This video, via Comparative Irrelevance, captures a performance of the traditional carol Oh, Holy Night (Adolphe Adam), arranged for a three-module Eurorack synth patch (Ears, Clouds & Tides).

Here’s what they have to say about the technical details:

I’m playing a sample from a completely randomly chosen song through Ears and into Clouds, while using the envelope follower and threshold gate signal generated from the sample to control the patch.

I’m using Tides as a typical LFO to scrub back and forth through Clouds’ buffer by way of the Position parameter, shuffling the input around somewhat. The gate signal from Ears enables Clouds’ winter themed freeze.

As the sample reaches its crescendo, the buffer is frozen and held until the levels recede.

However, the Position modulation keeps the frozen buffer from sounding static. Ears’ envelope follower is patched to Tides’ level, so the louder parts (i.e. when freeze is engaged) have the greatest modulation range – the most movement of buffer playback position, in other words.

You may notice that I have Clouds’ Pitch turned up fairly high. This is because the sample itself is played back at a much slower than natural rate and is consequently pitched down, so I’m compensating for some of that pitch drop in the granular playback.