Initial audio tests with atmospheric recordings

I initially ran a few tests to figure out whether the recordings would actually be usable. I tried cross fading between A and B (ie ‘land‘ and ‘mud’) atmosphere tracks over a period of 2 minutes. This didn’t work as almost right away I could hear atmosphere B coming in over A and similarly could hear A until very nearly the end. I tried off-setting the cross fade so that B starts fading in after approximately 30 seconds and A completes fading out 30 second before the end. This created a slightly more convincing transition.

Next I tried placing a detail sound over the atmosphere layer. The detail sound itself was very noisy but placed over the noisy atmosphere, the noise was not so apparent. Hurray – it appeared that the field recordings I had created in the limited time available, further reduced by a run of bad weather and mistakes, would actually be usable.

After some trial and error I came up with the approach of running some basic audio pre-processing on all sound sources to be used in the piece, and then to apply additional post-processing on the master output of Resolume Avenue (the master composition platform) as required, ie further equalization or volume adjustment. The pre-composition technique was to cut all audio from 17kHz and above using a high shelf in an attempt to reduce the high gain noise without compromising the higher frequency environment sounds such as water trickling through mud. Similarly, a low shelf was employed from 100Hz and below to remove much of the low end noise generated by wind and general sonic reverberation. (see below diagram for pre-processing audio profile)

It seems that the 80kHz cut I employed on the recorder at the point of capture was not particularly effective.

I had already realised that it would be necessary to run low-detail atmosphere track(s) for the duration of the piece. Low detail because the programmatically placed individual sounds would need to provide the ‘interest sounds’. In actual fact some of the atmosphere recordings had far too much foreground detail and I had to go through them cutting out these fragments to create a more ambient atmosphere track suitable as ‘base layer’ to place detailed sounds on top of.

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