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Crowd-sourced library recordings - onboard cycling SFX

This month, I recorded some sounds for a crowd-sourced sound effects library. These are a great concept to encourage sound designers to get out into the field and record, and are a fun and collaborative way to build up your sound library.

This month, the theme for the library was 'Sports'. I hadn't originally intended to contribute this month, as the subject matter is fairly niche, and I don't tend to do a lot of projects that call for sports-themed SFX. I realise that this is perhaps a short-sighted way of thinking though, as it is good to be prepared for every eventuality when it comes to tracklaying effects. For obvious reasons, sounds like traffic, doors and nature ambiences always have plenty of coverage in most libraries, and it's the niche sounds that will sometimes catch you out. I think in reality, I was just being too lazy to arrange a recording sesison!

On a weekend bike ride in the Surrey Hills, I

decided to try and capture the sound of my bike tires on the windy, singletrack gravel paths typical of the woodland in that region. I wanted to test out a new recording technique, with the aim of getting the microphone as close to possible to the spot where the tire makes contact with the ground, and hopefully record some close-up and detailed crunchy gravel friction sounds, in isolation from any environmental noise.

If you've ever ridden a bike over this type of sandy gravel surface, you will know the sound that the rubber of the tires makes as it compresses and squeezes the individual grains and rocks together, then as the tire rolls over, the sound of these individual pieces being flicked up into the air momentarily before being scattered across the surface. To me, its a very satisfying sound, but one which I have always failed to capture in the way I'd like when I've tried to record it. The problems that I've run into in the past mainly stem from microphone choice, and the difficulty of positioning the microphones.

Running alongside a cyclist, with a directional microphone pointed at the wheels tends to result in an inconsistent perspective as they move further and closer away. With this technique, I could also never get the sound quite as isolated as I would like. I've used small lavaliere microphones in the past taped to the frame of the bike, positioned near the tyres to try and get a closer sound. This worked well in terms of picking out just that detailed crunchy sound I was after, but the vibrations transmitted through the metal frame of the bike also made their way onto the recordings.


The technique I trialled recently to get the

recordings I submitted to the crowd-sourced library, has been the most successful yet. I used the same small-scale omni directional microphones I've used before to get nice and close to the contact patch of the tire on the trail surface, but the big improvement comes from the way the mics are mounted. Instead of taping the mics directly to the frame of the bike, or to a seatpost or luggage rack, I mounted them on a pair of 'Nite Ize Gear Ties'. These are flexible lengths of wire with a rubbery plastic sheath around them. They have loops at the end to hold cables, with the idea being that you then wrap the wire around the coiled up cable to keep them from unravelling. I found however that they can be re-purposed as effective spot mic shock mounts! In the photo, you can see how I've twisted the wire around the bike frame, at then slotted the microphone diaphragm with windshield through the cable slot at the end. The wire keeps the mic tightly secured, even down steep rocky sections of trail. It bounces just enough to absorb any impact from the bumpy surface, while the rubbery texture stops any vibration form being transmitted onto the recording. I think maybe these mono recordings will be the most useful in a project, either linear or interactive. Perhaps 'as is' on a close-up shot of a wheel, but I can also see them being used as a layer to give some more detail and intimacy to a production sound track. Listen below...

I also recorded a few takes with a second mic taped using one of the 'Gear Ties' to the front fork to capture the sound of the front tire contact patch in unison with the rear. This stereo version is more interesting than the 'rear wheel only' mono takes, but maybe not so useful? It sounds fairly unnatural, and artificially wide - it's a perspective that you'd never hear with your own ears. That being said, I think it's an interesting sound, and the individual detail of each tire feels quite immersive.



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