From: cma851@huxley.anu.edu.au (Brenton LeMesurier)
Subject: Re: Choosing a CD player
Organization: Computer Services Centre, Australian National University
Date:  8 Sep 92 23:53:27 GMT

u1056905@csdvax.csd.unsw.edu.au writes (omitting quetions that I can't
coment on at all):

>Anyway, I am now looking for a new player, and I need your help :)

>I am planning on spending no-more than A$300! Looking around this seems like a
>reasonable amount. ...

>First, what is this 1-bit tecnology (or something like that) that I see
>on many
>new machines? Does it make any difference to the sound?
>I mean, I was always under the impression that all CDs produce similar
>sound, but some provide extra features like remote control, shuffle playing.
>etc'...
>So is there REAL difference in sound b/w different machines??


>I also wondered if there are any preferred brands in this field. My old
>machine was a Sony, and I was quite happy with it (well, until it parished).


    Since I have just been on a similar search in a similar price range,
here are a few random comments, addressing the above questions.

    As far as sound quality, it depends on your standards whether the
differences are significant.  To my ears, very close comparative
listening tells me that amongst $400 machines, the NAD 5420 sounds
better than others at that price, with the Marantz CD-42 also a bit
better than most.  But when I listen to such players separately, I
can't notice the small differences, and even my bargain basement CD boom
box sounds fine to played through a good amp and speakers unless I am
very critical in my listening.  Certainly all these players sound a lot
better overall than, for example, my new $400 turntable and cartridge
combination that got good reviews (including from me!).

    So arguably the subtle differences in the $400 price range are not worth
worrying about for me at least, and if you are the same, it makes sense
to choose mainly on the basis of features (the NAD buys its better sound by
having very minimal features).

    The counter argument is that over time and lots of listening, your
ear gets trained, those small imperfections become obvious, and you
become dissatisfied (or is this just marketing talk?)  If so, a
potential sound quality bargain for $300, at the cost of minimal
features, is the new Marantz CD-32.

    If you compare a few CD players and they all sound OK, I would
suggest one thing besides features to think about seriously: WARRANTIES
(and related repair service).  Because there are some deceptive ones out
there. It seems that certain parts are far more likely than others to
break down in the first year or so, particularly the laser and perhaps the
"transport" mechanism.  Some warranties are billed as three or even five
years, but on those most sensitive parts, are restricted to as little as
90 days!

    NAD and Marantz keep coming up in my comments partly because they
have good comprehensive warranties (others do too, including Sony I
believe, but check it yourself!).  Also I prefer to buy from specialist
dealers that are manufacturer authorized to handle repairs (warranty and
otherwise) themselves.  A department store purchase can leave you
out on a limb for repairs, having to ship the player off to the distributor.

   Finally, here is what little I know about 1-bit versus multibit
(usually 18 or 20 bit) digital to analogue conversion.  First a spoiler:
both methods, done well, can produce vey good results.  Far better than
anything in the $300 or $400 price range.  So it is not a simple case of
one being better than the other.

   The main rationale for the development of 1-bit D/A conversion seems
to be a certain sort of distortion that multibit conversion is prone to:
"zero-cross distortion" for lovers of jargon.  This comes from the need
for the multibit converter to produce a series of outputs at precise
ratios of 1:2:4:8 etc.  If these ratios are not close enough, slight
audible distortion occurs.  Careful manual factory adjustment can
overcome this problem, but you will probably not get that on a $300
player.  1-bit approach apparently replaces differnent current levels by
the signals put out for varying short periods of time, which can be
controlled more readily, with quartz crystal oscillators and so on.

    Deciding whether the difference is significant to you comes down to a
listening test of course.  Zero-cross distortion is at roughly the same
level regardless of the sound level (like tape hiss and record surface
noise), and so is best checked for by listening to quiet passages amidst
louder music.

    Indeed it is somewhat characteristic of digital reproduction to have
this sort of infidelity, that is most noticible during quiet passages of
the recording.  (Sort of the opposite of the situation with amplifiers
and speakers, where high volumes often show up the faults).  All the
lab. assessments of CD players that I have seen show a rapid worsening
of the ratio of distortion to signal as the input signal gets quieter.
So don't let the sales people just dazzle you with spectacular music
full of the brilliant high frequencies and big dynamics that are a CD
player's particular strengths.

   Well, that is more than enough from me, I think.

-- 
Brenton LeMesurier
Centre for Mathematics and Its Applications, ANU
GPO Box 4 Canberra 2601 AUSTRALIA
Phone: (61) 8-249-3829, FAX: -5549