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bumr055
Wannabe

Joined: Jan 08, 2007
Posts: 2
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Re: record players
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| bumr055 wrote: |
hi, im new to this site....
the reason i registered was because i was wondering something, on a record player/turn table....
it has left and right speaker and they both have different sound like a mp3 or a CD...
i don't understand how this is possible with a record..
can anybody explain how this works...
i was thinking that the record player itself separates different Hz, or it is posible that it is my sound mixer doing it.
Thanks, bumross  |
When a record is "cut" into the vinyl the sound goes through a filter which removes all the bass, in fact it is an E.Q. slope which operates at -6dB per octave. The bass is removed during the cutting so that the grooves on the vinyl are not too large.
When the vinyl is played back there has to be the opposite filter inserted in order to correct this, i.e. the filter will put the bass back in.
This filter is known as an RIAA e.q. curve.
Dedicated record player amps have this filter built into the inputs, but standard mixing consoles do not.
I would imagine this is the issue you are having here.
You can see more details on this here:
http://en.wikipedia.org/wiki/RIAA_equalization |
thanks but, thats not really what i meant...
i dono how to explain it like.... when you have surround sound you hear things from all around...
and on a record player i can hear things left and right...
like someone singing on the left and a guitar on the right...
i don't understand how that would be possible with only one pin and one groove.
thanks for the reply thought and that is a very interesting fact.
EDIT: wow... i just looked at my mixer and there is a toggle switch for 0 db and +6 db, cool.
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Thu Jan 18, 2007 8:34 pm |
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RhoneRanger
Engineer

Joined: Nov 04, 2005
Posts: 332
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Simply put (there is probably a wiki about this somewhere) on a monophonic record, (one channel) the needle moves only in one direction picking up the vibrations. On a Stereo record player, the needle picks up vibrations from both sides, moving both vertically and horizontally.
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Mon Jan 22, 2007 8:11 pm |
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uncle_jerr
Moderator

Joined: Jan 05, 2005
Posts: 410
Location: Illinois |
wiki
That got me curious. I pulled this from http://en.wikipedia.org/wiki/Gramophone_record#Stereo_and_beyond
In 1958 the first 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.[4]
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 exploited 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.
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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Wed Jan 24, 2007 11:14 am |
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