LP Mastering EQ

Discussion in 'Playback Devices' started by PhilBoy, Nov 30, 2003.

  1. PhilBoy

    PhilBoy Second Unit

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    When an LP was mastered, say during the 70's, was any EQ applied to the master mix to compensate for the limitations of analog/vinyl playback ?

    I have been transfering some LP's of the 70's vintage and I am noticing some over-emphasis in the bass end.

    I have recorded all songs without any filtering but before I burn the tracks to CD I was wondering if I should run them through EQ to 'normalize' them.
     
  2. DavidLW

    DavidLW Stunt Coordinator

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    Yes, if you want to call it that.

    The Master Tape is EQed to sound the way they want it to sound.

    Another "EQ" occurs when they play the Master Tape to cut the Mother Disc (the Mother Disc is use to create the Stamper Disc and the Stamper Disc is what presses the album). There is a compression of the bass frequencies. Imagine taking a spring and squeezing it so it now occuply less space. This is done to make more time on the album (the more bass the wider the groove, the wider the groove the less grooves per album). The compression is a standard. It's compressed the same way for every 33 1/3 and 45 record made from the early 50's on. The
    de-compressor is in the phono section of your receiver, pre-amp, phono stage, etc.. There are different quality of phono sections. With separate phono stages being the best and receivers being the worst. I can only imagine the quality of phono section getting worse in new receivers, as hardly anyone plays vinyl anymore. Plus I think there's been a conspiracy to put low quality phono sections in receivers. This made the CD's sounds a lot better, than albums, than it really does. If you want to hear what the music sounds like after compression, plug your turntable into the AUX input. This plays the music without the proper de-compression.

    I also believe that the highs were stretched so that they occupied a litle more space on the vinyl. The extra space this takes is miminal compare to the space saved when the bass end is compressed.

    So the "extra" bass you're hearing is most likely cause by inaccurate de-compression. Your system may also have the bass right but inaccurately reproducing the mid-range and highs. Of course there's a chance that that's the way the artist wanted it to sound.

    Note: I may be missing a few steps when going from the Master Tape to the album. I kind of remember somthing call a Master and Sub-master Disc but not sure where that fits in or if it.
     
  3. Robert AG

    Robert AG Stunt Coordinator

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    The low frequencies on LPs was summed to mono below a certain frequency in order to keep groove motion completely lateral (and not vertical) in the bass. Vertical motion of the stylus was likely to make the needle skip out of the grooves, especially on cheap phonographs. Perhaps you are hearing excess bass as a result of this. Another possiblilty is that the RIAA equalization curve is not accurate in your phono preamp. When a record is cut, the low frequencies are reduced in amplitude and the highs are boosted. In playback, the reverse happens in the phono preamp, and the result should be flat reasponse. This EQ was done to keep bass frequencies from deflecting the grooves so much that skipping would be a problem. The highs were boosted to get them farther above the noise floor of the vinyl.
     
  4. Mattias_ka

    Mattias_ka Supporting Actor

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    Here is all you want to know about vinyl mastering:
    http://www.recordtech.com/prodsounds.htm

    The phonograph record is a marvelous medium for storing and reproducing sound. With frequency response from 7 Hz to 25kHz and over 75 dB dynamic range possible, it is capable of startling realism. Its ability to convey a sense of space, that is width and depth of sound stage, with a degree of openness and airiness, is unrivaled by anything but the most esoteric digital systems.
     

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