronic organ on which he practices at home. His device is entirely digital. It stores sound samples in a circular buffer and the samples are read out with various delays and summed in various proportions to simulate a variety of different acoustics. Folo observed that by selecting only values close to a particular delay it is possible to create an echo effect with a delay expressed in microseconds as a number greater than zero. He has now modified the software in the device so that it will accept negative numbers and this produces a negative delay. Thus he hears the singer in perfect synchronisation with his playing.

I told him that this contradicted the basic laws of physics. He passed me his Tascam sound recorder and sent me downstairs with the instruction that I should not press the start button until I heard his first note. I protested that the recording would omit much of the first second of his music, but he told me to try it. When we played it back there was a brief silence before his first note was heard clearly from the beginning. Somehow it had started recording before I pressed the start button. If readers doubt this, I urge them to experiment with a Tascam or similar recorder, and they will prove for themselves that these have the gift of prophecy, beginning to record two seconds before the record button is pressed.

 

 

 

 

 

· A Tascam can buffer the sounds that it hears before it starts recording, and when the record button is pressed it will transfer the contents of the buffer to the output file before it starts adding new sounds. For this to work it has to be switched to ‘pre-record’ mode.

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There is another effect at work in David's recording experiment besides the remarkable ability of the Tascam recorder to transcend the bounds of ordinary causality (which my little Zoom machine doesn't do, incidentally).

 

In fact there isn't any such thing as free will, because it has been amply proved that the brain gets ready for an action by up to 350 milliseconds before we even decide to do it consciously. See the work of Libet for example. Therefore what we like to think is 'free will' is in fact an artefact of our subconscious. This helps to explain the incredible dexterity of, say, a top-rank keyboard player who presses the notes apparently far more quickly than the brain itself can work!

 

Consequently, when any experiments are done where times are measured with human beings in the loop, the results are indeed strange.

 

I've come across Paril's work before somewhere - must look it up in more detail. But first I had better turn over the calendar in my study. Isn't it bad luck otherwise?

 

CEP

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Nice April 1st story. Many pro/semi-pro location digital recorders have a pre-record buffer as described - nothing magic about it, the machine is "listening" and saves the last few seconds of what it's heard at the start of the track. Primarily intended for recording unprefictable speakers in press conference & similar situations. Nothing magic about it at all.

 

Every Blessing

Tony

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Oh Tony. What a pity. I was so looking forward to seeing what came next ... ! (And I'm sure David was as well).

 

CEP

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Mark Fownes    0

Yet it remains an undisputed fact that the acoustic of Sheffield City Hall, as arranged by Hope Bagenal (1888-1879), is such that the reverberation ceases 350 milliseconds before the hands are lifted from the keys of the organ.

 

MF

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