Latency compensation doesn't work on I/O plugin?

Question

So, I thought this was supposed to work...
I tried to set up some parallel compression by sending my drum bus to another Aux which had the I/O plug inserted. The I/O plug sent the drum signals to my hardware compressor (and back). But the problem is, even with delay compensation set to "all", I still get an audible delay between the original untreated bus and the I/O bus.
Using Expert Sleepers' free plug "Latency Fixer", and a gain plug with the phase reverse, I was able to get it pretty close at 1400 samples. This number didn't seem to change with buffers set at 64, 128, or 256. And changing the 'record delay' didn't appear to affect anything either.
What up? I thought delay compensation was supposed to account for converter latency when using the I/O plug. No?
This makes using external hardware very problematic with Logic, and sure makes me wish they had a 'ping' feature like (ahem) the competition.

Answer 1

John Alcock wrote:
I use a lot of outboard processing too, and my experience is the same as yours.
I've sent feedback in the past to Apple asking for a roundtrip 'ping' feature - add yours!
As you suggest, LatencyFixer helps, as does the Latency bundle here:
http://www.artificialaudio.com/pluginmenu/1
With hardware reverbs it's not an issue as it works like pre-delay, so it can be compensated for by reducing the pre-delay settings, but for my EQ and compressors I sometimes reroute hardware outputs back in (rather than use I/O), and nudge the resulting processed file in place using click headers - still a p.i.t.a, but works ok for me. As I mostly use the same interfaces and external hardware I have a note listing round trip timings which I can quickly apply.
Thanks for the confirmation. I do the same workaround as you, recording the processed files and manually aligning them after the fact. But this really is a big p.i.t.a for what should honestly be a basic functionality in a "Pro" DAW.
I got curious about this issue after reading a post on another forum. The poster suggested that while inserting an I/O plug on an Aux bus was not correctly compensated by logic, the situation improved if you added a DUMMY (ie. bypassed) I/O plug on any channel strip, as long as it's sending to the same outboard destination. Why this works is a complete mystery, but it does seem to point to a bug in L8's implementation of PDC.
However, when I use the 'dummy I/O' workaround, the timing is tighter but not perfect. Still get phasing issues if things aren't nudged a few samples forward...
It would be so cool if this actually worked the way it does in Protools or Cubase/Nuendo and other "Pro" DAW's. I've sent notes to Apple Feedback as well. And as always, the response has been several months/years of deafening silence. Oh yes, I'm assured by many loyal followers that they ARE listening. Which is all well and good, but if they don't actually DO anything, how does it help my daily problem with integrating outboard compressors?
Anyway, I'm gonna do more testing to see what I can find out.