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Without going into pages of detail:
1. What exactly is "dynamic range" and how is it measured? What
does it all mean to the human ear and listening pleasure? My
CD player's dynamic range is 95 dB. What does dB stand for?
Is 95 dB good?
the db is decibel. dynamic range is the difference between the
loudest and softest sounds. It is logarithmic (sp) i think. (used
to know but forgot). 95 is fine - they are all very close.
2. Why are there CD cleaners? Is dust on a CD really noticeable?
Yes and No. Dust is noticable when the player has to try real hard to
track around a dirty record. The power used to move the servo's around
the dirt is taken from the power used to drive/amplify the music.
Some people can hear this distortion.
3. Is it true that one CD player is as good as another and that
the only factors separating their cost are things like remote
control and quality of materials in construction?
NO. read this entire notesfile and you will see. - thats blunt.
4. I just bought a CD of a recording made in 1967. Why is the CD
so superior to the tape/record of the same thing? Did they use
the master to record the CD? Where does the master reside? Is
it a tape, and if so what kind?
If the record was pressed in 1967, then it is almost 20 years old,
probably dirtier than a sock and pressed on very old equipment.
CD's are rather new, and it is possible that the original tapes
have been re-mastered and edited to make the CD.
ok? for now?
.dave.
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| .1 covers things pretty well, but I must add the following:
.3: Audible differences do exist, but their significance is
extremely subjective. Some people hear (or claim to hear)
significant differences. I find the difference in sound
between my Sony D-5 (a portable unit without oversampling
or dual A/Ds etc etc) and my Nakamichi OMS-7E (one of the
better units even for golden-eared listeners) essentially
irrelevant if what I am doing is listening to music (rather
than to equipment). If I'm listening for differences, I can
hear them (whether they exist or not).
The subject has been discussed at length in this file. It's one
of those religious issues like whether you can tell the difference
between different kinds of interconnect cable and whether too
many bends in your speaker cable introduce distortion by tiring
out the electrons who have to make the bends at extremely high
speed.
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| Re: 4. I just bought a CD of a recording made in 1967. Why is the CD
so superior to the tape/record of the same thing? Did they use
the master to record the CD? Where does the master reside? Is
it a tape, and if so what kind?
There are some interesting articles in the Septmbert Digital Audio
about accessing master tapes.
The CD is superior because it is capable of, for all practical
purposes, exactly reproducing the master tape. All previous consumer
media -- vinyl disks, cassette tapes, and reel-to-reel tapes, have
been incapable of doing this. So conscientious and capable recording
engineers, working with good equipment, have been able to make very
good master tapes for thirty years, give or take a few. After all,
they use tape running at 15 or 30 inches/second, wider tracks for
lower noise, etc. For examples, you can look to recordings engineered
by Rudy van Gelder on Verve in the late 50's, or to DG recordings
from that period.
.1 feels that dirt on the record and the 1967 state of the pressing
art would be the explanation. Dirt is always possible, I assume
you would know the sound of dirt if you heard it, and that is not
the significant difference.
As far as pressing goes, plastic technology may have improved slightly
since 1967 but I don't think that's it either.
I would point to the (vinyl) disk mastering stage as being the
culprit:
o High-volume excursions have to be limited in a vinyl record.
- First, entire passages that were performed at high loudness are
reduced in level (gain riding). This reduces the dynamic range
-- the difference between loudest louds and quietest quiets.
- Second, transient impulses of high level are reduced in level
(peak limiting). This is more subtle: for instance, a cymbal
crash would sound more muted and have less impact when peak
limited (but would not sound significantly quieter).
o If this is an original 1967 pressing of the record, it was mastered
so that it could be tracked by the readily available cartridges of
the day. Today's $15 Radio Shack is better than the Shure M3D that
many "audiophiles" had in 1967 -- so mastering engineers cutting
vinyl records today can get away with less peak limiting and
gain riding.
o Low-volume passages may have to be made louder to get above the
intrinsic vinyl noise, again reducing dynamic range.
o Bass frequencies are typically rolled off and blended into mono
on a vinyl disk to keep the groove undulations manageable. Low-
frequencies require larger groove movements -- blending into
mono keeps them side-to-side (out-of-phase information would
result in verticalmotion and potential groove jumping) while
rolling off the bass helps keep adjacent grooves from
overlapping.
All these manipulations can be avoided with a CD, and you get to
hear essentially the original master tape.
dq
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| > Why are there CD cleaners?
> Because there are people who will buy them, regardless of the
> necessity for them.
Uhhhhhh ....... yes.
At a party someone (possibly me) spilled a drink on one of
my disks. When I noticed the problem several (sticky) hours
later, I just gave it a bath in warm water. Plays OK now.
Just be careful not to scratch the surface. The bottom side
is the one that plays, and scratches in the round-and-round
direction are worse than scratches from the center to the
edge. -- So don't use Ajax and don't wipe it in the circular
direction.
Roland_who_is_glad_it_wasn't_another_record_which_got_spilt_upon
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