SkyHD+ and PLII problems after EPG update..?

Ultraviolet

Standard Member
All

Since the EPG update, I've lost my 5.1 sounds on SD channels. Dolby D comes through fine on HD, but SD only outputs in stereo.

The engineer gave some flannel about it now being 'simulated digital surround sound' and I needed to change my amp settings... does this mean anything to anyone?

The amp itself auto detects Dolby D, and used to auto detect PLII... but no more. So only the front L and R channels are detected, and the amp switches to stereo. I can force it to PLII mode, but it just sounds weird...

any ideas on how I can get 5.1 back on the SD channels? I have the first generation Thomson box if that helps...

UV
 

Starburst

Novice Member
Which SD channels?
Only certain SKY movies and Disney carry DD audio on their SD channels everything else is stereo with or without embedded DS info.
 

HDCriticalFan

Active Member
I've lost my 5.1 sounds on SD channels

As a general rule, SD channels do not broadcast DD (5.1 or otherwise). The notable exceptions are the Sky movie channels ... but they are (completely ?) replicated in HD, so you should be watching the HD variants anyway (assuming that you have an HD subscription of course !).

If you tell us which programmes/channels you think have been affected then I'm sure others here will be able to elaborate.

The amp itself auto detects Dolby D, and used to auto detect PLII...

Most Home Cinema AV Amps will indeed detect DD and give you up to six channels of sound (i.e. 5.1). However, I don't believe that Dolby PL (I or II) is "detectable".

Dolby Pro Logic (unlike Dolby Digital) is not a transport format comprising multiple channels ... it is a way of encoding surround sound info for extra channels within a normal two-channel stereo signal.

In other words, your amp doesn't "know" whether a stereo signal contains extra DPL info any more than it "knows" that the music contains a saxophone (or any other specific content).

What you can do is set the amp to perform a DPL decoding procedure on an incoming stereo signal. This will create a couple of extra channels; a Front Centre and a Rear channel. The FC channel is sent to your centre speaker and the R channel is sent, equally, to your two rear speakers. The downside is that these extra channels are relatively poor quality (specifically of limited frequency range) and there is no stereo effect to the sound behind you. Some amps also route the lower frequencies to your sub-woofer, but all this does is help out systems with relatively poor speakers - there is no extra sub-bass information to really warrant the use of a sub-woofer.

I can force it to PLII mode, but it just sounds weird...

If the incoming stereo signal contains no surround info, then the result can be pretty ugly. If you put your head close to the FL or FR speakers you may hear a sort of quiet gurgling sound. Most of the sound can end up coming from the centre speaker. Not only will it now be frequency limited but most centre speakers are not as good quality as the fronts (certainly not if you have added a relatively inexpensive centre speaker to a good stereo set up).

I'm not a "golden ears" kind of guy, but even I have noticed how much the sound can improve by going back to stereo for SD TV. It sounds less muffled and has a better stereo image.



So remember, you aren't detecting DPL, you are choosing to apply a DPL decode to a stereo signal. FWIW, you can equally well apply DPLI, DPLII or one of the "Neo:" algorithms from DTS.


It sounds like your default option of DPL has somehow fallen back to stereo. Without knowing more about your amp we can't help you change that (although I'm confused here, because usually amps tend to stick with the last option you selected).





Regards
 

Ultraviolet

Standard Member
Hi

thanks for the replies so far. Basically the problem is with ALL the non-HD channels. So BBC1, 2, 3, 4, 5, ITV1 etc..

I get DD fine on BBC HD and Channel 4 HD (I'm too tight to pay for the other HD channels).

Prior to the EPG upgrade, my amp would auto set to Dolby PLII, and sound would be directed to all channels (FL, C, FR, Sub, RL, RR). The schematic on the amp showed all of these channels active (Marantz SR4400).

Now, the amp autosets to 'Stereo' on all the SD channels. Only the FL and FR channels are shown as active on the amp. If I force to to PLII, or any other surround mode, it still only shows the FL and FR channels as active.... it seems that it can't decode or recognise the surround sound on the incoming audio signal any more.... previously all channels would be shown as active, and the amp would auto switch to PL II.... very perplexing!

thanks... any other pointers more than welcome!

UV
 

RazorRat

Standard Member
I know it sounds obvious but have you unplugged your sky box then back in.
my amp once done something similar and i spent hours playing with the amp, only to unplug the sky box as a last resort and it fixed my problem.
 

Ultraviolet

Standard Member
yep, tried the reboot of the sky box, and the system rebuild and the force install of the latest software....

no joy... have also tried turning the amp off and on....

UV
 

Knyght_byte

Distinguished Member
make sure that on the sky boxes settings you have it set right on the optical output, could be that. might not be, just a thought..
 

HDCriticalFan

Active Member
Now, the amp autosets to 'Stereo' on all the SD channels. Only the FL and FR channels are shown as active on the amp. If I force to to PLII, or any other surround mode, it still only shows the FL and FR channels as active.... it seems that it can't decode or recognise the surround sound on the incoming audio signal any more

This is sounding more like an issue about your amp, rather than a "Sky problem". You may get more joy in a Home Cinema type forum.

I had a similar problem with my previous amp. It would not allow me to apply any surround sound decoding to the digital input (i.e. the optical connection from the Sky box). It forced me to treat a digital stereo signal as just that - stereo. It would happily allow me to apply surround sound decoding to any analogue input though. So I connected up the phono left/right sockets to one of the analogue inputs and used that instead. You could try the same trick.

Hang on, I've just looked at your manual. On page 22 it clearly states :

PCM-audio signals can be subjected to Pro Logic processing when the sampling frequency is 32 kHz, 44.1 kHz or 48 kHz

When the Sky box is set to DD (and yours must be from what you say) then the output from SD channels is usually PCM 48 kHz. So it should work.

Perhaps you have inadvertently changes your amp's set up (or it has reverted to a default somehow). You may have to plough through that manual again :(


Have you tried using Neo:6 instead ? After careful listening I actually preferred this to DPLII anyway !





Regards
 

JonStatt

Well-known Member
Ok...I can clarify this.

This IS an amplifier setting issue, and nothing to do with the Sky box.

PLII and PLIIx are technologies that can derive up to 7 channels of discrete audio from 2 stereo channels. These 2 stereo channels may have been specifically optimised for derived surround or they may not. There is NO possible way for the amplifier to determine whether a recording is a surround mix downmixed to 2 channels or not....it will just apply its decoding no matter what.

On your amplifier, you just need to reselect the PLII mode. Right now it is set to stereo. As soon as you press the right button on your amplifier to select the correct surround mode...it will start working again.

As mentioned above BBC1 etc do not do anything special to transmit surround. They only ever supply stereo. It is then up to your amplifier to do some surround wizardry with it. Re-enable the mode on your amp and you should be happy again.
 

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