09-23-2023, 04:37 AM
I did a null test of Mixbus and Ardour. There is a slight difference but nothing that would be heard I believe. The null difference is about 80dB lower.
How I tested it using a set of multitrack stems:
Turning the Ardour one's fader down by super small amounts made the sound start to disappear. By -0.066 I couldn't hear anything, headphones still at max.
Using the Export Audio Files > Only Analyze tool I checked the Peak and [Integrated Loudness] measurements:
I confess to being a bit muddled on what this means so please somebody correct me if I'm wrong:
The only audible difference between the two is that the Ardour one was 0.0675 dB higher in overall gain. Reduce it by that amount and there is no audible difference. Whatever difference there is is ~80dB lower than the signal itself, so would never be heard underneath that signal, indeed could not be heard at all on its own with my headphones on max.
Meaning that the Mixbus summing engine doesn't colour the sound in any way that can be heard. Nor does anything else in Mixbus other than EQ, dynamics and saturation.
I wasn't game to try panning anything. I guess some hard left/right panning would have been fine but anywhere in between would have skewed the results because the two DAWs use different implementations.
How I tested it using a set of multitrack stems:
- Import stems into Mixbus, group and route sets of tracks through four mixbusses (drums, bass, vocals, rest), all pans centred, turn off all compressors/EQ/drives including master limiter and its drive down all the way. Master fader at -10, all others at zero. Export as 32bit float.
- Import stems into Ardour, all pans centred. Master fader at -10, all others at zero. Export as 32bit float.
- Import exports into new Ardour session. Phase reverse one of them.
Turning the Ardour one's fader down by super small amounts made the sound start to disappear. By -0.066 I couldn't hear anything, headphones still at max.
Using the Export Audio Files > Only Analyze tool I checked the Peak and [Integrated Loudness] measurements:
- Playing just the Mixbus one (Ardour one muted) = -3.5 dBFS [-22 LUFS]
- Both playing, both faders at 0 = -45.7 dBFS [-63.8 LUFS]
- Both playing, Ardour fader at -0.0675 = -83.3 dBFS [LUFS could not be measured]
I confess to being a bit muddled on what this means so please somebody correct me if I'm wrong:
The only audible difference between the two is that the Ardour one was 0.0675 dB higher in overall gain. Reduce it by that amount and there is no audible difference. Whatever difference there is is ~80dB lower than the signal itself, so would never be heard underneath that signal, indeed could not be heard at all on its own with my headphones on max.
Meaning that the Mixbus summing engine doesn't colour the sound in any way that can be heard. Nor does anything else in Mixbus other than EQ, dynamics and saturation.
I wasn't game to try panning anything. I guess some hard left/right panning would have been fine but anywhere in between would have skewed the results because the two DAWs use different implementations.