Question C5HD audio

[Clem_Dye]

Is it just my kit, or has anyone else who routes their audio through a surround sound system noticed that the C5HD audio (Freesat channel 105) seems to be permantently in DD5.1? I have two Humax boxes, and if I route their audio through my Yahama DSP4100 sound bar it shows that the transmissions are in DD5.1 all the time. It's clearly wrong, at least to my ears, and I certainly, for example, can never recall an advert for soap powder having a surround sound audio track! All other channels seem to be fine. For example, the switch from stereo to DD5.1 for the last two episodes of Cardinal on BBC4HD was fine. Things switched back to stereo when the last episode concluded, as expected.

I have no idea if it's just that C5 have got it wrong or there's something in the audio stream which is confusing either the Humax boxes or my Yamaha soundbar.

I plan on dropping C5 and/or Humax a line about this, but just before I do could somebody else check please, if they have the time and suitable kit?

C5HD on Freeview is only ever in stereo, and I've checked by routing the audio through my Yamaha sound bar -- no issues there.

Cheers, Clem

 

[Rodders53]

Yes that is how C5HD signal it on Digital Satellite. (I have commented on this in other posts). It's been like that from day one of its' free to air launch on satellite and Freeview.

On Freeview it is HE-AAC with a fixed bitrate of 128kbit/s and that is transcoded to DD 2.0 by receivers. (BBC & C4 HD have a variable bitrate of up to 320kbit/s for when they transmit in 5.1 sound).

See DIGITALBITRATE : Le debit des chaines en numerique - ASTRA 28.2°E - Main page for the tech data as received with PC based tuners, both satellite and terrestrial.

I also feel that C5HD (on sat at least) is some 6-8dB louder than it ought to be, but that's another issue I can't be bothered over much about.

As to whether any 5HD programmes are actually in 5.1, I'm not certain but major UK and US series, live sports, and Films are the most likely suspects to be so (i.e. exactly as per BBC & C4 programming for 5.1).

Channel 5 are the sole people to ask about this as it will be in their power to fix ... How do I contact Channel 5 Viewer Enquiries?

 

[grahamlthompson]

Just checked - Humax HDR-1000S and Yamaha AV receiver,

Transmission is flagged as 5.1, but has no output on front centre and surround Left and Right Channels, only Front Left, Front Right and Subwoofer (I guess due to crossover settings rather than a discrete channel ie 2.0 not 2.1). The on screen info shows channel outputs. No DSP switched on.

Will try recording a movie but suspect it will be the same as Rodders53 suspects.

 

[Clem_Dye]

Thanks for the replies. What I think is making things sound worse in my case is that the Yamaha sound bar is trying to project a surround sound delivery but with bits missing, so the soundstage is really weird. It sounds quite 'tunnelly' a lot of the time. I'll send C5 a message about it, but I suspect that nothing will come of it.

Clem

 

[grahamlthompson]

Can't you turn off DSP (Digital Sound Processing) so the sound bar treats it as plain stereo instead of trying to create a pseudo 5.1 effect ?

It sounds OK with my Yamaha.

 

[Rodders53]

Odd. Proper DD 5.1 systems treat the 5 discrete channels as just that: 5 separate channels.

So yours is doing something very strange to the sound to give the effect you describe, so do see if there's an easily-selectable alternative 'mode' you can listen to C5HD programmes with on the bar?

Their NARration audio track is 160kbit/s stereo on satellite and might be acceptable to you for some programmes? (Or there's the option to record the SD version, if all else fails?)

 

[Clem_Dye]

I haven't experimented any further at present, simply because we watch so little on the channel. It was only because SWMBO wanted to watch the new series of Blind Date (shudder!) that I noticed this issue again. Having to switch modes on the sound bar just to listen to one channel is a bit odd though, and I suspect that it will still sound wrong due to the missing audio channels, as noted above in this thread. I will experiment a bit more when I have a few minutes spare then report back.

Clem

 

[grahamlthompson]

It should sound the same as any other HD channel using stereo audio. The other channels just don't have any audio data. No idea if they are pro-logic 11 encoded.

 

[Clem_Dye]

SWMBO wants to watch Blind Date tonight so if I'm around I'll try switching my sound bar to stereo to see how it sounds. However, as it's such an awful programme I think that she should watch it via the TV ..... ;-)

Clem