Tape Recording Calibration and Metering: Difference between revisions

From Smithnet Wiki
Jump to navigation Jump to search
m (1 revision imported)
 
(4 intermediate revisions by the same user not shown)
Line 25: Line 25:
** 0 dB is 250 nWb/m  
** 0 dB is 250 nWb/m  
** Dolby level shown at -1.2 dB
** Dolby level shown at -1.2 dB
** Used by Sony, TEAC
** Used by Marantz, Sony, TEAC
* Nakamichi
* Nakamichi
** 0 dB is 200 nW/m
** 0 dB is 200 nW/m
Line 34: Line 34:
** Most common, used by Aiwa, Akai, Pioneer, Technics, etc
** Most common, used by Aiwa, Akai, Pioneer, Technics, etc


True VU Meters have a tightly controlled professional definition of response, but are more approximate in consumer grade equipment. They show an average signal level over time, and smooth out sharp peaks.
True [https://en.wikipedia.org/wiki/VU_meter VU Meters] have a tightly controlled professional definition of response, but are more approximate in consumer grade equipment. They show an average signal level over time, and smooth out sharp peaks.


* 3 % distortion level is usually around +6 to +8 VU
* 3% distortion level is usually around +6 to +8 VU


Peak Meters have fast response, showing peak levels. Better for use on cassette decks with their lower headroom compared to faster tape speeds of Open Reel decks.
Peak Meters have fast response, showing peak levels. Better for use on cassette decks with their lower headroom compared to faster tape speeds of Open Reel decks.


* Generally 0 dB on a VU meter is a lower flux level than 0 dB on a peak meter, by about 3 dB.
* Generally 0 dB on a VU meter is a lower flux level than 0 dB on a peak meter, by about 3 dB.

Latest revision as of 11:43, 24 May 2024

Accurate calibration of a tape based recording is necessary to match record and replay levels, and is critical for Dolby tracking.

Reference:

Recorded Flux

  • 3% distortion is generally considered maximum acceptable.
  • MOL (Maximum Output Level):
    • Level that produces 3rd harmonic distortion of 3%
    • Frequency dependent. At high frequencies can't be used as harmonics won't be reproduced.
  • SOL (Saturated Output Level):
    • The level which produces the maximum output. More record level reduces playback output.
  • Measurement of flux can be open circuit or closed circuit
    • 200 nWb/m closed circuit = 220 nWb/m open circuit (Dolby Level)

Metering

Three standards:

  • DIN
    • 0 dB is 250 nWb/m
    • Dolby level shown at -1.2 dB
    • Used by Marantz, Sony, TEAC
  • Nakamichi
    • 0 dB is 200 nW/m
    • Dolby level shown at 0 dB
  • Old Philips
    • 0 dB is 160 nWb/m
    • Dolby level shown at 2.8 dB
    • Most common, used by Aiwa, Akai, Pioneer, Technics, etc

True VU Meters have a tightly controlled professional definition of response, but are more approximate in consumer grade equipment. They show an average signal level over time, and smooth out sharp peaks.

  • 3% distortion level is usually around +6 to +8 VU

Peak Meters have fast response, showing peak levels. Better for use on cassette decks with their lower headroom compared to faster tape speeds of Open Reel decks.

  • Generally 0 dB on a VU meter is a lower flux level than 0 dB on a peak meter, by about 3 dB.