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March 15, 2013 / tonychurnside

Car Controlled Radios

I recently bought a new radio and so much about it is lovely. It looks beautiful, and underneath the attractive retro exterior lies a capable computer with a wifi card and an FM and DAB radio. You can even download an app to use as a remote control.

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Now because my lovely new radio can receive FM, DAB and Internet streams I can choose to listen to Radio 4 either on FM, DAB or via the Internet. And I hate it. Whenever I switch it on, once I’ve decided which station I want to listen to I have to decide which broadcasting technology I want to use. As a user experience this is ridiculous, I really don’t care if it’s FM, DAB or Internet. I just want a good quality signal that doesn’t break up or noticeably suffer from interference. All I want to do is choose a station or programme. Why can’t the radio work out the best way for it to be delivered? After all it is a capable computer.

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This brings me to a discussion I had on twitter recently. There have been a number of articles about the auto industry removing FM/AM radios from cars. The first claims that AM/FM will not exist in cars in 5 years. The second contains the results of an online study which seems to ask you if you’d rather “automakers removed FM/AM radios from my next new car” or not. Unsurprisingly people don’t want something they use and like using “removed” from their new car.

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This survey isn’t that useful because it implies the options are either an in car FM radio or your mobile phone and its data connection. In reality this is very unlikely – how would this benefit the auto industry? FM receivers are so cheap it’s unlikely to be about saving automakers money. It’s far more likely to be about them owning the in car experience. If automakers can be the entertainment gatekeeper it is highly valuable to them (in terms of licensing, advertising etc.) Removing a traditional FM radio from the car dashboard allows them to be the gatekeeper. I’m not saying this is a good thing for the consumer. But it’s a thing that I can see happening in the near future, and if the car manufacturers do it right they’ll abstract the distribution method from the user experience as much as they can. And if they make use of all the technology available to them (GPS, IP distribution perhaps in combination with FM/DAB) I can see innovations along the lines of Radio DNS, Absolute’s In-Stream, and mine and Ian Forrester’s Perceptive Media being applied in very interesting ways.

September 26, 2012 / tonychurnside

To be There or Not to be There?

Every so often a story like this makes it into the hi-fi press. High-end audio equipment manufacturers often claim to be able to accurately recreate the sound of being at a live event. Recreating the experience of being at an event is often perceived to be ultimate aim of recording and producing live music events. The people who work behind the classical music sound desk often like to be called sound balancers (not engineers or designers). This implies they are subtly balancing the audio levels rather than doing any extreme mixing, that they are just transparently channeling the performance from the concert hall to the audience’s living room.

But is this what’s happening? And should they be trying to accurately recreate the sound of being at an event? I suggest the answer is they currently don’t, and probably shouldn’t.

Sound balancers have a difficult job. They have to take the complex sound sources of around 100 musical instruments (along with the response of the concert hall and audience to these instruments) and squeeze that experience into two (or sometimes six) loudspeakers. If more loudspeakers are added it may be acoustically easier to recreate the sound of being there, but I’m still not sure that accurate recreation should be the aim. Although it could be argued that the best mixes convey a sense of the actual space in which the performance occurred, most sound engineers will admit to using artificial reverberation or other tricks to improve their mix. The very act of careful microphone repositioning is the first step in acoustic mediation, and that’s before any balancing occurs.

There is also a regular debate amongst sound engineers as to whether an audio mix should follow a vision mix. For example, should the sound balancer push up the level of the piccolo when the vision mixer cuts to a close up of the instrument? One side of the argument goes: being more dynamic about the audio mix ties the audio and video together. The other side of the argument goes: the director should know the piece well enough to direct the vision in sympathy with the music, therefore there should already a tie between the audio and video. If this debate is of interest, compare the BBC Proms mix on BBC1 TV with the on Radio 3 to get an idea of the difference.

So, currently the aim is not to recreate the sound of being there. The reality of attending a classical performance (in all but the best concert halls) often has undesirable early reflections, a non-ideal direct to reverberant sound balance, and that’s not mentioning rustling crisp packets and audience coughing. The sound balancer is not mixing the audio to match the best seat in the house, actually they are creating a hyper-real audio balance that only exists in the engineer’s control room. It’s a virtual position in the concert hall, perhaps floating somewhere around the conductor, and from an absolute quality standpoint, probably sounds far better than the best seat in the house.

So why go to an event if the best sounding seat is actually in an engineer’s control room? Well, there are at least 4 other senses at work when you’re attending a concert, and technology (although it’s trying) has a long way to go before it can replicate the whole experience.

February 14, 2012 / tonychurnside

Woofers and Tweeters

I’ve seen a few tweets about a television advert that’s been broadcast recently. The advert claims to have a soundtrack designed for dogs, not humans. I thought I’d take a closer look at this claim.

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First some facts. The average range of a dog’s hearing is 40Hz to 60kHz, this is much wider compared to a human’s which is 20Hz to 20kHz. These figures are pretty rough (or should I say ruff) and vary from human to human (and dog to dog). Hearing loss at high frequency is a normal part of getting old and can begin in people as young as 25 years old. Well, you might think, then it’s easy to create a TV advert that dogs can hear and humans can’t. You’d be wrong.

The biggest problem you’ll face is inherent in the design of the whole audio broadcasting chain: it’s currently not designed for dogs. So everything from the microphones used to record the advert right through to the speakers in your living room has been designed for the human hearing range. Building transducers that can create or capture sounds above 20kHz is rare and specialist. This is before I even mention the processing done to the audio to get it to your TV. Broadcasting audio above 20kHz is wasteful and most coders drop frequencies of that order. For example, if you understand sampling theory you’ll know that CDs (with a sample frequency of 44.1KHz) have a Nyquist frequency of 22.05kHz. This means the frequencies which can be represented by linear PCM audio are below 20kHz. Audio carried in a DVB-T multiplex has been through lossy compression which is designed to remove the bits of the audio that humans can’t hear. While these lossy compression schemes are thoroughly tested, they are not yet tested on dogs. Given this information the range of audio that is broadcast and perceivable by dogs but not perceivable by (the majority) of humans is now much narrower that you might have thought, roughly 17 to 20kHz. That’s not much to play with.

A quote from the first story I read about this advert claims:

“Vet Zara Boland says the sounds are between 18,000 and 20,000 kilohertz, and denies using dogs in an unfair way to publicise a product.”

18,000 to 20,000 kilohertz? KILOHERTZ?! That’s a lot of kilohertz. Far more kilohertz than can be heard. Even by a dog. Let’s assume that this is a typo, and what they meant to type was 18 to 20 kilohertz. (or 18,000 to 20,000 hertz). My hearing can’t get quite that high anymore, so I thought I’d use a computer to help examine the advert.

This is what the sound of the advert looks like:

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When I performed a spectrum analysis of the audio it looks like this:

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I even slowed down the file to see if I could hear anything (by lowering the frequency and bringing it into a frequency range I can perceive).

So there is something up there in the 19kHz range, but it’s actually very quiet compared to the rest of the audio and could easily be masked.

And remember this analysis is of a recording of the transmission and doesn’t consider how your sound system might effect the audio. If you have a fancy flat screen TV, but use its built in speakers the chances are the audio spectrum that comes out of them has been further compromised. Here’s a picture of the spectrum coming out of my flat screen TV’s internal speakers during the dog advert (according to a simple iPhone app).

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Whether or not any of this would trigger a reaction from your dog is down to highly scientific studies like the one described here. I’m not a dog psychologist (and feel free to correct me about the following if you are) but my guess is it would take more than the presence of 19kHz audio to provoke a serious reaction, unless it was very loud, in which case it would be likely to cause a similar reaction in human audiences (those under 25 years old, anyway). Working with the constraints of broadcast-able content I think it would be much easier to attract the attention of dogs using audio that humans AND dogs can hear, at least until the arrival of smell-o-vision, but that doesn’t get headlines.

So in conclusion, this is much more about getting free press coverage than entertaining dogs, and it worked perfectly.

September 13, 2011 / tonychurnside

Taking my Tablets

I’ve just returned from the International Broadcasting Convention (IBC) in Amsterdam. This is the second year I’ve been, last year I was honoured to be invited to the event as a guest after being awarded this. This year I was asked to help on the committee. I also produced a session about sound design for sport, and one about audibility on TV.


I’m not going to blog about those two topics, other people have covered the subjects better than I could here and here. I’m going to talk about my experience presenting at a conference using only a tablet for the creation, editing and presentation of my sessions and perhaps give a few tips to other speakers brave enough to leave their laptop behind.

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Keynote is available in both iPad and iPhone flavours, although I wouldn’t like to create a full presentation on a screen as small as an iPhone, but perhaps it would be ok for quick and simple edits. Keynote on iOS doesn’t offer all the features of it’s bigger brother on OS X, and the big missing feature that hit me was not being able to insert audio files. Both my presentations needed numerous audio files (both were about sound) so this was more than slightly annoying. Keynote will allow you to open and edit presentations containing audio but there’s no way to import a .mp3 or .WAV. Because I needed audio I found this rather convoluted way around the problem: First I recorded some random video with the built in camera, imported that clip into iMovie and disabled it’s audio. Then I added the desired audio from the iPad’s iTunes library* to the video clip, adjusting the length of the video to match the audio then exported the finished file to the camera roll. This video file, which contains the audio, can be imported into keynote then resized and moved out of the frame so the video is not visible during the presentation. Once finished plugging in a VGA adapter (and using the headphone out for the sound) allows you to view the presenter notes on the device while the slides are shown the the projector.

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Tips:

1) Do as much of your presentation on a real computer, before you leave. I didn’t, but only because I viewed this as an experiment.

2) Export your presentation to PowerPoint, Keynote and PDF, try them all on OS X and Windows, in case your tablet lets you down.

3) Make sure your presentations and all the media you plan to use in your presentation is available everywhere. i.e. DropBox, a USB stick, your iTunes media library* on the device.

4) When editing on an iPad copy and paste are your friend, these can be used for moving content (like pictures and sounds) between presentations and apps.

5) Ensure you’ve topped up the battery before you get on stage.

6) Turn notifications off, turn silent on, sign out of Skype, enable airplane mode if possible.

Conclusions:

I could do everything I needed to do on the iPad, but certain tasks had to be completed in a very round-about way. As a presentation tool, the iPad worked well for me and when I head off here next month I may have created the presentation on a real computer first, but I’ll definitely be leaving the laptop behind. NB. This post was made on a tablet.

August 31, 2010 / tonychurnside

Featured in this week’s Ariel (BBC’s internal magazine)

I was in this week’s Ariel talking about an average day. I don’t really have an average day, but I did my best to generalise.

August 30, 2010 / tonychurnside

Hello world!

I thought it was about time to consolidate my internet presence, so here is my blog.