copp@petrus.UUCP (09/08/85)
I sometimes play home-dubbed Dolby-B Type II tapes in my car,
which has no Dolby and no provision for other than Type I tape.
The sound is bright--I expected that--so I back off the treble.
But playing one of these tapes produces, within five minutes,
a feeling of pressure in my ears, sometimes followed by a headache!
I do NOT have this problem with commercial pre-recorded tapes,
which are typically Dolby-B on cruddy Type I stock.
Hypothesis 1: Lots of high frequency energy, too high for me to
hear (my old ears can't even respond to 15,750 hz any more).
My daughter can hear 15,750 hz right through the bedroom
wall ("...please turn off the TV, daddy!...grrr...).
I put on a bad-guy tape and asked her if she heard
anything unusual. No reaction, except some criticism
of my choice of music. Hmmm.
Hypothesis 2 (and now I'm reaching): Same as H1, with an additional
qualification: the offending high-frequency sound is narrow-band,
and quite high--perhaps due to oscillation in the deck that
made the tape.
Although my daughter beats me at 15,750 hz, for some
strange reason I can easily sense some ultrasonic alarm systems
that she can't hear at all. Implies that somewhere 'way
up there my ears go back into action, and might even be,
ahem, exceptional.
Has anybody run into this problem before?