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HD sound for the Electric Proms

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Chris Kimber Chris Kimber | 18:04 PM, Wednesday, 27 October 2010

Two miniature likenesses of Neil Diamond, from Kathleen Mosley, Montrose Scotland

You may have heard that we offered an extra high quality (320kbs AAC) online audio stream for the last week of the BBC Proms this year (read about the experiment on the BBC Internet blog). The feedback we received was almost universally good. Listeners really appreciated the richer sound quality which made a fairly obvious difference even to the casual listener. Well, I can now confirm that for the first time for non-classical output, we'll offer the same higher quality audio stream for this year's BBC Radio 2 Electric Proms concerts.

So if you listen to the concerts live via the Electric Proms web site you'll hear our highest ever audio stream quality. We'll also offer the full concerts on-demand in HD Sound, again exclusively via the Electric Proms site. If your connection cannot handle this new higher quality, you can choose to listen at the standard quality.

We chose to pilot HD Sound with the Electric Proms because these live concerts represent something unique, something you can't get elsewhere. Radio 2's Head of Music, Jeff Smith, has written a post for the About the BBC blog in which he explains the unique nature of this annual event. Of course, once we've assessed feedback from listeners and looked at the technical and cost aspects, we'll look to extend this improvement to other services.

Why is this important? Well with the growth of music streaming services such as We7, Spotify, and of course YouTube, an increasing number of people are hooking up their home computers to high quality sound systems and speakers, meaning that what was previously acceptable in terms of sound quality for small computer speakers or cheap headphones is rapidly becoming less so.

As more and more people start to listen to music via internet streams, as opposed to listening from CDs or from downloaded audio files, we expect that it will sound at least as good. Similarly, as more people start to listen to radio online, both live and on-demand, we are way past the point where people will readily accept poor audio quality simply because it's being delivered over the internet.

So, if you're a fan of Elton John, Robert Plant or Neil Diamond, listen live or catch-up via the Electric Proms site. As Robert Plant once said, the song remains the same; it'll just sound better now.

Chris Kimber is Managing Editor at BBC Audio & Music Interactive


  • Comment number 1.

    I'm sure this is answered elsewhere but I can't find it on FAQ. My computer is plugged into my hifi. I have the option of stereo, Dolby PL, or EARS (fake Dolby surround) What is the best setting for HD sound? Are you looking to send down a dolby digital signal in the future (for both Audio transmissions and iPlayer video programs?)

  • Comment number 2.

    I am a composer who had a BBC training in audio engineering.

    The so called HD sound bitstream rate of 320 bps is considered a minimum for demo quality delivery in professional circles.

    As a comparison industry standard recording for film production and CD mastering 48k/24 bit has a stereo bit stream rate in excess of 4600 bps so the so called HD service the BBC is promoting is stripping out nearly 95% of the original data to provide what is basically an iTunes quality stream.

    If you compare freeview with the analogue Tx still available in many areas you see drastic reduction in colour depth and general quality - same between FM and DAB in radio terms. You really can't get something for nothing - throw away 95% of the original material and you may be able to create the illusion of an acceptable sound but only that - listen on high quality apparatus, listen carefully and you wlll find all the depth and spatial information has bee stripped away - the performance has had it's soul stripped away.

    I applaude any attempt to improve technical delivery and 320bps bitstreams may be an advance from the current digital bottlenecks but to promote it as "HD sound" is questionable when the actual technical quality does not match the sound transmitted over FM or even nicam analogue TV which was available 40 years ago!

  • Comment number 3.

    HD sound hmmm really at 320 kbps??? misleading terminology to say the least!

  • Comment number 4.

    To answer BillC’s question, you should set your computer for stereo when listening to HD Sound. We may be able to offer surround sound of some sort in future but have no plans to do so at present.

    “Cloudbattles” and “Wenger101” both raise important questions about what is meant by HD Sound.

    The term HD Sound is used by the BBC in a broadcast context, just as HD TV means high definition broadcast TV. Of course HD Sound doesn’t contain the same amount of data as a 24 bit 96kHz uncompressed audio stream from a Blu-ray disc, any more than broadcast HD TV does. This doesn’t detract from HD Sound as a higher quality broadcast than the “standard definition” we have previously provided. Listeners to the experimental BBC Radio 3 Proms “XHQ” stream, the pilot for HD Sound, were extremely positive about the quality and many compared it favourably with FM. You can read comments from Radio 3 listeners here.

    Whilst judgements of absolute quality must always be subjective, it is clear from a technical comparison between FM radio and HD Sound that:
    • HD Sound has a wider dynamic range.
    • HD Sound has a lower noise floor.
    • HD Sound has a wider frequency range extending to 20kHz as where FM is of course limited to 15kHz.

    Against this, HD Sound uses a digital codec, albeit a modern, very high quality one at a high bit rate. But HD sound is not unique in having a digital codec in the signal path; the same is true of the majority of our outside broadcasts whatever platform is used for listening. The BBC used digital codecs to get audio signals from live outside broadcasts to Broadcasting House, and in general these are “lossy” codecs. We are careful to use suitable codecs at appropriate bit rates and avoid “cascading” different codecs as far as possible. Distribution to the FM transmitters is by a 13 bit range switched codec (NICAM) which introduces some artefacts of its own.

    When making comparisons with other platforms it is important to remember that HD Sound isn’t just “normal radio” coded at a higher bit rate. The entire signal path from the microphone has to be of appropriate quality and we offer a much wider dynamic range than we can deliver on other platforms, all of which contribute to making these streams “HD”. Where necessary we are also using higher quality links from the outside broadcast for HD Sound, and these improved links will of course benefit listeners on all platforms.

    Rupert Brun. Head of Technology for BBC Audio & Music.

  • Comment number 5.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • Comment number 6.

    Hi, HD sound for Elton is great, but DAB/iPlayer audio for Radio 1 has taken a turn for the worse over the past week or two. Sounds like they've changed audio limiter/compressor settings. It's all a bit thinner now, with more audible pumping/breathing. Be great if they could change it back. Sounded perfect before.


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