# Noise when changing channels



## web1b (Oct 3, 2006)

I replaced a 2 year old HTIB that started making a "feedback" noise whenever I watched an analog source using the digital optical audio.

I bought a new Samsung HT=WZ412 and now that problem is solved, but there is a new audio problem. Now when I change channels, there is a weird ZAPPING noise that sounds like a Tazer. I went to the store and replaced the receiver and the problem remains.

This is the setup:

Tivo HD hooked up to an OTA antenna and output the video to my Panasonic 42" plasma monitor via HDMI (there is no audio on the display because it is just a monitor). 
For audio I have the digital optical audio output on the Tivo HD hooked up to Samsung HTIB.

This is what it looks and sounds like:






Does anyone have any idea what the problem is or is this receiver just incompatible with the Tivi HD.


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## rvmeush (Dec 25, 2001)

I have started to get weird audio pops and glitches when I do a 30 sec skip. I am also using a Samsung set with HDMI connection to Tivo. The skip had been working fine but just started to mess up tonight. This started happening after the Tivo did a reboot in the middle of changing screens on Tivo. I did another restart to see if this would correct the sound problem, but it didn't help.


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## bkdtv (Jan 9, 2003)

If you are using HDMI to your TV, be sure to set Settings -> Audio to PCM Output. Most TVs do not support Dolby Digital 5.1 through HDMI and may produce pops or screeching sounds in response to a 5.1 signal.


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## bkdtv (Jan 9, 2003)

web1b said:


> This is the setup:
> 
> Tivo HD hooked up to an OTA antenna and output the video to my Panasonic 42" plasma monitor via HDMI (there is no audio on the display because it is just a monitor).
> For audio I have the digital optical audio output on the Tivo HD hooked up to Samsung HTIB.


Is the zapping sound coming from your TV or the HTIB?

Is the volume on your TV muted?


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## web1b (Oct 3, 2006)

bkdtv said:


> Is the zapping sound coming from your TV or the HTIB?
> 
> Is the volume on your TV muted?


The TV is just a monitor. It does not have sound or speakers. All the sound is coming from the HTIB. 
I'm using the HDMI cable only as a video input to the monitor.


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## bkdtv (Jan 9, 2003)

web1b said:


> The TV is just a monitor. It does not have sound or speakers. All the sound is coming from the HTIB.
> I'm using the HDMI cable only as a video input to the monitor.


Sound receivers (especially cheaper ones) have trouble handling the breaks in the audio signal that result whenever you fast forward, rewind, 30s skip, replay, or change channels using the current TiVo software. Some receivers respond to these breaks with a high-pitched noise. Others lose audio temporarily for 2-4 seconds. And still others lose sound entirely until the next trickplay function.

From reports on this forum, the TiVo didn't always cause these problems for these receivers. Some believe that TiVo used to _mute_ the audio during trickplay functions, rather than breaking the audio signal -- they use this to explain the fact that their receiver did not exhibit these problems with the older TiVo software. Regardless, it is clear now that a) there are breaks in the TiVo audio signal during trickplay (FF, REW, etc) and channel changes, and b) this cause problems for some percentage of HITBs and A/V receivers.

I own Denon and Panasonic A/V receivers and neither has a problem with the TiVo audio output. Both acquire and output audio [near] instantly after trickplay, and there is never a loss of audio, nor is there ever any noise other than what is coming from the program.


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## bkdtv (Jan 9, 2003)

To the above, you might try disabling TiVo sounds, if you have not already. I think one person mentioned that disabling TiVo sounds eliminated the problem for them. But this clearly is not a solution for all.


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## web1b (Oct 3, 2006)

bkdtv said:


> If you are using HDMI to your TV, be sure to set Settings -> Audio to PCM Output. Most TVs do not support Dolby Digital 5.1 through HDMI and may produce pops or screeching sounds in response to a 5.1 signal.


I tried changing the setting and it fixed the noise.


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## bkdtv (Jan 9, 2003)

web1b said:


> I tried changing the setting and it fixed the noise.


That is not really a solution for a HTIB.

When you change the audio output to PCM, you lose Dolby Digital 5.1 audio on HD channels. That's fine if you are using TV speakers, but not so good if you have a 5.1 surround speaker system.


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## web1b (Oct 3, 2006)

bkdtv said:


> That is not really a solution for a HTIB.
> 
> When you change the audio output to PCM, you lose Dolby Digital 5.1 audio on HD channels. That's fine if you are using TV speakers, but not so good if you have a 5.1 surround speaker system.


Won't I still get 5.1 sound to the HTIB through the optical digital audio cable?
I'm just using the HDMI for video to the monitor. I can't plug the HDMI into the HTIB because it doesn't have an HDMI input.
I could swap cables and connect the Tivo to the monitor via component video and then connect the HTIB to the monitor via HDMI instead, but I don't see what that would accomplish.


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## bkdtv (Jan 9, 2003)

web1b said:


> Won't I still get 5.1 sound to the HTIB through the optical digital audio cable?
> I'm just using the HDMI for video to the monitor. I can't plug the HDMI into the HTIB because it doesn't have an HDMI input.
> I could swap cables and connect the Tivo to the monitor via component video and then connect the HTIB to the monitor via HDMI instead, but I don't see what that would accomplish.


I can't recall whether Settings -> Audio -> PCM affects optical output, or only HDMI.

If your HTIB indicates DD5.1 on HD channels, then I suppose you are fine.


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## web1b (Oct 3, 2006)

I don't think I have 5.1 surround with the new settings, so I don't think this is a good fix and I don't know what else to try.

I tried changing the cables so that the HTIB uses the HDMI cable and the Tivo uses the component video cables and when I turn Dolby Digital back on, the static noises returned.

Does anyone have any other suggestions? It doesn't make sense that you can't use a HTIB with a Dolby Digital audio from a Tivo without these audio problems.


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## web1b (Oct 3, 2006)

bkdtv said:


> To the above, you might try disabling TiVo sounds, if you have not already. I think one person mentioned that disabling TiVo sounds eliminated the problem for them. But this clearly is not a solution for all.


I tried turning the Tivo sounds off and it doesn't help.
Muting would have been much better than hearing annoying static noises when changing channels, pausing and FF.


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## kucharsk (Feb 2, 2007)

bkdtv said:


> Sound receivers (especially cheaper ones) have trouble handling the breaks in the audio signal that result whenever you fast forward, rewind, 30s skip, replay, or change channels using the current TiVo software. Some receivers respond to these breaks with a high-pitched noise. Others lose audio temporarily for 2-4 seconds. And still others lose sound entirely until the next trickplay function.


To be fair that's not really a digital audio receiver issue per se.

There are two philosophies - one that all data should be output, and one that a certain number of good packets need to be seen to output sound.

The latter approach quiets bursts of noise, but also means that you may have delays in audio being output after changing channels.

There are also two approaches in audio output - one abruptly stops the digital data on pause or channel change, and one explicity sends a muted audio stream when valid received audio is not present. TiVos apparently do the former.

This same issue is seen when connecting Pioneer DVD players to the same devices as they also abruptly stop sending data rather than send a data stream of no audio.


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## M3 Adjuster (Feb 11, 2009)

I have this issue.. I bought a Tivo HD last week... I am using a Lexicon MC-1 preamp, which runs into an Adcom 5 channel amp for surround and a Velodyne sub. All of the components are connected to a Panamax power conditioner, and both cable and off the air antenna connections run through the conditioner and then into the Tivo. Clearly not a budget receiver setup. I switched from analog inputs to the optical audio out last night. The sound is FAR better, much more dynamic, especially on the low end with the sub. My daughter noticed that there is a popping when changing channels and sometimes when forwarding/rewinding. It primarily comes from the right front speaker. It quickly became VERY annoying. I went into the preamp menu and changed the audio to analog and the noise when changing channels went away. 

The Lexicon has the ability to look for the digital input in several ways.

Automatic (searches and detects input..PCM, AC-3 Dolby Digital, or DTS) 
PCM only 
AC-3
DTS

With the setting on Automatic on the Lexicon, and Dolby Digital on the Tivo, the noise occurs. I can see that the preamp is struggling with decoding 5.1 vs 2.0 on certain channels as well and flips back and forth for 2-3 seconds and then it eventually locks in on 2.0.

I switched to the PCM setting for the digital input on the preamp, and the noise is not there, when using the PCM output from the Tivo. Unfortunately, the sound is also very thin and uninvolving. 

With the setting on AC-3 (Dolby Digital) and the Dolby Digital output selected on the Tivo, there is not any noise. I recorded a Wyclef Jean concert from HD Net and it sounds terrific! For the most part, the HD channels are in 5.1. Lots of television channels however only come up in 2.0 and not 5.1 however... which is not optimal, and a few channels have NO output. I can't quite sort out why some channels come up with 2.0.. 


No channels are encoded in DTS of course, although I imagine it would behave the same as AC-3 Dolby Digital.

I tried turning off the Tivo sounds, and this does not make a difference. Bkdtv.. I think you are definitely correct in that the Tivo is not muting it's output with the current software. Indeed, it seems that the audio signal is garbled or varying, which causes an issue with many preamps/receivers.


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## tmckay (Oct 7, 2009)

I also had this problem - screeching and zapping sounds coming from the TV when I changed channels. I have a 37" LG LH40 directly hooked up to TiVo HD. I went into the audio settings and changed Dolby Digital to PCM and the sounds disappeared (thanks to advice I received here). I don't have a surround sound system so the I don't think I'm missing much with the audio - the audio from the TV is good by itself. I thought it might be a faulty HDMI cable, but I have a Monster 900 series and it's one of the better cables available.

If I get an optical audio cord will that enhance the sound quality, or is it not worth the $$ not having a sound system?


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## jjcool (Sep 24, 2009)

bkdtv said:


> If you are using HDMI to your TV, be sure to set Settings -> Audio to PCM Output. Most TVs do not support Dolby Digital 5.1 through HDMI and may produce pops or screeching sounds in response to a 5.1 signal.


Noticed this the other night on the parents setup. They have the Tivo HD hooked up to the tv with an HDMI cable and hear a noise when they change channels. I will try your solution tonight.

UPDATE: Tried the fix, and it did indeed fix the problem. Now if someone can answer the question below, that would be fantastic.


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## jjcool (Sep 24, 2009)

tmckay said:


> I also had this problem - screeching and zapping sounds coming from the TV when I changed channels. I have a 37" LG LH40 directly hooked up to TiVo HD. I went into the audio settings and changed Dolby Digital to PCM and the sounds disappeared (thanks to advice I received here). I don't have a surround sound system so the I don't think I'm missing much with the audio - the audio from the TV is good by itself. I thought it might be a faulty HDMI cable, but I have a Monster 900 series and it's one of the better cables available.
> 
> If I get an optical audio cord will that enhance the sound quality, or is it not worth the $$ not having a sound system?


Mmmmm, monster cable.

This begs the question, what happens if I add a surround sound receiver inteh future? The current setup is the Tivo HD going to the LG LCD TV via HDMI, and audio going through the tv speakers. Switching the audio settings to PCM right now is fine, but what happens when I add a receiver to the setup? Can I leave the HDMI to the tv alone, and get an optical cable and run that to the receiver to get the digital audio?


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## 13rian (Oct 13, 2009)

I'm having the same problem here. HDMI going to my 46" LCD and audio going to a Panasonic PT960. 

I hear audio pops when I change the channel and when I FF/RW. The screen also goes black temporarily sometimes, then comes back 2-4 seconds later. This has become very annoying. I have tried a new Tivo box (HD Series 3), new cables, and 2 different TV's. I haven't tried PCM yet since I do have surround sound, but will as a test. 

Any thoughts?


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## bkdtv (Jan 9, 2003)

13rian said:


> I'm having the same problem here. HDMI going to my 46" LCD and audio going to a Panasonic PT960.
> 
> I hear audio pops when I change the channel and when I FF/RW. The screen also goes black temporarily sometimes, then comes back 2-4 seconds later. This has become very annoying. I have tried a new Tivo box (HD Series 3), new cables, and 2 different TV's. I haven't tried PCM yet since I do have surround sound, but will as a test.
> 
> Any thoughts?


I assume you have HDMI going from TiVo to the LCD and optical going from TiVo to the Panasonic?

Do that and make sure your TiVo is set to fixed 1080i output.


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## lesscrappy (Feb 1, 2010)

Has a reasonable solution come out for this problem yet?? I am using my new HD tivo on a yamaha RX-V465 and switching to PCM is not an option for me. If i have to hear a high pitch feedback sound every time i change the channel, i think i will be using that 30 day money back guarantee.


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## DeWitt (Jun 30, 2004)

I solved this problem with a setup option on my receiver.

The input I was using for the Tivo was set to autodetect. Since my connection was a digital optical cable, I changed that to specify digital input and the problem went away.

Apparently the HD does not output during FF etc. Some receivers (Mostly older I suspect as my newer receiver was not a problem) will detect the missing signal and attempt to get input from the analog inputs until it detects the signal on the digital in.

Simple fix to an annoying problem.


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## sr1111 (Sep 21, 2011)

Changing the tivo audio settings to PCM thankfully fixed the problem for me too.


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## WTRickman (Feb 21, 2013)

I'm getting the chirp on channel change too. I recently upgraded to a Q/4 in my living room, and the dual-tuner premiere I had before didn't make the chirp. Changing to PCM does eliminate the chirp.

Anyway, my setup is a Tivo Premiere Quad Tuner, connected via HDMI to a Denon Home Theater Receiver, then HDMI out to a 55" Samsung LED.

Right now I only have two front speakers and a sub, but if I want to upgrade to 5.1 or 7.1, I'll need the Dolby Audio from the Tivo turned on, and thus the chirp comes back.


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## olber (Feb 8, 2014)

DeWitt said:


> I solved this problem with a setup option on my receiver.
> 
> The input I was using for the Tivo was set to autodetect. Since my connection was a digital optical cable, I changed that to specify digital input and the problem went away.
> 
> ...


This advice worked regarding: Clicking or popping noise when fast forwarding on the 2 or 3x mode. I use a TiVo 3 with a new model Samsung soundbar connected by optical to the high def TV (rather than HDMI between soundbar and TV though connection method may not matter). On the TiVo Central menu I went to Messages and settings-->Audio-->Switch Dolby to PCM. That page on TiVo actually says if you're using external speakers you should switch to PCM. Sound is now good no static or pops when forwarding. Apparently the factory default on TiVo is not the one you need for external speakers. I did not notice this sound problem on my older Samsung sound bar but regardless changing the TiVo audio setting worked. Thanks guys!


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## olber (Feb 8, 2014)

sr1111 said:


> Changing the tivo audio settings to PCM thankfully fixed the problem for me too.


Yes this fix worked. As I mentioned above TiVo recommends switching from Dolby to PCM it says it right there on the audio settings page :up:


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