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  Reply # 374231 29-Aug-2010 17:30
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hdinsider: Is your Dolby decoder compliant with the TB-11 standard set by Freeview? Sony and Samsung IDTV's aren't downmixing correctly and this causes a lower audio level on AC3 relative to AAC.

I have perfect matching levels between different channels and between the AC3 and AAC tracks on both my new V-series Panasonic plasma IDTV and my old Zinwell DTT box.



As my TV doesn't have a digital decoder built in I am using a STB..




Regards,

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  Reply # 374307 29-Aug-2010 21:36
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sbiddle:
scuwp:Worst time for me?  TV3 news.  Seems to coincide with kids getting noisy (typical) which makes things worse!  Don't know if thats 5.1 or 2ch, but I can never get it loud enough to hear over everything else thats going on.  If it's an indemic problem then they better get it sorted or their viewer ratings might take a dive once the full changeover is complete. 


You could just always switch the audio to AAC.



Never dawned on me it might be the TV?  Its a Sharp Aquos...how on earth do I change the audio to AAC.  Can't find a setting to do that anywhere?





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  Reply # 374310 29-Aug-2010 21:50

sbiddle: I assume you're comparing TV3's AC3 feed with the AAC feed on other channels? This is a slightly "softer" sound.

TV3's AAC feed should be pretty much the same as AAC on other channels.






Yep that is the reason. If you switch the sound channel, the volume matches the other channels. I find this annoying to, but there are bigger problems in this world.

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  Reply # 374319 29-Aug-2010 22:19

Hi Geekiegeek. I'm glad that someone else had noticed that the ads had got quieter compared with programs. It's what we have all wanted for years! How much quieter are they?




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  Reply # 374322 29-Aug-2010 22:25

HI Old3eyes. Are you decoding ac3 with an external amplifier? Maybe it's not TB-11 compliant causing the level changes. Or is it the STB downmix that's not right. What brand STB are you using?




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  Reply # 374373 30-Aug-2010 07:02
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scuwp:
sbiddle:
scuwp:Worst time for me?  TV3 news.  Seems to coincide with kids getting noisy (typical) which makes things worse!  Don't know if thats 5.1 or 2ch, but I can never get it loud enough to hear over everything else thats going on.  If it's an indemic problem then they better get it sorted or their viewer ratings might take a dive once the full changeover is complete. 


You could just always switch the audio to AAC.



Never dawned on me it might be the TV?  Its a Sharp Aquos...how on earth do I change the audio to AAC.  Can't find a setting to do that anywhere?



No idea. But TV's such as the Sony's and Panasonic's allow you to just push a button and change between AC3 and AAC.

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  Reply # 374390 30-Aug-2010 08:43
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hdinsider: HI Old3eyes. Are you decoding ac3 with an external amplifier? Maybe it's not TB-11 compliant causing the level changes. Or is it the STB downmix that's not right. What brand STB are you using?


1. I am sending the AC3  on a optical link to the HT amp from the STB.


2. I am sending the HD video thru component to the TV and the  audio via analog connectors to the TV.  No HDMI involved..

My STB is now a HDT HD801 http://www.freeviewshop.co.nz/hd801s-digital-terrestrial-receiver-freeview-p-496.html

The one I had before this was a Draco.  Both have the same issue..




Regards,

Old3eyes


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  Reply # 374413 30-Aug-2010 09:43
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old3eyes:
hdinsider: HI Old3eyes. Are you decoding ac3 with an external amplifier? Maybe it's not TB-11 compliant causing the level changes. Or is it the STB downmix that's not right. What brand STB are you using?


1. I am sending the AC3  on a optical link to the HT amp from the STB.


2. I am sending the HD video thru component to the TV and the  audio via analog connectors to the TV.  No HDMI involved..

My STB is now a HDT HD801 http://www.freeviewshop.co.nz/hd801s-digital-terrestrial-receiver-freeview-p-496.html

The one I had before this was a Draco.  Both have the same issue..



1.  That is the cause when TV3 isn't transmitting a program that is in AC-3, the center and rear speaker and possibly the sub channel are transmitted as silence.   When viewing TV2 in AAC, you have 2 channel PCM going to the receiver which will probably upmix it to use all speakers.  More speakers = more perceived  volume.

If you put your receiver in direct mode, it should only use 2 speakers on the decoded AAC PCM as well.   Which should make them similar.

OR

Tell the set top box / tv to downmix AC3 to 2 Channel PCM, then it will be upmixed like AAC.




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  Reply # 375028 31-Aug-2010 17:45

old3eyes:
hdinsider: HI Old3eyes. Are you decoding ac3 with an external amplifier? Maybe it's not TB-11 compliant causing the level changes. Or is it the STB downmix that's not right. What brand STB are you using?


1. I am sending the AC3  on a optical link to the HT amp from the STB.


2. I am sending the HD video thru component to the TV and the  audio via analog connectors to the TV.  No HDMI involved..

My STB is now a HDT HD801 http://www.freeviewshop.co.nz/hd801s-digital-terrestrial-receiver-freeview-p-496.html

The one I had before this was a Draco.  Both have the same issue..


It sounds like the HT amp is not matching the Dolby decode level with the AAC level. It would be good to try another Dolby decoder (different brand amplifier maybe) and see what the level change is then.

My own experience with a Yamaha HT amp (fed optically) has been that the levels match when changing channels, (even if the Yamaha automatically goes into prologic mode when on TV1 or 2).

Looks like the STB isn't the problem if you aren't using it to decode or mixdown the Dolby.

Cheers.




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  Reply # 375029 31-Aug-2010 17:47
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My DVB-T STB is connected directly to TV (panasonic) via HDMI cable and I have the TV3 low volume issue




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  Reply # 375031 31-Aug-2010 17:58

JimmyLizar: My DVB-T STB is connected directly to TV (panasonic) via HDMI cable and I have the TV3 low volume issue


Hi,

Is your DVB-T STB doing the Dolby decode and downmix to HDMI? If it is it could be the STB causing the sound to be low. What brand STB have you got- does it have the Freeview certification?

Cheers. 

Sorry- just read your earlier post re it being a JC Mathew box. I'll try to test one myself and see what they do.




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  Reply # 375050 31-Aug-2010 19:19
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hdinsider:
old3eyes:
hdinsider: HI Old3eyes. Are you decoding ac3 with an external amplifier? Maybe it's not TB-11 compliant causing the level changes. Or is it the STB downmix that's not right. What brand STB are you using?


1. I am sending the AC3 ?on a optical link to the HT amp from the STB.


2. I am sending the HD video thru component to the TV and the ?audio via analog connectors to the TV. ?No HDMI involved..

My STB is now a HDT HD801 http://www.freeviewshop.co.nz/hd801s-digital-terrestrial-receiver-freeview-p-496.html

The one I had before this was a Draco. ?Both have the same issue..


It sounds like the HT amp is not matching the Dolby decode level with the AAC level. It would be good to try another Dolby decoder (different brand amplifier maybe) and see what the level change is then.

My own experience with a Yamaha HT amp (fed optically) has been that the levels match when changing channels, (even if the Yamaha automatically goes into prologic mode when on TV1 or 2).

Looks like the?STB isn't the problem if you aren't using it to decode or mixdown the Dolby.

Cheers.


That may explain the HT amp but not the STB to TV set which is over analog..




Regards,

Old3eyes




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  Reply # 375069 31-Aug-2010 20:30
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Fixed the problem (I think). Went through the decoder setup and un-selected anything that had a reference to dolby digital or digital sound. On this decoder we only use the TV sound so can't hear any real difference, other than the volume levels all now seem to be around the same.

Thanks for the clues eveyone has provided. I hope TV3 get there act sorted.




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  Reply # 375079 31-Aug-2010 20:50
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scuwp:
Thanks for the clues eveyone has provided. I hope TV3 get there act sorted.


There isn't anything for them to actually "sort". It's simply a result of the differences in audio characteristics betwen a 5.1 Dolby Digital encoded audio stream and a 2 channel AAC feed.

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  Reply # 375129 31-Aug-2010 23:53

old3eyes:
hdinsider:
old3eyes:
hdinsider: HI Old3eyes. Are you decoding ac3 with an external amplifier? Maybe it's not TB-11 compliant causing the level changes. Or is it the STB downmix that's not right. What brand STB are you using?


1. I am sending the AC3 ?on a optical link to the HT amp from the STB.


2. I am sending the HD video thru component to the TV and the ?audio via analog connectors to the TV. ?No HDMI involved..

My STB is now a HDT HD801 http://www.freeviewshop.co.nz/hd801s-digital-terrestrial-receiver-freeview-p-496.html

The one I had before this was a Draco. ?Both have the same issue..


It sounds like the HT amp is not matching the Dolby decode level with the AAC level. It would be good to try another Dolby decoder (different brand amplifier maybe) and see what the level change is then.

My own experience with a Yamaha HT amp (fed optically) has been that the levels match when changing channels, (even if the Yamaha automatically goes into prologic mode when on TV1 or 2).

Looks like the?STB isn't the problem if you aren't using it to decode or mixdown the Dolby.

Cheers.


That may explain the HT amp but not the STB to TV set which is over analog..


Hi old3eyes,
 
I guess in this case that the Dolby decoder in the HDT STB can't be doing the correct decoding either. Is it a Freeview approved box?

Maybe the Draco was also not decoding correctly. I've got a dead Draco here. I'll try and make it go and check the levels and let you know.

There are a lot of different boxes out there now, that's for sure!





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