Реферат: Audio Format Wars Essay Research Paper Audio
Audio Format Wars Essay, Research Paper
Audio Format Wars
By: Sheldon Khan
Before buying a new car, getting married, or adopting a new audio format it is wise to ask a few questions, peer under the hood, and ask the advice of someone you trust. Will the new format satisfy your needs not only now but, also in the future? Will it look (and sound) as good on all the mornings after you first met?
The analogue cassette is an old and trusted versatile friend that went with you on those morning jogs and cruised in the car with you on Friday nights. However, the powers that be, have declared our trusted friend to be in the last phase of the life cycle. It’s successor must sound better, work better, and have new features such as a digital display for song titles. There are currently two formats competing to be the consumers next choice for sound on the go. They are Philips’ Digital Compact Cassette (DCC) and Sony’s Mini Disc (MD).
What exactly is digital recording? The definition is, “An electronic format that is designed to duplicate sound, while affording extremely accurate control over any changes you might wish to make in the recording” (Mclan & Wichman,1988). In simple terms it means that the digital circuitry samples the signal and then reproduces what it has seen. The quality of the recording depends on the sampling rate of the machine. The sampled signal is then encoded to the tape or disc in 1’s and 0’s, just like a computer disk drive would encode information. However, the biggest advantage of digital recording is the fact that it eliminates tape “hiss” that is usually found present in analogue recordings.
In the Eighties, a Philips invention captured the limelight. The Compact Disc introduced us to a new era of digital sound, or “perfect sound.” In the nineties another Philips invention has taken centre-stage, the Digital Compact Cassette (DCC). DCC is the marriage of the analogue cassette to Digital Audio. Together they form a union that combines perfect sound, high convince and greater versatility. ” DCC is a medium on which audio information is digitally encoded and which reproduces CD quality sound” (Philips Electronics, Sound & Vision, 1995). A number of features have been incorporated into DCC tapes and decks to achieve CD like sound and convince. DCC decks can locate a chosen track on either side of the tape because track and time codes are recorded on the tape. This combined with autoreverse, which is standard on all DCC decks, makes track access effortless but, not as fast as a CD. Another attractive feature of DCC is the text mode. Text mode allows the deck to display support information about the recordings on the tape such as the album title, a complete list of track titles, names of the artists on each track, and lyrics (displayed in sync with the music). Television screens or remote control units can also be connected to the deck to display more extensive information. The tapes have recording and playback times of 60, 90, and 100 minutes. “The well known durability of cassettes is enhanced by the use of videochrome tape: chromium dioxide- or cobalt- doped ferric-oxide” (Philips Electronics, Sound & Vision, 1995). With the new tape shell, the tape and tape drive wheels, which are exposed on the analogue tape, are concealed by a metal sliding panel called a “slider”. The slider helps protect the tape from dirt and dust which contributes to tape breakdown. This along with the videochorme tape and DCC’s digital error correction system help prevent tape dropout. Numerous digital first generation DCC to DCC copies can be made. Any further copies (ie. 2nd, 3rd, etc generation) made from the first generation copy will not be digital. The biggest advantage that DCC has over the competition is its compatibility with its analogue predecessor.
Sony’s Mini Disc is a miniature version of the compact disc that comes in a plastic shell like that of a 3 1/2 computer floppy. “Unlike CD’s, MiniDiscs can be recorded using magneto-optical technology” (Dmytryk, 1993, p. 62). Mageto-optical technology allows a MiniDisc to be recorded on many times. A MiniDisc is smaller than a DCC tape and has random track access like a CD. It also gives the user the capability to edit songs, and the order that they appear in on the disc. To record on a partially full disc, simply hit Record, with no concern for cueing. Recording starts immediately and the new material is added as a new track. It is also simple to remove dead air and unwanted material. The deleted time is added to the total time remaining on the disc. All of this makes it very easy to create your own custom compilations. The MiniDisc, like the DCC allows the user to make multiple first generation digital copies. But second and third generation copies will not be digital. One of the biggest advantages that MD has over DCC is it’s small slim size and durability. By comparison the sharp edged DCC cassette seems a bit clunky and less durable.
Both MD and DCC use data-compression techniques to squeeze digital audio data into a fraction of the space required by a CD or a Digital Audio Cassette (DAT). ” DCC’s Precision Adaptive SubCoding (PASC) achieves slightly better than 4-to-1 compression. While Mini Disc’s Adaptive TRansform Acoustic Coding (ATRAC) is slightly worse at 5-to-1″ (Dmytryk, 1993, p. 65).
Both developers justify the use of compression with these statements,
“The human ear only hears sounds above a certain loudness (dB) level, called the hearing threshold. The threshold of hearing depends on the frequency of the sound. Therefore, only sounds above this dynamic threshold need to be recorded.”(Philips Electronics, Sound & Vision, 1995)
Loud sounds can completely mask softer sounds that are close in frequency. Because our hearing is far more acute in the mid-range than at the high or low end of the spectrum, what you hear is defined by the frequency content during each time slice.” (Dmytryk, 1993 p. 65).
In other words no one will know the difference if certain frequencies are missing.
What will all of this new technology cost the average consumer? Well, a Philips DCC deck cost about $600, pre-recorded DCC tapes cost about $20, and blank tapes cost about $8. While a MD player cost about $500, the pre-recorded discs cost about $20 and the blank disc cost about $10. Of course as the popularity of the format grows, the cost will drop.
Manufacturers are trying to give the public a more durable and better sounding medium for those of us that are always on the go. However, since their introduction about three years ago very few MD and even fewer DCC players have been sold. Some audio experts feel that the reason they have not sold many units of either format is because the average person thinks that there is nothing wrong with the sound quality of a good CrO2 (Maxell’s XLII) or metal (Sony’s CDit IV) analogue cassette. Many people still live by the old saying, “If it ain’t broke, don’t fix it.” Manufacturers have built up these new formats as “the greatest thing since slice bread,” in the hopes of changing the way people listen to music. Yet, the public has not jumped on the band wagon of either of these new formats. However, one thing is certain, the days of the analogue cassette are numbered.
It is only a matter of time before either MD, DCC or some new digital format such as the recordable CD takes the place of the analogue cassette.
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