Digital Cable Box - Stereo Passthrough - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 5 Old 12-06-2000, 04:37 AM - Thread Starter
Member
 
ALarryR's Avatar
 
Join Date: Feb 2000
Location: New York, NY, USA
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I just had Time Warner (New York) install one of their Digital Cable Boxes, Scientific Atlanta - Explorer 2000. This box replaced a General Instrument CFT2200 that I had been using. I noticed that with the new Box I no longer get a Stereo signal light on my TV indicating a Stereo Broadcast. When I plug my raw cable into the TV the Stereo light comes on. In addition, when my old GI box the Stereo signal was present.

Can anyone with an Explorer 2000 box confirm this behavior?
This question has nothing to do with my ReplayTV functionality, which works fine with either box.
Thanks,
Larry
ALarryR is offline  
Sponsored Links
Advertisement
 
post #2 of 5 Old 12-06-2000, 07:26 AM
AVS Special Member
 
DrJoe's Avatar
 
Join Date: Aug 2000
Location: Franklinton, NC, USA
Posts: 2,228
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
How are you plugging it in to your TV? If you are using the RF output from the cable box, you will probably be getting a mono-audio signal. If you are using the composite audio outs you will get stereo; if you run the composite audio through a surround or dolby prologic surround receiver you should get 3- or 4-channel surround sound. You will ONLY get dolby digital 2.0 for the digital channels (most of the channels you get below 85 or so -- that you also get when you plug the cable into a cable-ready TV -- are ANALOG). Note that Dolby Digital 2.0 is NOT DVD-style DD 5.1 -- DD 2.0 is the dolby digital version of 2-channel composite audio (and can also be decoded into 3- or 4- channels with a surround receiver).

Has to do with the way the signals are processed. In a previous discussion, it was explained that when the cable company sends a cable signal, it is stereo RF modulated. If you plug the wall-cable into a device such as a TV, VCR, or Cable box, it demodulates the signal into stereo baseband to send through the composite audio/video/s-video jacks. Because RF stereo modulators are EXPENSIVE; your "box" PROBABLY only contains a $.75 mono-RF modulator. So your box gets the stereo signal, demodulates it for the composite outputs, then remodulates it in mono format for the RF output to your TV.

One of the posters reported that a few higher-end VCR's have stereo modulators for RF outputs -- but most don't. I would expect that the cable box doesn't.

If you haven't read up on Scientific Atlanta 2000 setups and how the digital cable actually works (the lower half of the channels are ANALOG) please review my posts (go to search, ReplayTV Forum/DrJoe) -- I have posted the best IR settings, some suggested hookups, and some suggestions on getting the most out of the box (#1 after the IR settings -- split the RF cable at the wall; send it to both the cable box and the ReplayTV unit. Setup Line 2 for the digital cable; set up the RF input for "cable ready TV". In the channel guide the digital box will be channels 0-1000; the analog RF will be 1001-1087. Delete all channels below 1000 that are also above 1000).

good luck

Joe

Home Page (click to enter)
RCA Television Service Information (DTV306/7 and ITC222)
DrJoe is offline  
post #3 of 5 Old 12-06-2000, 11:21 AM
Senior Member
 
MikeNY718's Avatar
 
Join Date: Aug 2000
Location: Queens, NY
Posts: 210
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
A few notes:

I'm still waiting for Time Warner DTV in NYC, but my family upstate has Digital Cable from Time Warner (previously from TCI, but they spun off their upstate NY cable systems to Time Warner before the AT&T deal). Up there, they use the GI DCT-1000 box. What I have noticed is that the digital channels (121-930) are only broadcast in mono (no matter how you connect the box to the TV), while the original analog channels (2-96) come through in stereo, even when the box is connected via RF to the TV.

DrJoe is correct about the lower channels being analog. Channels 1-93, which you had previously (I'm assuming you had the MetroChoice package, since you had a CFT-2200), are still analog, even if you have DTV. Only channels 100 and up are actually digital.

One thing doesn't sound right about that though. I have never heard of a popular cable box (one that a cable company would use) not having a stereo RF modulator. You SHOULD be able to get stereo sound through your cable box no matter how it is connected to the TV. I would try tuning to an analog channel (1-93) through your cable box. If that doesn't/didn't work, there might some menu setting that's wrong. I can't confirm though, I don't have that box yet.

I'd tell you to call Time Warner, but they're useless. I once called them during an outage, and after being on hold for 20 minutes, I got a hold of one of the "customer service" people. I told him the cable went out in my area, which I know for a fact was true because my friend down the block lost his service too. He then asked me what my zip code was. After I told him, he said, "There's no service outage in your area."
MikeNY718 is offline  
post #4 of 5 Old 12-06-2000, 02:06 PM - Thread Starter
Member
 
ALarryR's Avatar
 
Join Date: Feb 2000
Location: New York, NY, USA
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
DrJoe & MikeNY thank you. I have a bit of an update.
As to DrJoe's question..I do split the incoming Raw Cable...I run a Raw Cable input to the RF input of the ReplayTV, set to Time Warner (Cable Ready TV), those channels show up in the Channel Guide as 1000+. I take the RCA Audio Jacks and the S-VHS from the cable box and plug them into Input 2 on the ReplayTV, set to Time Warner Digital, these channels show up in the Guide from Channel 1 up to 500+, lot's of gaps. By the way there are a number of mismatches in the Channel lineup that I have to report to ReplayTV Customer Service.

In addition, since my TV can take two RF inputs, I have Raw Cable in one and Cable Box RF output to the other. If I tune the TV using the Raw Cable RF input the Stereo light comes on, just about all channels. If I tune the TV via the Cable Box (Scientific Atlanta - Explorer 2000) the Stereo light does not come on at all and the sound is noticably different than the corresponding channel using Raw Cable input. By the way my VCR Tuner behaves the same way, Raw Cable - Stereo signal, Cable Box - No Stereo Signal.

To make life interesting I took the Digital Output from the Cable Box (RCA Jack) and plugged it into a Surround Sound Amp that automatically seeks the Digital Signal. I do get a digital signal and sound on some lower stations, Channel 3, TNT, 14, Fox Family, and some of the Movie Channel up in the 200+ Range.

As MikeNY stated calling Time Warner is useless so I called Scientific Atlanta Technical Support. The Tech told me that the Explorer 2000 does not support Stereo passthru on the RF output but that their newer boxes, Models 2010, 2100, and their 3000 series do support it.

I will try contacting Time Warner to see if they have any of the newer models. I won't hold my breath.

By the way is there any way to know whether or not the ReplayTV box is seeing a Stereo Signal?

Stay tuned,
Larry
ALarryR is offline  
post #5 of 5 Old 12-06-2000, 02:34 PM
AVS Special Member
 
DrJoe's Avatar
 
Join Date: Aug 2000
Location: Franklinton, NC, USA
Posts: 2,228
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I can tell you some good stories of their service here in Austin... I was one of the first in the service area to get digital service... they came and hooked it up and all I got was analog sound -- no dolby digital for ANY channels... So I talk to tech service and they want me to take the issue up with KENWOOD (makers of my dolby digital A/V receiver)!!!.... After going through three layers of customer service, and swapping out two units, I finally talked to engineering's department head -- he had no clue why it wasn't working... he got back to me three day's later to let me know that HIS engineers hadn't informed him, the marketing team, or customer service, that they hadn't gotten around to activating the digital audio yet -- and wouldn't for 4-6 weeks! All this while they are bombarding the market with adverts for "CD QUALITY SOUND"!!

Then, they didn't know it was DD 2.0 and not 5.1, and they didn't know that it was only provided for the digital channels...

I find that ALL my channels are stereo when I use the composite audio outputs, and if I run them through a dolby prologic receiver, I get 3- or 4- channels of surround sound (depending on how the source program was originally recorded)... I have never tried using the RF connection -- so I don't know whether or not it is stereo or mono. I do know that most VCRs and some cable boxes have a MONO output through the RF (check http://www.avsforum.com/ubb/Forum13/HTML/001844.html for more details). I will hook up the RF to the TV and see what I can tell...

I'll give the simpler non-A/V Receiver description of the hookup I use to get everything in stereo (run it through an A/V receiver and you get surround sound too)

A hookup that works good for me -- and gives me a good picture/sound in all cases, is to split the RF feed at the wall, sending it into the ReplayTV unit and the Explorer 2000. The Explorer 2000 has three video and three audio outputs (s-video, composite audio/video, RF audio/video, dolby digital audio)... I send the s-video to the ReplayTV Line 2, and the composite video to Line 2 on the TV. The composite audio I split using "Y" audio cables, sending it from the Explorer 2000 box to Replay Line 2 and Line 2 on the TV. The s-video from ReplayTV goes to Line 1 on the TV, along with the composite audio. With a strong signal I split the RF feed at the wall 3 ways and run it into the TV's RF connection.

When I set up the Replay, I use "digital cable" for line 2; "cable ready tv" for the RF feed. In the channel guide I delete all the channels under 1000 (box channels) which are duplicated above 1000 (RF analog cable channels).

So I can...

a)Watch Analog cable on the TV at any time (TV's Cable Ready Tuner)
b)Record analog cable on the Replay at any time
c)Watch the cable box while recording on the Replay from an analog station (or watch the same digital channel I am recording without losing resolution due to MPEG encoding)(TV line 2)
d)Watch a recorded show or live feed on the Replay (TV line 1)

Inserting an A/V receiver between the units and the TV is not difficult and you get surround sound... You can add more components then (VCR, DVD, CD/TAPE, etc); you can also send the dolby digital 2.0 to the same line input on your dolby digital ready A/V receiver as the composite audio/video cable box connections -- then you can utilize the "CD Quality Sound" -- note I can't tell the difference between surround-decoded composite analog audio and surround-decoded dolby digital 2.0 audio.

hope this helps


Joe


Home Page (click to enter)
RCA Television Service Information (DTV306/7 and ITC222)
DrJoe is offline  
Closed Thread ReplayTV & Showstopper PVRs

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off