DAB (terrestrial digital radio) - Stereo accuracy (for fake surround)

[kfbkfb]

https://en.wikipedia.org/wiki/HD_Radio

(see Footnotes section, item c): "The stereo image is smeared..."

I was doing some research for a post in radiodiscussions.com and found the above statement, although it's unlikely that matrix surround sound will be broadcast using DAB, it could be interesting to compare the fake surround sound created from stereo DAB and stereo FM (of the same content), has anyone with a DAB receiver done this?


Kirk Bayne

 

[SeeMoreDigital]

Over here in the UK, the newer DAB+ radio signals (which utilize HE-AAC) is awful as it's broadcast at stupidly low bit-rates and low power. Also many stations are in mono... And sadly, accessing the same stations via the internet isn't much better!

Content wise, DAB has been a step forward but 'quality wise' DAB has been a real step backwards.

 

[DuncanS]

Over here in the UK, the newer DAB+ radio signals (which utilize HE-AAC) is awful as it's broadcast at stupidly low bit-rates and low power. Also many stations are in mono... And sadly, accessing the same stations via the internet isn't much better!

Content wise, DAB has been a step forward but 'quality wise' DAB has been a real step backwards.

I listen a lot to Planet Rock and it went from Mono on DAB to Stereo on DAB+, but the signal strengths are so bad I need a high gain antenna on a large pole on the roof and booster amps in the loft, and driving about its just about impossible to receive unless you're near a large city (I'm not). The internet stereo is a bit better as it doesn't suffer from RF fading! FM would have been a better medium.

As you say content has improved but sound quality hasn't

 

[atrocity]

Content wise, DAB has been a step forward but 'quality wise' DAB has been a real step backwards.

Just like HDTV in the USA.

"Oh, we have all these bits? Let's give 90% of them to multiple hideously compressed shopping channels!"

 

[Owen Smith]

Over here in the UK, the newer DAB+ radio signals (which utilize HE-AAC) is awful as it's broadcast at stupidly low bit-rates and low power. Also many stations are in mono... And sadly, accessing the same stations via the internet isn't much better!

Try Classic FM for the least worst in DAB+, it's 64kbps stereo HE-AAC and does not use parametric stereo ie it is a full stereo left and right signal. I agree that most other DAB+ stations sound diabolical, eg Scala at 40kbps stereo HE-AAC v2.

For the least worst in DAB, it's BBC Radio 3 without a doubt. Either 160kbps joint stereo when 5 Live Sports Extra is on air or 192kbps full stereo in the evenings without sports extra. At that bit rate it actually sounds quite good.

Online streaming I agree most stations aren't much better. Scala however is 128kbps AAC which is a substantial step up, and the BBC stations in the UK are all 320kbps AAC which sounds absolutely sublime provided the material being broadcast is up to it.

 

[kfbkfb]

Here, one way to put a new FM signal OTA is to retransmit an (FM) HD signal, KPRS 103.3 FM HD2 has been OTA for several years and recently put the HD2 signal OTA at 106.9 FM (a translator).

(my question over in radiodiscussions.com was about the sound source for 106.9, turns out that it [probably] isn't the audio after its been through the HD audio codec, it's the "pure" undatareduced audio)


Anyone in the UK tried using fake surround sound creation with DAB/DAB+ stereo as the sound source?


Kirk Bayne

 

[JeremyG]

Not sure if this is what you mean but I use a setting on my receiver that synthesises reverb/echo onto the rears from a stereo source. Picking the right "auditorium choice" gives a pleasant sound to the music on Radio 3 but does sound a bit strange on the announcements.

 

[Owen Smith]

Anyone in the UK tried using fake surround sound creation with DAB/DAB+ stereo as the sound source?

Yes. Dolby Pro Logic II Music on my old AVR, and Dolby Surround (Upmix) on my new one both sound as you would expect (ie like a CD in fake surround with somewhat reduced fidelity) assuming the DAB/DAB+ bit rate for the station isn't too dire. Classic FM, all BBC stations and Greatest Hits Radio (112kbps DAB joint stereo on many transmitters) all sound OK in fake surround. I haven't tried the stereo stations with dire bit rates, they sound too awful to bother.

 

[Owen Smith]

If anyone wants to check bit rates and encoding parameters for a DAB station on a particular transmitter I have found this site very useful, opens at DAB in Yorkshire:

https://www.digitalbitrate.com/dtv.php?mux=9A&live=635&liste=2&lang=en

Site can do digital terrestrial, satellite and other things I haven't investigated.

 

[SeeMoreDigital]

For anyone who's interested, a link to Ofcom's DAB transmitter coverage maps can be found here: https://static.ofcom.org.uk/static/radiolicensing/mcamaps/DABmaps.htm

 

[DuncanS]

For anyone who's interested, a link to Ofcom's DAB transmitter coverage maps can be found here: https://static.ofcom.org.uk/static/radiolicensing/mcamaps/DABmaps.htm

me thinks Ofcom's propagation maps were rather optimistic for non-BBC stations! especially for reception in the car

 

[Owen Smith]

For anyone who's interested, a link to Ofcom's DAB transmitter coverage maps can be found here: https://static.ofcom.org.uk/static/radiolicensing/mcamaps/DABmaps.htm

That's only for the local DAB multiplexes. There are also three single frequency network national multiplexes.