Steve, I didn't read your post until after my little rant. Please keep in mind that USB is not an audio interface - it's a source to peripheral device connectivity bus. As far as USB is concerned, there is no difference between audio files and jpeg photos, an Oracle spreadsheet or java code. The "audio interface" part starts on the outbound side of the DAC.
I agree with you about timing variations. There's also latency, packet loss/corruption, and a host of other issues that can affect USB (or any almost any other data connectivity protocol). But I was responding to a poster that claimed that changing USB cables provided " The top end air, the transparently and better defined bass are easily distinguished differences." That's not a phenomena that can be attributed to error correction, or timing, or latency, or voltage regulation, or phase lock, or... whatever.
It's easy to say ignore or dismiss the science involved in audio. Over the course of human history, anything we can't explain (or didn't want to take the time to understand) is described as magic. Well, guess what? There is no magic in audio, just a lot of science. Circuit design is a science. Tube design is/was science. Acoustic speaker and cable design is science. Transformers, resistors, capacitors - all based on good, hard scientific principles.
About two years ago we had a job for a major aerospace company, designing a system to collect and sample broad spectrum analog audio feeds some remote sources. Very remote. Anyway, when we used USB 2.0 for part the low-res portion of the system, and in our testing we found that for cable runs of up to 20'-25', the actual cable (manufacturer, country of origin, jacket, etc.) made no difference. The connectors use for the USB cables made a measurable difference in the amount of packet error correction that was required. Upgrading the USB connectors on the source systems and target devices made a huge difference, dropping the packet error rate down to almost zero; even if used with the least expensive commercial cables.
My last word on this incendiary topic: all this information is available online. Anyone who wants to can find and read Gordon Rankin's excellent white papers on USB and specifically asynchronous mode operation. They provide an excellent explanation on how USB works, so nobody has to guess.
I agree with you about timing variations. There's also latency, packet loss/corruption, and a host of other issues that can affect USB (or any almost any other data connectivity protocol). But I was responding to a poster that claimed that changing USB cables provided " The top end air, the transparently and better defined bass are easily distinguished differences." That's not a phenomena that can be attributed to error correction, or timing, or latency, or voltage regulation, or phase lock, or... whatever.
It's easy to say ignore or dismiss the science involved in audio. Over the course of human history, anything we can't explain (or didn't want to take the time to understand) is described as magic. Well, guess what? There is no magic in audio, just a lot of science. Circuit design is a science. Tube design is/was science. Acoustic speaker and cable design is science. Transformers, resistors, capacitors - all based on good, hard scientific principles.
About two years ago we had a job for a major aerospace company, designing a system to collect and sample broad spectrum analog audio feeds some remote sources. Very remote. Anyway, when we used USB 2.0 for part the low-res portion of the system, and in our testing we found that for cable runs of up to 20'-25', the actual cable (manufacturer, country of origin, jacket, etc.) made no difference. The connectors use for the USB cables made a measurable difference in the amount of packet error correction that was required. Upgrading the USB connectors on the source systems and target devices made a huge difference, dropping the packet error rate down to almost zero; even if used with the least expensive commercial cables.
My last word on this incendiary topic: all this information is available online. Anyone who wants to can find and read Gordon Rankin's excellent white papers on USB and specifically asynchronous mode operation. They provide an excellent explanation on how USB works, so nobody has to guess.