"Daryl O." wrote:
>
> I've just accessed the link from the community page to Video Direct
> Distributors' page regarding the new Sony MDS-JB940, and one feature
> particularly piqued my interest: a long-play mode that "[c]aptures up to 5
> hours, 20 minutes of stereo music on a single 80-minute MiniDisc." Does
> anyone know anything about this? Discs recorded in this special long-play
> mode couldn't possibly be compatible with older decks, right?
I have a Sony MDS-JE530 deck, and this unit has Pitch Control. This
means you can play back slightly faster or a lot slower, 1/16 of the
original speed is no problem at all. (I mean for the deck, not for the
listener :-)
I have a computer with a digital connection to my deck (duplex), so if I
have a wave file (16 bits 44100 Hz, stereo), I can convert it to 11025
Hz, and play it back as if it is a normal 44100 Hz wave file.
Effectively playing it back at 4x normal speed. When I record this on my
deck, I can play the recording back at the right speed with Pitch -24
(1/4 of normal speed). The quality is still surprisingly good. No noise!
I see (hear!) three problems with this:
- 1. With the conversion from 44.1 to 11.025 kHz you lose all the sounds
above +/- 5500 Hz,
- 2. ATRAC reduces the high sounds also. I mean if you have a 5 kHz
tone, than ATRAC will treat it as a 20 kHz tone.
- 3. Recording at 1/4 of the normal speed, also means only 1/4 of the
information that is normally recorded can be stored.
My guess is that the JB940 only has problem 1 and 3 in long-play mode.
If the recording in long-play mode is achieved by converting the
compressed (ATRAC) data, than problem 2 doesn't exist.
So, I think that long-play tracks can be played back in all decks, but
only decks with pitch control are able to play it back at the right
speed. :-)
I also think recording in long-play mode would be great for portable
units. Imaging recording 10 hours of lectures in mono on a single
74min59sec MD. If Sony would sell such a unit (without end search button
of course), it would make MD famous even in the USA ;-)
Niels
--------
Amstelveen, The Netherlands
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