First an apology. This has been covered in the archives (I remember seeing it sometime ago) but with the search function down I haven't been able to access it - Yes even using Googles search engine.
I have been using: Senns 600, Cardas headphone cable, a Corda HA2. an Oracle turntable with a McCormick phono stage and a Audio Analogue Maestro CDP
Question: What is a better headphone than the 600's to use for Acoustic Jazz? (Acoustic Bass,Wind instruments - sax, trumpet, trombone etc, Drum Kit. Upright or grand piano and the only electric instrument-guitar -Joe Pass, Ed Bickert etc.)
I like the 600's for but something is just missing. Being a professional musician for the past 23 years I know the sound I'm looking for but haven't been able to find it with the 600's.
I had the same problem as you did, and found the solution in speakers. Not just any - single driver fullrangers. they sound terrible - on everything other than jazz. if you dont need headphones, take a look around for some really cheap designs(built mine with Radioshack fullrangers, total project cost approx. $75)
there is just something very right about the way they sound. No deatil, bass drops out ~60hz, but I enjoy them more than my HD600s on jazz, and only jazz.