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somemightsay
join:2005-07-16
Rockwall, TX

3 edits

somemightsay

Member

[CATV] Anyone else ever seen audio synch issues on analog?

I have a repeating issue on one of my analog basic channels, and was wondering if anyone else has seen it and knows what would cause it.

On Channel 9 of my analog basic tier (no DVR or box involved, this is straight from the wall into my Sony CRT), I get audio synch issues almost every evening, especially after nine o' clock. It's off by about a half-second to a second. If you've never seen this, let me tell you, it's VERY annoying.

Here's some troubleshooting I've done -- I have checked the OTA HD feed from the channel on another TV, and it is fine. Also, let me again mention that this is the ONLY channel on the tier that exhibits this problem. Of course, it's usually OK by the morning, and will then reappear later on at night.

I've posted in the direct forum about this, and big surprise, they want to roll a truck. Apparently I have magic coax that only delays audio on one channel.

Anyhow, any ideas?

EDIT: And in the time it took me to type and post this, the issue has resolved itself, magically. This is driving me crazy.

hootabius
join:2009-02-12

1 edit

hootabius

Member

Verifying the OTA feed is a good step. You can rule out the programmer, or at least their transmitter. I'd like to say it sounds like a headend encoding issue, however typically if that's the case, everyone fed from that headend would hear/see it too.

RF distortions on the cable line wouldn't really cause a delay. Until it reaches your TV, the audio on a TV channel is broadcast as an FM signal, which is really just a form of transportation for the actual soundwaves. Analog distortions and signal issues will cause problems such as low, high or distorted sound, but wouldn't delay it.

Do you have any other TVs in the house, and if so, does the problem occur on those TVs also? If it were me troubleshooting, I would want to rule out the TV, because to be honest, after the headend it's the most likely cause of this particular problem. When you change the channel, you are changing the frequency that the receiver inside looks at. I won't get too detailed as to the internal workings of a television, but basically the received signal is mixed with a local oscillator to produce an IF signal, that can be broken down to its basic audio and video elements so it can be displayed on a screen. It is possible that there is a detector or audio filter that is having a problem on that particular frequency("channel"), and causing a delay of the audio processing. The fact that it's intermittant could be related to how long the television is turned on for. I'm guessing at 9 PM it's probably been on for several hours. It could also be electromagnetic interferance causing something inside the TV to flip out - something like this could be caused by another electronic device that's in use somewhere nearby.

Troubleshooting anything like this is generally a process of elimination. If it's doing it on another TV then it's something that Charter needs to investigate, however if no other customers are reporting the same issue then they have nothing to go on. It could be that people are having the issue but not reporting it. Either way, without anything to suggest it's a widespread issue then the next logical step is to roll a truck to your house. I'm not saying it isn't something on the coax line, but it's highly unlikely, and if it is, it would be the first time I've ever seen it.

somemightsay
join:2005-07-16
Rockwall, TX

1 edit

somemightsay

Member

Thanks for the reply.

It's not a function of how long the TV has been on, I turned it on tonight and noticed the problem within less than 10 minutes of the TV being on (when I happened to pass by that channel. It is local "Channel 33" in Dallas, FWIW). I also am pretty sure (99 percent) that I checked the other TV in the house that is also fed from the analog basic, and it also shows the issue, but I would need to double check that the next time I see the problem occur.

I don't want to get into too much detail here, but let me just say that after dealing with the local office, and with other issues I've had worked or attempted to have worked, I suspect that other customers are just living with it. Like I said, it is (like so many of these problems seem to be) intermittent.

I know you realize this as well, but if they roll a truck at three in the afternoon, they won't see the problem. I need to be able to get a hold of someone when the problem is actually occurring. And since that is around 8 or 9 pm, that probably isn't going to happen.

As another bit of data, I see the same issue, although not as frequently, on Channel 17, which is G4TV. However, when Channel 9 was acting up tonight, Channel 17 was fine. Ack.

Thanks again.

hootabius
join:2009-02-12

hootabius

Member

said by somemightsay:

I know you realize this as well, but if they roll a truck at three in the afternoon, they won't see the problem. I need to be able to get a hold of someone when the problem is actually occurring. And since that is around 8 or 9 pm, that probably isn't going to happen.
That's an excellent point, and probably worth pointing out to the direct forum guys. I can't speak for your particular system, but "master" headends are often manned 24 hours a day, so it wouldn't be a big deal for a 2nd shift guy to check it out. Even if there isn't someone working, I don't think it would be much to ask for a headend tech or engineer to check it out at home one evening.

somemightsay
join:2005-07-16
Rockwall, TX

1 edit

somemightsay

Member

That's a good idea. I'm not sure I have the energy to pursue that right now (I've really had some struggles with my HD service, as you can see from the direct forum -- just look for Rockwall or 75087), but I'll keep it in mind if the problem keeps recurring.

Thanks again for all the input.
somemightsay

somemightsay

Member

9:15 pm local time, this is happening AGAIN on the same channel.

I've confirmed it happens on two separate TVs that are on analog basic, so it's not the TVs themselves. OTA is fine. Just had the splitter replaced last week due to a separate, unrelated HD signal strength issue, so it's not the splitter. Is it magic RG6 that just causes issues on Channel 9??

How hard can this be? I've been down to the local office so much they know me on sight.

What's even more confusing is how can no other subscribers in my area be seeing this? It's mind-boggling.

DocDrew
How can I help?
Premium Member
join:2009-01-28
SoCal
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DocDrew

Premium Member

Just wondering....

Is the TV set to stereo, mono, or SAP?

Delayed audio is definitely a headend, broadcaster issue, and/or something in-between, but it may not be detected quickly by others if it's only noticeable when the TV is set to mono or SAP.

Oh yeah, what actual program is playing when the delayed audio occurs?

somemightsay
join:2005-07-16
Rockwall, TX

somemightsay

Member

TV is set to stereo. Don't know exactly what is being sent from the headend. It certainly doesn't sound like stereo. I suspect all of our basic channels here are sent in mono from the local office.

Analog basic Channel 9 here is the local "CW" (OTA it is 33.1) affiliate. I have seen the issue on CW primetime programming (my better half watches The Vampire Diaries). The 9 o clock hour is local news. I often see it at this time as well.

As I type this, the audio is back in synch again -- which of course makes the problem even more frustrating.
MOTO6809
join:2007-11-05
Springfield, MA

MOTO6809 to hootabius

Member

to hootabius
said by hootabius:

Verifying the OTA feed is a good step. You can rule out the programmer, or at least their transmitter. I'd like to say it sounds like a headend encoding issue, however typically if that's the case, everyone fed from that headend would hear/see it too.

If Charter receives the channel by fiber then it could be the way the channel provider processes it before sending to them. I've also seen this when a broadcaster switches from local to national feed , So anytime switching takes place (commercial insertion, national feeds and back to local) you may see a sync problem.

If they are receiving by antenna it could be the VSB receiver. Depending on which type they are using (Wegner, KTech, Tandberg ect..) it may be just a simple firmware update for it.

Another possibility could be a grooming device that charter may be using.

Rolling a truck is not going to fix this problem, I would start by talking with the local supervisor and he/she should be able to have the headend staff look into it.