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NetMix: Create your own sound balance from Centre Court

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Rupert Brun Rupert Brun | 13:31 UK time, Tuesday, 28 June 2011

Or: how much base-line grunting can you take?

The hashtag is #NetMix


As a life-long radio engineer I care a great deal about sound quality and I know many of our listeners do too. Last summer during the last week of the BBC Proms I ran an experimental extra-high quality audio stream and asked you what you thought of it.

After a couple of days, in response to your suggestions, I made some adjustments to the sound and the response was then overwhelmingly positive. As a result of your comments the BBC made the extra-high quality stream permanently available for Radio 3 as “HD Sound”.

I now want to ask for your help with another experiment using audio delivered over the internet.

We receive regular feedback about sound quality on both radio and television and the most common complaint is that the speech (commentary or dialogue) is too quiet compared with the sound effects or music.

As a result of your feedback we have made changes to our sound balance guide-lines but we can’t please everyone all the time. Whilst some people want the speech to be much louder than the music, others complain that the announcer is louder than an entire orchestra. Making the speech too loud can destroy the sense of immersion in the event for those listening in quiet rooms on good quality sound systems or headphones.

This year I am running an experiment which lets you decide on the sound balance you want for some of our coverage of the Wimbledon Tennis. I’m afraid that for rights reasons the stream is only available in the United Kingdom.

You can download a special player and it will let you adjust the sound balance whilst listening to the tennis. You will be able to adjust the sound mix from one extreme with lots of crowd sounds and base-line grunting and the commentary as a very quiet voice, to the other extreme with loud commentary and very quiet sounds from the match. I would like you to try this, play with it for a while then complete the on-line survey to let me know what you thought of it.

I hope to learn a number of things from this experiment.

  • What are the production challenges do we face in creating this sort of stream?
  • Given a choice, where do you, the listeners, set the sound balance?
  • Do you find it useful being able to create your own sound balance between the commentary and the effects?
  • Do you think it would be useful for other types of content or on other devices?

So please go download the player and give it a try. And whilst I’m happy to answer questions here, please complete the survey to give feedback. If you are going to mention the experiment on Twitter please use #NetMix so we can follow your comments.

How does it work?

We have stereo microphones on the umpire’s chair on Centre Court and the sound from these is coded with the mono commentary as an MPEG4 audio stream with additional control data, which allows the player to “unmix” the sound.

With the player fader in the centre the commentary and court are heard at levels which are often broadcast. When you move the slider towards “court” the commentary gets quieter whilst the court atmosphere stays the same. Conversely if you move the slider towards “commentary” the court sound gets quieter whilst the commentary stays the same.

Please note that neither the court nor the commentary ever get louder than they are with the fader in the central position; for this experiment the effect is achieved by reducing the volume of the sound you want to hear less, not by amplifying the one you want to hear more.

Note for those listening on a computer on a business network.

The player does not auto-detect proxy settings.

If used on a computer which accesses the internet through a proxy (as many computers on business networks do) right click on the player and select menu option "Proxy". Enter the IP address of your proxy server and remember to finish with :80 as that’s the port where the stream can be found.

As an example, you might enter xx.xxx.x.xxx:80 or you can enter the URL, for example www.something.something.something.co.uk:80. You may be able to find the address of your proxy server in the “settings” menu of your web browser.

Update 30 Jun: The 5Live blog has posted an audio clip about Netmix

Rupert Brun is the Head of Technology for Audio and Music


  • Comment number 1.

    Fantastic! I just which I'd read this before watching the first Centre Court Women's Quarter Final earlier today.

    The noise of the rain hitting the Centre Court roof was very loud indeed - being able to down-mix that would have been great! :-)

    Cheers, daveac

  • Comment number 2.

    Could be a godsend if it's Sharapova v. Azarenka in the final .......!!!!!!!!!

  • Comment number 3.

    This is certainly an interesting experiment. I will try it out latter.

    You mention in your blog that you actually care about sound quality and we are all very grateful for you introducing the high quality Radio 3 stream. That all begs the question as to why the BBC is waisting so much money on DAB radio which produces such a poor sound quality. As far as I can see DAB and DAB+ has not been successful in any country in the world. The public simply don't want it.

    For some time now listeners have been asking for the higher quality AAC streams be available for Internet radios without flash. Someone noticed that these streams have become available on itunes but there has been no announcement from the BBC. I have now configured my Internet radio to receive these streams but why hasn't the BBC announced this.

    Returning to your experiment there is another issue here and that is surround sound. This surely must have influence on the sound balance as humans can focus concentration in a particular direction. Commentry normally comes from centre front and the sound of rain would come from all directions. So this produces another problem how to create a balance that works in both surround and stereo. For the highest quality I would sugest that there should be seperate surround and stereo streams.

  • Comment number 4.

    trevorjharris - DAB radio and surround sound are off topic on this post.


  • Comment number 5.

    would this functionality be added to bbc iplayer in the future if the trial is successful?

  • Comment number 6.

    I am blind and am using the Jaws Screen Reader on my PC. I can play the audio, and it is nice to have the stereo court sounds.
    I can't find a way to adjust the balance. Is there a way to do this using the keyboard?

  • Comment number 7.

    This is just so unscientific as well as an insult to real sound engineers.

    The whole point of a sound mix is that it is made in a controlled environment by a person trained and experienced in creating the right product to work for the majority of listeners. Those listeners will be in a range of environments and using a variety of listening equipment.

    Therefore any feedback regarding the ambient sound levels or the commentary level are completely meaningless. The survey questions cannot tell you enough about the individual circumstances of each listener and do not even ask about the state of their hearing!

    To suggest that this home mix, as suggested in the survey, could be offered for music and drama broadcasts just makes the mind boggle. Not only an insult to the sound engineers but also to the director and artists.

  • Comment number 8.

    Thank you for the feedback, Jim O. I am afraid it is not possible to control the slider using the keyboard. If we do this experiment again I will make sure the controls can be operated from the keyboard, as this is clearly an important point.

    Rupert Brun
    Head of Technology for BBC Audio & Music

  • Comment number 9.

    Jim O, I now have instructions from the developers on how to use the player from the keyboard. When you launch the player, the tab key will move the focus around the controls. The order is "Find out more", "Tell us what you think", "Play / Stop", "Volume", "Balance". Play & stop are toggled with the space bar. Volume and the fader can be operated with the keyboard left and right arrows. So if you launch the player and hit the tab key 5 times you can then use the left and right arrows to move the slider.

    Rupert Brun
    Head of Technology, BBC A&M.

  • Comment number 10.

    Thanks, have been able to control the balance from the keyboard now. Hope you guys will be able to get text labels on all these buttons for next time.
    Only additional comment I have is that it doesn't seem possible, certainly using the keyboard, to have either the commentary or the court sound completely muted. Think it would be nice to do this at times, particularly when 5live goes away from the tennis, it is quite strange having the court sounds there during the news.

  • Comment number 11.

    Thanks Jim O. It is not possible to completely remove either the commentary or the court sounds for technical reasons; there is only a certain range of control available. I agree it is a little odd to get the court sounds during the news and if we ever do something like this in a more formal way we would mute the court when there was not a match playing. For the experiment we wanted to let people hear the effect whenever they tried it and I decided to leave a little "ambience" running under short news bulletins. I have noted the importance of text labels on the controls for future experiments. I hope you will complete the survey now you have tried the player, you can find it here http://ecustomeropinions.com/survey/survey.php?sid=600940241

    Rupert Brun
    Head of Technology for BBC Audio & Music

  • Comment number 12.

    Hajj_3 - There are no plans to roll this technology out to iPlayer. We would face very significant challenges making it available across a range of output. To make NetMix work we have to keep the speech and the effects separate all the way through the production chain to the point where we code if for distribution over the internet and our infrastructure and production processes are not set up for this. The experiment is aimed at getting feedback from listeners about the idea of listener-adjustable sound balance and the feedback we get will inform future research. This isn’t to say that it won’t be incorporated into iPlayer or other products at some point in the future, but it will be very much an experiment for the foreseeable future. Please help us by completing the survey. http://ecustomeropinions.com/survey/survey.php?sid=600940241

  • Comment number 13.

    Are there any plans to use the multiple-soundtracks inherent in several of the distribution methods - FreeView, FreeSat, etc. - to provide alternatives? These facilities were, I think, originally intended to provide the option of having speech in different languages. I have often wondered, where multiple languages are not being provided, whether the facilities could be used to offer different amounts of certain things - for example, sports with ambience but without commentary, documentaries (and drama!) with speech but without background music. It seems a pity not to use something which is already in place in transmission and reception equipment, but is currently mostly not used (like the pan-scan postion in widescreen TV or the option of turning off the pilot tone on FM radio).

  • Comment number 14.

    An interesting idea, but hard to see what value it has, given people's different hearing abilities, equipment, and background noise levels.

    In the comment number 12 - "we have to keep the speech and the effects separate all the way through the production chain to the point where we code if for distribution over the internet and our infrastructure and production processes are not set up for this."
    - I would point out that if you specify 5.1 mixes to only have narration and other dialogue in the centre channel, then you have the required separation of speech from music and effects in a completed sound mix. I am well used to providing this kind of mix to other broadcasters, having over 20 years experience in sound post-production.

  • Comment number 15.


    I am the U.S. Trademark holder for the word mark: netmix. I believe the use of the mark is infringing, as the application is available for use by U.S. users. In addition, you are explicitly promoting the hashtag "#netmix" and my Twitter account is @netmix. While I appreciate the love, I am concerned by your use of my mark and seek to speak with you to rectify the situation[Personal details removed by Moderator]

    My USPTO registration is posted below:

    Word Mark NETMIX
    Goods and Services IC 035. US 100 101 102. G & S: On-line retail store services featuring downloadable pre-recorded music and video. FIRST USE: 20051215. FIRST USE IN COMMERCE: 20051215

    IC 038. US 100 101 104. G & S: Communications services, namely, transmitting streamed sound and audio-visual recordings via the Internet. FIRST USE: 19951215. FIRST USE IN COMMERCE: 19951215
    Design Search Code 16.01.05 - Albums, record; Compact discs (CDs); Digital versatile discs or digital video discs (DVDs); DVDs; Phonograph records; Record albums; Records, phonograph
    16.01.07 - Head phones; Headphones; Headsets; Microphones
    24.15.04 - Arrowheads
    Trademark Search Facility Classification Code ART-16.01 Telecommunications and sound recording or reproduction equipment
    ART-24.15 Arrows
    SHAPES-BAR-BANDS Designs with bar, bands or lines
    Serial Number 78893639
    Filing Date May 26, 2006
    Current Filing Basis 1A
    Original Filing Basis 1A
    Published for Opposition June 16, 2009
    Registration Number 3676517
    Registration Date September 1, 2009
    Owner (REGISTRANT) Zeoli, Anthony P INDIVIDUAL UNITED STATES 44 Milburn St #2504 Bronxville NEW YORK 10708
    Description of Mark Color is not claimed as a feature of the mark. The mark consists of an animated depiction of a phonograph recording with computer mouse pointer at its center wearing stereo headphones.
    Type of Mark SERVICE MARK
    Register PRINCIPAL-2(F)
    Live/Dead Indicator LIVE

  • Comment number 16.

    Hey Rupert, we have yet to hear back from you regarding our question as to whether the Netmix app released by the BBC and Fraunhofer infringes on our trademark. Please get back to us when you can. Thanks.

  • Comment number 17.

    While our web site (including this blog) is capable of being viewed anywhere in the world, the audio stream offered under the name NetMix was geoIP blocked and was only available in the UK. Since we didn't offer any streamed services in the U.S. we do not think we have infringed this U.S. trademark.

    Rupert Brun
    Head of Technology for BBC Audio & Music


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