In this short post I will propose different midi connection schemes that are used in practice.
It is important to mention that these schemes are related to my practice, so the sound will be hosted on a computer (MAC) which has vsti and daw. On the other hand, the interface has (in addition to audio inputs) a MIDI input (5pin).
SETUP 1 - "The Fast"
MIDI CONTROLLER - USB - MAC - BUILT IN AUDIO OUTPUT - MINI PLUG to RCA with JACK ADAPTORS on PHONES - MIX - SPEAKERS
Pros: The Fastest
Cons: Limited polyphony, only possible in MAC, although in WIN low latency can be achieved, polyphony is not applicable to play pianos and keyboards in harmonic high density styles.
SETUP 2A - "The Unused One"
MIDI CONTROLLER - MIDI - INTERFACE - FIREWIRE - MAC - BUILT IN AUDIO OUTPUT - MINI PLUG to RCA with JACK ADAPTORS on PHONES - MIX - SPEAKERS
A strange setup, I have never used an interface just to synchronize, normally if I use the interface to connect via MIDI I also send the audio through its outputs and not the MAC.
SETUP 2B - "The one we almost all use"
MIDI
CONTROLLER - MIDI - INTERFACE - FIREWIRE - MAC - OUTPUT INTERFACE - JACK or XLR - MIX - SPEAKERS
Classic combination computer + interface + controller.
Pros: Guaranteed stability, functional polyphony, pro audio output.
Cons: More things to load and increased assembly time.
SETUP 3 - "For those who use more than one controller"
MIDI
CONTROLLER 1 and MIDI CONTROLLER 2 - MIDI and / or USB - INTERFACE - FIREWIRE - MAC - OUTPUT INTERFACE - JACK or XLR - MIX - SPEAKERS
This is my setup, I connect one via USB and one via MIDI to the interface. In this setup the musicians usually use different midis channels, in my case I prefer to use the CHAIN selector from my DAW (Ableton Live).
* When this setup mutates depending on the show, I sometimes have a controller: I have one for piano mode (88 heavy keys) and another light one (61 light keys) with knobs (knobs and faders). When I use the full piano and I require the knobs (knobs and faders) I add a Wi-Fi midi controller with which (through a template written by me) I have mapped exactly the same knobs and midi faders as in my light controller (from done, first I wrote that model and then took it to my lightweight controller, but that's another story.)
SETUP 4 - "Nowadays"
MIDI CONTROLLER - Bluetooth / Wifi MIDI - MAC - OUTPUT INTERFACE - JACK or XLR - MIX - SPEAKERS
Today there are bluetooth controllers, although I have not tried them, I understand that they provide similar latency to those connected via USB or MIDI (5pins).
SETUP 5 - "Golden Days"
This is a setup that I've only seen, and I've never used since instead of a MAC or PC (win) it uses RACK of sounds and SYNTHS (keyboards with their own sounds); normally used in the 70s to have many keyboards and modules controlled from a couple of keyboards.
MULTIPLE MIDI CONTROLERS - MIDI THROUGH (allows you to interconnect several keyboards and the final keyboard that reaches the brain brings all the signals in it, normally separated by 16 channels - that is, this technique allows up to 16 interconnected keyboards that reach the same brain by 16 different channels) - SOUND MODULE or SYNTH - Module or Synth OUTPUT - JACK or XLR - MIX - SPEAKERS
For several years I have not seen keyboards with MIDI THROUGH, the last one I had in my possession and that I had it was an X5D from the 90's. However I have seen this technique (connect multiple keyboards or controllers to a single brain) in music from the 70s to bands with keyboards of the "old school" that still use midis channels and sound modules, who knows if with the cyclic movement of the aesthetics we will see them again.
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These are the possibilities that I use in my experience and I have seen used in practice; It is possible to combine with each other, as well as replace the MAC or PC with a module, synth or even an iPad. The important thing is to find the one that suits you and suits your needs.
I leave a video where I show a couple of these schemes:
I hope this information is useful for you.
Greetings
D. Dawson