William Sommerwerck wrote:
Q: Do Nakamichi tapes not sound good on Non-Nak decks?

A: The degree to which this may bother a listener will vary. Nakamichi tapes
are
certainly listenable on other machines but to fully appreciate the capability
of a
Nakamichi deck the tape should be played on one. Since the gaps on both the
record and playback head is much narrower on a Nakamichi deck, the signal is
recorded on a much smaller portion of the tape. The result is clearer detail,
definition, and reduced crosstalk. However, other machines heads are not
designed to read information in such a small area. As a result high-end and
overall sound quality is reduced. Of course when this tape is placed in
another
Nak, all the sound is there and far surpasses what other machines could
reproduce from the beginning. Almost important--all must realize that subtle
differences in azimuth between any two decks can create as great (if not
greater) of a difference in sound quality between machines as the difference
between Nak and non-Nak decks.

Forgive me, but this is not (to the best of my knowledge) a correct explanation,
and it also contains a number of serious technical errors, regardless of whose
tape deck you're talking about.

The fellow that runs the site claims that his company serviced and sold Naks for
years. His FAQ seems pretty thorough. I don't see anything there about an
EQ difference. It also includes this entry, which again
notes a design difference between Nak heads and others':

Q: Why does Nakamichi use different calibration tapes and are they really necessary?
A: As the head gap is different than other brands, the tape must be specially cut
using equipment that lines up properly with the Nak head. Using other tapes
will not result in the accurate alignment and bias/level calibrations
necessary to make a Nakamichi sound as it should.

Briefly... Nakamichi's playback heads appear to have been far superior to those
of any other manufacturer. They had much lower HF loss, and got more HF energy
off the tape. As a result, not as much HF pre-emphasis is needed during
recording. So Nak tapes tend to sound "dull" when played on other decks, while
recordings made on other decks tend to sound bright.

The first time I heard this was listening to a master tape dubbed onto a Sony
deck. The sound nearly sheared off my ears.

--

-S.