So let me enlarge a bit on an opposing viewpoint. As I have said elsewhere, I have heard a fair amount of live unamplified music, not as much as some, more than others, and I have heard sometimes gross variations in tonal balance, etc., so I have some idea of how much live music varies. I also play the piano recreationally, and know how much individual pianos vary in sound. I am relatively tolerant of equipment flaws. My long time speakers have been original Quad electrostatics, which are widely regarded as relatively neutral, transparent, and "musical" reproducers. I would also add that I have a somewhat different philosophy vs. DACs, which is that the DAC should be as neutral and transparent as possible, as should all the previous links in the reproduction chain, because what you lose upstream you cannot recover downstream.
To me, the Stax SR007 Mk I was a bit too soft, the SR009 a bit bright and the SR007 Mk II with spritzer port mod just about right. I would also note that a brighter tonal balance tends to subjectively result in more transparency. I realize that others on this thread such as astrostar59, Ali-Pacha, arnaud, purk and mulveling all prefer the SR009l. That's fine. But I feel the opposite, as do spritzer, recording engineer Bob Katz and, based on his comments from Big Sound 2015, Tyll Hertsens. Now, this is not to say that we're right and those who disagree are wrong. But, simply to point out that the SR009, although nearly twice as expensive, is not THE TOTL Stax headphone. In my view, the SR009 did not displace the SR007 at the top of the Stax heap, they are equally valid as TOTL headphones and either can be considered an end-stage phone, depending on subjective preference.
