I am trying to use the overbridge plugins for my A4 & AR at the same time in Bitwig…
However, the first inserted plugin works and syncs, the second does not send sync information correctly and the Control Panel freezes all level meters for the second device. If I use only one (A4 Plugin for example) in the project, It is fine.
Am I missing something? attached both (MKI Devices) to Overhub, which is directly connected to my MacBook (High Sierra).
Last year i was on A4 & AR & AH… all on Overhub in Bitwig… macOS El Capitan. All worked as expected.
Now with Firmware updates, Mac High Sierra (not officially compatible but people seem to report it’s working for them…) + Next OB version coming in February.
I personally at the moment waiting for the next OB version to enjoy it again… I prepare my Mac on Two image disc backup each one with everything I need one on Sierra 10.12.6 and one on High Sierra 10.13.2… I just only have Overbridge to install and I’m ready to go. I make music only on hardware or record the old way my Jams in Bitwig through my X18 mixer to try construction idea then. (for now…)
For people in the same scenario like you, and so they can reply and help you I would post my elektron firmware version. I imagine your on OB 1.15
wich version of High Sierra ?
So people with the same can help you if they actually have the same scenario working on they’re own Mac.
Also, it doesn’t really make sense but I would try no sound card except the internal one. only your Mac : your RYTM connected on the USB Mac port 1 and your A4 connected on the USB Mac port 3 …
And told us if the results are the same without Overhub. on 2 USB port not shared. 1 & 2 are shared and 3 & 4 are shared : so it’s common techniques to use 1 and 3 for important stuff like USB audio for instance.
uhhh thought I was alone - also having the problem but was too lazy to post.
I can swear that it was working before I updated macos to latest
AR single - fine
A4 single - fine
together - depends which device gets first hit on usb bus or electrical signal (don’t know) using Live 9.7.5
OB 1.15
also tried connecting direclty to my macbook - AR left, A4 right - no overhub in place.
software in use:
mac os 10.13.2
OB 1.15
Four OS 1.24C
Rytm OS 1.31B
mk1 devices
Live 9.7.5
I actually made it work by only activating stereo outs on both… that way it seems to work. Less than ideal though 
macOS High Sierra 10.13.3
AR MKI 1.31b
A4 MKI 1.24c
Overbridge 1.15.0
I have the exact same issue! this really sucks! 
why bother with OB if i can only record the main outs?
did a solution evolve? im also on live 9.75 and my macbook only has zwo usb outs so if i connected directly i would be without a connection for my actual soundcard.