Just thought I’d update this.
The very helpful and friendly support guys gave a perfect answer that makes sense for me to share (in case anyone else wants to find this information).
TLDR is, if you use a UAD or (most) Focusrite interfaces, set your preamp gain to 0, and plugin input level at unity/0 and you have the perfect gain response (the same as plugging your guitar straight into the amp). If you use something else, check your specs sheet (it’ll give your value with gain at 0). If it’s a number bigger than 12.2, you’ll need to boost by the difference, if the number is smaller then you’ll need to subtract by the difference.
Our plugins are made with the following audio interface gain:
- Analog domain sine waveform 1 Vp = 0.707 VRMS = -0.79 dBu equals -13 dBFS in the digital domain.
- In other words, when feeding the audio interface input a sine 1 Vp from a signal generator, it results in -13 dBFS in the digital domain.
If you want to calibrate your interface in order to mimic the input gain our engineers use when creating and testing the plugins, I would advise you to feed a sine waveform 1 Vp = 0.707 VRMS = -0.79 dBu to the interface and set the interface gain to such level that the DAW peak meter shows -13 dBFS. Feeding a sine waveform on different interfaces will result in different values (again, this is the reason why we cannot provide a concrete value). Check these examples of feeding a sine waveform 1 Vp:
- UAD Apollo x6: -13 dBFS
- UAD Apollo Twin: -12.9 dBFS
- Quad Cortex: -15.1 dBFS (1M impedance) Input level at 0 on QC.
- Focusrite Scarlett: -13.1 dBFS
- Focusrite Clarett: -14.6 dBFS
- Apogee Duet: -14.5 dBFS
However, I have to tell you that can be achieved by connecting your guitar to the Hi-Z input of a UAD interface with the gain at minimum (to ease the pain of doing that with all your interfaces and electric guitar combinations). If your interface features a Hi-Z input, leaving the gain input by default (minimum) is more than enough. Add input gain if one of your guitars lacks output level (as our support team suggested, increase it as much as you can without clipping).
What if you use Quad Cortex as an audio interface?
If you use Quad Cortex as an audio interface and you want to get its input close to a UAD interface (-13dBFS), just connect your instrument with the QC’s instrument input at 0.0 dB. If you wanna match them exactly, you have to boost Quad Cortex USB output by approx +2.3 dB before reaching the plugin’s input.