DEMO / MUSINGS: Let's listen to some jitter simulations with sideband distortions...

A couple weeks ago, we started getting into the topic of jitter and the concept of whether jitter is audible and at what level. As I had expressed at that time, my belief based on experience with the equipment I have looked at / listened to is that with almost any reasonable modern day digital audio device, the likelihood that one would hear sampling jitter effects is extremely unlikely. No need for crazy expensive cables that claim jitter improvements. No need for high-priced servers (like this), expensive streamers, or "de-jitter"/"reclock"/"regen" devices. But one of course does want to have a good DAC with excellent jitter rejection, and these days, competent asynchronous USB devices almost universally will achieve excellent results by reducing jitter from the interface (remember, the older S/PDIF digital interfaces typically perform worse than modern USB or ethernet even though newer devices like the Oppo UDP-205 perform excellently with any of the inputs).

The reason I say this comes not just from measurements and my own listening to devices with different severities of sampling jitter, but also experimentation over the years in simulating the distortions introduced by jitter.

As I mentioned last time, with Yamamoto2002-san's WWAudioFilter, we can easily use DSP to introduce fixed amounts of sinusoidal periodic jitter to "bake in" the kinds of sideband anomalies often found with devices that suffer from jitter. For today's post, what I want to do is provide some test files you can use to actually hear what severe jitter distortions with sideband anomalies sound like. Think of this post as similar to one years ago when I demonstrated what poor USB cables sound like.

Furthermore, coming out of this article, I hope the audiophile reader can appreciate the magnitude of jitter that is necessary in order for the effect to become audible. In so doing, I hope it will help us appreciate the results from the J-Test FFT's I publish here and also when you look at measurements elsewhere (like on Stereophile).