AI suggests the following. Not guaranteed to be 100% accurate, but it should point you in the right direction...
"To ensure all your semi-playback WAV files have the same overall volume in NCH MixPad, you must manually adjust the mix levels before exporting, as MixPad does not offer an explicit “export at this volume” setting in the export dialog.
Workflow for Consistent Volume
Set each track’s volume and panning so the mix sounds balanced in your monitoring system.
Pay close attention to the master volume fader. Lowering the master volume (e.g., to -3 dB instead of 0 dB) will reduce the output level for the export.
Use metering: Watch the meter on the master output and aim for consistent peak levels (for example, peaks at -3 dBFS). This can help match volumes across different mixes.
Use MixPad’s effects: If some tracks are much louder or softer, use compression or gain plugins to even out levels before exporting.
Export your final mix by selecting "Export Project as Audio File" and choosing WAV as the file type. The output level will reflect whatever your mix and master meters are showing at export time.
Comparison and Batch Processing
To match levels across many songs:
Normalize each exported .wav file using an external editor like WavePad or a dedicated batch normalizer, if MixPad’s adjustments aren’t enough.
Consider referencing a “standard” backing track: Use it as a template for levels, so each mix is balanced to sound equally loud in the hall and in-ear monitors.
Practical Tips
Always check the exported file with a meter or waveform viewer for consistency.
Document your target peak volume (e.g., -3 dBFS) and use it across sessions.
MixPad supports bit depths up to 32-bit float; this can preserve headroom for mastering.
For your application, controlling the master fader and observing the output levels in MixPad before export is key. Repeating this process for each playback file ensures uniform volume for live use."