Converting Records and Tapes
to MD (Mini Disc) and CD (Compact Disc)
Another Audio Journey
Ethnic Dance Chicago Home Page - Door
County Folk Festival Home Page - Mini
Disc Page Index
Mini
Disc Technology Issues
(back to MD index) |
A single MD holds the same
amount of music as a CD (up to 80 minutes in "SP" recording mode) but does
so in one fifth as many bits by using an audio compression method Sony
calls ATRAC (Adaptive TRansform Acoustic Coding). ATRAC is a form of perceptual
coding, a data reduction technique that attempts to encode only the information
audible to the human perceptual system. Sony describes the details of their
ATRAC system in an Audio Engineering Society technical report. A (translated)
interview that appeared in MJ Audio Technology Magazine with the creators
of Sony's top of the line MD-JA3ES deck also helps explain the MiniDisc
signal compression technology. ATRAC is the basis of Sony's SDDS cinema
digital audio system.
From the original Sony
Press Release of 05/16/1991:
The Mini Disc (MD) system
is a format for personal listening enjoyment. Capable of providing more
than one hour of recording and playback on a 2.5-inch (diameter) disc,
MD is a truly portable digital audio system that marks an important step
in the evolution of new music media. The Mini Disc format will provide
the following benefits and features:
In 1992 the MiniDisc system was introduced in the consumer audio market as a new digital audio playback and recording system (Fig. 1). The introduction time was just ten years after the introduction of the Compact Disc (CD). As is known, CD has effectively replaced the vinyl LP records in the audio disc market. CD technology is based on 16-bit quantization and 44.1-kHz sampled digital audio recording. The CD sound quality was fairly improved compared to any consumer analog recording equipment.
Before starting the CD business, many engineers engaged in the development of the CD solely for its improvement in sound quality, but after the introduction of the CD player into the market, we found out that the consumer became aware of the quick random-access characteristic of the optical disc system. In addition, the size of the 12-cm disc was easy to handle compared to that of the LP. The longer lifetime for both the media and the player strongly supported the acceptance of the CD format. The next target of development was obviously to be the rewritable CD. SONY and Philips jointly developed this system and made it a technical reality in 1989. Two different recordable CD systems were established. One is the write-once CD named CD-R and the other is the Rewriteable CD named CD-MO.
With a diameter of 64 mm, which is smaller than a CD, MiniDisc can hold only 1/5 of the data. Therefore, we need data compression of 5:1 in order to offer 74 min of playback time. A high-quality audio compression technology called ATRAC is used for MiniDisc. The ATRAC encoding process starts with the 16-bit quantization and 44.1-kHz sampled stereo audio signal. The key to ATRAC's efficiency is its unique method of analysis. ATRAC employs a nonuniform slitting in both frequency and time axes, reflecting psychoacoustic principles.
Based on the original MiniDisc
audio format, the MD-Data system was developed in July 1993. The MD-Data
disc and key devices (optical pickup and LSI chips) are almost the same
as those of the MD audio system. Therefore, the manufacturing infrastructure
of MD Data is commonly used with that of MD Audio. Actually, it is similar
to the way CD-ROM is manufactured. The MD-Data disc has approx. 140-Mbyte
data capacity (Fig. 15). By featuring a variation of disc type (pre-mastered
disc/read-only disc, recordable, and hybrid disc) and compact size, the
MD-Data system is expected to be a new standard in data storage and publishing
media systems.
From Eddie Talbot's Home
Page (http://www.talbot.org):
The only real potential rub
for audio enthusiasts is that MiniDisc uses a compression technique to
fit music onto that small disc. This involves the loss of information
in the music that is supposedly audible to the human ear. This argument
is frequently used against MiniDisc, and in the beginning of 1992, the
critics had a point, but the compression technique (a system called ATRAC)
now is so good [after] six years that only sophisticated electronic analysis
equipment can tell the difference between CD and MD - the human ear cannot
distinguish (although audiophiles claim to be able to tell the difference,
then again, these are the same individuals who claim vinyl is better than
CD).
From SingingWood Music
(http://www.singingwood.com/Accessories.html):
While MiniDisc recorders do
not produce true digital audio recordings the fidelity is great! The "compression"
scheme is called ATRAC. (Sony prefers not to use the term compression and
refers to ATRAC as "data reduction.) In normal record mode (called LP1)
ATRAC employs a 5:1 "reduction" ratio -- meaning that it discards 80% of
the audio data. Yet the fidelity is surprisingly [good], and it sounds
great even on recordings that sound bad when compressed with MP3 -- which
is normally uses a 10:1 ratio.
MDLP tracks cannot be played back on an older
SP (Standard Play, non-LP) machine, however, SP tracks can be played and
recorded on an LP machine. LP2 mode is reportedly quite close to
standard ATRAC. LP4 mode can have noticeable noise artifacts, but is still
suitable for portable applications. When you record in LP4 mode,
momentary noise may be produced with certain sound sources. This
is due to the special digital audio compression technology that enables
recording time 4 times longer than normal. If noise is produced,
it is recommended that you record in normal SP mode or in LP2 mode to obtain
better sound quality. Newer machines by Sony (Sony MXD-D40), JVC,
Sharp and Teac support MDLP.
NOTE: While I am biased towards MD, I do use both MD and CD. I feel that this table focuses on the issues that you will need to consider. Neutral Fact - Advantage Either Way - Perceived Advantage - Perceived Disadvantage |
||||
(Compact Disc) |
(Compact Disc-Recordable) |
(Compact Disc-Recordable) |
(Compact Disc-Rewritable) |
(Mini Disc) |
Pre-recorded
CDs are available everywhere.
CDs can be played on any CD player or CD-ROM drive. |
CD-Rs
can be made on your PC or on a stand-alone CD writer.
CD-Rs can be played on most CD players and CD-ROM drives. |
Same as CD-R | CD-RWs
can possibly be made on your PC or on a stand-alone CD writer, but may
not be playable on other CD players or CD-ROM drives.
Sony MD-CD Combination Decks can play CD-RWs |
A
stand-alone MD recorder is needed to make MDs.
CD-like interface for recording MDs on PC/Mac is currently not available in the U.S. There are limited numbers of pre-recorded MDs available. |
More people have CD players thus making CD-R a more universal medium for exchanging music. | Same as CD | Same as CD | CD-RW
discs can be re-written thousands of times, but may not be playable in
other CD players or CD-ROM drives, thus making CD-RW a less universal medium
for exchanging music.
Sony MD-CD Combination Decks can play CD-RWs |
Fewer people have MD players thus making MD a less universal medium for exchanging music. |
Pre-recorded CDs cannot be edited in any way. | CD-R
discs cannot be edited in any way. If you wanted to remove, add,
or edit any tracks, you would have to create a new disc and throw the old
one away.
All dividing, combining, moving, erasing or editing of tracks must be done prior to creating CD-R disc |
Same as CD-R | CD-RW
discs can be re-written thousands of times, but may not be playable in
other CD players or CD-ROM drives.
Sony MD-CD Combination Decks can play CD-RWs |
MD
discs (SP or Standard Plat or LP1 mode) can be re-written thousands of
times and can be played on any MD machine.
Any MD track can be titled, added, divided, combined, moved and erased. |
Most CDs are not created with disc or individual track title information. | CD-R disc and individual track title information can be added only when writing discs in "disc at once" or "write entire disc" mode. | Same as CD-R | Same as CD-R, but CD-RW disc can be re-written thousands of times. | MD disc
and individual track title information can be updated at any time.
Disc/track title information can be entered in a number of ways. Manually: from MD console; via hand-held Infra Red remote; some models support PC keyboard interface; some models support PC/USB connection with PC software interface. Automated: PC software for Infra Red batch titling via PC/serial connection (WinRemote). |
Most pre-recorded CDs when
played on a computer can have their disc and track titles downloaded from
the internet.
Also, disc and track titles can be created in a data file and inported as a playlist. |
When using software such as Roxio's CD Label Creater or Neato's MediaFace to print labels for CD discs and jewel cases, the downloaded (or created) disc and track titles can be easily loaded into pre-defined fields on CD label forms. | Same as CD-R | Same as CD-R | Without
a computer interface, there is no automated way to get disc track titles
from an MD, loaded into software for labeling MD discs and jewel cases.
Whle disc and track titles can be created in a data file, there is currently
no way to import these into into pre-defined fields on MD label forms.
The latest version of Neato's MediaFace (4.0) may offer a solution by providing a list management function and allowing list information to be loaded into pre-defined fields in label forms. Software literally just arrived and I'll test it and update this document. |
Most CD Player/Recorders do not support the text display of disc and track title information. | Same as CD | Same as CD | Same as CD | Most MD Player/Recorders support the text display of disc and track title information. |
CD playing
time is 74 (stereo) min.
Pre-recorded CDs may play slightly longer than maximum rated disc capacity. |
CD-R
recording time is:
74 (stereo) min or 80 (stereo) min or 60 (stereo) min (obsolete), depending on disc capacity CD-Rs cannot be recorded in mono |
Mini-CD-R
recording time is 21 (stereo) min
Mini-CD-Rs cannot be recorded in mono |
CD-RW
recording time is 74 min (stereo)
CD-RWs cannot be recorded in mono |
MD (SP
or Standard Play or LP1) recording time is:
74 (stereo), 149 (mono) min, 80 (stereo), 161 (mono) min, 60 (stereo), 121 (mono) min, depending on disc capacity. MDs can be recorded in mono doubling the record/play time. |
CD (as
we know it) currently has no extended playing time feature.
There is new CD technology format called SACD (Super Audio CD). It uses a dual layer disc with extended capacity and play time (requiring an SACD machine), or a hybrid disc (playable on both CD and SACD machines). |
Same as CD | Same as CD | Same as CD | For
newer MD machines with MD-LP (Mini Disc Long Play), using 80 minute discs,
the recording time is:
LP2 mode 160 (stereo) min, LP4 mode 320 (stereo) min. SP (LP1) tracks can be played and recorded on any MD machine. LP2 and LP4 tracks can only be played and recorded on MDLP machines. |
CD media 4.625" (12 cm) in diameter. | Same as CD | Mini-CD media 3.25" (8 cm) in diameter. | Same as CD | MD media 2.5" (7 cm) in diameter. |
CD Sound Compression Ratio is 1:1 | Same as CD | Same as CD | Same as CD | MD Sound Compression Ratio is 5:1 (Compare MP3 @ 10:1) |
Pre-recorded CDs: $10-$20ea | 74 min
CD-R blanks $.20ea
80 min CD-R blanks $.30ea |
Mini-CD-R blanks $.40ea | 74 min CD-RW blanks $1.70ea | 74 min
MD blanks $1.90ea
80 min MD blanks $2.20ea |
CD media is susceptible to damage with its exposed surface. | Same as CD | Same as CD | Same as CD | MDs media is enclosed in a case that can be touched all over much like a floppy disk. |
Most
CD players have varying anti-shock memories from 3-50 seconds.
Most older CD players skip when subjected to movement and/or vibration. Standards are improving for newer models. |
Same as CD | Same as CD | Same as CD | Most
MD players have anti-shock memories from 30-160 seconds.
Most older MD players do not skip when subjected to movement and/or vibration. Standards are inproving for newer models. |
Portable CD Player footprint larger than portable MD Player. (6" x 5" x 1") | Same as CD | Same as CD | Same as CD | Portable MD Player footprint smaller than portable CD Player (3" x 3" x .75") |
Portable recording with CD is not easily done. | Same as CD | Same as CD | Same as CD | Portable recording with MD is easily done and it can be used like a dictaphone! |
Portable
CD Player (Walkman): $99-$150
No CD Portable Player/Recorders |
Same as CD | Same as CD | Same as CD | MD Portable
Player (Discman): $120-$220
MD Portable Player/Recorder: $144-$399 |
CD Player/Recorder: $270-$790 | Same as CD | Same as CD | Same as CD | MD Player/Recorder:
$195-$375
MD Player/Recorder - CD Player Combo $300 |
PC/Mac Interface (USB, SCSI, Firewire, IDE, EIDE) for Add-On External CD-ROM Play/Record Drive: $100-$370 | Same as CD | Same as CD | Same as CD | CD-like interface for recording MDs on PC/Mac is currently not available in the U.S. |
PC/Mac Interface (SCSI, IDE, EIDE) for Add-On Internal CD-ROM Play/Record Drive: $60-$325 | Same as CD | Same as CD | Same as CD | CD-like interface for recording MDs on PC/Mac is currently not available in the U.S. |
Converting Records and Tapes
to MD (Mini Disc) and CD (Compact Disc)
Another Audio Journey
Ethnic Dance Chicago Home Page - Door
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