Focusrite VoiceMaster Pro - Technical Specifications: Input Stages; Technical Specifications: Filters and Meters

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SPECIFICATIONS
MIC INPUT RESPONSE
• Gain range = 0 dB to 60 dB continuously
variable.
• Input Impedance = 1K4 Ω from 10 Hz to 200
kHz.
• EIN = 128 dB measured at 60 dB of gain with
150 Ω terminating impedance and 20 Hz/22 kHz
bandpass filter.
• THD at minimum gain (0 dB) = 0.0004%
measured with +16 dBu input signal and with a
20 Hz/22 kHz bandpass filter.
• THD at maximum gain (60 dB) = 0.003%
measured with a –36 dBu input signal and with a
20 Hz/22 kHz bandpass filter.
• THD at maximum input level (26.5 dBu) =
0.005% measured with a 20 Hz/22 kHz bandpass
filter.
• Frequency response at minimum gain (0 dB) =
flat at 10 Hz and –2 dB down at 200 kHz.
• Frequency response at maximum gain (60 dB) =
–2 dB down at 10 Hz and 200 kHz.
• CMRR at full gain (60 dB) = 80 dB.
LINE INPUT RESPONSE
• Gain range = -10 dB to +10 dB continuously
variable.
• Input Impedance = 10K Ω from 10 Hz to 200
kHz.
• Noise at main output with gain and fader set to
unity (0 dB) = -94 dBu measured with a 20
Hz/22 kHz bandpass filter.
• Signal to noise ratio relative to max headroom (27
dBu) = 121 dB.
• Signal to noise ratio relative to 0 dBfs (+22 dBu)
= 116 dB.
• THD at unity gain (0 dB) = 0.0006% measured
with 0 dBfs (+22 dBu) input signal and with a 20
Hz/22 kHz bandpass filter.
• Frequency response at unity gain (0 dB) = 0.25
dB down at 10 Hz and –3 dB down at 200 kHz.
INSTRUMENT INPUT RESPONSE
• Gain range = 0 dB to 40dB continuously variable.
• Input Impedance = > 1 Meg Ω.
• Noise at minimum gain (0 dB) = -90 dBu
measured with a 20 Hz/22 kHz bandpass filter.
• Noise at maximum gain (40 dB) = -78 dBu
measured with a 20 Hz/22 kHz bandpass filter.
• THD at minimum gain (0 dB) = 0.006%
measured with –10 dBu input signal and with a 20
Hz/22 kHz bandpass filter.
• Frequency response at unity gain (0 dB) = 0.5 dB
down at 10 Hz and –1 dB down at 200 kHz.
• Frequency response at maximum gain (40 dB) = 6
dB down at 10Hz and –1dB down at 200KHz.
INPUT METER
• 6 LED peak reading meter is calibrated relative to
0 dBfs where 0 dBfs = +22 dBu (the maximum
level which can be correctly converted by the
optional internal A/D converter before overload
occurs). The meter calibration points are as
follows: -
Meter panel
calibration value
Equivalent dBu value
O/L +22.4 dBu (the point at which
the converter will overload)
0 dBfs +22 dBu (the maximum level
into the converter)
-3 dBfs +19 dBu
-6 dBfs +16 dBu
-10 dBfs +12 dBu
-20 dBfs +2 dBu (the average level to
allow 20 dB of headroom for Eq
and dynamics processing).
HIGH PASS FILTER
• Roll off = 18 dB per octave 3 pole filter.
• Frequency range = continuously variable from 30
Hz to 400 Hz measured at the 3 dB down point.
OPTICAL EXPANDER
• Threshold hold range = -20 dBfs (0 dBu) to –60
dBfs (-40 dBu).
• Expander ratio = 2:1
• Attack time = 750 µs.
• Release time = 0.25 s to 4 s.
• Noise with maximum expansion = -96 dBu
measured with a 20 Hz/22 kHz bandpass filter.
• Signal to noise ratio relative to max headroom (27
dBu) = 123 dB.
• Signal to noise ratio relative to 0 dBfs (+22 dBu)
= 118dB.
• 6 LED meter shows downward expansion
calibrated in dB increments.
Threshold range: