Digital Cable vs. Fiber Optic

[Halon451]

Oddly enough I haven't come across this topic yet - perhaps I didn't search back far enough, but I've recently began to wonder about a couple of things.

Mostly concerning the audio capabilities of each of these options...

I currently am subscribed to my local cable provider's HD digital cable service, which provides a handful of true HD channels, and Dolby Digital 5.1 audio for most of those. All other 'non-HD' channels are not 5.1, so I have to rely on good ol' Pro-Logic.

I have my cable box connected to the Receiver via optical - and although I can completely surmise that the quality of audio coming over the standard RF cabe line into my home is probably fairly prone to loss and degneration of the square wave forms that make up my digital signal - as a result, this leads to some fairly inadequate listening experiences on some of these channels - again I am only assuming that this is the case.

On many of the channels, the sound seems very compressed and hollow, and lacks any kind of richness or fullness.

I am wondering if anyone else out there has this issue, or possibly has some insight into the inner workings of a typical digital cable network, and how the audio signal is processed either pre-transmission, over the lines, or at my cable box/Receiver connection?

Also, of course I am sure this is taking place everywhere, but everyone's FAVORITE Ma Bell service is working in overdrive to shove Fiber Optic service in our face as if it is the next best thing since sliced bread. I've refrained from subscribing to them based on poor customer service in general, but I've often wondered about the quality of the actual service in comparison to digital cable. Does anyone have any input on this?

Any other frustrated customers out there?

 

[Runamuck]

Are you talking Verizon or AT&T fiber? FiOS is a darn good product i enjoyed mine allot. AT&T's IPTV is really good also and the possibilities with it are greater then cable or satellite. Why do you think Dish and DirecTV are partnered with them? Fiber is a very good thing and once its paired with IPTV it will be even better. IPTV has its pitfalls but nothing visual or audible more on the tracking what you watch side...

The future.

Could you imagine not having to buy dvd's ever again and having a movie collection with about 10,000 movies in HD? Might only be 720p but I could live with that, for now. This is closer to reality then vapor ware.

 

[mtrycrafts]

On many of the channels, the sound seems very compressed and hollow, and lacks any kind of richness or fullness.

I am wondering if anyone else out there has this issue, or possibly has some insight into the inner workings of a typical digital cable network, and how the audio signal is processed either pre-transmission, over the lines, or at my cable box/Receiver connection?


Any other frustrated customers out there?

I don't have digital cable, nor is the analog hooked up to my boomboxes but, the digital signal is robust enough to withstand the transmissions. Or, you would get noise or nothing, unlike the old RF analog. So, it would be the original signal that was transmitted.
How is the DD5.1 when it is there?

 

[Halon451]

Ah, I wish I knew how to do multiple quotes so I could respond in an orderly fashion. Thanks guys for your input.

I would be referring to Verizon of course - I kept it general on account of not knowing exactly who else is out there perhaps west of the Mississippi that isn't running Verizon these days. I do accept the fact that fiber is probably the much better option as far as overall quality, but for me customer service goes a long way too. I've dealt with them before and will not willingly enter into another agreement with them on account of my experiences.

So, I'm stuck with digital cable (and strongly considering a satellite HD option).

I do understand the nature of digital versus analog (be it RF or otherwise) all too well - but just don't quite know how well this signal is carried over such a large network and through shared lines that are still utilizing standard modulated analog signals - I suspect that overall bandwidth becomes a concern, and hence my question regarding the 'compressed' quality to my audio from some channels.

To answer your question - the channels that do carry 5.1 seem to do so well enough, but no where near the quality as when I am watching a DD formatted DVD, if that tells you anything.

 

[mtrycrafts]

Ah, I wish I knew how to do multiple quotes so I could respond in an orderly fashion. Thanks guys for your input.

I would be referring to Verizon of course - I kept it general on account of not knowing exactly who else is out there perhaps west of the Mississippi that isn't running Verizon these days. I do accept the fact that fiber is probably the much better option as far as overall quality, but for me customer service goes a long way too. I've dealt with them before and will not willingly enter into another agreement with them on account of my experiences.

So, I'm stuck with digital cable (and strongly considering a satellite HD option).

I do understand the nature of digital versus analog (be it RF or otherwise) all too well - but just don't quite know how well this signal is carried over such a large network and through shared lines that are still utilizing standard modulated analog signals - I suspect that overall bandwidth becomes a concern, and hence my question regarding the 'compressed' quality to my audio from some channels.

To answer your question - the channels that do carry 5.1 seem to do so well enough, but no where near the quality as when I am watching a DD formatted DVD, if that tells you anything.

Cable bandwidth should be even greater over fiber. They multiplex somehow all those channels, perhaps frequency hop? If they carry all those TV stations, imagine the bandwidth on the video signal alone. It is 6Mhz in the old analog with audio in there which was nothing. Now, with digital and hi def, it is even broader yet audio is still just a bit higher than before; hundreds of video channels in fiber and coax, and the video get here and there.

It is magic

 

[j_garcia]

To answer your question - the channels that do carry 5.1 seem to do so well enough, but no where near the quality as when I am watching a DD formatted DVD, if that tells you anything.

That would be about typical. I would imagine the signal being transmitted is even more compressed than normal due to them wanting it to be as small as possible to transmit. I would say it would be rare for broadcast to exceed that of most DVDs.

 

[Petro]

That would be about typical. I would imagine the signal being transmitted is even more compressed than normal due to them wanting it to be as small as possible to transmit. I would say it would be rare for broadcast to exceed that of most DVDs.

AC-3's implementation for cable and standard DVDs is effectively the same format by the time it reaches your player - a single 448KB/s stream of lossy compressed audio. It's not really the kind of thing that can be demuxed and tinkered with during transmission without running into issues with video sync. (Not to mention that fact that doing so would introduce problems with zero gain.)

You don't see AC-3 exceeding 448K until you start talking about newer high-def media formats. There's no need to compress this format beyond the level of compression that's already been carried out on it - the Dolby E format fits quite nicely into a standard stereo AES/EBU channel without it.

 

[dannyk]

I have found that digital coax is generally better then fiber optic but that could be because the quality of my fiber optic is not as good.

 

[no. 5]

Ah, I wish I knew how to do multiple quotes so I could respond in an orderly fashion. Thanks guys for your input.

The "+ button next to the quote button.

 

[mtrycrafts]

I have found that digital coax is generally better then fiber optic but that could be because the quality of my fiber optic is not as good.

I think he was talking about these two in the cable TV system, not in the home hookup. He was wondering which cable system had a broader bad capability. Fiber does. One reason for the conversion to it.
Repeaters can be many time further than in coax cable transmission, no RFI issues with fiber over miles of cable runs. And, no sig int from fiber, not that simple any more.

 

[tbewick]

Ah, I wish I knew how to do multiple quotes so I could respond in an orderly fashion. Thanks guys for your input.

I would be referring to Verizon of course - I kept it general on account of not knowing exactly who else is out there perhaps west of the Mississippi that isn't running Verizon these days. I do accept the fact that fiber is probably the much better option as far as overall quality, but for me customer service goes a long way too. I've dealt with them before and will not willingly enter into another agreement with them on account of my experiences.

So, I'm stuck with digital cable (and strongly considering a satellite HD option).

I do understand the nature of digital versus analog (be it RF or otherwise) all too well - but just don't quite know how well this signal is carried over such a large network and through shared lines that are still utilizing standard modulated analog signals - I suspect that overall bandwidth becomes a concern, and hence my question regarding the 'compressed' quality to my audio from some channels.

To answer your question - the channels that do carry 5.1 seem to do so well enough, but no where near the quality as when I am watching a DD formatted DVD, if that tells you anything.

'...while signals remain in the digital domain where jitter is appropriately bounded so that signal recognition and arithmetic processing are not impaired, then there is no degradation of information even though the digital words may be displaced from their optimal location.'

Hawksford, M.O.J. (1991). "Introduction to Digital Audio", Images of Audio, Proceedings of the 10th International AES Conference, London, September 1991. Page 25. http://www.essex.ac.uk/ese/research/audio_lab/malcolmspubdocs/C27 AES lecture Introduction to digital audio.pdf

I've included links to two more papers which you may find useful:

Dunn, J. (2003). "Measurement Techniques for Digital Audio", Audio Precision Application Note #5, Audio Precision.
http://ap.com/library/technotes.htm

'Engineering Guidelines: The EBU/AES Digital Interface'. John Emmett. European Broadcasting Union, 1995.
http://www.ebu.ch/CMSimages/en/tec_AES-EBU_eg_tcm6-11890.pdf

 

[Halon451]

'...while signals remain in the digital domain where jitter is appropriately bounded so that signal recognition and arithmetic processing are not impaired, then there is no degradation of information even though the digital words may be displaced from their optimal location.'

Hawksford, M.O.J. (1991). "Introduction to Digital Audio", Images of Audio, Proceedings of the 10th International AES Conference, London, September 1991. Page 25. http://www.essex.ac.uk/ese/research/audio_lab/malcolmspubdocs/C27 AES lecture Introduction to digital audio.pdf

I've included links to two more papers which you may find useful:

Dunn, J. (2003). "Measurement Techniques for Digital Audio", Audio Precision Application Note #5, Audio Precision.
http://ap.com/library/technotes.htm

'Engineering Guidelines: The EBU/AES Digital Interface'. John Emmett. European Broadcasting Union, 1995.
http://www.ebu.ch/CMSimages/en/tec_AES-EBU_eg_tcm6-11890.pdf

Hmmm... I'll need a while to digest all this, but thank you.