Synchronising pipe speech.

[davidh]

Last year Folo Paril told me of the problems that he had synchronising with singers, given the distance and the finite speed of sound. He told me that his negative delay system hadn’t worked well as he had hoped. He now has a far better arrangement, a detached wireless console which allows him to sit almost among his choir.

Folo is never satisfied, and now, listening to the organ where he can hear it better, he is aware that the pipes in the treble speak sooner than the ones in the bass. He thought  about the design of the pallets, aware that their perimeter was more important than their area and he increased their leverage to admit air more rapidly in the bass. He also played with the voicing and concluded that the physics of the system would always mean that a larger pipe would take longer to reach full speech.

The only way to achieve simultaneity was to delay the treble pipes so that they began sounding at the same time as the ones in the bass. He accordingly added delays to the signals from the console, in proportion to the speaking delay of each pipe. Of course that means a slightly longer time before the notes are heard, but nothing like the delays that resulted from tubular pneumatic actions – and organists coped with them.

Now he is not sure that he likes the sound of it. Perhaps the slightly different delays help us to distinguish between the different voices in contrapuntal music. Perhaps the ear is aware that in nature large things move more slowly than small ones. He is assembling a panel of psycho-acoustic experts and musicians to judge the effects of sychronising pipe speech.

Notes.

1. The designers of electronic instruments should not make all voices sound simulteously without considering whether this is really desirable.

2. Televisions, DVD players and soundbars all perform a lot of processing, each with its own delay time. The standard remedy is to add extra delays to the fastest units so that sound and vision are in synchronisation. This is easily defeated by television stations which do not equalise the processing times of sound and video paths, but sometimes the fault is in the receiver - try changing channels and then change back again to clear the sound buffers.

[Martin Cooke]

Well, good old Folo Paril.

Meanwhile, down here in Wiltshire we're reeling from the news that the proposed A303 tunnel to divert traffic away from Stonehenge is no longer going ahead after public consultation. Instead, they're going to move Stonehenge along the A303 and re-erect in on an industrial estate in Wincanton - just behind McDonald's - where it can't be seen from the road and thus there will be no needless slowing down of traffic. 

Still, that's a bit off-topic... and I am left wondering if the occasional lack of synchronisation between my sound bar and my telly can be resolved by a quick flick to another channel!