SP Delay Formula ???

[Nunoc]

Hello All,

I came across a magazine a recently and for the life of me can not seem to find it again. Cant remember the name either.
It had an article that told you how to work out the delay for your surround and center speakers.

Remember something along the lines of every 30cms = 0.5ms.

Figure someone here might know.
Thanks for the help.

[Jase]

Hi

Have a look here:

http://www.dolby.com/tech/co.br.0103.DDFAQ.html#q20

[deckard]

Spot on Jase but I find those graphs a bit vague - I'm only a simple chap!

The calculation is 1ms delay for every 30cm your mains are further from your rears.

Personally I would not add delay to your centre speaker as it will effect lip sync - just try to keep your mains the same distance from your seating position as your centre.

[cskates]

Sound travels around 330m/s, so for every millisecond it travels around 33cms (1 foot).

The object is to get the sound from each speaker reaching your ear at the same time. This is more important than most people realise and makes more of a difference to stereo imaging than level differences between the speakers.

If your receiver doesn't allow you to enter the speaker distances directly then you'll have to work out the delays yourself. The speaker furthest away will have no delay, any speakers nearer than this will be delayed 1ms per foot or 33cm.

To take an example, say your left speaker was 10 feet away, your right speaker was 9 feet away and your centre was 6 feet away. These would be delayed:
left - 0ms
right - (10ft - 9ft) 1ms
centre - (10ft - 6ft) 4ms