Digital compression explained

[HedgehogSandwich adi]

Thought this might be worth a new post ( i posted most of it on the end of another thread). Just explains how MP3 and MD work.

Digital compression on MP3 and MD works by removing 68-70% of the original audible frequencies from the source signal.  Much of the audio when you are listening to your CD player is completely lost to your ears, due to the fact that these sounds are covered over by similar sounds in the frequency range of the music (or speech or whatever) All of the frequenices are still present on the CD, they're just not audible to us.

MP3 and MD take advantage of this and remove the inaudible sounds from the signal, as much as 70% of the original sound is effectively discarded (the technical way this happens is obviously more complicated but this is the easiest way to explain it).

You *can't* put MP3 on minidisc due to the way minidsc stores the
data.  MD way of recording data can only be applied to audio. MP3 is already a data format, as  it is basically the end result of the digital compression process, therefore it cannot be compressed in the same way as audio before it gets laid onto a minidisc.

AS a footnote, obviously MP3 isn't CD quality, nor is MD despite what the manufacturers tell you.  I have a full sound check faciltiy on CD and MD.  The difference when aligning equipment etc when done from the CD is much more accurate than done off MD.
Having said that, i still love MD...fantastic product.

adi

[Gareth Davies]

If I recall MD's have about 100MB of actual storage on them. Which ment if everyone had their entire collection in MP3, there could be a MD Mp3 player so they could have compatible formats across all their systems. (Note i'm not saying it would play, i'm saying it could be done).

Doubt Sony would go for that though ;)

[HedgehogSandwich adi]

In theory yep, providing you have the correct recording format you could record mp3 data onto a minidisc (not wishing to contradict myself) , although the limited size of storage on the disc is a problem as you say.  Which is why they were only intended for small compressed files such as digitally compressed audio.  There's no reason why they couldnt hold mp3 data which is roughly the same size as MD audio data, it's just that it'd be pointless in terms of storage space. ie you'd get very few tracks onto a MD, maybe 30 max, roughly the same as MD.

[Adam W]

Quote: from HedgehogSandwich adi on 1:18 pm on Sep. 24, 2001[br]

AS a footnote, obviously MP3 isn't CD quality, nor is MD despite what the manufacturers tell you. ^I have a full sound check faciltiy on CD and MD. ^The difference when aligning equipment etc when done from the CD is much more accurate than done off MD.
Having said that, i still love MD...fantastic product.

adi




I think a lot of people miss the point with MD - I never intended mine to be a replacement for CD's.  I have a lovely high quality CD player and those silver discs sound fantastic on it.  When I plug in my MD recorder and play it back through the same amp and speakers, theres a noticeable drop in quality.

What I intended it to do (and what it has done admirably) was to replace my in car cassette player, and it provides much higher quality sounds than my old Kenwood used to.  You also get all the ease of recording and re-recording of an old fashioned C90, with even more convenience features than you get on CD

Also, there's the benefit of portability - I can download a track off the net, record it to MD, take my MD player round my mates house and play it to him in digital quality.  I can take the recorder to a gig and see how well the band was playing that night, whether we need to alter the mix or whatever.  I love it!

[Paul Booth]

Conversely, I can only record audio/I'net data onto CD which I then have to copy over on to MD.

I too replaced the Kenwood cassette player with a MD player. I can carry more MDs than I could cassettes and the MD walkman I use on planes is better on batteries than a cassette player and not as large as my CD walkman.

Unfortunately, if I do what I think I want to do with the dashboard, I'm going to lose the CD player in the lower half of the double DIN slot and I'll only be left with the MD player.

[Flipfinger]

I use my portable MD recorder to record sets, really fantastic things, just bung them in the output plugs and off you go.  The new Sony ones that record for 4 hours are the business.

Have used it to bootleg many many bands!

[HedgehogSandwich adi]

Adam, the drop in quality is most probably down to the fact that you are plugging the minidisc in as an external source, which the manufacturers of the car stereo wouldn't have bothered to fit high quality signal handlers for an external plug in device.  Unless you're using a digital patch with the car stereo and the minidisc then the quality will be noticeably lower (also portable MD's dont have decent components fitted which doesn't help either) .
Im afraid that anyone will be hard pushed to hear a noticeable difference between MD and CD, especially in a car setup.  To hear a noticeable difference you would need lab or studio equipment.  even a top of the range home system won't pick up and reflect the differences, despite what people think.

Id aggree though, Md was and should be a replacement for cassette, which im shocked is still being used today..it's nearly thirty years since the cassette came out.

Md is the way to go in terms og high quality easy recording for backup and home use.  It has a HUGE professional appeal to the entertainment industry,mainly theatre, being the most popular medium for background music, sound effects and anything else.

[Flipfinger]

You think still using tapes is shocking - I've been trying to change to playing CDs (DJing) and the uproar that it creates with people is amazing - they seem stuck on their vinyl BIG TIME!

And how old is vinyl?

[Paul Booth]

Quote: from Flipfinger on 12:25 pm on Sep. 25, 2001[br]You think still using tapes is shocking - I've been trying to change to playing CDs (DJing) and the uproar that it creates with people is amazing - they seem stuck on their vinyl BIG TIME!

And how old is vinyl?

Why do they give a toss?

[Flipfinger]

I've wondered this for ages.

The only two points I can come up with -

DJing with vinyl looks 'cooler' (a big thing with egomaniac DJs)

and, perhaps the crux of the matter:

Beatmixing is easier to do with vinyl than CDs, and most are lazy to$$ers

[Paul Booth]

Quote: from Flipfinger on 12:33 pm on Sep. 25, 2001[br]I've wondered this for ages.

The only two points I can come up with -

DJing with vinyl looks 'cooler' (a big thing with egomaniac DJs)

and, perhaps the crux of the matter:

Beatmixing is easier to do with vinyl than CDs, and most are lazy to$$ers

I'd say it's more likely that they are too dumb to know how to mix any other way.

[Flipfinger]

I'd say you're right!

I've been whacking them over the head with Pioneer stuff but they won't listen.  Maybe one day I'll take the headshells off the turntables and see how well they get on......proof of their professionalism....

[Gareth Davies]

I recall reading recently the differences in traditional record players and professional stuff. To my suprise vinyl seems capable of levels of refinement far greater than CD's are. I know a sweet fa about the various pieces of DJ technology so I don't know if they fall into this bracket, but that might be why they don't like it.

Why even bother with CD's? Think of a MP3'ish solution? You could do some seriously impressive effects then. Then again how automated do you want to get? I think DJ and vinyl are pretty inseperable. Well not for a while anyway...

I always though it would be great to have something like a 50 DVD jukebox system that ran off Mp3. You could have a LOT of music on that ;) (about 1.5 years). Then i'm sure you could fill virtually any request, might be good for bus trips or something.

[Flipfinger]

The major problem with MP3 is sound quality.  The speaker system in the club we hire out is majorly impressive - about half a million quids worth - and MP3s aren't anywhere as near nice sounding.

Vinyl does have a different sound, it does sound warmer.

As for effects, this is the main thing.  CD players have really good effects that could be used, seamless looping as well......*sigh* I guess some people won't leave the 20th century...

[HedgehogSandwich adi]

Yep Mp3 is definately worse than its MD equivalent.

[Adam W]

Quote: from HedgehogSandwich adi on 12:02 pm on Sep. 25, 2001[br]Adam, the drop in quality is most probably down to the fact that you are plugging the minidisc in as an external source, which the manufacturers of the car stereo wouldn't have bothered to fit high quality signal handlers for an external plug in device. ^Unless you're using a digital patch with the car stereo and the minidisc then the quality will be noticeably lower (also portable MD's dont have decent components fitted which doesn't help either) .
Im afraid that anyone will be hard pushed to hear a noticeable difference between MD and CD, especially in a car setup. ^To hear a noticeable difference you would need lab or studio equipment. ^even a top of the range home system won't pick up and reflect the differences, despite what people think.

Id aggree though, Md was and should be a replacement for cassette, which im shocked is still being used today..it's nearly thirty years since the cassette came out.

Md is the way to go in terms og high quality easy recording for backup and home use. ^It has a HUGE professional appeal to the entertainment industry,mainly theatre, being the most popular medium for background music, sound effects and anything else.



No, it's my £150 portable MD recorder which I'm plugging into my amp (i have a Sony MD player in the car - are you thinking of those car cassette players with a 3.5mm line level jack input for CD players etc?), and frankly I'd be a little disappointed if I couldn't tell the difference between that and my CD player which cost a whole lot more than that!
When I was auditioning gear for my seperates system, one CD player sounded very different from another, and my MD recorder sounds very different again. ^I'm sure there's a difference in quality between a £150 MD recorder and a £300 MD recorder, let alone between different digital mediums in totally different price bands.

You're right though, with in-car systems there's a lot more to be gained in sound quality by improving speakers etc than you will lose by switching to Minidisc from CD, and on a stock, or average aftermarket set-up I don't think there would be anything in it.