Any reason to not use "External Instrument" plugin with instruments?

Libertine, in order to keep the confusion to a minimum, you have to be clear about the following connections found on a hardware device:

• MIDI Output
• MIDI Input
• Audio Output

MIDI Output

A hardware device that has a MIDI Output (USB or 5-pin DIN connector) is considered a "MIDI Controller". This is usually a MIDI Keyboard that you use to record your MIDI parts in your DAW. A MIDI Keyboard that includes its own sound source has also a MIDI Input.

MIDI Input

A hardware device that contains a MIDI sound module (generates sound) has to have a MIDI Input. A MIDI signal is connected to this MIDI Input in order to "play" the sound module (create an audio signal out of MIDI signals)

Audio Output

A hardware device that functions as a MIDI sound module has to have an Audio Output that you connect to a Mixer in order to hear/record its generated sounds.

Now lets look at MIDI Instrument Channel Strip in Logic:

Software Instrument Plugin

Usually, you load a Software Instrument at the top of the Software Instrument Channel Strip. This is a MIDI Sound Module that receives its MIDI Input from your (External) MIDI Controller and from the MIDI Region on its Track Lane. Its Audio Output (the sound it produces) is sent along its Channel Strip to process that audio signal.

External Instrument Plugin:

This plugin works as a routing mechanism to do two things.

1. The incoming MIDI signal on that Channel Strip (from the external MIDI Controller or MIDI Region) is sent out of Logic through your MIDI Interface (that you define) and that signal, you must connect to the MIDI Input of your external hardware MIDI sound module.
2. The Audio Output of that hardware device has to be connected to an audio in on your audio interface (i.e. input 3/4). If you select that input on the External Instrument Plugin, then that audio signal is routed to the top of its Channel Strip and runs through the rest of the Channel Strip.

Real-time audio v.s recorded audio

This is one important aspect you have to keep in mind with all the MIDI/Audio routing. A Software Instrument Track in Logic only records MIDI signals (MIDI Regions) and not audio signals (Audio Regions). When you play your MIDI, those signals are sent to the Software Instruments and External Instruments in your Project and their audio signal plays "live" in real-time. When you want to record those audio signals, then you have to route them, for example, to an Audio Track. This might be a good idea for External Instruments, when you later work on a Project and can't reproduce the exact sound on the hardware device. Also, External Instruments are not included when using Real-time bounce.

As you can see, the topic is a little bit more complex. Here is an expert from my book "Logic Pro X - The Details" where I explain all that with lots of graphics and diagrams.

Hope that helps

Edgar Rothermich - LogicProGEM.com

(Author of the "Graphically Enhanced Manuals")

http://DingDingMusic.com/Manuals/

'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'

Could you tell me how I would capture the actual audio signal of a track recorded by the External Instrument Plugin? You mentioned routing the track to an audio track. I'm unfamiliar with that.

On the Output Button of your Instrument Channel Channel Strip, select a Bus (i.e. Bus 1) instead of the Stereo Out and then create a new Audio Track, where you select that same Bus (i.e Bus 1) as the Input. Now the signal on the Instrument Channel Strip is routed directly to that Audio Track where you can record it as an audio signal.

So since you can "convert" the recorded MIDI signal into an audio signal, it's even harder now for me to understand why someone wouldn't always record a hardware instrument that outputs MIDI data to a External Instrument track instead of an audio track. Are there any reasons not to?

Working with a "live" instrument (software or hardware) lets you change the MIDI notes (what it is playing) at any time. Usually you record an Instrument Channel Strip to an Audio Track if you know that you don't need to change it anymore. The benefit is that you avoid any issues with the instrumnet later on where it changes it sounds, you cannot load it, or you exchange your Project with another studio that doesn't have that device.

Lastly, I just noticed that when I adjust the effects parameters on my hardware synthesizer as it's being recorded to an External Instrument track the effects tweaking aren't actually captured. I adjusted the frequency cutoff filter, from 12 o'clock to 3 o'clock (knob position), while recording and the entire recorded region was recorded as if the knob was at 3 o'clock the whole time. Is this another disadvantage of External Instrument recording?: it can't collect MIDI signals of real time effects parameter tweaking?

Thank you.

Logic "doesn't know" anything that you change on the external device, only what comes back as audio. You have to do it the other way around Send the MIDI message from Logic (i.e. COntinuous Control 74) to the external device, that controls a specific parameter. You can create that signal from inside Logic manually or send it from you keyboard controller if you can assign the appropriate CC to a knob or wheel. This works, of course, only if your external device supports that. Check your documentation.

Hope that helps

Edgar Rothermich - LogicProGEM.com

(Author of the "Graphically Enhanced Manuals")

http://DingDingMusic.com/Manuals/

'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'

Again, you have to be aware of the signal flow:

MIDI Controller:

MIDI Out: Your MIDI Keyboard (COntroller) is only sending the MIDI signal to Logic (assuming that it doesn't have any built-in sound module). MIDI Out of the Keyboard connected to the MIDI IN of your MIDI Interface that you use with Logic. In the case of USB, connect the USB of your Keyboard to your computer.

External Synthesizer:

• MIDI IN: You are sending a MIDI signal to that device in order to "play" it. MIDI connection from Logic TO the Synthesizer. You don't generate any MIDI data on the Synthesizer itself, no MIDI signal going back to Logic. That's why any movement of any hardware controller on the synthesizer doesn't get recorded in Logic.
• Audio Out: The Synthesizer has to send its audio signal back Logic so you hear it/record it.