Audio / Video Introduction
Tape was a little better and took care of the scratches and dirt in the grooves since tape did not have a needle or grooves in a record. The tape just slid across a tiny little pick up called a “HEAD”. The head is the pick up device that reads the information on the tape and sends it to the amp as music. We got rid of the pops and clicks but we had a slightly different problem.
“HISS”. Hiss is the constant sssssssss sound heard in the background of music on tape. If you had a good stereo system, that hiss could be very annoying. New noise reduction ideas like Dolby NR and higher quality recording tape made a big difference in the noise, but the fidelity range was still limited.
There was another porblem called WOW and Flutter. This was caused by worn down motor drive wheels and belts. If they became uneven from wear, the sound would have a constant fast and slow and fast and slow pitch change in the audio. Improvements were made there too as the belts and wheels were replaced by direct drive motors. But the one thing about tape that we all found out was that after time and a lot of use, the tape began to wear out and lose its quality.
The Quality Of The Old Stereo Systems
Noise and hum was a problem that was dealt with in part by how the stereo amplifier was designed. Higher quality stereo amps used better filters to reduce the noise without taking away too much of the fidelity. Cheaper stereos did not have those big filters so they just limited the frequency response to the speakers. They cut back on some of the high frequency sounds because that is the range where you find most of the hiss and noises.
The music sounded better but it lost some of the crispness at the higher end of the frequency spectrum. You had to spend much more money on better equipment with good filtering that limited the incoming sound from a turntable or tape deck, and then increased the high frequency response to the speakers to bring some of that crispness back. It worked to a point.
THEN THE DIGITAL REVOLUTION CHANGED EVERYTHING!
Ever since the CD first hit the markets, the quality of sound has changed in ways that have to be experienced to understand. Words would not do their meanings justice. But I am going to try.
Today every type of audio and video is recorded with digital technology. The audio is read with a laser instead of a needle or a mechanical tape head. Or the digital data is read from integrated circuits as binary coding, then converted to audio and video.
The interesting thing about digital is how it is recorded and decoded. Binary codes of 1’s and 0’s make up all of the digital encoding to discs and files. When any digital playback device, plays back the audio or video, it uses digital circuits that search only for the 1’s and 0’s of binary coding. If it is not coded with binary codes, the player will not recognize it.
Noise of all kinds that may have made it into any digital recording, is not encoded with binary 1’s and 0’s. So the decoding circuitry in the playback device does not recognize any of the noise. The result is crisp clean, and noise free audio and crystal clear video. The same goes for sound from motor vibrations. Motor noise is also not coded as 1’s and 0’s, so it is not recognized by the players decoder. Basically, the player circuitry ignores the noise and only decodes the 1’s and 0’s that make up the audio and video.
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