How to record good sound on a GoPro Hero3+ with external mic

In the past I have always struggled to capture decent quality in-car footage when at a trackday. Having spent ages watching countless videos on YouTube I finally decided on the two main things that make a good video. Firstly the camera must be positioned in the correct place. Typically between the front seats facing out of the front windscreen. It must be located far enough back to capture the driver inputs and far enough forward so you can clearly see the road ahead - and the car you are just about to overtake! Secondly the sound has to be awesome and capture that all important exhaust note you have no doubt spent hundreds or thousands trying to achieve.

Vid just taken with a sony digi-cam before I got the GoPro

The Lotus Elise lends itself perfectly towards capturing this in-car footage. Just mount the GoPro on a suction cup mounted to the rear screen, take the roof off and the quality of the video and sound is naturally pretty impressive. This video was taken using Sony digi-cam on a suction mount before I had the GoPro.

Capturing footage that is equally as impressive in saloon cars, hot-hatches or four seat coupes is a bit more challenging. For example, I own a two door Subaru Impreza WRX STI 22B where the rear window is located about a meter behind the front seats. You can just hang a GoPro upside down on a suction mount on the rear screen, turn on upside-down mode on the GoPro and hit record. However, being so far back the GoPro captures a lot of the interior which is quite dark. It therefore automatically over exposes the footage resulting in the road ahead being very light and lacking in quality, detail and richness. This can be adjusted in the camera settings by switching on 'spot mode'. By then playing about with the image settings when editing the video in the GoPro cineform studio software, it is likely that the footage can be improved. But ideally the camera needs to be located a lot further forward so that it captures less of the dark interior. In order to do this I have made a list of the following GoPro accessories you will need to buy:

2 x GoPro Suction Cup Mounts

3 x GoPro Bar Mounts

1 x Lightweight aluminium tube approx 1.5m long

1 x GoPro mini USB to 3.5mm adapter lead

1 x Olympus Mic

1 x 2m long 3.5mm extension cable

1 x Skeleton GoPro case

1 x Fluffy mic windshield

The suction mounts will need to be mounted on the inside of the rear three quarter windows and then linked to a bar mount in order to carry the aluminium tube. Two of the bar mounts will need to be modified.  Do this by using a hacksaw to cut off each of the lobes with the chrome nut locator on them. The two bar mounts will then be compatible with the suction mount as shown in the picture to the left. Once the suction mounts and bar mounts are attached to the inside of the rear windows, measure the distance between them and cut the aluminium bar to length. This bar will run just behind the front seats.  It will act as the mount for the GoPro camera using a third unmodified bar mount and any extension to achieve the required angle for a specific vehicle.

Next you simply have to attach the 'mini USB to 3.5mm adaptor' to the GoPro, run the extension cable through the gap in the rear seats and then under the carpet in the boot. I also recommend running the cable underneath the rubber seal around the mouth of the boot, this will ensure that the boot lid does not damage the cable when shutting the boot. The mic lead can now be taped to the rear bumper or mounted on to a suction cup out of the airflow, on the rear of the bootlid for example. 

This photo shows the 'fluffy' microphone windshield to further minimise road and wind noise