Signal path for surround sound

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• chrisjr Posts: 33,282

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  24/02/11 - 23:02 #2

  Freeview SD is stereo. If there is any surround information it will be Dolby ProLogic at best. Freview HD does have a true surround sound format which should be output as Dolby Digital.
  
  I would suggest using Dolby ProLogic on your receiver. I have a Onkyo 507 and find that using the Music button on the remote to dial up ProLogic gives me the best sound processing from a stereo source. I tried neo6 and frankly it sounded crap. Interestingly using the Movie button on the remote to select ProLogic I find sounds naff as well. You'd think it wouldn't make any difference which version of ProLogic you used.
  
  But the PLII Movie option sounds thin and lacking bass and there is definitely something not right about the midrange speech frequencies. Makes my Tannoy pro studio monitors sound like a cheap Tesco's tranny
  
  But use PLII Music and it is a much better sound, to my ears anyway.

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• gomezz Posts: 44,611

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  25/02/11 - 07:18 #3

  chrisjr wrote: »

  Freview HD does have a true surround sound format which should be output as Dolby Digital.

  Surround sound on Freeview HD is broadcast as AAC which most AV amps cannot cope with. I believe the Onkyo 608 is one of those older designs that cannot. So unless the Freeview HD box is one of those that can transcode AAC to DD5.1 then the OP is going to be stuck with DPL, at best, on all Freeview broadcast.

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• webbie Posts: 1,614

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  25/02/11 - 12:53 #4

  Yes, it was good of freeview to change to AAC at the last minute from the standard Dolby that just about all amps/receivers can cope with.

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• chrisjr Posts: 33,282

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  25/02/11 - 12:58 #5

  webbie wrote: »

  Yes, it was good of freeview to change to AAC at the last minute from the standard Dolby that just about all amps/receivers can cope with.

  There is an explanation as to why here
  
  http://www.bbc.co.uk/blogs/bbcinternet/2010/06/questions_around_surround_soun.html
  
  And from April this year it will be mandatory for all freeview HD boxes to transcode AAC to AC3
  
  http://www.freeview.co.uk/Resolutions/About-Freeview-HD/Can-I-get-5.1-surround-sound-with-Freeview-HD

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• webbie Posts: 1,614

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  25/02/11 - 13:15 #6

  Bit late now isn't it? People who bought tvs and or boxes a year ago may or may not have ac3 output. And transcoding from one type to another has the potential for undesirable effects. I like trevorjharris's posts in your bbc link. I think there's a page on whattvs website about non-compatible tvs. Complete cock-up all round.

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• [Deleted User] Posts: 1,617

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  25/02/11 - 15:37 #7

  soul and some wrote: »

  What is transmited via freeview, and what is/can be processed by an AV receiver?

  
  Very little on SD, especially on the channels that broadcast with insufficient bandwidth to display a decent picture. At best it will be stereo with some Dolby encoding. The best will be Prologic II on your Onkyo.
  
  I'm not sure what freeview HD offers.
  
  On Freesat BBC HD will give 5.1. for some programmes and Prologic II on others.
  

  btw ONKYO TX-SR608 with some Tannoy speakers SFX 5.1 , not to impressed
  
  Sound is rather lack luster

  
  Make sure that you are not forcing a 5.1 decoding when there is nothing to decode. My Onkyo sits there displaying Prologic IIx (Movie) which tends to give the best sound for Freeview SD but sometimes on the lesser TV channels mono from all speakers sounds better.
  
  If your Onkyo can do more than one Prologic mode experiment with the settings but still don't expect too much unless viewing a film on say BBC1 or BBC2 (or maybe ITV1)

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