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Calibrating the Meters
The main idea behind the design of these meters is that 0 VU can be set to whatever the user feels
is useful for measuring average loudness of mixes and masters, and sometimes that includes
calibrating the meters based on a reference track. This idea takes precedence over maintaining
fixed resistance for the sake of keeping the VUs mechanically up to spec. However, If the user
wants to calibrate the meters based on a standard, like 1.223 Volts (+4dBu) or 0.775 Volts
(0dBu) it is still possible to do so and be able to keep that position’s calibration as the meters use
very stable, high quality potentiometers for calibration.
Calibrating the unit using 1kHz sine wave tones:
If you don’t already have a full scale 1kHz tone (0dBFS), you can download one here:
www.redsecta.com/1ktone.zip
1.
Import the 1kHz tone audio file to an audio track in your DAW.
Important:
make sure
your monitors are turned off or way down, you don’t want to play this tone at unity gain
on them.
2.
Bring the tone track’s fader all the way down.
3.
Copy the tone track to two new audio tracks (to calibrate positions 2 and 3 later). Mute
both new copies.
4.
Insert a peak meter in your DAW’s master output fader.
5.
Select both position switches to position 1
6.
Press play on your DAW and bring up the tone track’s fader while looking at your peak
meter. Stop where you want to set the position’s calibration point (we’ll use -18dBFS for
this example). Name the track “-18dBFS”.
7.
Adjust both meters’ calibration 1 pots until the needles of each meter raise to 0 VU. You
just calibrated the first position.
Repeat steps 5 - 7 for positions 2 and 3. Save this DAW session to something like “VU
Calibrations” to go back to if needed, or to add more calibration reference tracks later.
Calibrating using reference tracks:
If you’re interested in calibrating the meters to the average level of a reference track, perhaps to
use as a target loudness for your own work, you can do so by following the above steps (you’ll be
using a reference track instead of the 1kHz tone file), except for step number 6:
Instead of bringing the fader up, leave the reference track at unity and turn the calibration knobs
all the way down for both meters (counterclockwise). Focus on a busy section of the track, like the
chorus, and loop it. Adjust the knobs until the needle is peaking as close to 0 VU as possible. The
