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Re: ATRAC (Sharp) artifacts?

Subject: Re: ATRAC (Sharp) artifacts?
From: Walter Knapp <>
Date: Tue, 24 Dec 2002 22:56:54 -0500
Joe P wrote:
> I recently bought a Sharp MD MT770 minidisc recorder.  I'm having a heck
> of a time with odd sounds in any recording that includes strong white
> noise (e.g. rain, river rapids, waterfalls, etc.)
>
> The unwanted sounds are loud, high pitched chirps, beeps, and clicks.
> They can be quite loud. These sounds are most definitely NOT in the
> environment I'm recording. I can recreate the problem with white noise
> generated with Cool Edit.
>
> The sounds happen more often at higher recording levels.  For example,
> if I stand near a rushing river and set the record level so that peaks
> hit -4 dB, I hear more of these chirps than if I record the same
> river with peaks at -12 dB.
>
> The most peculiar thing about them is that they seem to be worst around
> 45 - 60 minutes into a disc.  If I start with a new disc, the first 45
> minutes or so are relatively chirp free.  Around 45 - 60 minutes, they
> come faster until becoming almost continuous.  After 60 minutes, they
> seem to taper off again.
>
> I've tried setting levels lower, different discs (TDK & Sony), mic vs.
> line in (happens on both), using an external battery.  Nothing I do
> seems to make any difference. A friend who uses a Sony MD assures me he
> has recorded water/rain many times and never had this problem.
>
> I am about to return the unit to exchange for a new one, but I'm
> wondering if I should see if they'll replace it with a Sony or different
> Sharp model.  I question whether this is just a defective deck or if
> this problem is somehow inherent to Sharp MD recorders (or this model.)
>
> Some research has turned up this link, which describes various sounds
> that seem to give ATRAC problems:
> http://www.minidisc.org/atrac_breakdown.html
>
> And this link, which talks mentions a problem similar to what I
> describe except with a different Sharp model (see last
> entry.) http://minidisc.ch/problems.asp?todo=3Dshow&typ=3DSharp+MD%2DMT87=
7
>
> So, does anyone have any insight into this problem? Is it a character
> flaw in Sharp decks, or do I just have a defective unit?  Any comments
> or advice welcome.

I would guess you have a defective unit. I don't have any experience
with sharps, used Sony MZ-R30's until I moved up to the HHb Portadisc.
But, this sounds somewhat similar to a problem I had with the very first
MZ-R30 I got. It would do similar things if running off battery, but not
if plugged in. Needless to say it was exchanged and the new MZ-R30 is
still running fine, even through some buttons are way worn down.

This is not a ATRAC problem. My suspect is that the laser in it is weak,
poorly focused, etc. Or, it's not regulating voltage well. Or there is a
head alignment problem. In any case, the cure is to replace it. I like
Sonys, and they do appear to have less problems, but both brands have
given many people good service.

Walt





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