This has nothing to do with logarithmic scaling, so humor me and keep that out of discussion here for a minute.
I think you are trying to find a way to use VSL's CC7 default values since that appears to be the way VSL is level-balancing Synchron instruments against each other. Yes so far?
So the defaults are to have CC11 at Max.... and then you can adjust CC11 from 0-127 which will essentially attenuate the signal even further as you desire over the range set by CC7. Note that in a way CC7 provides the total dynamic range...and CC11 adjusts the level linearly within that range. When CC1 and CC11 are set to max 127 you can think of that as the max possible volume of the instrument, which VSL is level balancing against other instruments and their max levels...by using CC7.
Now I think you are saying that's all fine and good, but you want some breathing room because if you use that default setup and you start drawing in a bunch of expression curves to your composition and then suddenly you find out that its not quite loud enough even when both CC1 and CC11 are set to max. And you need to be able to bump it up a little more. Fair enough. Also level balanced sample orchestras are probably never perfectly balanced. So you need some room to fudge it. Fair enough.
That means you didn't probably have the max volume level set right to begin with via CC7. So assuming that you could bump up CC7 a little bit to get the max level where you want it...but then all the curves you already drew for CC11 would all be too loud. So I don't think that's a good solution really, you probably should leave CC7 alone once you start recording tracks and programming CC11 curves.
So you suggest that you could have CC11=110 set as the home base "max" position, and that way if you get halfway into your composing you realize that you need more max volume then you originally thought, then you can just pump up cc11 past 110...take it to "Eleven" so to speak...
So assuming you set CC11=110 and generally treat that as your max instrument level....and only rarely go to Eleven...I don't think there is anything else you need to do to compensate anything. Just be consistent with all your tracks, always use the same approach. Me personally I still prefer generally to use CC1 (velocity XF) for each instrument dynamics anyway...and I would generally leave CC11 set to its home base position (whether that is 110 or 127), and only rarely use CC11 to change dynamics slightly louder then max perhaps. I don't see the point of using CC11 instead of velocity XF. But no matter, some other sample libraries don't provide velocity XF, so that would be the case when you would use CC11 and just always treat the max as 110 except for rare situations where you have to go to Eleven as mentioned above.
In the above, yes the overall instrument output will be lower then factory, since you'll be using CC11=110 as the max in order to have room to go to Eleven. That is an attenuated signal by a factor of 13%. That doesn't really matter as long as all your instruments are following the same rule, then their output will all by attenuated by 13% and the level-balancing will be preserved...just everyone at a lower level.
As a side note, MIRPro does essentially exactly this. When you use MirPro instrument presets, they are all dropped way down in level in order to preserve level balancing against some other really loud instruments such as Timpani. It means that other instruments output from MirPro and very low levels, way way way below -18db, which many people including myself have struggled with a little bit, but it doesn't matter, its all relative.
If you want you can simply add a trim plugin to the master bus to bring them all back up again evenly by the same amount. How much gain to add would be 13%...but of course gain plugins often use use DB units to specify the gain,, so you'd have to figure out how many DB's of gain to add, one setting for the entire orchestra. One master bus with just one trim plugin using some amount of gain that brings them all back up, relative to each other, by a factor of 13%.
That's all you really need to do.
Adjusting CC7 back up
I think it would be very difficult to try to adjust all the CC7 values up from the factory setting in order to compensate for the 13% reduction you are making with CC11=110 because of the math I mentioned where its a percentage of a percentage. I am not sure you could simply raise CC7 by 17 (which is 13% of 127) and have the level balancing preserved. It needs to be bumped up by 13% from the current cc7 range.
If you want to try the math, you need to use percentages, maybe you were already suggesting this but I could not understand what you wrote, but simply take the following math, assuming VSL's cc7 val and changing CC11 from 127 to 110.
@Another User said:
new_cc7_val = oldCC7val / (110 / 127)
Then change CC7 to the above and use 110 for CC11 and it should be the same output.
Also, some of the instruments may not have room to go up enough to compensate, before hitting the ceiling of 127 after running this calculation.
Therefore its going to be easier to compensate that 13% signal loss from CC11 by simply adding trim plugins after Synchron in the plugin chain, you can either add one trim plugin on every track, and make sure they are all set the same...or just send them all to some common bus and put one trim plugin there that raises the level ~13%.
I am essentially doing exactly that with MirPro now when I have ensembles and stuff that will never have loud sounds playing....
I think involving DB calculations just complicates the issue because of the logarithmic nature of DB as a measurement. You just need 13% of gain added back. whatever DB that turns out to be will be different depending on the loudness of the instruments.