difference between MIDI automation and Audio automation on Instrument Track?

[mariam]

Hi, I'm a newbie to protools, currently using Protools 12 right now.
(I used to work with Logic Pro 9.)

I have a question about the automation options that you can edit in an instrument track.

Why is there both MIDI Volume/Panning AND Audio Volume/Panning for Instrument Track?
I've checked the manual and it explains that the two types of data are treated differently, but I am not sure how to differentiate the two when working on virtual instruments.

If you're working on MIDI data surely the automation data will be MIDI (wouldn't it?) so why have the option of audio automation?
(I remember in Logic Pro that whether you're working on MIDI or Audio, you would have one type of volume/panning...)

And my knowledge in DTM is not very deep, so if anyone could explain it to me simply that would be totally appreciated :)

Thanks!

[crizdee]

Originally Posted by mariam

Hi, I'm a newbie to protools, currently using Protools 12 right now.
(I used to work with Logic Pro 9.)

I have a question about the automation options that you can edit in an instrument track.

Why is there both MIDI Volume/Panning AND Audio Volume/Panning for Instrument Track?
I've checked the manual and it explains that the two types of data are treated differently, but I am not sure how to differentiate the two when working on virtual instruments.

If you're working on MIDI data surely the automation data will be MIDI (wouldn't it?) so why have the option of audio automation?
(I remember in Logic Pro that whether you're working on MIDI or Audio, you would have one type of volume/panning...)

And my knowledge in DTM is not very deep, so if anyone could explain it to me simply that would be totally appreciated :)

Thanks!

Hi,

Audio volume and pan controls the audio channel. You would mainly use these for automating your mix along with all the other audio tracks in the session

MIDI volume and pan controls the midi instrument. You would mainly use this for being creative with the instrument to be part of the performance.

Chris

[mariam]

I see... Thanks very much, that was very helpful! :)

Just to clarify,
You would fiddle with audio automation when you're done with editing the virtual instrument itself (like panning as well as expression/breath controls etc), and wanting to balance vol/pan with other tracks as a whole. yes? Like treating the track as an audio track?

[JuanPC]

Some softwares & some hardware allow to control Audio with Midi....

But problem is that MIDI is limited to 128 steps ("0~127"), 7-bit.
the stepped automation can be very audible... Sometimes disappointing, sometimes crazy but interesting.

Some hardware & software manufacturers use DSP interpolation to smoothly change values without audible jumps...
cirrus logic DA converter chips do interpolation between each 44.100Hz sample, most AKM chips do not... Some Analog Devices do, etc...
The result is that interpolated Da chips, but if interpolation is aggressive, sound more analog in small speakers, but fake in big horn loaded speakers.
The stepped DA converters can sound grainy, like sand in your mouth.

Yamaha DSP Factory soundcard was the first that did interpolation in the DSP audio volume faders...

That's why there are Audio automation, and Midi automation....
Audio automation if done properly can have more steps, making a "step less" volume control.
Midi C.C. continuous controllers have 7-bits, but some Midi controllers used proprietary NRPN & RPN Midi to avoid stepped midi automation,
Peavey had some controllers, similar to Avid Artist Mix, back in 1999 the StudioMix.
I think Eleven Rack & Eleven AAX Mk2 also have NRPN & RPN.
Other example is the midi pitch wheel, if I remember has 8192 steps up & 8192 steps down... = 14-bit.

Robot lights "DMX" has the same problem, some lights use 2-channels for automation, to avoid stepped automation.

[mariam]

Right, so I guess it's just to have more options of types of automation data, for those who have a MIDI controller that is limited to do certain things...

Thanks for your time!!

[nigelpry]

Originally Posted by mariam

Right, so I guess it's just to have more options of types of automation data, for those who have a MIDI controller that is limited to do certain things...

Thanks for your time!!

Easiest way to get your head around it is to imagine the bad old days when PT didn't have instrument tracks at all.

In those days you'd use a midi track for the midi data, and send it to a virtual instrument (VI) instantiated on an aux track.

So the midi track has everything you use to alter the sound that the VI produces, notes with their velocities and lengths, pitch bend, modulation, aftertouch, and a whole host of other specific parameters relevant to the exact VI in use.

The key thing is that these are parameters sent INTO the VI that alter the sound the VI emits.

The aux track hosts the VI AND allows you to further modify the sound AFTER it has left the virtual instrument, volume, pan and mute are obvious, but you can also add fx plugins into insert slots after the VI on the aux track ... eq, compression, delay, chorus, flange, reverb, etc etc. As well as sending it off to other tracks for further processing, or recording (printing) of course.

So with aux tracks, everything you do is manipulating the sound AFTER it has come out of the VI.

Having got that clear in your mind, now just imagine combining all of the functionality of the midi track and the aux track into one track .... that's an instrument track.

You can achieve exactly the same result using midi and aux tracks, or instrument tracks, but imagine if you have 50 instrument tracks .... You'd need 100 tracks to achieve the same thing using midi and aux tracks.

Instrument tracks are just a space saver, by cutting down the number of tracks in your session.

Finally, just to clarify further .... What JuanPC is really talking about is something slightly different, at least a different perspective.

Taking a simple example like a real hardware synth, not a VI ..... some (many) synths, as well as letting you change the actual sound using midi data (filter cutoff, resonance, envelope ADSR for amplitude, filter, LFO rates and depths, modulation routings etc etc) will also allow you to control their audio output using midi commands .... They may let you control output volume, pan etc.

If you think of that, it's very much like the split I described for midi and aux tracks. Some midi data sent to the synth is intended to alter the sound it creates, while other data alters what happens to the sound after it is created.

And this is where his talk about the limitations of midi are relevant ... If you are adjusting a synth's audio output volume using a midi track volume fader, the resolution of that midi data is not as fine as if you use the audio volume fader on an instrument/aux/audio track.

And yes there are midi capabilities such as combining MSB (most significant byte) and LSB (least significant byte) plus RPN and NRPN (registered and non-registered parameter numbers) used in different ways by different hardware manufacturers to improve the resolution (preciseness of control) when using midi.

But that's quite a complex subject that, in reality, you don't need to know anything about unless, like me, you have a lot of midi equipped hardware that you are using.

I think, unless I'm totally misunderstanding you, that my descriptions at the beginning of this post are more relevant to the questions you were asking.

Feel free to ask for further clarification if we haven't covered what you are looking for.