So Ralph, are you saying that the data output (to be sent the the input of the Gan 1) sampled at 96kHz would not necessarily be a restrictive limiting factor to the ultimate performance of the Gan -1?
I am. The limitation is in the word length, not the scan frequency.
Gentlemen. I see that @kuribo has entered this thread. I've crossed swords with him in the past, but on this point of load dependent frequency response he is correct. @ricevs , if you want to find out what the effect of this might be, try a load that varies between 3 and 16 Ohms over the audio band (which is typical of many speakers) and find out what actually happens. Its not sufficient to look at the difference in FR with a simple resistive load.
Now I made a career of building zero feedback OTL tube amplifiers so I have a fair amount of hands-on experience with this. The output impedance of the amplifier plays an enormous role here. So I would expect that the FR of a zero feedback class D amp to be less 'reactive' (if you see what I did there) than that of a tube amp. The variable here though is the output choke, which is a critical part of any class D design, especially a GaNFET, which will require the choke to operate at a lower frequency rather than a higher one, on account of its inductive kickback being used to initiate the off state of the output device.
Its complicated.
Now how much this will affect the audio FR with a variable load is a good question. The On resistance of GaNFETs is stupidly low, so if it were up to them this would be a non-issue. IOW the output filter choke is really the variable. Based on my own experience (since a number of our prototypes were zero feedback) my guess is its a minor issue.