Vinyl records do not break easily, but the soft material is easily scratched. Vinyl readily acquires a static charge, attracting dust that is difficult to remove completely. Dust and scratches cause audio clicks and pops. In extreme cases, they can cause the needle to skip over a series of grooves, or worse yet, cause the needle to skip backwards, creating a "locked groove" that repeats over and over. Locked grooves were not uncommon and were even heard occasionally in broadcasts.
Vinyl records can be warped by heat, improper storage, or manufacturing defects such as excessively tight plastic shrinkwrap on the album cover. A small degree of warp was common, and allowing for it was part of the art of turntable and tonearm design. "Wow" (once-per-revolution pitch variation) could result from warp, or from a spindle hole that was not precisely centered.
There is controversy about the relative quality of CD sound and LP sound when the latter is heard under the very best conditions (see Analog vs. Digital sound argument).
A further limitation of the record is that with a constant rotational speed, the quality of the sound may differ across the width of the record because the inner groove modulations are more compressed than those of the outer tracks. The result is that inner tracks have distortion that can be noticeable at higher recording levels.
7-inch singles were typically poorer quality for a variety of the reasons mentioned above, and in the 1970s the 12-inch single (sometimes referred to as a "doughnut"), manufactured at both 33 1/3 and 45 rpm, became popular for DJ use and for fans and collectors.
Another problem arises because of the geometry of the tonearm. Master recordings are cut on a recording lathe, where a sapphire stylus moves radially across the blank, suspended on a straight track and driven by a lead screw. Most turntables use a pivoting tonearm, introducing side forces and pitch and azimuth errors, and thus distortion in the playback signal. Various mechanisms were devised in attempts to compensate, with varying degrees of success. See more at phonograph.
In 1925, electric recording extended the recorded frequency range from acoustic recording (168–2000 Hz) by 2½ octaves to 100–5000 Hz. Even so, these early electronically recorded records used the exponential-horn phonograph (see Orthophonic Victrola) for reproduction.
The frequency response of vinyl records may be degraded by frequent playback if the cartridge is set to track too heavily, or the stylus is not compliant enough to trace the high frequency grooves accurately, or the cartridge/tonearm is not properly aligned. The best cartridges and styli have response up to 76 kHz.[citation needed] The RIAA has suggested the following acceptable losses: down to 20 kHz after one play, 18 kHz after three plays, 17 kHz after five, 16 kHz after eight, 14 kHz after fifteen, 13 kHz after twenty five, 10 kHz after thirty five, and 8 kHz after eighty plays. While this degradation is possible if the record is played on improperly set up equipment, many collectors of LPs report excellent sound quality on LPs played many more times when using care and high quality equipment. This rapid sound degradation is not usually typical on modern Hi-Fi equipment with a properly balanced tonearm and well balanced low-mass stylus. The RIAA standard represents only the minimum acceptable losses. Most properly setup Hi-Fi systems can provide much higher record life and sound quality.[citation needed]
CD-4 LPs contain two sub-carriers, one in the left groove wall and one in the right groove wall. These sub-carriers use special FM-PM-SSBFM (Frequency Modulation-Phase Modulation-Single Sideband Frequency Modulation) and have signal frequencies that extend to 45 kHz. Many record collectors report that the CD-4 sub-carriers are still playable, even though the records have been played extensively and are in excess of 30 years old.[citation needed] It should be noted that these records could be played with any type stylus as long as the pickup cartridge had CD-4 frequency response. The recommended Stylus for CD-4 as well as regular stereo records was a line contact or Shibata type.
Gramophone sound suffers from rumble, low-frequency (below about 30 Hz) mechanical noise generated by the motor bearings and picked up by the stylus. Equipment of modest quality is relatively unaffected by these issues, as the amplifier and speaker will not reproduce such low frequencies, but high-fidelity turntable assemblies need careful design to minimize audible rumble.
Room vibrations will also be picked up if the pedestal—turntable—pickup arm—stylus system is not well damped.
Tonearm skating forces and other perturbations are also picked up by the stylus. This is a form of frequency multiplexing as the "control signal" (restoring force) used to keep the stylus in the groove is carried by the same mechanism as the sound itself. Subsonic frequencies below about 20 Hz in the audio signal are dominated by tracking effects, which is one form of unwanted rumble ("tracking noise") and merges with audible frequencies in the deep bass range up to about 100 Hz. High fidelity sound equipment can reproduce tracking noise and rumble. During a quiet passage, woofer speaker cones can sometimes be seen to vibrate with the subsonic tracking of the stylus, at frequencies as low as about 0.5 Hz (the frequency at which a 33 1/3 rpm record turns on the turntable). Another reason for very low frequency material can be a warped disk: its undulations produce frequencies of only a few hertz and presentday amplifiers have large power bandwidths. For this reason, many stereo receivers contained a switchable subsonic filer. Some subsonic content is directly out of phase in each channel. If played back on a mono subwoofer system, the noise will cancel, significantly reducing the amount of rumble that is reproduced.
At high audible frequencies, hiss is generated as the stylus rubs against the vinyl, and from dirt and dust on the vinyl. Noise can be reduced somewhat by cleaning the record prior to playback.
Another method, introduced by the Lenco company is playing the disk "wet". Using a special dispenser the groove is wetted ahead of the stylus passing by and dries up afterwards. This certainly reduces hiss, but when it became clear that any disk once played wet, should forever be played this way because of residue left behind, people did not change over in great numbers. With normal cleaning this problem does not occur (this also seems to remove Lenco residue if present).
Vinyl records can be warped by heat, improper storage, or manufacturing defects such as excessively tight plastic shrinkwrap on the album cover. A small degree of warp was common, and allowing for it was part of the art of turntable and tonearm design. "Wow" (once-per-revolution pitch variation) could result from warp, or from a spindle hole that was not precisely centered.
There is controversy about the relative quality of CD sound and LP sound when the latter is heard under the very best conditions (see Analog vs. Digital sound argument).
A further limitation of the record is that with a constant rotational speed, the quality of the sound may differ across the width of the record because the inner groove modulations are more compressed than those of the outer tracks. The result is that inner tracks have distortion that can be noticeable at higher recording levels.
7-inch singles were typically poorer quality for a variety of the reasons mentioned above, and in the 1970s the 12-inch single (sometimes referred to as a "doughnut"), manufactured at both 33 1/3 and 45 rpm, became popular for DJ use and for fans and collectors.
Another problem arises because of the geometry of the tonearm. Master recordings are cut on a recording lathe, where a sapphire stylus moves radially across the blank, suspended on a straight track and driven by a lead screw. Most turntables use a pivoting tonearm, introducing side forces and pitch and azimuth errors, and thus distortion in the playback signal. Various mechanisms were devised in attempts to compensate, with varying degrees of success. See more at phonograph.
In 1925, electric recording extended the recorded frequency range from acoustic recording (168–2000 Hz) by 2½ octaves to 100–5000 Hz. Even so, these early electronically recorded records used the exponential-horn phonograph (see Orthophonic Victrola) for reproduction.
The frequency response of vinyl records may be degraded by frequent playback if the cartridge is set to track too heavily, or the stylus is not compliant enough to trace the high frequency grooves accurately, or the cartridge/tonearm is not properly aligned. The best cartridges and styli have response up to 76 kHz.[citation needed] The RIAA has suggested the following acceptable losses: down to 20 kHz after one play, 18 kHz after three plays, 17 kHz after five, 16 kHz after eight, 14 kHz after fifteen, 13 kHz after twenty five, 10 kHz after thirty five, and 8 kHz after eighty plays. While this degradation is possible if the record is played on improperly set up equipment, many collectors of LPs report excellent sound quality on LPs played many more times when using care and high quality equipment. This rapid sound degradation is not usually typical on modern Hi-Fi equipment with a properly balanced tonearm and well balanced low-mass stylus. The RIAA standard represents only the minimum acceptable losses. Most properly setup Hi-Fi systems can provide much higher record life and sound quality.[citation needed]
CD-4 LPs contain two sub-carriers, one in the left groove wall and one in the right groove wall. These sub-carriers use special FM-PM-SSBFM (Frequency Modulation-Phase Modulation-Single Sideband Frequency Modulation) and have signal frequencies that extend to 45 kHz. Many record collectors report that the CD-4 sub-carriers are still playable, even though the records have been played extensively and are in excess of 30 years old.[citation needed] It should be noted that these records could be played with any type stylus as long as the pickup cartridge had CD-4 frequency response. The recommended Stylus for CD-4 as well as regular stereo records was a line contact or Shibata type.
Gramophone sound suffers from rumble, low-frequency (below about 30 Hz) mechanical noise generated by the motor bearings and picked up by the stylus. Equipment of modest quality is relatively unaffected by these issues, as the amplifier and speaker will not reproduce such low frequencies, but high-fidelity turntable assemblies need careful design to minimize audible rumble.
Room vibrations will also be picked up if the pedestal—turntable—pickup arm—stylus system is not well damped.
Tonearm skating forces and other perturbations are also picked up by the stylus. This is a form of frequency multiplexing as the "control signal" (restoring force) used to keep the stylus in the groove is carried by the same mechanism as the sound itself. Subsonic frequencies below about 20 Hz in the audio signal are dominated by tracking effects, which is one form of unwanted rumble ("tracking noise") and merges with audible frequencies in the deep bass range up to about 100 Hz. High fidelity sound equipment can reproduce tracking noise and rumble. During a quiet passage, woofer speaker cones can sometimes be seen to vibrate with the subsonic tracking of the stylus, at frequencies as low as about 0.5 Hz (the frequency at which a 33 1/3 rpm record turns on the turntable). Another reason for very low frequency material can be a warped disk: its undulations produce frequencies of only a few hertz and presentday amplifiers have large power bandwidths. For this reason, many stereo receivers contained a switchable subsonic filer. Some subsonic content is directly out of phase in each channel. If played back on a mono subwoofer system, the noise will cancel, significantly reducing the amount of rumble that is reproduced.
At high audible frequencies, hiss is generated as the stylus rubs against the vinyl, and from dirt and dust on the vinyl. Noise can be reduced somewhat by cleaning the record prior to playback.
Another method, introduced by the Lenco company is playing the disk "wet". Using a special dispenser the groove is wetted ahead of the stylus passing by and dries up afterwards. This certainly reduces hiss, but when it became clear that any disk once played wet, should forever be played this way because of residue left behind, people did not change over in great numbers. With normal cleaning this problem does not occur (this also seems to remove Lenco residue if present).
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