questions about pops (diginoise?)

jso

My digital cable box occasionally cuts-out audio when the signal degrades. This is really annoying because it can result in a loud popping sound. I'm thinking that can't be good for the speakers. Up until a few days ago I was using old speakers I don't care about, but now I have new RTi A5s (see this thread for more info). So I haven't used the A5s much when watching TV because I'm concerned a pop could happen.

So there's a few questions I have:

1) Do these pops damage speakers? If so, what are the signs of damage? So far my old bookshelfs don't sound any worse for the wear and there have been probably hundreds of pops over the years from various sources. But I'm wondering if the A5s materials are more sensitive to this sort of thing.

2) Would digital outputs (optical or coax) from the cable box eliminate or mitigate the problem? (e.g. silence instead of pops)

I'm using analog line out from the cable box b/c my Sherwood RX-4105 receiver is pure analog. I'm intending to get a recever with digital inputs anyways for an eventual 5.1 system.

3) What's the technical term for these pops? I've seen them called diginoise in the online tape trader communities.


I've been enjoying all the helpful info on this site while searching and reading up on all sorts of things. Couldn't find anything on pops/diginoise though so thought I'd ask.

fbm211

Maybe you could try one of those things that boost the signal by 12db or so.

dudeinaroom

I would contact your cable company and explain your problem, you should not have signal degradation. Have them come out and check the cabling and signal strength. their might be a charge for problems inside the house. If this is some thing that only during times of wet weather/ high humidity make sure you let them know.

jso

Thanks for responding guys.

fbm211 - so boosting the signal 12dB would eliminate pops?

dudeinaroom -

That's a useful tip about high humidity. It's been fairly dry in my place the last month or so (usually about 35% humidity - I have a hygrometer b/c of past sinus issues) and I can't recall hearing a pop in weeks. I only got cable in July and it was probably the summer months when the humidity could get 60+% that there were the most problems.

By "signal degredation" I should clarify that I was thinking of what likely is buffer underflow for digital video streaming. I've observed that if there's not enough data coming in, both audio and video the audio will cut-out sometimes with a pop, usually not, and the video will get blocky and distorted. But I could be thinking about that wrong, becuase there could be actual signal degredation too. I do recall that the most frequent problems over the summer were streaming Showtime On-demand in July and August when I watched Season 1 of "Dexter". I remember hearing lots of pops in conjunction with buffer underflows and possibly other causes.

Does anybody else have the Scientific Altanta 3250HD cable box? That thing runs really hot, and is quite warm even in standby!

dudeinaroom

With cable you should not have any type of buffer underflow. I could be wrong. Does the box tell you that it has a buffer underflow? When I had digital cable we had a Motorola cable box and it was always hot. You might want them to take a look at your cable box just to be safe.

jso

^ no, I have no way of knowing for certain that it's buffer underflow, it just seems like it could be. But it could be something else.

About the humidity, is that a symptom of an electrical problem or just a poorly designed piece of electronics?

I'll be sure to give Time Warner a call. Thanks for your help!

dudeinaroom

Neither. I have a friend who had problems with his cable internet dropping out and once in a great while it would affect the TV. It was the worst when raining, or times of high humidity. It turned out their was a pin hole in his coaxial cable coming into the house. As we all know water conducts electricity, and in a situation where wires are bare and close enough high humidity can case the same effect.

Good luck, hope you get it figured out,
dude

jso

Just posting an update to this situation. I ended up getting a Denon receiver so now I can use the optical output of the cable box. And what a difference in sound quality! It's quite noticable improvement. And the good thing is there have been a few glitchy/laggy/underflow type moments so far but the optical simply cuts out and there's silence without pops.

I did have the cable guy come out and look at everything and the signal was fine, no problems.

I suspect it may simply be the cheap electronics in the cable box, particularly the DAC->line out circuitry. The woman I spoke to on the phone for tech support admitted she too has had this problem using analog line out. Hopefully the problem is put to rest...

Thanks again for your help and suggesting I call them, dudeinaroom