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View Full Version : Does any device exist that can delay audio?


devil's advocate
09-28-2005, 10:53 AM
For example, Fiber optic cable IN, Fiber optic cable OUT, and a dial that can vary the delay applied.

I think if cheap enough, it would be useful to have such a device to achieve synchronization of video and audio. I've always seen it where the video trails the audio. From what I understand certain network equipment imposes a delay to video but leaves audio as is, so a video delay WRT audio takes place.

Such a device shouldn't be too difficult to design and build. Probably no more than a second of delay should be enough to synch most signals.

What would it take? Receive port, memory, control circuitry for the delay, output port .....

dbett
09-28-2005, 11:22 AM
Many AV receivers have this ability.

Robert Spalding
09-28-2005, 11:33 AM
I talked to an engineer at my local CBS station once when we were seeing delay between audio and video (HDTV) and he said he actually delays the "video" not the audio on his end when this happens. Kinda interesting I thought.

Kevin L
09-28-2005, 11:38 AM
I could probably count on one hand the amount of times this year I've seen a lack of sync between audio and video, and I have three HR-10s and one HDVR2 hooked up to my home theater. All my audio goes through my Onkyo receiver. Two component video feeds go through the receiver, too, but one of the HR10's component video goes direct to the TV. I don't see/hear any difference between the units. If I do get out of sync, rewinding a couple of times seems to allow it to resync.

If you're having that much of a problem, it's time to look at the a/v setup you have. As dbett said, many a/v receivers handle this, so perhaps that's what my Onkyo does. However, since one of my video feeds bypasses the receiver, and I don't, or rarely, have problems with any of them, I don't see how that would be the case.

BTW, I watch both OTA and by sat with the NY locals.

danvines
09-28-2005, 11:51 AM
Yes, there are boxes that do this. Sorry, no link, but I've found them pretty easily w/ a google search. I've been considering one myself, since my Pioneer 1014 does not have that feature built in. I've put it off, though since just about the only time I seem to encounter it is on Discovery HD, and then only about 1/2 the time.

chris_h
09-28-2005, 12:14 PM
I had the lip sync issue with Gilmore Girls last night. I think it has been many months since I have encountered a lip sync issue with a broadcast. I think it has to do with the fact that much of the equipment at the station was fried by a lightning strike and they are hobbling along on backups.

The solution I used last night was to listen to the sound from the SD tivo (downstairs, but usable in the great room) and look at the pic from the HD tivo in the greatroom. It takes a few minutes to get the sync right, but it is very doable. I realize this is not an option for most users.

The other solution I have used in the past is to delay the audio thru a DVD recorder, which provide 1.5 to 2 frames of delay. I realize that this option is also not available to most users.

I am still considering the DD540 device from www.felston.com (no affilation) but it still seems kinda pricey at $229. The advantage is that I do not have to rewire my home theater, which I would have to do if I bought an amp with built-in delay.

mdryja
09-28-2005, 12:41 PM
AS noted above, many receivers have this feature. Many sound processors do as well. Although they're expensive (but check audiogon.com for great used deals -- I picked one up for half price), Lexicon audio processors have this functionality.

wam319
10-06-2005, 09:20 AM
check out delayplayradio

monkeyboy1010
10-06-2005, 09:54 AM
http://www.felston.com/buy.htm

chris_h
10-06-2005, 01:02 PM
check out delayplayradio

wam319,

Do you work for them? Have you ever used this device? Since it provides up to 16 seconds of delay, with what looks like an analog slide switch, I doubt that you could get the granularity needed to fix lip-sync issues. I sure would be glad to be wrong about this. The cost is $140 instead of $229 like the felston, but it only does analog audio, whereas the felton DD540 does digital IIRC.

ps for those that want to check it out: www.delayplayradio.com

Their spec sheet is a little short on specs, IMHO.

JimSpence
10-06-2005, 01:13 PM
The end user shouldn't have to resort to this approach to fix audio/video sync problems.
The stations/networks need to get their ducks in a row. :)

I have seen this problem quite a few times, mostly on network HD from DirecTV. Sometimes it is very obvious, but other times it is so subtle that it can be ignored.

chris_h
10-06-2005, 01:36 PM
A friend of mine is interested in feedback on the delayplayradio device from anyone that has actually used it, whether for lip-sync issues or just delaying a radio broadcast (which is his use model). Thanks in advance.

jor-el
10-06-2005, 02:15 PM
I just realized my receiver can do some level of delay. But how long? I suffer thru lip sync alright when it happens (just using TV speakers most of the time), but I wouldn't mind being able to listen to some sports events live using the radio announcer feed in place of the dreadful networks.

digitalant
10-06-2005, 02:42 PM
Where is it that receivers have an a/v delay? I have the Onkyo TX-SR702 and I don't know where I would look for such a thing. It was a pricier receiver so I would hope it would have it if "many" receivers have it. Any help?

Kevin L
10-06-2005, 03:02 PM
Where is it that receivers have an a/v delay? I have the Onkyo TX-SR702 and I don't know where I would look for such a thing. It was a pricier receiver so I would hope it would have it if "many" receivers have it. Any help?Onkyo's are great receivers. Sorry to tell you, though, that the TX-SR702 does NOT have Adjustable Digital Delay (as Onkyo calls it).

I have it in mine, but I have the TX-SR800. I only think it's in the 800 and higher series. I can adjust from 0.0ms to +76.0ms, and can sync the surround speaker plus or minus to that, though I haven't had need to move it off the default of 0.0. Here's what the manual says about it:

3-4. Delay Sub-menu
This sub-menu gives you various ways to adjust the timing of the
audio output from the speakers to give certain soundfield effects or
to adjust for unwanted asynchronous video and audio tracks.
This sub-menu does not appear if “Direct” is selected as the listening
mode.
Setting Values Initial value
a. A/V Sync 0.0 ms to 74.0 ms 0.0 ms
Relative Delay
b. Center –4.0 ms to +6.0 ms 0.0 ms
c. Surr L/R –4.0 ms to +6.0 ms 0.0 ms
d. Surr Back –4.0 ms to +6.0 ms 0.0 ms

DeDondeEs
10-06-2005, 03:09 PM
I have a Harmon Kardon AVR-235, it has a sound delay feature (never used it though). I picked it up for $300 from J&R Music world.

TyroneShoes
10-08-2005, 08:15 PM
I talked to an engineer at my local CBS station once when we were seeing delay between audio and video (HDTV) and he said he actually delays the "video" not the audio on his end when this happens. Kinda interesting I thought.
Interesting in that either he didn't understand the question or didn't know the answer.

Delay between MPEG-encoded SDI video and AES audio, which is typically what is used at modern TV stations, is almost always audio leading video, first of all. MPEG video can actually slow down when the decoder is working very hard, which allows the audio to continue on at its normal rate. In decades as a professional broadcast engineer, I can't ever remember seeing video leading the audio. It could happen, but would probably be very rare and very brief.

Delay in video processing other than in MPEG is also common. Most video signals traverse at least a couple of, sometimes half a dozen or more, frame synchronizers on their way through the facility. Each of those can add as much as 2 frames of delay to the video, again making audio lead video. Good engineering technique uses devices to add delay back to the audio, recalibrating them. We have a few installed just before our STLs for this exact purpose, but those are probably not within most folks' budget.

"Delaying" video by itself, other than REALLY delaying it (by recording it and playing it back later) is just not done. There is no reason for it and no equipment that I have ever heard of for that purpose. Broadcasters regularly delay video timing or pulse signals so that sources can switch or transition cleanly, but we are talking about nanoseconds of delay. It takes 7 milliseconds of delay for human perception to perceive audio delay, and more like 1/5th of a second when detecting lipsync delay.

If a consumer has a continuing issue with one or more sources having a detectable non-changing lipsync problem, what I would recommend is a trip to your local Guitar Center, where you will find numerous devices from companies like Alesis that can dial in delay for $100 or so (analog...more for digital). Just look for stereo capability and the ability to pick off the delayed signal separately, rather than mixing it back in with the original (what these devices are usually used for).

wam319
10-10-2005, 05:45 PM
chris_h,

I don't have one of the delayplayradio units yet, but looking it over. A friend sent me the link, and then I've been hearing the local sports DJ's talk about it as a gizmo to use to sync network sports broadcasts with local radio. Just thought it might be something to help.

A couple of years ago, I had searched and found some software for a PC that would provide an audio delay, but at the time it only had a 2 second range.

chris_h
10-19-2005, 02:19 PM
chris_h,

I don't have one of the delayplayradio units yet, but looking it over. A friend sent me the link, and then I've been hearing the local sports DJ's talk about it as a gizmo to use to sync network sports broadcasts with local radio. Just thought it might be something to help.

A couple of years ago, I had searched and found some software for a PC that would provide an audio delay, but at the time it only had a 2 second range.

Thanks for the info. My friend actually went ahead and bought one of these. It is now living in my home theater on loan. I have not yet run into a show that has a lip-sync issue, so I have not tried it for that. I find myself in the odd position of hoping to have lip-sync issues...

If anyone can recommend a show to record from the D* HD-pack which often times has lip-sync issues, I am all ears. I also get HD OTA in the Sacramento DMA, and am open to suggestions for network shows to record that often have lip-sync issues.

chris_h
11-15-2005, 08:12 PM
I have been using this unit in my home theater for a few weeks, and it seems to work pretty well. No remote control, analog-only, and the 16 second delay range makes it a little tough to "tune in" but overall pretty good.

Mark Lopez
11-16-2005, 01:46 PM
Doesn't the Felston unit only have coaxial in/out where the HD Tivo has optical out?

chris_h
03-20-2006, 08:44 PM
Doesn't the Felston unit only have coaxial in/out where the HD Tivo has optical out?

No, the felson unit takes both coax and optical in.

I just recently got one off of ebay (open box) for $139. Much closer to my buy threshold than $239. Works great so far.

doug25
03-22-2006, 11:20 AM
I have had (until recently) a major audio/video sync problem especially on HD discovery channel. I own a Sony Vega with 1080i video option. It was always set on this option. I noticed that when I set the option to 720p the sync problem disappeared completly. I think the 1080i takes longer to process thus making the sound seem ahead of the picture. Any comments on this theory?

AbMagFab
03-22-2006, 02:20 PM
Because of what DirecTV does to the HD signal (changing the resolution to something non-standard and wacky), I've always thought that the HD Tivo has to do more work to fill in all the missing data to make it 1080i, where it just has to smooth a little out to make it 720p.

If you never see this on OTA HD, then it's a side effect of the crappy DirecTV HD.

DeWitt
03-22-2006, 03:02 PM
Different TV sets will have different issues. The reason the AV receivers typically have this now is that digital tv's have to process the signal before displaying it. If the sound is not going through the tv any time lost processing the video will need to be compensated for in the audio path.

Having said that, it is also nice to have a variable delay for those times when the broadast is out of synch as well.

chris_h
03-22-2006, 03:55 PM
I have had (until recently) a major audio/video sync problem especially on HD discovery channel. I own a Sony Vega with 1080i video option. It was always set on this option. I noticed that when I set the option to 720p the sync problem disappeared completly. I think the 1080i takes longer to process thus making the sound seem ahead of the picture. Any comments on this theory?

As stated by others, the less processing of the video your TV has to do, the less it will be delayed. My guess is that the set has a native resoltion of 720.

newsposter
03-23-2006, 11:11 AM
Seems on topic so i'll ask here. I have hdmi from tivo to my tv and of course S vid to my dvd burner.

Why is there a delay on sound if i'm viewing the tivo through my dvd burner (like when i'm tranferring shows etc)? I had forgotten to turnoff the receiver one day and noticed this weird behavior once i switched from the input of my tivo for audio to my input for the dvd burner. It doesn't affect anything but it produces a pretty cool echo on some shows :)

chris_h
03-24-2006, 11:10 AM
Seems on topic so i'll ask here. I have hdmi from tivo to my tv and of course S vid to my dvd burner.

Why is there a delay on sound if i'm viewing the tivo through my dvd burner (like when i'm tranferring shows etc)? I had forgotten to turnoff the receiver one day and noticed this weird behavior once i switched from the input of my tivo for audio to my input for the dvd burner. It doesn't affect anything but it produces a pretty cool echo on some shows :)

Because your DVD burner takes some time to process the audio and video. I actually used this delay to my advantage for a while, prior to getting the felson unit. I had a 2 to 2.5 frame delay (quantifying that was an adventure involving PIP, a video tape of my TV in PIP, and slow-motion playback of a DVD copy of said video tape). On those rare shows that had audio leading video, about 80% of the time this 2 frame delay was about right to make them sync up. I had to do some minor rewiring of my setup each time, but it made the shows viewable. Obviously much easier with the felson unit, just hit the button on the remote (and it is adjustable too).

jberman
10-03-2007, 09:54 PM
I realize that this thread started a long time ago, but with the NFL season upon us and MLB playoffs in full swing, I thought I would update it. I can't stand listening to the national announcers for local games -- too impartial for me :D -- but the local radio coverage is always 5-7 seconds ahead of my TiVo, which is annoying at best. There's a computer in the same room as my TV, so I plug my radio into the audio line-in jack on the computer, and then run a free program called Radiodelay (http://www.daansystems.com/freestuff/Radiodelay.exe). Radiodelay lets you introduce up to 10 seconds of delay from the line-in (or any other source, including tuner cards) and play the delayed audio. It usually only takes me a couple of tries to line up the radio broadcast with the TV. :cool:

Here's a screenshot of Radiodelay in action:

http://www.daansystems.com/freestuff/Radiodelay.gif

old64mb
10-03-2007, 11:32 PM
Wow, that's a really neat program but way too sophisticated for me. :) I just sync up the Tivo with the XM/Sirius broadcast usually (given it has a longer delay) and pump it through the amp.