Better sound with GoPro Hero 2 plus external mic

GoProThe best place to get decent forward facing video is by mounting the GoPro camera on the front fairing. The best place to hear your exhaust note is to mount the camera around the tail piece near the end of the exhaust pipe.

Mounting the camera on the front fairing means that the sound you hear on your video is typically induction noise rather than exhaust note. On my Daytona 675, my camera is mounted very close to the air intake, and so the internal camera mic picks up the induction sound to the exclusion of any exhaust sound. Now that’s a real shame because the 675 triple engine makes the most glorious sound through its Arrow can especially without a baffle. This exhaust typically registers a static 97-98dB @6500rpm on trackdays… even without the baffle!

Even when mounting the camera on the tail piece and relying on the internal GoPro mic, I’ve found that the exhaust note on video is still not that great, and nowhere near as good as the sounds you get when riding the bike around the track. Listen below to see what I mean.

GoPro-Hero2The solution is to add an external mic to the GoPro. The Hero 2 has an external mic port on the lower left hand side as you look at the back of the camera. Unfortunately, the waterproof case has no hole in it to allow you to connect the mic to the camera through the case.

You have two choices; either buy the skeleton case or drill a hole in the waterproof case. Because the skeleton case has the sides almost totally open it is not really a sensible option for the track. If you did use it you’re likely to get a lot of dust or water in the sockets on the side of the camera.

Hole is centered but doesn't look it due to the camera angle

Hole is centered correctly but doesn’t look it due to the camera angle

Drilling the waterproof housing or case will destroy its integrity but since I’m not likely to be taking the camera underwater this is something I can live with. The trick is to put the camera into the housing and identify and mark where on the case you need to drill your hole for the 3.5mm microphone jack plug. It’s vital that you do this accurately otherwise you will have to make the hole bigger than the jack plug. I needed to use an 8mm drill bit for the hole.

AudioTechnica-ATR-3350The microphone that I purchased is the Audio Technica ATR-3350 ATR Series Omnidirectional Condenser Lavalier for £28 (typically available in the US for US$30-40). After much some research, I chose this mic because it uses an internal battery to power the mic and because the microphone is omnidirectional. It comes with a 6m cable which is more than enough to route between the camera at the front of the bike and the mic at the back (near the exhaust pipe).

The mic is fitted above the number plate hanger close to but below the mouth of the exhaust pipe. I’ve placed it here to try and keep it out of the wet in case it’s raining. The cable is then routed with the indicator loom up under the tailpiece into the area under the seat. This is where the mic switch and battery pack sits – out of the rain and harms way. It also means that I only need to pop the seat to switch the mic on or off. The wiring loom is finally routed along the left hand side of the bike into the fairing. From here it is taped to the exterior of the fairing before finally arriving at the GoPro camera.

The sound difference between the internal GoPro mic and the external one is massive! If you listen to the video below, you can hear how much better the bike sounds when the external mic is used.

The only issue I have yet to resolve is how to waterproof the GoPro case where the 3.5mm microphone jack plugs into the camera through the case. Since it’s summer at the moment, I won’t worry too much, although I think I’ll eventually use some silicon bath sealant to make a grommet-like bead of sealant around the plug which should keep any water out (I hope!).

I reckon that this is a very worthwhile mod if you have a decent sounding engine and exhaust pipe!

Update Summer 2014

MicTailpieceAfter a track day in the rain where the mic was destroyed after it became saturated with water, I decided to relocate it to under the tail piece.

The new location is much better because it’s still close to the end of the exhaust so the mic picks up the sound nicely, but it’s also completely protected from the elements.

One thing I’m still not sure about is battery life. I generally change the battery after every second (or third) trackday as there is no visual indicator on the mic to help you see how much battery is left. I also switch the mic off between sessions to try and conserve battery life.

Check out the video below to see how the mic sounds in its new location.

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3 thoughts on “Better sound with GoPro Hero 2 plus external mic”

  1. John I had similar problems with the Drift HD camera i use… have the external mic now that comes as optional accessory although yet to really try out!
    Just had all clear after knee op to get back out riding on track will take a look at dates and see if we can catch up on a day together!

    1. It’s software that I wrote to process the export files from RaceChrono. I think that there is other software available that will create video overlays from your data logger files, although I don’t know what they’re called – sorry.

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