Yes, I mean parallel bussing. Isn't that and the term double bussing pretty much interchangeable? I'm actually curious to know if they are different in any way.
When you say you calculate the latency once and then you don't have to again, I don't really get that. You have to calculate the latency for the entire signal path to analog, including the interface and any digital mixer and then the DA converters. Then also calculate the various plugin latencies. Each plugin has different latency. And then what if you change the buffer for some reason? That's going to change all the calculations. If you are popping many different plugins in and out on various tracks that's a lot of delay calculations.
My goal is to *totally* eliminate that kind of mathematics from the process. Mixing should be ears, listening, taste and judgement. Speaking purely for myself, I've found that simplifying the process in certain ways makes it go a lot more naturally and better.
I used to have my studio setup with all digital routing and processing. I used the same outboard, but patched digitally. It was amazing the routing I could do, everything being recalled and all that. I could put any signal anywhere, it was great in a theoretical sort of way. However, I got nothing done. It seemed like all I did was troubleshoot and deal with getting the signal from here to there, and deal with latency issues with bussing.
I tore that setup out, bought my Speck
XtraMix's and severly limited my routing options. I'm back to analog patchbays, analog mixers, analog outboard, fx processing outboard is routed analog now not digitally. It is actually faster to work with, much more productive. It also sounds better in the sense that mixes gel a lot easier. When mixing in the box it is so easy to just get wrapped up in tweaking this plugin and that plugin, trying to get it to gel or sound right.
Those issues just go away for the most part in analog. Maybe I'm not just a good enough mixer, which is highly likely. I'm strictly a good demo mixer, I hire pros to do my "real" mixes. Although my recording engineer does seem to "borrow" my ideas from time to time.
Anyway, I've dealt with latency and I just can't stand it. I don't trust the process, and I think that even with all the calculations for latency, if you were to double buss some tracks you'd probably still get phasing when putting them together in analog.