I made a field recording of the nighttime view of Eugene, Oregon from Skinner Butte with a Lite2Sound HD Stereo 62mm photodiode amplifier. We can hear many lights emitting hums and harmonic tones simultaneously, and the pulsing rhythm of radio mast lights. There is also a 60 BPM clicking pulse sound, it seems to be from an infrared source, maybe its the IR illuminator of a slow-frame night vision surveillance camera somewhere downtown.
Incidentally, while I was recording, there was a Friday night party atmosphere behind me with about a dozen cars and a mobile DJ blasting tunes, but it was not an issue because LiteSound does not pick up acoustic sounds – only optical sounds. The ambient droning soundscape I heard in my headphones was unaffected by all those background noises. But I did have to move my view position to get away from the auto headlights and mobile phone devices. Those things can make unwanted optical sounds that come through in the recording.
Lite2Sound HD Stereo is the highest performing Lite2Sound version I have built so far. It was developed specifically to give low noise, clean audio at long distances, and that makes it possible to hear an entire cityscape at once. Its sensors are 200 times larger than Lite2Sound PX/PX2, and these are coupled with my newest low noise preamplifier circuitry behind a large light-concentrating lens.
The other Lite2Sound devices I offer, Lite2Sound EP, Lite2Sound QB Stereo, and Lite2Sound PX/PX2 will also pick up some of these sounds, although the noise floor will be higher. That means there would be a louder background static hiss or ‘snow’ noise, which covers up some of the finer details of the audio waveforms.
Below is an illustration of the setup I used for this video. So far, I have built a total of four units like this. A serious videographer could do groundbreaking things with it. Contact me through rarewaves.net if you’re interested! -Eric
