IDM Mailing Archive

Since some people on this list have shown an extensive knowledge on minidiscs in the past I thought I'd pose these two questions that I've been pondering about: Query 1 The cost of blank minidiscs in UK varies considerably. I've found the cheapest non-bulk place to purchase them is in the many Richer Sounds outlets. They have the well-known brands such as Sony, Maxell, TDK etc. which are 3 quid. I've seen professional standard blank ones for a lot more. But they also have ones by a Japanese Brand called Kao and these cost just 2 quid (all 74 min. discs BTW). Does the quality of the disc have any bearing on the quality of sound? With a digital recording isn't the data either 'present' or 'absent' rather than stored in a way that allows qualitative differences (ie. tape quality matters a lot)? Query 2 Here is the theoretical situation: I get a sample direct from a CD and I also get a sample from a minidisc and, for the sake of argument, cannot tell the difference between them. I then use various filters and manipulations within a sample editor. Are the samples going to sound the same at the end? In other words, does the missing information from the minidisc sample (initially unapparent to my ears) become apparent to my ears when you muck about with the sample? Just curious. Cheers, Nick

On Thu, 18 Jun 1998, Jeremy Wells wrote:

quoted 7 lines Technically, the sound waveform *will* be different. Whether you will hear

> Technically, the sound waveform *will* be different. Whether you will hear > the difference is debatable. The Minidisk uses a loss compression scheme > and will throw audio data out. The compression codec then tries to > reassemble the audio close to the original--but it will never be the same. > I have heard tests that when you dub from a Mididisk to Minidisk, you > start hearing audible differences after the 5-10th generation. >

As soon as you feed a pristine digital signal through a processor of any kind, any subtle effects in the original are pretty much right out. And compare a fifth generation cassette with a fifth generation MD if you want an idea of what you gain with the new format. I would shy away from minidisc as a mastering format, because that's just the beginning of a long chain of indignities that your music is going to suffer before it reaches the ears of listeners. Why start with less data than you have to? But for applications like walkman listening, auto, and field recording, I say go for it. The mechanical advantages of MD over DAT or cassette are substantial, and the sound is quite good enough. Better, in fact, than those MP3 files everyone's so hot under the collar about. Also what I absolutely LOVE about MD is how the fast forward and reverse cue works -- no pitch change, and no ticky tickies as with CD. If anyone makes one with pitch control and provides a good control surface, they'll be lightyears better than CD's for DJ'ing.

Judging by some of the responses I have received about the second query I made, I feel I may not be expressing myself very well. I do actually own a minidisc recorder at the moment which I use to sample from to make music on my PC. I was just wondering whether filtering and other manipulations would bring out the difference in quality between a sample from a minidisc and one from a CD (assuming that I hadn't noticed one before filtering).

quoted 7 lines Judging by some of the responses I have received about the second

> Judging by some of the responses I have received about the second > query I made, I feel I may not be expressing myself very well. I do > actually own a minidisc recorder at the moment which I use to sample > from to make music on my PC. I was just wondering whether filtering > and other manipulations would bring out the difference in quality > between a sample from a minidisc and one from a CD (assuming that I > hadn't noticed one before filtering).

Why not try this and see if you can tell a difference? You could record something from a CD onto a Minidisk. Sample direct from the CD, and apply your mods. Then sample from the Minidisk and apply your mods. Is there a difference? My gut feel is the only difference you *might* hear is a difference in levels. Most of the same distribution of frequencies should be in a sample that originated from a minidisc so as far as filtering goes, it should sound the same... -Jeremy http://users.owt.com/conflux

On Fri, 19 Jun 1998, -wheeler- wrote:

quoted 8 lines Judging by some of the responses I have received about the second

> Judging by some of the responses I have received about the second > query I made, I feel I may not be expressing myself very well. I do > actually own a minidisc recorder at the moment which I use to sample > from to make music on my PC. I was just wondering whether filtering > and other manipulations would bring out the difference in quality > between a sample from a minidisc and one from a CD (assuming that I > hadn't noticed one before filtering). >

The succinct answer is: No, you won't notice the difference. I said words to that effect, but I must have been too discursive in my redaction. Some time you should take a CD, record it to MD, and then take an analogue sample of both. If you get the two samples chopped and normalized so that they start at the same time and have the same amplitude, you can invert the MD signal, and mix it with the CD signal. This removes the common component of the two signal, leaving only the difference between them. Then if you normalize that and listen to it, you'll hear what the compression took out.