Well, I've been rereading this thread.
Here are the issues I see:
1. Trial and error. These DACs you all are talking about range from $1,000 to $9,000 and I don't have any dealers to go hear the DACs. Trial and error is essentially impossibly expensive for me.
2. The Spatial Audio speakers are not the same with the M series differing from the X series so not quite apples to apples.
3. What is the job of a DAC? Isn't it supposed to do a better job of converting a digital signal to an analog signal (clarity and time)? But now we also think it should color the sound either with a tube sound If you are using a tube amp, why do you need double the tube sound? (Real question). Does that mean you just want more distortion in your music (even order harmonics)? Is that something properly coming from a DAC or the amp? Again, why do you have to spend another $3 - 7K to add more distortion to the music if a $1k DAC does a decent job of converting the signal?
4. R to R or chip? I understand R to R is an older system which seems to be in vogue now. My issue with the chips is that they get outdated quickly and never stop updating.
5. Is anyone ever satisfied with a DAC? On the other place to sell, the DACs seem to outnumber everything else in terms of lists of "for sale." My concern is that the DAC is an audio "black hole" which never seems to be filled. I wonder if that is because there is the thought that DACs are supposed to do everything including tucking you in bed at night.