Hi Arthurmail
The 615 has the same type of "sound" as the D700, but lacks 3D, imaging compared to the latter : it has only a 8" vs 10" Dual Concentric driver.
The Turnberry is more smooth compared to 615 and d700, which are closer to System 800 and 10DMTII, that I have also.
Perhaps due to the paper cone ?
Furthermore, the 615 looks like a Darth Vader's starfighter ;-) !