Tuesday, January 10, 2012
Preserving your memories III - A short history lesson on media - Vinyl Albums, Audio Cassettes, Reel-to-Reel Tape and yes, even 8 Track Tapes
In this third blog of my series on preserving your memories, I am going to talk about audio source media.
in the next couple of blogs I'll talk about about preserving your analog sound media.
First a little history.
Vinyl Records such as 78's or LP's
Records were a huge driving force for music and entertainment. As usual, there were many formats over the years. Each successive format got a little better and more versatile with some exceptions.
The first really commonplace record was the 78, so named because it had to be played back on turntables that could rotate at 78 revolutions per minute.
Developed in the late 1890's, it was the only readily available format (other than cylinders) until the 50's when 33 1/3's and 45's were developed.
Fidelity wasn't great but it was reliable. They were also quite fragile because the material used was hard and somewhat brittle so as to improve wear characteristics. At the 78 speed recording companies could not put much on each side of the disc. A capacity of 3 to 5 minutes per side was possible depending on the record diameter.
When 33 and a 1/3 LP's were developed, record companies were able to increase the amount of media recorded on a disc. They were also less fragile than the 78's as different types of vinyl were used for pressing.
By lowering the number of rpm's and making the disc somewhat larger in diameter, record labels could put approximately 45 minutes of music over the two sides of an album.
The 45 rpm, or single, was the engine of radio play from the 50's to the 70's. Artists would release their new songs on a 45 and then follow up with the long play album as a 33.
These formats were fabulously reliable but prone to wear and tear. They had to be played back on a turntable with a stylus or needle. The needle would eventually wear the grooves of the record and the needle itself would wear out. This compromised audio clarity and reliability and contributed to a lot of background noise, hiss and clicks and pops on playback.
There are still many people who mourn the loss of the vinyl format. They pine for the "warmth" of the acoustic and analog recording and tend to ignore the artifacts that appear through constant playback.
Recording to tape started with reel-to-reel units. Professional recording decks had several speeds available to them. The rule was the faster you record the better the quality as there was less signal being recorded on more tape.
As a rule, professional recordings were made at a speed of no less than 7 1/2 inches per second and more often than not at 15 inches per second. In many cases 30 ips was used for higher fidelity. Consumer decks generally had lower speeds allowing for longer duration on spools of tape. As a rule consumer decks had 1 7/8 ips, 3 3/4 ips and 7 1/2 ips.
Interestingly enough there was a speed slower than those that was used for extremely long duration purposes such as radio station log tapes. The speed was 15/16 inches per second. As a boy hanging around the stations where my Dad was a broadcaster I remember seeing these tapes moving super slow, recording the program output of the station.
The move to tape recording allowed for something that was not possible before. Editing now was now a part of the workflow. Using specialized recorders, razor blades, a splicing block and splicing tape, audio engineers could cut and paste to their hearts content giving the recording industry a whole lot more flexibility and versatility.
The problem with reel to reel recording for consumers was the high price of admission. Decks were expensive and had to be maintained constantly for optimal perfromance.
In 1963 the Phillips company introduced the audio cassette as a new standard for the consumer. It was a standard size tape, recorded at a standard speed and offered instant load and playback without ever having to touch the tape. It sold like crazy. For the first time ever you could play the music you wanted in your car. This drove te format to huge volumes of sale. The format was robust and reliable although car playback exposed tapes to very harsh conditions which could deteriorate the tape quickly. Wow and flutter would be exhibited on tapes which degraded audio fidelity as the ribbon would distort and change with the heat and cold extremes.
Later in the 60's a new format called 8 track was brought to market. This again was a tape cartridge that you inserted into a deck for playback. Playback decks generally had a button to select one of four available "sides' of a tape, allowing some flexibility in access to the tracks you wanted to hear. it was also and "endless" format. An 8 track would play its contents forever if you let it. This was great for some applications like restaurants and stores. Drawbacks were that it was much bulkier than the audio cassette and suffered from some mechanical weaknesses. Sometimes it switched tracks in the middle of a song. Record labels would change album play orders around to accommodate the amount of time allowable on each track. Fidelity was almost the same as the audio cassette.
Signal to Noise Ratio
This is described as the amount of the desired recorded signal you want to hear vs. the level of background noise. The chart below illustrates the differences between the various medias that have been available. It should be noted that higher numbers are what is wanted for audio clarity.
78 - 35 db
33 1/3 - 40 db
45 - 40 db
8 Track - 40 to 45 db
Audio Cassette - 45 db
Reel to Reel - 40 to 45 db
VHS mono or stereo - 45 db
VHS stereo HiFi - 90 db
Compact Disc - 95+
DVD - 95+
In the next instalments we will talk about what to expect if you want to transfer your precious sound files from any of the above formats into a digital format.
Thanks for reading. Remember, if you have questions or comments please feel free to add them. Also keep in mind that KEMEdia Studios offer these transfers services should you require them.
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Mike Reid can be heard approximately once a month on the Dave Fisher Show, weekends on CJAD 800 in Montreal. Mike and Dave talk about technology and new directions during these ten minute spots.