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Bronze Member Username: Fredrico_alvarezPost Number: 14 Registered: Apr-08 | To some of you old vinyl vets this might sound like a stupid question but I cant figure out how it works. Unless I'm wrong, there is one needle, one groove, and two channels. It just doesnt add up the way I see it. Thanks for your thoughts. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 12626 Registered: May-04 | . You can find this on the web and have pictures to look at. The groove is cut at a 45/45 degree angle. The motion of the stylus in the vertical plane resolves frequency and loudness. Movement in the horizontal plane resolves L/R stereo separation. |
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Bronze Member Username: Fredrico_alvarezPost Number: 15 Registered: Apr-08 | Jan, I searched for a while but couldn't find anything. Do you have a link? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 12627 Registered: May-04 | . I'll see what I can find but it may take me a day to get around to this. |
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Silver Member Username: DarthPost Number: 138 Registered: Aug-05 | Just some info http://www.needledoctor.com/core/media/media.nl?id=2701&c=ACCT106601&h=192e59a68 f2e49fdd1f8&_xt=.html |
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Silver Member Username: DarthPost Number: 139 Registered: Aug-05 | From Wikipedia, In 1958 the first group of stereo two-channel records were issued -- by Audio Fidelity in the USA and Pye in Britain, using the Westrex "45/45" single-groove system. While the stylus moves horizontally when reproducing a monophonic disk recording, on stereo records the stylus moves vertically as well as horizontally. One could envision a system in which the left channel was recorded laterally, as on a monophonic recording, with the right channel information recorded with a "hill-and-dale" vertical motion; such systems were proposed but not adopted, due to their incompatibility with existing phono pickup designs (see below). In the Westrex system, each channel drives the cutting head at a 45 degree angle to the vertical. During playback the combined signal is sensed by a left channel coil mounted diagonally opposite the inner side of the groove, and a right channel coil mounted diagonally opposite the outer side of the groove.[2] It is helpful to think of the combined stylus motion in terms of the vector sum and difference of the two stereo channels. Effectively, all horizontal stylus motion conveys the L+R sum signal, and vertical stylus motion carries the L-R difference signal. The advantages of the 45/45 system are: greater compatibility with monophonic recording and playback systems. A monophonic cartridge will reproduce an equal blend of the left and right channels instead of reproducing only one channel. Conversely, a stereo cartridge reproduces the lateral grooves of monophonic recording equally through both channels, rather than one channel. a more balanced sound, because the two channels have equal fidelity (rather than providing one higher-fidelity laterally recorded channel and one lower-fidelity vertically recorded channel); higher fidelity in general, because the "difference" signal is usually of low power and thus less affected by the intrinsic distortion of hill-and-dale recording. This system was invented by Alan Blumlein of EMI in 1931 and patented the same year. EMI cut the first stereo test discs using the system in 1933. It was not used commercially until a quarter of a century later. Stereo sound provides a more natural listening experience where the spatial location of the source of a sound is, at least in part, reproduced. In the 1970s, it was common practice to generate stereo versions of music from monophonic master tapes which were normally marked "electronically enhanced stereo O" on track listings. These were generated by a variety of filtering techniques to try and separate out various elements which left noticeable and unsatisfactory artefacts in the sound, typically sounding phased. The development of quadraphonic records was announced in 1971. These recorded four separate sound signals. This was achieved on the two stereo channels by electronic matrixing, where the additional channels were combined into the main signal. When the records were played, phase-detection circuits in the amplifiers were able to decode the signals into four separate channels. There were two main systems of matrixed quadrophonic records produced, confusingly named SQ (by CBS) and QS (by Sansui). They proved commercially unsuccessful, but were an important precursor to later 'surround sound' systems, as seen in SACD and home cinema today. A different format, CD-4 (not to be confused with compact disc), by RCA, encoded rear channel information on an ultrasonic carrier, which required a special wideband cartridge to capture it on carefully-calibrated pickup arm/turntable combinations. Typically the high frequency information inscribed onto these LPs wore off after only a few playings, and CD-4 was even less successful than the two matrixed formats. |
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Platinum Member Username: NuckPost Number: 10212 Registered: Dec-04 | Thanks, Vader. |
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Bronze Member Username: Fredrico_alvarezPost Number: 16 Registered: Apr-08 | Thanks for the links and copy and paste from wikipedia. If anyone else has something to add, please do. |