Something very interesting I noticed regarding the gain knobs that I haven't seen mentioned before: The knobs don't appear to function as continuous digital encoders as I thought they would. Instead, you turn them until they hit a threshold which activates a programmed level change in the software to the next "step" of gain. It's not a continuous control, even though it feels like one. So, the result of you moving the knobs is similar to analog stepped pots but without the detented tactile feedback.
Evidence to support this:
1. While monitoring the output with headphones, set a gain pot to zero. Very slowly bring it up. You won't hear anything for the beginning of its travel, but then around 7:00 / 8:00 the channel will suddenly come to life, as though you had a console with the fader up but you had just disengaged the mute switch.
2. With an empty room, I've been able to set my levels of all 4 channels pretty equally by eye using the room tone / steady HVAC noise and watching the meters. If you turn the pot past a certain point, the dB meter pops up a couple segments and stays there. Even if the pot position of the other channels isn't exactly the same, I've fount that as long as you're in that range of "wiggle room" then you're getting a matched level.
Can anyone verify this? If I'm right, then this would somewhat lessen the need for ganged gain controls as some of us here have called for. We still definitely need a per-channel numeric level though, and I would also like to know exactly what the gain steps are in the software.
Hoping Tom Duffy from Tascam will be able to weigh in on this - I've had no luck getting a response from him after numerous attempts.