Hi all,

I think I found a bug in TM FX 1.75. (Driver package 3.39 on macOS Catalina).

Using SpeakerB button on ARC can change SpeakerB volume setting inadvertedly if you have a volume offset between Main and SpeakerB.
In the worst case, both volumes raise until they are at + 6dB!

Here's a Screencast.

First half I'm clicking with mouse, then I use ARC SpeakerB button. This is Case 3.

Offset values with .3, .4, .5, .6 ,.7 decimals are buggy.
.0, .1 , .2, .8, .9 are not buggy.

Here's how to reproduce the issue(s):

Case 1:
Put volume of Control Rool MAIN to 0.0 dB, SpeakerB to 0.6. Don't LINK.
a. Now push SpeakerB in TM: volume values stay same, as expected.
b. Now push SpeakerB on ARC: volume SpeakerB jumps to 1.0 dB! Bad. Well, at least value is rounded up or down once.

Case 2:
Put volume of Control Rool MAIN to 0.0 dB, SpeakerB to 0.6. LINK them.
a. Now push SpeakerB in TM: volume values stay same, as expected.
b.Now push SpeakerB on ARC: volume SpeakerB jumps to 1.0, Main to 0.4. BAD! Disengaging SpeakerB on ARC the values go back to 0.6/0.0. But: Disengaging SpeakerB in TM the values stay at 1.0/0.4! WORSE!

Case 3:
Put volume of Control Room MAIN to 0.0 dB, SpeakerB to 0.5. LINK them. (you may have to click on dB value to enter with keyboard)
a. Now push SpeakerB in TM: volume values stay same, as expected.
b. Now push SpeakerB on ARC: volume SpeakerB jumps to 1.0, Main to 0.5. BAD! Disengaging SpeakerB on ARC the values go to 1.5/1.0. WORSE! AND: Each push of SpeakerB on ARC continues to raise both volumes! Aaargh!

I think the issue stems from a rounding issue between clean dB display values and the actual 'dirty' decimal values that are underlying. I noticed already while working with OSC that there is something going with the scaler function inside TM.

I haven't checked how it is with macOS 11/12.

For now, I'm just NOT using a .5 increment offset between the two, to work around the issue. But it really drove me nuts until I knew what's going on.

I hope this can be fixed in the future.