The Kusunoki concept is an interesting analog-lover's approach toward digital-to-analog conversion for audio. The idea harks back to the days of bad digital, where sound was raspy, sharp, painful and soulless. With the advent of better digital mastering and steady improvements in audio systems, it is an opportune time to come full circle and explore that old technology. I was very intrigued by this concept and designed a very high-performance version filterless DAC to explore the idea, and now use it exclusively. I now offer it as a complete D-to-A conversion system for purchase or for building as a kit if you are interested in experiencing the results of this very unique design concept.
We use old technology to create a waveform that has all the 22KHz+ switching noise and harmonics and let it fly through the system. Provided that the amplication chain does not intermodulate into the audible frequency range, the sound that comes out of the loudspeakers will be naturally filtered beginning at about 19KHz and will have a steep rolloff above that, masking the noise. This throws much of psychoacoustics research to the wind, especially the work done to date that claims that humans can easily detect sounds into the ultrasonic range. Without filtering in the digital domain, we lose a lot of the artificial contrast that digital filtering negatively imparts to the sound; we avoid unnaturally clean and crisp highs, super-hard edges on transients, and lack of air and space. We gain cohesiveness, musicality, and naturalness - abstract things that the majority of digital designers laugh at the mere mention of.
Click here (or on the circuitboard on the right) to find out more.
