CH> The above two systems ABSOLUTLY REQUIRE that the tape be accuratly
  > calibrated to the machine in question to prevent losses during
  > record/playback.  Levels & EQ both must be precise.
"Levels" as in recording levels?   What is the proper recording level
for Dolby B/C ?
My tape deck has an auto tape selector.  I suppose it changes automatically
to the correct EQ when I insert a metal or chrome tape.   But now I'm not
sure whether or not its working because turning on Dolby B on a metal tape
causes the sound to be flatter than normal.   (this doesn't occur
to such extreme on a Normal Bias tape).
So, say that the EQ level is that of a normal bias tape when I made
the NR recording.  Will the playback sound flatter?  Or are metal tapes
not designed for NR recording since from your explanation, metal tapes
seem to do the same thing.   How do I test the tape deck whether or not
it has a broken tape selector?  (I was fine with a tape selector switch,
but nooo, they got to make it AUTO with no lights).
Now what is "Bias" anyway? :)
CH> Dolby dynamically alters the frequency response and level during record
  > to boost low-level sounds.  A complementry cut back takes place during
  > play.  Hence the noise goes down with it.
So basically, a tape recorded with Dolby NR must be played back with
NR ON, otherwise the sound will not be the same since Dolby alters it
during the recording process.
What if a tape is recorded with Dolby C or HX PRO but the playback is
on a machine that doesn't support C/HX.  Will the sound be compromised
if a C/HX recording is played back on type B machine?
CH> Nice thought. :-)  There is methods in the CD decoding to deal with
  > minor rotational problems.
But since the sound on the CD is digital, rotational accuracy will not
alter the sound, correct?   If the rotational problem is not minor, then
I presume the music will just skip, rather than degrade.
CH> The CD rotates at roughly 500 rpm at the start as it is read from centre
  > to outside edge.  At the outer diameters, the speed is 200 rpm.  This is
  > done to ensure the data that comes off the disc is at the proper rate.
But is there more data at the outer rim of the disc than at the inner rim?
CH> Portable CD Players with the memory feature tend to double this rotation
  > speed and plow the cd music into a memory so the memory contents can be
  > "played" during bumps etc.
Shock/skip protection?
CH> Hope the above is of assistance.
It was very helpful, thank you.
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