# losing center channel audio



## Hubb1e (Oct 3, 2014)

So my Tivo is dropping the audio on the center channel sometimes. The dialog goes mute and all I get is the audio from the side and rear speakers which on some shows like kid's shows means that there is little audio except the music. It will happen in the middle of the show, not just at the start of the show. 

I can fix the issue for awhile by going into the settings/audio menu and clicking up and down a few times until the tivo beep noise comes back. At first I thought I needed to change the audio to PCM and back to DD, but I found all I need to do is to just click up and down in the menu and the audio comes back. The audio is then fixed and I can watch my show again for awhile. This makes me think it is something wrong with the way the Tivo beep noise has been programmed.

I'm pretty confident that the issue is not with my audio reciever as it doesn't have this problem on any other source, and I can fix it from within the Tivo itself.

I noticed this after the last update a few days ago. Anyone else see something like this? Tivo chat support hadn't heard of it.


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## NorthAlabama (Apr 19, 2012)

i have experienced this twice, both times during awards shows, and only with singing performances - vocals would drop from the center channel a fraction of a second into the vocals, and would return when the singing stopped.

i chalked it up to faulty production equipment settings or bad live surround mixing by the technician for both shows, and switched the audio on my avr to multi-channel stereo.


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## Hubb1e (Oct 3, 2014)

Multi channel stereo on the AVR doesn't work because it drops the whole audio channel before processing, so you might be able to hear a little more, but the majority of the dialog is mapped to the center channel so I'll notice the dialog gets very very faint even in stereo mode. It's happening in the Tivo processing and not in the AVR.


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## NorthAlabama (Apr 19, 2012)

you're right, switching the avr is not a solution, simply a workaround to level the sound, and prevent alternating loud blasts of vocals followed by faint trickles. i never imagined it was a tivo issue since it's happened so rarely for me.


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## Hubb1e (Oct 3, 2014)

An update for anyone who sees this problem:

So I was able to get around the issue of no dialog by switching the Tivo to output PCM audio vs Dolby. It's only 2 channel, but at least it works for now. I haven't had the problem come back with PCM.

I was also able to fiddle with the Tivo while it had lost the center channel. When I'm missing the center channel audio, I can make the center channel audio come back whenever I enter an OLD standard def Tivo menu. Once you enter the menu and click around a few times, the Tivo beep comes back and my audio is fixed for a few minutes. So this issue is with how Tivo has implemented the DD audio output and is probably a bug having to do with muxing the Tivo beeps under DD audio.


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## XIBM (Mar 9, 2013)

What audio output are you using? - HDMI - optical etc,


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## Hubb1e (Oct 3, 2014)

Hdmi

Update 2: PCM didn't fix it. It worked for awhile and then broke again. I'm switching to Optical. Thanks for the idea.


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## NorthAlabama (Apr 19, 2012)

XIBM said:


> What audio output are you using? - HDMI - optical etc,


i've experienced the issue with both hdmi and optical, specifically the lead vocal track. it happens intermittently, and only with songs (not spoken dialog).

normally lead vocals can be heard through the center speaker when using dolby surround. now, on certain songs, the lead vocals are missing from the center channel, and only resonant lead vocals can be heard on the remaining l & r channels.

this is affecting existing recordings, and can be resolved by switching my tivo or my avr to pcm audio only (no dolby).


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## JohnS-MI (Jan 25, 2014)

Are you sure you have ruled out AVR? I am having a similar issue, but I think I have narrowed it down to my AVR. Basically my TV optical out and my Roku (fed into an optical takeout box) do it too. I can solve it by changing the AVR to another optical input for a moment, then switching back.

In the case of the Tivo, I can pause, back up and correctly play the recorded passage after I have "tweaked" the AVR. That tells me the error is not in the Tivo recording.


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## Dan203 (Apr 17, 2000)

You can transfer the show to a PC and see if it's in the source or not.


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## NorthAlabama (Apr 19, 2012)

JohnS-MI said:


> Are you sure you have ruled out AVR?


how, when i have only 1 avr? no other audio is effected (blu-ray, audio cd, pc or online streaming), and pandora works great.

i've tried different hdmi cables, optical vs hdmi, and multiple decoder settings on the avr. it isn't happening on every existing recording, only a few. i've noticed it a couple of times on "live" awards shows (above).


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## nooneuknow (Feb 5, 2011)

Just to chime in a few notes:

I have two Sony Bravia TVs, one with Sony apps, right before "smart TVs", and one with nothing of the sort. Both support 5.1 input via HDMI. I use analog outputs to drive a set of stereo speakers w/subwoofer, as poor man's rear surround channel. There are no AVR/receivers in use here.

A few TiVo updates back, the dialog seemed "underwater", so I had to switch both to PCM, via the base Roamios. This is the first time I have had to use PCM, and don't like that I had to turn off all TiVo sound effects, to not get a deluge of them doing trickplay.

The simulated surround (for TV internal speakers) for both TVs had worked well before. Now with or without it, PCM is the only way I don't lose dialog (or have that "underwater" effect on it).

I'm still getting the losses/dropouts between full-screen and menus, but not between guide and full-screen. TiVo now rewinds the programming to make up for what was lost, often overlapping with what wasn't lost. I don't get the bailing wire & duct tape nature of this...

Just some data, in case it helps...


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## NorthAlabama (Apr 19, 2012)

Dan203 said:


> You can transfer the show to a PC and see if it's in the source or not.


i think i've eliminated the source for my issue, the songs in my saved recordings played ok just a few months ago.


nooneuknow said:


> Just to chime in a few notes, in case it helps...


others have mentioned center channel dialog issues recently, too, but i'd forgotten...thanks.


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## Dan203 (Apr 17, 2000)

AC3 is a compressed audio format so it's basically impossible for TiVo to do anything to the AC3 bitstream that would only effect the center channel. They would need to decode the stream, manipulate the PCM audio and then recode it to effect a single channel like that. And we know from the fact that they can't even insert their "bee-doop" sounds when playing an AC3 source that they're not doing that. I guess they could be corrupting the header in some way, but even that seems to be unlikely to cause an issue with a single channel. A corrupt header would most likely cause a complete decode failure which would result in silence on all channels or random noise. Unless maybe they're messing with the channel layout portion of the header. I guess that could cause the decoder to do weird things depending on how it's designed. But they'd have to be doing that intentionally as the header is a pretty random sequence of bits.

This is almost certainly an AVR issue. I just can't think of anything else that could cause an issue with a single channel like that.


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## NorthAlabama (Apr 19, 2012)

Dan203 said:


> This is almost certainly an AVR issue. I just can't think of anything else that could cause an issue with a single channel like that.


but only for songs, and never spoken dialog? and only certain songs in certain recordings? and only tivo, not blu-ray or other dd media devices?

i'm not convinced it's my sony avr, not yet.


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## nooneuknow (Feb 5, 2011)

NorthAlabama said:


> but only for songs, and never spoken dialog? and only certain songs in certain recordings? and only tivo, not blu-ray or other dd media devices?
> 
> i'm not convinced it's my sony avr, not yet.


Plus I'm not using any AVRs, other than what is built into my Sony Bravia TVs.

As it has been stated/debated in some threads, TiVo does not offer any method of a true "stereo" (L+R only) output option, even when PCM is selected. Essentially, my TVs have internal AVRs, which must take the DD or PCM supplied by my TiVos and convert it to stereo output.

Every other device I can connect to my TVs offers the option to output stereo via HDMI. Yet, TiVo never has offered any options but DD or PCM, and TiVo Roamios (base models) are the only "problem childs", when it comes to audio issues, for me. Roamio has been the only device I have been forced to stop using DD over HDMI with.

I wonder if there is something about Sony (and some Samsung) devices, being part of the equation as a whole, when it comes to the bigger picture. I also wonder if TiVo offered internal passing or downmixing of/to true stereo, via HDMI, to the processing/receiving device, if my dialog (typically a center-channel heavy target), would not suffer, as it has been throughout TiVo's adventures in tweaking the HDMI audio, trying to fix all the various issues it seems only TiVo fails to know how to output for maximum compatibility.

This is all just speculation, based on years of observations, plus issues I never had with HDMI, until the Roamio, and the new issues TiVo seems to create for me with nearly every software update. Every now and then, they roll a version with minimal issues for me, but then bring them back, or add more, when the release notes say they fixed something, which was not broken for me...


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## Dan203 (Apr 17, 2000)

NorthAlabama said:


> but only for songs, and never spoken dialog? and only certain songs in certain recordings? and only tivo, not blu-ray or other dd media devices?
> 
> i'm not convinced it's my sony avr, not yet.


How could TiVo possibly know that it's playing a song and not spoken dialog? It's no smarter about that then your AVR.

Maybe the audio is switching to 2ch in those broadcasts? AC3 has the ability to mix 2ch and 5.1ch in the same stream. It's common to see the stream drop to 2ch during the commercials. Maybe your AVR doesn't deal with the transition well. Or maybe TiVo is screwing with the headers and marking them all 5.1ch even when the stream drops to 2ch and that's what's causing the issue. That's the only thing I can think of that TiVo might be doing that could cause this sort of issue.

If you transfer the show to a PC you can see if this is the case using VideoReDo. You can set the tumbnails to display 2ch and 5.1 as different colors and then look at the point where the center channel drops out see if it drops to 2ch.


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## NorthAlabama (Apr 19, 2012)

Dan203 said:


> How could TiVo possibly know that it's playing a song and not spoken dialog?


i agree, and the same goes for my avr. i've now noticed it with spoken dialog on "today", only with live announcer voice-overs (sponsorships) during the segue from studio to outside plaza events (is losing sponsor announcements a feature or a fault?). after the segue, everything's fine.


> Maybe the audio is switching to 2ch in those broadcasts? AC3 has the ability to mix 2ch and 5.1ch in the same stream.


my avr reports changes to the audio stream mix on it's main display (2ch stereo, 2.0 dd, & 5.1 or 7.1 dd surround). each time it's happened my avr is reporting 5.1 dd surround (no mix changes). if i pause and resume, the display still reports 5.1 surround.

it happens so rarely at this point, it's not really worth buying another avr or taking tivo to another avr to test. i posted primarily in response to the op, was curious to see if anyone else experienced the issue, and because it was a change from previous behavior.

the recordings affected are also available on demand, using on demand as the source doesn't change the result. if it becomes more frequent, i'll start looking to testing options.


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## pgoelz (May 1, 2005)

FWIW, just as a data point I have noticed that at transitions between program and commercial, the phase of the left and right channels will very occasionally change. It will suddenly sound like the phase of one of the channels reversed. Depending on program content and how the audio is being processed, this could kill the center speaker if I had one? 

Further, if I back up and play through the transition point, the next time it won't do it. That would seem to eliminate the program source, no? 

I'm using HDMI from the Tivo to my Samsung TV, then optical from the TV to the AV receiver. The receiver decodes to Dolby with four speakers.... front left, front right, rear left and rear right. No sub and no center speaker. 

Paul


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## Dan203 (Apr 17, 2000)

NorthAlabama said:


> my avr reports changes to the audio stream mix on it's main display (2ch stereo, 2.0 dd, & 5.1 or 7.1 dd surround). each time it's happened my avr is reporting 5.1 dd surround (no mix changes). if i pause and resume, the display still reports 5.1 surround.


If TiVo was mucking with the headers then that's what you would see. I recommended transferring to a PC because that gives you the raw stream so you can see if it ever drops to 2ch.

If it does and your AVR still reports 5.1ch then that's the issue. Either the TiVo is mucking with the headers or your AVR isn't detecting the change and it's trying to play 2ch as 5.1, which could explain the weird mixing.

The standard for 2ch is L/R and the standard for 5.1 is L/R/C/LFE/SR/SL so if a 2ch was decoded as 5.1 the decoder might just fill the missing channels with silence which would produce the effect you're describing.


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## Hubb1e (Oct 3, 2014)

Update: I switched to optical from hdmI and the issue went away. But now it's back. It happens for me on kids shows on Disney like doc mcstuffins. I can get the center channel back simply by entering into one of the old style menus like settings. Once I hear the TiVo beep noise from the center channel I can resume the show and everything is fine for awhile. This shows me it's in the TiVo and not the Avr. This issue doesn't happen on my TiVo mini with the same show so it's not the recording either. TiVo offered to replace my TiVo but I'm not sure that will fix it and I'll lose all my settings and shows.


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## Dan203 (Apr 17, 2000)

Bizarre. I was checking out the new menus in the update yesterday and at one point my AVR just started squealing random noise. I backed out a menu and it went away but the menus were silent. I dropped to live TV, where the audio returned, and then went back to the menus and it was working again. So there is something starge going on with the audio there.

Although, knowing what I know about AC3 I'm still wondering how they could effect just the center channel. Are you sure when this happens the AVR isn't dropping out of DD mode and into PCM mode?


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## Diana Collins (Aug 21, 2002)

Dan203 said:


> If TiVo was mucking with the headers then that's what you would see. I recommended transferring to a PC because that gives you the raw stream so you can see if it ever drops to 2ch.
> 
> If it does and your AVR still reports 5.1ch then that's the issue. Either the TiVo is mucking with the headers or your AVR isn't detecting the change and it's trying to play 2ch as 5.1, which could explain the weird mixing.
> 
> The standard for 2ch is L/R and the standard for 5.1 is L/R/C/LFE/SR/SL so if a 2ch was decoded as 5.1 the decoder might just fill the missing channels with silence which would produce the effect you're describing.


But if the actual audio data was just L&R then the voices (which would otherwise be on the center channel in 5.1) would be mixed into the L&R audio wouldn't they? To get ONLY the left, right and possibly the surround channels but not hear ANY voice content would mean that the data being decoded *was* in 5.1 but you are only hearing 2 or 4 of the 5 channels.

Though I agree, whatever the issue, it is bizarre. We have one Roamio connected to a Panasonic plasma via HDMI and a Yamaha AVR via optical (the AVR is old enough to only have component video). The other Roamio is attached to a Pioneer AVR via HDMI. FWIW, we have never had a problem with missing audio channels. So perhaps it *is* an interaction between the Roamio and certain AVRs. DirecTV Genies have had similar DD issues with certain AVRs.


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## Dan203 (Apr 17, 2000)

Yeah it would require some seriously funky mixing for it to drop the center channel completely like that. Any real downmix would include the center channel in the L&R channels. That's why I thought maybe it was switching to PCM and TiVo was doing the mixing wrong. But if it's showing AC3 still on the receiver then I'm back to it being the receiver or TiVo corrupting the headers of the AC3 stream.


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## NorthAlabama (Apr 19, 2012)

Dan203 said:


> Yeah it would require some seriously funky mixing for it to drop the center channel completely like that. Any real downmix would include the center channel in the L&R channels. That's why I thought maybe it was switching to PCM and TiVo was doing the mixing wrong. But if it's showing AC3 still on the receiver then I'm back to it being the receiver or TiVo corrupting the headers of the AC3 stream.


to be clear, in my case there isn't a complete loss of the center channel, only certain sub-channels in the center channel mix. my opinion now is that my issue is my avr as dan suggested.

i don't know if this is new or if i just started noticing, but my avr now indicates a switch to pcm audio if i pause and enter tivo menus. i don't remember that in the past, and was thinking it might have been a change implemented to correct audio issues with some users.


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## JoeKustra (Dec 7, 2012)

I remember reading on another thread about the sound effects and the DD license. The TiVo turns off DD when the beeping/noise is used. When a live picture is showing which has DD and you have DD enabled you lose the beep but gain the 5.1 output. If I remember that right. When in SD menus the beep is there but the picture is not, etc., which may be related. Since I don't use a center speaker I would not be able to duplicate the problem even though I have a 7.2 Yamaha AVR. I can see the LFE indicator for broadcast 5.1 and most cable networks with HD channels.


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## Hubb1e (Oct 3, 2014)

I did some more research on this issue and found out that onkyo receivers of my generation, 875, have an ac3 bug that does this on some equipment. Switching to the old menus worked because it jumped out of ac3. There's a firmware update that should fix it so I've got to send the unit in or attempt it myself using rs232.


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## Dan203 (Apr 17, 2000)

Do you even own a PC with an RS232 port? I haven't seen one of those in years.


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## Hubb1e (Oct 3, 2014)

I used to work a lot with embedded systems and legacy hardware for work so I have a usb serial port. They are not expensive. What I dont have is windows Xp which is the last supported os. I'm also scared of bricking a $900 receiver.


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## h2oskierc (Dec 16, 2010)

Hubb1e said:


> I used to work a lot with embedded systems and legacy hardware for work so I have a usb serial port. They are not expensive. What I dont have is windows Xp which is the last supported os. I'm also scared of bricking a $900 receiver.


Really? I just bought a Windows 7 Machine for work that has a serial port. Wonder if it actually works...


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## SeanTivo (Sep 13, 2006)

I've had a Roamio for a few months and this just happened to me for the first time.

I have mine hooked up to a Sony receiver. In the middle of watching a recording of The Americans the Dolby center channel audio disappeared. I checked a recording I'd already watched with no problems and the center channel audio was gone from that too. 

I got the dialogue channel back when I switched to PCM. swapping back to Dolby and it drops the center channel again. 

I'll try rebooting the Tivo and see if that does anything but this will suck if it's not fixed.


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## mikeb33 (Dec 10, 2001)

My Roamio started doing this a few months ago too. I am connected via HDMI to a Yamaha avr. Anybody found a solution? Anybody tried Tivo support?


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## JoeKustra (Dec 7, 2012)

mikeb33 said:


> My Roamio started doing this a few months ago too. I am connected via HDMI to a Yamaha avr. Anybody found a solution? Anybody tried Tivo support?


I have a Yamaha X-V867. The center channel has an LED indicator when enabled and the dialog lift can be seen with the OSD Audio Information. If the LED is there, but no sound, something is bad. Just guessing: TiVo support is a waste of time.


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## V7Goose (May 28, 2005)

This is a very old thread, but since it was just revived with a post containing almost no needed information, I add this comment to possibly help others who think they are seeing the same things.

While many of the original posts from back in 2015 mention multiple stations and indicate a possible problem in the TiVo box, I will say I have never seen those issues as described. HOWEVER, there IS a very similar problem I have seen with ONLY NBC in both Texas and New Mexico. NBC has a problem with their Dolby signal that causes dropouts with the center channel, and *I have seen this with S3 and Bolt TiVos on both FiOS and OTA signals AND THE SAME IDENTICAL PROBLEMS WERE THERE WITH SATELLITE SERVICE AND DISH HOPPER DVRs. I stress that last part simply because it proves that this issue with NBC has absolutely nothing to do with TiVo hardware or software.* The only solution I have found to the center channel issues with NBC is to use PCM audio instead of Dolby.

I will describe the symptoms to help others in trying to determine if they are seeing the same thing that cannot be fixed by TiVo:
First, the problem was in the recorded signal, so rewinding playback would show the same center-channel drops at the same points in the program.

Different hardware DOES handle the Dolby signal problems differently. It is especially bad on my Sony AVR, with the audio drops on the center channel making it impossible to watch many programs. On my Yamaha AVR, you can clearly hear the signal switching in and out of normal Dolby sound, with the dialog moving from center to the L/R channels, but the total volume does not particularly drop like it does on the Sony, so the same programs are still watchable (but irritating). BOTH amps have displays that show not only the presence of a "Dolby" signal, but also which specific channels are being received, and this problem does NOT change those displays, so the receivers still think they are getting a complete Dolby signal, even when the modulation drops out of the center channel.

In Dallas on FiOS, the problem seemed to affect all programs similarly (using the Yamaha AVR and optical audio connection), with the NBC audio significantly lower than any other station due to the loss of audio on the center channels. Strangely, I do not recall significant issues on the same station with the Sony AVR and HDMI audio, but I guess it is possible I always had that box set up for PCM audio out. Here in New Mexico, the problem is MUCH worse with local broadcasting (non-network originated), such as the news programs. As soon as the morning news is over and the _Today _show starts, the problem mostly goes away (mostly, but not completely). The engineer at the Albuquerque NBC affiliate insists that they do not transmit any Dolby signal at all, despite the fact that any Dolby-capable AVR shows that it is receiving a Dolby signal.

Finally, I will note that both of my AVRs were purchased way back around the time that the S3 TiVos were relatively new (so about 10 years old now). Perhaps newer hardware handles this problem better? Certainly seems possible, considering how different the symptoms are between my Sony and Yamaha receivers; I have no way of knowing.

Bottom line for me is that you should first see if the audio signal issues are recorded in the program and repeat identically when you rewind the program. If they are, then there is probably nothing you can do about it except use PCM audio out.


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