Picture & sound synchronization from AV amps

[Graham Fletcher]

Hi all,

Got my Yammy V2600 & B&W MT30s on order, but got a quick query about the speaker delays that can be setup in the AV amp.

I get the idea of speaker delays is to compensate for distance variations between speakers - but do AV amps also delay the pictures accordingly.

Might be best if I illustrate that with an example

Lets say I've got one speaker 5m further away from me than other speakers, so I add 5m worth of delay to all the other speakers. Speed of sound in air is around 340m/s at room temp, so it takes around 15ms for the sound to travel 5m - so the amp delays the sound to the other speakers by 15ms.

When an explosion happens in a film the amp first produces the noise from my most distant speaker, and 15ms later the noise comes out of all my other speakers, arriving at my ears some time later.

So does the amp delay the picture as well? Or am I thinking too hard about all this - are the delays of audio no consequence to our feeble human brains when they resync the sound & pictures in our head to form a coherent event?

 

[Jase]

A lot of Amps now come with a specific master audio delay adjustment if there is any problem with Lip-sync etc due to video processing. You usually have to set this manually though. Some dvd players/video processors have automatic correction built-in to avoid this problem.

Once your Amp has set the normal speaker distances & channel levels etc you won't have to worry, it will sort itself out in terms of delaying the sounds so they arrive at your ears when they should do.

 

[Ultra2man]

Hi all,

Got my Yammy V2600 & B&W MT30s on order, but got a quick query about the speaker delays that can be setup in the AV amp.

I get the idea of speaker delays is to compensate for distance variations between speakers - but do AV amps also delay the pictures accordingly.

Might be best if I illustrate that with an example

Lets say I've got one speaker 5m further away from me than other speakers, so I add 5m worth of delay to all the other speakers. Speed of sound in air is around 340m/s at room temp, so it takes around 15ms for the sound to travel 5m - so the amp delays the sound to the other speakers by 15ms.

When an explosion happens in a film the amp first produces the noise from my most distant speaker, and 15ms later the noise comes out of all my other speakers, arriving at my ears some time later.

So does the amp delay the picture as well? Or am I thinking too hard about all this - are the delays of audio no consequence to our feeble human brains when they resync the sound & pictures in our head to form a coherent event?

There is a possibility that the amp will cause a delay to the picture if it is doing any processing to the picture i.e. upscaling the pic.
However there is no delay adjustment to the video signal. The normal reason that sound goes out of sync with the video is that the processing of the picture takes a lot longer than the sound Hence you need to delay the audio not the video. This is why most modern amps have an audio delay function built in along with some scources such as Sky Hd.
Also do not confuse the audio delay function with the speaker distance settings. The audio delay is an add on which has become more neccessary in these days if digital video processing.
You should set your speakers to the relevant distances they are from the seating position and then if you notice a lip sync problem adjust the audio delay on the amp ( assuming your amp has that feature).