Gadgets posted by

Felston Audio Synchronizer – sync the lips back to the audio on your home theater set up


Felston Audio Synchronizer. Fed up with the audio sync on your home theater being off? You know, where the lips move a fraction later than you hear the audio, like some cheap martial arts B movie? Well fret no more, dear siblings, for we have the solution. This little doobry gives you an adjustable delay of up to 680ms, so you can tune those lips into perfect harmony, no matter how strange the language or dress code. Frankly we think the manufacturers should fix the actual A/V hardware that causes the problem in the first place, but what do we know…? $209.99.

 When you watch TV, do you ever notice how the picture and sound are sometimes out of sync – the presenter’s lips don’t move quite at the same time as his voice? Irritating isn’t it? This is known as lip sync error. And if you think you are alone with this problem, think again. Lip sync error affects a huge number of users of modern plasma TVs, LCD screens, DLP TVs and digital projectors. Felston’s digital audio delays solve the frustrating problem of lip sync error for anyone with an A/V amplifier or home theater system.


  • What I am looking for is something to slow down the radio commentary so it matches the football action on TV. Radio is quicker than the TV – I guess it has one less journey to space and back.

  • Martin. If you’re writing about the NFL/AFL, you’ll have to go into space twice. If you’re writing about the kind of football that’s played with the feet (not the hands), then you should already be in sync.

  • I am watching “soccer” in the UK on sat TV listening to AM radio. I am guessing that both leave the ground by sat up link, then both come down in the UK somewhere (TV / radio studio) get to a transmitter and then TV goes up to the equator near Africa and comes back to my roof (80,000 KM roundtrip) and the AM comes over the air from a big tower. The speed of light is 300,000km/second so the differance should be 1/4sec, but the difference is more like 1.5 sec. I am taking this to askmetafilter.

  • For a dedicated box, that does one thing, why is it limited to 680ms? Why can’t it fix sync problems up to 2 or 3 seconds. I think most people would be hard pressed to detect sync issues under 250ms.

  • Martin, don’t forget that as well as the 0.25sec round-trip, your TV signal also has to be converted to a digital stream, and then converted back again by your set-top box. That’s why if you watch BBC1 on analogue and digital they’re out of step – even if it’s on Freeview and so therefore from the same transmitter. On my telly (I’ve an old freeview box) the difference between the same programme can be as much as 3 seconds!

  • Lip-sync error can’t be fixed by any equipment manufacturer because it occurs in tiny increments starting at image capture and continuing through post production and broadcast and even DVD encoding. Since it is cumulative it often adds up to more lip-sync error than is caused by modern LCD, DLP, and plasma displays that catch most of the blame but often cause less than half the problem.

    A/V receivers that claim to correct it really don’t since they address only the fixed delay caused by a display and overlook the changing delay already in the signals that arrive.

    Three companies’ products address this:

    Alchemy2, Felston and Primare. They make digital audio delays that intercept the s/pdif audio and allow you to delay it in 1 ms increments (actually down to 1/3 ms for felston – and “yes” some people can actually detect that small a lip-sync error).

    The most important thing is they have enough delay (most receivers don’t) and they allow adjustment 0n-the-fly while watching with no image disturbance which is essential and most (all we’ve seen actually) a/v receivers disrupt the screen with menus during adjustment making it essentially impossible to ever achieve lip-sync. (look for “delay box”)

  • I forgot to comment on another device made expressly for longer delays to sync radio with TV:

    One is called “delay play radio” and another is made by Motron:

    Both are analog delays not s/pdif like the products I mentioned above but they have very long delays – like 15 seconds if I recall correctly – to allow listening to a radio commentary on a sports event broadcast on satellite.

  • Excellent information Nick, thanks very much. :-)

comments powered by Disqus

Side Advert

Write For Us


Managing Editor:
Nigel Powell

Associate Editor:
Caitlyn Muncy
Associate Editor:
Dan Ferris
Ecological Editor:
Debra Atlas
Technology Editor:
Fritz Effenberger
Asian Editor:
Hu Ping
Reviews Editor:
Kevin Evans

FB Like Box