Recording to MD - less quality?

V

VCO

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hi!

I use to record my techie stuff to my MiniDisc, and I am still wondering if my tracks are loosing some depht and punch during the process. Cos' when I listen back, I sometimes feel that something is lost, but is it real, or is it only because I know there is destructive data compression when (re)-burning a MD?
 
This is something i've been fiddling with this weekend, as i'm having a nightmare recording decent quality into my PC through my SB Live soundcard.

I suppose if everything you output is already being 'suitably' compressed at the final stage, then what goes into your MD should sound the same quality (easier said than done, i know).

You're right in what you say though, your MD does compress the signal, i suppose if you can find out how, and by how much it compresses you'll be half way there so you can simulate and cancel out the MD compression b4 (that's unless it's automatically adjusts like some of the budget hardware compressors i've seen, then you'll be funked !).

However, if you're recording into your PC first (i.e for Cubase mixdown, or whatever), then some of loss of clarity could be getting cut by your soundcard's inputs and the resulting output signal going into your MD could just be gradually getting worse as the signal gets transferred (again !), if you're not using a card with decent A/D converters.

If you find out about the MD compression though, i'd love to know.

Solve me a lot of problems, believe !!!!
 
If you find out about the MD compression though, i'd love to know.
Click to expand...

MD compression is not compression in the sense of an audio compressor but compression of the data destuctively. It saves space by throwing away data . The choice of data is based on a the theory of perceptual coding. If a tone occurs at a certain frequency the ear is desensetised to frequencies slightly higher than this which occur at a low amplitude. Think of it as a certain frequency will cast a shadow over higher freqs. This is the data that is thrown away.

I can hear minidisc compression it is especialy evident in the top octave and the sense of air around instruments , but some people like this ... it imparts a certain tightness to the sound.

Going back to full quality , the missing data is just padded out with zeros.
 
I have listen to music on a MD..and I dont notice any loss of sound quality .
 
when it *throws away* information, wouldn't that be kind of like it's own proprietary dithering process. like when you go from 20 or 24 bit down to 16, dither sort of lops off those extra bits
 
No it is much more complicated. It is a dynamic process based on the program material.

Dithering is the addition of a random noise to mask the low amplitude resolution stepping that occurs in digital ststems.

The process of perceptual coding is creating zeroes out of certain numerical information that it reckons the ear won't perceive. It then throws this away as redundant data, Mini Disk is still at a 16 bit level. This is different from truncation ( 24 bit to 16 bit ) which merely chops off the bottom 8 bits.
 
minidisc uses ATRACK compression, which squashes the sound file down to about the size of an mp3 file. It analyses the sound, extracting the actual frequencies, and then creates a file using this information selectively.

I haven't got very good ears, and I can't hear ATRACK compression, it shouldn't alter the dynamics too audibly, though even through good ears. Maybe its that youre doing something wrong. Each piece of equipment that the sound goes through adds noise to the signal.

I used to put all my stuff onto minidisc, but the problem with it is (if you only use the analog connections), that is probably where youre going to lose the quality.

Once you want to get it off the minidisc, you've got to get it out of the minidiscs really schitty Digital-analogs, and then down a schitty cable and then into your soundcard's not-so-schitty A-D convertors.

Theres some new cheap minidiscs that you can connect with a USB cable by sony for $150

HTH
 
It really depends on what you're listening to. Dance music tends not to suffer too much to minidisc, but check out the reverb tails on cymbals on real live music, you'll hear the compression then - basically the sound just stops.

KasioRoks
 
Marek Bereza said:

Theres some new cheap minidiscs that you can connect with a USB cable by sony for $150

HTH
Click to expand...

i bought this...i think it's a joke because the USB connector isn't a digital connection. you plug the audio output of the MD into the USB box, then the USB box plugs into the computer. therefore, it's doing some kind of A-D conversion....still using crappy (and probably crappier than the farking MD converters onboard) conversion...

back to the drawing board. as long as you don't expect too much from MD you won't be disappointed. it's nice FWIW but it's not going to be as good as going to a DAT or a computer system of some kind which does not utelize cheap a/d d/a converters.
 
The easiest way to look at this is by looking at the top frequencies. On an analogue recording, the frequencies above the recording range will clip and distort but you will still be able to hear the distorted sound. With a digital recording (such as minidisc) these frequencies will be completely discarded. This is why, on cymbals mainly, you will hear dropouts and/or 'digital clipping'
 
I'm sure you can get MD's with a USB connector actually on it. Maybe it's not the one you bought kasio, but I'm sure it exists. The only bad thing is, if you store your stuff as mp3's, its got to convert it to uncompressed audio, then to ATRACK compressed audio, which will compromise the signal even more. (That is if your minidisc doesn't support mp3 format. Why do you need to master to a minidisc anyways?
 
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