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IDProjectCategoryView StatusDate SubmittedLast Update
0010449ardourfeaturespublic2026-07-25 09:362026-07-25 09:36
ReporterGhostsonAcid Assigned To 
PriorityhighSeveritytweakReproducibilityalways
Status newResolutionopen 
PlatformmacOSOSMojaveOS Version10.14.6
Product Version9.7 
Summary0010449: Ensure “gaincontrol”/"trimcontrol" (i.e. fader/trim) values are “1” and “0.5” for any “-0.0” and “-6” in-DAW values respectively
DescriptionAlthough this is partially a bug, I suppose it's mostly a feature request to tweak how two specific fader (gaincontrol) values are set and used by Ardour.

When doing fairly extensive ‘invert+sum’ testing for various mixing techniques that rely on the *perfect* inversion then summing of certain signals in order to cancel-out everything *except* whatever specific processing I’m trying to isolate, I uncovered some inconsistencies (and/or inconveniences) with how Ardour is calculating and saving its “gaincontrol” values (i.e. fader values) as shown in the XML.

I devised a simple, quick test below to reproduce the behavior.

In the XML, instead of the expected fader values of:
value=“1”
value="0.5"

-You will often get values such as:
value="0.99999994039535522"
value="0.50118720531463623"

-And this is partially dependent on what specific sequence of *actions* you take in the DAW. (-Again, follow the demo below.)

In a nutshell, my request is that when setting a fader (or Trim knob) to exactly *-6dB*, the corresponding “gaincontrol” value should always = exactly “0.5”. And whenever (and *however*) any fader is explicitly set to “0” (or shows “-0.0”), that the corresponding “gaincontrol” value always = exactly “1”, not some approximation.

If approximate values are used instead, then the result is that any use of an ‘invert+sum’ signal flow does NOT cancel-out completely, and instead leaves you with a fairly prominent audio ‘bleed’ into the rest of the mix. (-Pinpoint accuracy is key here.)

Anyway, THANK YOU for considering this tweak/'fix'! : )

Cheers,
-Joe
Steps To Reproduce1. Create a test project (at 48kHz, or whatever).
2. Add 1 stereo Audio Track, and 1 stereo Audio Bus.
3. In the Track’s mixer strip, click on the fader value and type to change it to “-6”, hit Enter.
4. In the Bus’s mixer strip, click on the fader value and type to change it to “-15” (or whatever), hit Enter, *THEN use Shift+LMB* to ‘reset’ it to “-0.0”, supposedly.
5. Save the project.
6. Open the XML (.ardour file) in an XML-viewer, and search for the 3 instances of “gaincontrol”.
7. Observe how you will have something like “0.50118720531463623" and "0.99999994039535522" for the Track and Bus respectively.
(Note: The latter, near-1 approximation only occurs with a use of Shift+LMB, as far as I can tell.)
Additional InformationNote that this approximating behavior ALSO effects the *Trim knob*, saving a value for -6dB in the XML like:
<Controllable name="trimcontrol" id="200" flags="GainLike" value="0.50118744373321533"/>
Tagsfader, gaincontrol, trim knob

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Issue History

Date Modified Username Field Change
2026-07-25 09:36 GhostsonAcid New Issue
2026-07-25 09:36 GhostsonAcid Tag Attached: fader
2026-07-25 09:36 GhostsonAcid Tag Attached: gaincontrol
2026-07-25 09:36 GhostsonAcid Tag Attached: trim knob