Might I ask why you are in need of a low frequency generator? If it's only needed for the bass, the Hifiman HE-400 has some very low measured distortion in that regard (looks like 0.3%). Fairly sensitive. Unfortunately, having never actually heard it, I can't tell you about things like comfort, or how the distortion above 200Hz pans out firsthand. Costs $400 USD.
12/2/12 at 7:17am