Although this isn't meant to refer to the Tera-Player directly, one must keep in perspective that precious few earbuds or IEM's, or for that matter few full-sized cans, can accurately reproduce frequencies much below 45 hz without roll-off or worse, doubling, which gives the illusion of great bass response. After all, it takes a pretty good-sized, high-quality speaker to accurately reproduce the lowest octave of the audio spectrum. To expect this type of full-range performance from such tiny transducers is, to say the least, optimistic.
The AKG K1000, which has been for years one of the headphones held in high regard by audiophiles, has significant roll-off below 50 hz. This is often unnoticed due to the superb imaging and accuracy of the rest of the audio spectrum.
Phones with a mid-bass hump are often considered to be quite "bassy" whereas in actuality, they may exhibit significant bass roll-off.
Another factor to keep in mind when attempting to evaluate the synergy between source and phone is not just the manufacturers stated impedance (typically measured at 1Khz), but how the impedance varies with frequency. This will greatly affect not only bass response but performance at other points within the audio spectrum. B-A transducers typically have the greatest variation of impedance with frequency whereas the planars have essentially a flat resistive value regardless of frequency. Dynamic transducers typically have less variation of impedance due to varying frequency than do the B-A devices, but nowhere near the stability of the planars.
