""The SOF packet consisting of an 11-bit frame number is sent by the host every 1ms ± 500ns on a full speed bus or every 125 µs ± 0.0625 µs on a high speed bus". If the timing of this shifts or is variable, this could elicit a different & variable reaction from the USB receiver & translate into a different & varying jitter or noise spectrum."
Certainly possible, but this does not matter. The data is reclocked externally with a free-running clock, eliminating all of the jitter from the USB receiver.
USB and networked interfaces can be virtually identical in performance. They both have buffered packetized data that is slaved from the source computer. They both have a free-running clock that retimes the data. Either one is the optimum way to do audio interfaces.
Steve N.
Empirical Audio
Certainly possible, but this does not matter. The data is reclocked externally with a free-running clock, eliminating all of the jitter from the USB receiver.
USB and networked interfaces can be virtually identical in performance. They both have buffered packetized data that is slaved from the source computer. They both have a free-running clock that retimes the data. Either one is the optimum way to do audio interfaces.
Steve N.
Empirical Audio