Dorico doesn’t have a built in method to bring Audio into the mixing console like a tracking DAW would provide.
The simplest solution is most likely to take advantage of any monitoring/mixing capabilities built into your audio-interface drivers. Plug audio out from your external kit, to audio in of your interface. Assuming your interface has some kind of ‘mixing console’ as part of its driver package, you should be able to come up with something that will allow you to hear Dorico’s Output at the same time as your Outboard gear.
Beyond this, here are some approaches I’ve taken over the years.
So, here’s one way (out of many, but it’s the next simplest) I do it…though it’s a kludge that breaks ASIO rules, and depending on your system it might introduce too much latency to ‘mix and match’ your external kit’s audio with plugin instruments hosted in Dorico.
I’m using Dorico via the Windows 11 OS…
I use a pair of M-Audio Delta 1010 audio interfaces (So something like 20 audio inputs). My external gear is plugged into these interfaces. Some via analogue connections, some over SPDIF, etc.
I use a plugin called Audio Connect.
I can have Dorico add an AUX Send channel, and host an instance of Audio Connect there in the first effect slot. I can chain other effect plugins lower down in the same channel if desired. Audio Connect in turn grabs an Audio Signal/Stream from my choice of ‘non-ASIO’ drivers of my Delta 1010, and does whatever buffering and jitter control is required to inject my instrument(s) output into the Dorico Mix.
Alternatively, I’ve also hosted it in Dorico’s instrument rack before (with the help of bidule). Something like Kushview Element, or Audio Gridder might also make it possible to host it in the ‘Dorico VST instrument rack’.
Is it worth it? It depends. The only real advantage to doing this is if I wish apply/use the bundled ‘Steinberg Host Only’ effect plugins to process the external kit’s audio. It’s kind of nice to have a fader right there on the Dorico mixing console.
Disadvantages include possible stability issues on some machines (it’s a kludge that isn’t supposed to be done according to ASIO protocol rules), and possibly noticeable latency issues on some systems if you also wish to host and use plugin instruments in Dorico at the same time. For me it’s not that bad…only a few ms, and not that noticeable, but that might not be the case for all systems.
My preferred method is to use ASIO Link Pro or Jack2, and route Dorico’s main audio output stream into a different host that can in turn, bring in the audio from my external kit. This way I can ‘mix’ the signal from Dorico and my outboard gear, and apply whatever processing/mixing I like in this ‘other host’ to ‘blend’ these two mixes together. (If no ASIO Link Pro or Jack2 is installed…some high end interfaces include built-in ‘routing-loopback’ abilities. Also, hard patching with real cables is almost always an option).
For the secondary host…sometimes I use a stand-alone instance of Bidule as the other host/mixing app. This low overhead host also can run as a plugin (if registered, usually there are free, fully featured stand-alone demo versions) and is kind of a Swiss Army Knife hosting/snooping/serving/client/sound-design utility that is so weird yet USEFUL that I don’t know quite how to describe it. I almost always have at least one standalone instance of this running on my system, and use it for all sorts of MIDI/Audio routing/transformation jobs. On Windows Systems, when combined with a virtual MIDI port or two, it helps correct a number USB/MIDI diver issues that are unavoidable byproducts of the way Windows USB<>MIDI driver implementation works.
Sometimes I opt for Cubase and run the TXL Timecode Plugin in Dorico (If I’d also like to involve some audio tracking). The TXL plugin provides a way to lock the Cubase transport with Dorico’s transport using MIDI Time Code (over a virtual MIDI port). Of course TXL is totally optional if I don’t have any need to sync the transports together.
If you’re on a Mac…
Sorry I don’t have enough experience with a Mac to know if ANY of my kludges above apply. My understanding is that you can do similar things as I am describing with Windows (Maybe even better). I simply don’t know what apps and tools are out there to try.