I'm having a problem that I'd appreciate some advice/opinions on. 

I have a Yamaha RX-V1800 (fairly new), 5T fronts, 5C center, 5B surrounds and a Bravus 10D subwoofer.  I also have a Cox HD cable box that's hooked up to the Yamaha via HDMI.  The Yamaha outputs to a Sharp Aquos 52" LCD HD television.

Over the past few weeks I've been having an audio problem while watching cable TV.  On many of the stations, both SD and HD, the dialog is what can best be described as screechy/boomy/echo-like.  The problem is especially noticeable at higher frequencies (a woman's voice for example). At first I thought maybe it was something with the 5C so I set the Yamaha to 2-channel stereo and I have the same problem when getting the dialog through the 5T's.  If I flip the Yamaha through enough of the preset filters, including "straight" the problem is minimized but it doesn't go away. 

What's interesting is that it's the dialog for the TV program. When they switch to a commercial the dialog sounds just fine.  I also don't experience the problem with the tuner, CDs or DVDs, just cable broadcast.  Obviously that would lead one to believe the problem is with Cox.  But, if I watch the same TV program on a TV and use the TV speaker, the dialog sounds just fine. 

Do you think the problem might be with the cable box?

HDMI? I could connect without it but it's a hassle.

The Yamaha? 

God forbid, the speakers?

My 60 year old ears? :-)

 Any suggestions on how to track this problem down would be greatly appreciated.

Thanks!

 

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Joe
If you can't have fun doing it, it's probably not worth doing.

I'd recommend (if you haven't already done so) calling your cable company to see if they've had similar problems as of late with customers and see if you could switch out your cable box.  Sounds like the problem is on their end to me

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Do or do not, there is no try.

What I find interesting about your situation is you state when it goes to commercial, it sounds fine. It makes me wonder if your amp is choking on the particular codec (if that is the right word). Most commercials are just regular 2 channel sound. Most TV show broadcasts are in some sort of dolby surround. I can actually hear my amp clicking when a commercial comes on when it switches from the 5.1 to two channel. Sometimes, I miss a word or two of the commercial, due to the switching of the audio codecs.

I have not had the issue you describe, other than the clicking, which is normal. I am not running HDMI for my cable though. It is not even an option with Charter in my area (MOXI boxes....ugggggh). I have to use component, and optical for audio.

I will be interested to hear what others think on this.

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Scottiemon

Hmmm...I understand what you're saying, but (there's always a "but") it does it with standard definition channels that are coming in as 2 channel stereo as well as the digital channels that are coming in as 5.1 and, at times 2 channel stereo. The Yamaha front panels shows me what audio signal is coming in.  Something interesting happened today; I had the TV on a SD channel and the Yamaha was set to 2 channel stereo and I was getting the booming/echo/screeching problem.  I switched the Yamaha to 7 channel stereo and it sounded OK. I switched it to "straight" and the problem came back. 

I have talked to Cox about it and they said it isn't a known problem. They also politely informed me that they don't support HDMI. Their logic is that there isn't an HDMI standard so they won't support it (I know, I know, but it's the cable company!).  Important to note that their installer hooked it up using HDMI and told me I'd be nuts to use component video cables along with their supplied audio cables.

The very odd thing is that it doesn't happen all of the time; could it be that the original audio was pretty screwed up and the TV speakers didn't much care because they're low quality anyway and the Yamaha is actually trying to do something with the signal and just magnifies the low quality?

I'll keep you posted. I love a good mystery.

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Joe
If you can't have fun doing it, it's probably not worth doing.

joetag:

Hmmm...I understand what you're saying, but (there's always a "but") it does it with standard definition channels that are coming in as 2 channel stereo as well as the digital channels that are coming in as 5.1 and, at times 2 channel stereo. The Yamaha front panels shows me what audio signal is coming in.  Something interesting happened today; I had the TV on a SD channel and the Yamaha was set to 2 channel stereo and I was getting the booming/echo/screeching problem.  I switched the Yamaha to 7 channel stereo and it sounded OK. I switched it to "straight" and the problem came back. 

I have talked to Cox about it and they said it isn't a known problem. They also politely informed me that they don't support HDMI. Their logic is that there isn't an HDMI standard so they won't support it (I know, I know, but it's the cable company!).  Important to note that their installer hooked it up using HDMI and told me I'd be nuts to use component video cables along with their supplied audio cables.

The very odd thing is that it doesn't happen all of the time; could it be that the original audio was pretty screwed up and the TV speakers didn't much care because they're low quality anyway and the Yamaha is actually trying to do something with the signal and just magnifies the low quality?

I'll keep you posted. I love a good mystery.

Joe,

Cable companies and Dish companies are heavily compressing there programming so they can get more HD channels for marketing reasons.  They can do this show by show if they want.  When you are getting the poor audio do you notice any softness or other artifacts?

Cheers

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Russ

Joined you!

Russ,

Nope, the video looks great. The cable box it outputting 1080i to the Yamaha which is passing it through to the television.  No complaints about the picture quality at all, no *blips*, etc.  It's just the audio that gets messed up.  In case it wasn't clear, while the problem isn't consistent, meaning across all channels all the time, it is consistent for any given television program and, I've noticed, for a specific  channel for more than one television program.

Thanks for your help - keep those ideas coming.  I may just take some vitamins and move the entertainment center so I can re-cable the box to the Yamaha with component video/digital audio and see what happens but it may take a few days for me to work up the energy.

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Joe
If you can't have fun doing it, it's probably not worth doing.

What I think I learned:

I have a small portable TV that displays the audio signal it's receiving (Mono or Stereo). When I got a "booming" audio on the HT system I turned the portable on and it said the audio signal was Mono.  I think the Yamaha is getting the mono signal and pushing it out to the fronts like it was in stereo and it just doesn't sound right.  Note that this only happens on standard def. broadcasts.

The other night I was watching a game show (lots of dialog) on a HD channel. It didn't sound quite right.  The Yamaha showed that it was receiving a 5.1 audio signal from the cable box but all of the sound (dialog and background music) was coming from the fronts. Switching the Yamaha to different sound fields had little or no effect on the sound other than to make it "boomier" (is that a word?) when you'd set it to something like Live/Club. Turning on my portable TV I saw that CBS, in this case, was broadcasing the standard def. program in stereo.  The HD channel wasn't showing the show in wide screen (although they did add the CBS bars on the side). What I think is happening is that CBS through Cox is putting the standard def. show on a HD channel and I'm really getting stereo but for some reason the Yamaha is being told that the audio signal is 5.1 and it treats it as such. 

I wondered if there was something wrong with the Yamaha. But, the very next program on CBS in HD was broadcast in full screen, the Yamaha said it was receiving a 5.1 signal and, in fact, it was. 

I also swapped cable boxes (I have two high def. TV's) and the same thing happened with the other box.  One bad cable box I'd understand - but 2? Nah...the problem lies somewhere with Cox and/or the broadcasters.

If anyone has any other thoughts I'd appreciate the input.

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Joe
If you can't have fun doing it, it's probably not worth doing.

HI Joe,

 I just raced through this string and will need to come back to it, but two things come to mind:

1. Is there a setup menu for your cox box? If so, find the audio portion and make sure it is set to Bitstream and not PCM (there may be an option for bitstream/pcm or digital/pcm or dolby/pcm- in any case, make sure you're not getting just PCM)

2. The Yamaha may try to process the mono signal it gets into a surround friendly format. When you're getting mono, I would try switching to one of the stereo modes, be it 7-channel stereo or plain old stereo. See if that makes some difference.

Either way, this is a great string. Thanks for sharing your problem. I think others will benefit!

Caleb
 

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Caleb Denison
Home Theater Guru
Aperionaudio.com

Thanks Caleb.

I took a look at the set-top box menu.  There are only 2 audio related settings.

The first is Audio: Digital Out.  You can choose Dolby Digital, Other, and HDMI. I'm hooked up to the AVR via HDMI so I have it set to HDMI.  I experimented and set this to Dolby Digital and I lost sound so clearly that's not the right choice. My other HDTV is connected to a Sony X1 receiver (a 2.1 system) for audio - that TV is set to Dolby Digital but is connected to the cable box via RCA jacks, not HDMI.

The second is Audio Range. The options are Wide, Normal and Narrow.  It was set to Narrow. I have no idea what that does but I'm guessing it's dynamic range; I switched it to Normal to see if that makes a difference (I'll let you know).  My other HDTV which is connected to a cablebox (although a different model) also has this set to Narrow.

You're dead-on with what I have to do when I suspect a mono signal is coming into the Yamaha. Sometimes it sounds OK (just OK) in 2-channel stereo but sometimes it has an echo/booming in 2-channel and if I switch to 7-channel stereo it sounds better. It's interesting though that if it's mono coming in and it sounds OK in 2-channel stereo it has that echo/booming effect if I switch to 7-channel stereo.  OK, maybe it's not interesting, but I do find it odd.

I'll play around and keep you posted. If you think of anything else, let me know.

Thanks!

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Joe
If you can't have fun doing it, it's probably not worth doing.