Frequency 40Hz-17kHz
The total harmonic distortion plus noise (THD + N) was 0.003 to 0.004 percent from 20 to 2,000 Hz.
Tested works well.
The Nakamichi 500 is the most advanced two-head cassette deck ever made.
At the heart of this outstanding system is Nakamichi's unique head, a technological breakthrough that closely approaches the performance capabilities of our world famous three had cassette decks.
The new Nakamichi 500 is of special significance because of newly-developed Focused-Gap type record/playback heads designed by Nakamichi to give a far better head-saturation level than is found in other two-head systems.
Link about Nakamichi 500
https://www.hifiengine.com/manual_library/nakamichi/500-dual-tracer.shtml