So... the Stax have enough bass for you?
What amp are you using with your Stax?
I've been thinking of trying them... but... have been scared off by the reports of limited, or distorted bass, and clinical highs.
I'm amazed that that you think the HD650s are comparable to the Stax - they have such different sound.
As I have stated many time before, overall for total sound reproduction, the Stax, in a variety of types, are alone at the top of my list.
The stax amp that I am currently using is the SRM-313 which works quite well for the Lambdas that I have as well as the newer 303s and 404s. It is the best overall, reasonably priced, Stax amp that is currently available used and which is capable of driving a wide range of Stax phones. Their are others available but they cost at least twice, and often more, as much for limited improvement.
After all those glowing comments about Stax phones, do I consider them the "best" phones I have heard? Not necessarily. It all depends on what you mean by "best". That is why I seldom respond to thread polls that ask us to rate the "best" phones. If you mean best at overall sound reproduction, then for sure the Stax are first, hands down. But there is a lot more to the over all music experience that just "sound reproduction." In the world of "live music" which is ultimately where most of what we call "music" starts out, many other factors enter in. Individuals use terms like "sound stage", "feel",
"texture", "ambiance", "color" to try to capture these elusive elements. Quite frankly, none of the above is scientically measureable except for "sound reproduction".
All that being said, the Stax are not the best for "color", "feel", "texture" and other intangibles that are very important to most of us music lovers. With the Stax you get ruthless accuracy. Very little of what I use call "coloring."
Frankly I love the "warm", "intense", "all enveloping" feel of a live music concert in a small club. The stax are not "warm" and they are not "cold". The music is simply presented with almost total perfection.
If the Stax have a weakness, it is in the bass realm. From my research and experience, this has little to do with "sound reproduction", the bass is all there acurrately reproduced. It is the "feel" and "texture" of the bass that is the slightest bit missing compared with the HD650s.
I prefer the bass of the HD650s myself, but it is not because there is "more bass" or that is "better bass". It is just bass with more color and texture.
Senn is very up front that that created the HD650 deliberately that way. They were going after as much the "feel" and "texture" of live music as we acually experience it. And that they did very successfully.
In summary which would I choose as my "favorite" current phones or as the "best of the best." I simply refuse to make such a choice. That is why I have both of them!!!!!
If I were you I would pull the trigger and get the Stax. The bass is absolutely not "distorted" or "limited" in any sense, it is simply not supplemented or "enhanced" as most of us have come to expect. Whoever told you that the Stax highs are "clinical" needs to have an ear transplant.
The stax highs are simply the best period, no contest. They may be "transcendant" or "sublime" but they are definitely not "clinical."