Out on the mountain

After some successful trial recordings using both binaural and b-format techniques it was time to put all the theories into practice. I went out for the day accompanied by another snowboarder to Glencoe Mountain to capture some video and audio footage. The backpack recording system which contained the b-format recording gear, and the portable digital stereo recorder used for the binaural microphones were used along side the GoPro helmet camera.

The following slide show documents the equipment used on the day:



One of the major challenges of field recording is being able (or not being able as is the case most of the time) to monitor audio effectively. To do this in the field one would normally use headphones but as my ears were being used to house the binaural microphones this was not an option for the entire duration of the recording. Instead I had to set levels by eye on the recorders and trust my judgments based on previous recordings that I had made. The first opportunity I had to check whether the recordings were satisfactory was in the car at the end of the day using a laptop. Even then it wasn't until the recordings were heard through studio monitors that proper judgments could be made.

On listening back to the recordings through a 5.1 system it became apparent that there was a continual 'thump' and 'banging' sound audible throughout the b-format recording. I was not aware at the time that this was the case and decided to try to fix this using the spectral analysis tool in the Adobe Audition software. The spectral analysis was showing a broad range of problematic frequencies which would prove to be too difficult and time consuming to eliminate. The images below indicate excessive peaks in the audio. These peaks are also the deep red areas on the spectral analysis tool.



Despite the fact that the video footage was really bright thanks to a glorious day on the mountain I would need to return to get the recordings that were required.

That weekend I also recorded some motorbike footage and audio. The problems with the mic noise were evident there also. After listening to both sessions I had to establish what the problem was. It transpired that the microphone was knocking against the side of the rycote windshield. The microphone is mounted inside a shockmount and the shockmount is placed inside the windshield. After connecting the recording system to the studio playback monitors and shaking the microphone as hard as I could I discovered what the problem was. Although I had spent two days recording without producing any successful results I had managed to discover what the problem was and take steps to address it. I shall discuss this process in my next blog post.

The videos below demonstrate the problematic noises in the b-format recordings. The audio examples that accompany the footage were mixed using the Mid-Side decoding technique discussed in previous posts.

Untitled from Colin Gunning on Vimeo.

Untitled from Colin Gunning on Vimeo.