LP-25  Eight Channel Bargraph

The model LP-25 offers 8 high resolution bargraphs and a phase correlator. It is intended for tape machine and mixing console monitoring in control or machine rooms.
Applications include multitrack recording, film & T.V. post production, transfer and mastering in various formats including 8 channel discrete, LCRS, 5.1, DTS, SRD, 7.1 and SDDS.

Each bargraph has two inputs. A master switch toggles between inputs for bus/tape or A/B monitoring. Each input is paralleled to an output connector for easy insertion of the unit in an existing chain. Both inputs and outputs are balanced, on XLR connectors.

The bargraph scale is four inches long, illuminated in green and ranges from -30dB to +6dB.

Dynamic response is switchable between VU or PPM modes.

The VU mode complies with the ANSI-C l6.5 standard which specifies that a sinusoidal source of 1.228 volts at a frequency between 35Hz and 10kHz applied at the input will produce a rise time of 300 milliseconds to reach 99% of the 0dB scale with an overshoot of at least 1% but not more than 1.5%. Fall time to is also 300 milliseconds and display is fully stabilized in less than 340 milliseconds. Transients shorter than 300 milliseconds are not fully displayed and should not be monitored with a VU meter.

The PPM mode complies with DIN 45406 and IBC 268-10 standards. Rather than respond instantaneously to peak, PPM specifications require a finite integration time so that only peaks wide enough to be audible are displayed. DIN 45406 calls for a response of 1dB down from steady state for a ten millisecond tone burst. IBC 268-10 requires 2dB down for a five millisecond tone burst which is met for a constant attack time of 1.7 milliseconds. The decay time constant is 650 milliseconds and produces a fall time of 1.5 seconds from 0dB to -20dB.

Both VU. and PPM modes uses the same scale. Each bargraph has independent level arid offset calibration for both VU and PPM modes. 20 position calibration trimmers are accessible from the rear of the unit.

Two push-button selectors enable any combination of signal source to the inputs of the phase correlator. In addition to the eight internal sources, two XLR balanced external inputs are assignable to the phase correlator, with offset calibration.

Note: Model LP-258 is equipped with a logic port for remote control of A/B and VU/PPM mode selection.





Input impedance: 5Okohrns balanced
Scale accuracy: 0.2dB
Frequency linearity: 30Hz / 16kHz +/- 0.2dB
  20Hz / 20kHz +/- 0.5dB
VU meter ballistics: ANSI-C16.5
PPM ballistics: DIN45406; IBC 268-10
Power requirements: 115 VAC / 60Hz 240VAC/50Hz 50 watts
Physical size: 19" x 4U rack cabinet (19" x 6.97" x 6.1")
  (483mm x 177mm x 155mm)

Large format of front and rear panel of the LP-25 in PDF format, click here.



Lafont Users Include:

4MC; All Post; American Zoetrope; AstralTech; Brasher Sound; Buzz Audio; Bark Audio; C.B.S. TV; Casablanca Sound; Chace Productions; Chicago Audio; Chicago Pacific Recording; Cliff Schwarz Recording; Cinar Films; Creative Cafe; Enterprise Post; Flying Monkey; International Recording; Location Sound; Magno Sound; Millennium Studios; Medallion PFA; Post Modern Sound; Novastar; Olympic Sound Studios; Sonolab; Soundfirm; Paramount Pictures; Premier Post; Signet Sound; Skywalker Sound; Sony Pictures; Sound One; The Beach; The Walt Disney Company; Todd AO Studios; Universal Pictures; Virtuality Recording; Warner Brothers; Warrenwood Studios; Westwind Media; 20th Century Fox