14-bit MIDI/NRPN: When to use it, Impact on Sound Quality

[Libertine Lush]

Hi everyone,

By chance, I recently encountered the concepts of 14-bit MIDI and NRPN. After some googling, I only have some fragments of understanding.

1) Are 14-bit MIDI and NRPN equivalent in their ability to accurately relay parameter tweaking?
2) At what points in the interaction with a DAW is it necessary to have 14-bit MIDI/NRPN? My understanding is that when recording to a MIDI track, then bouncing it to an Audio track, the resulting audio will reflect the 7-bit, 14-bit or NRPN resolution of the knobs tweaked from the MIDI track.

But what about this scenario?: If I monitor/record a synth's filter sweep to an Audio track, will the monitoring and recorded audio capture the filter in all its nuance, ignoring the MIDI resolution, since that's not what's being recorded?

3) Amongst better synths, is 14-bit MIDI/NRPN or some kind of interpolating used for the parameters that need that resolution, even when the rest of the pots/encoders are simply 7 bit MIDI?
4) If your synth/controller gives you the option to use 7-bit, 14-bit or NRPN, is there any good reason to use 7-bit instead? And if the choice is between 14-bit MIDI or NRPN, my guess, for a reason I can't say, is to use 14-bit MIDI.

Thank you for any help.

[pljones]

Hardly anything supports 14bit controller resolution - usually, the low order bits just get ignored. Hardware controllers are rarely up to the job - and it's hard to physically control a knob that accurately. There's also the issue of available bandwidth for a "real" MIDI port (i.e. hardware MIDI often can't cope with streaming 14 bit data swamping the cable).

In the software world, there's no point using MIDI to automate anything - VST automation is more accurate.

[Libertine Lush]

There's also the issue of available bandwidth for a "real" MIDI port (i.e. hardware MIDI often can't cope with streaming 14 bit data swamping the cable).

You mean MIDI In/Out/Thru ports can struggle with 14-bit MIDI?

In the software world, there's no point using MIDI to automate anything - VST automation is more accurate.

I'm too new to understand that statement. Do you mean if I use the mouse to adjust the automation curves of a software synth in my DAW (Logic) it will render the adjustments more accurately than if I made the same adjusts with the knobs on my hardware (even if it's a synth sending 14-bit MIDI or NRPN)?

Thanks.

[pljones]

You mean MIDI In/Out/Thru ports can struggle with 14-bit MIDI?

It is not to do with the message - it's to do with the number of bytes of data per second. Older hardware ports are designed for olden times when data rates were low and nothing really used 14 bit. Whilst pitch bend is 14 bit, it's sent as a single MIDI message, not a pair, so it's half the amount of data. Even so, many synths ignore the low order bits on pitch bend.

Do you mean if I use the mouse to adjust the automation curves of a software synth in my DAW (Logic) it will render the adjustments more accurately than if I made the same adjusts with the knobs on my hardware (even if it's a synth sending 14-bit MIDI or NRPN)?

VST automation uses a different mechanism - it does not use MIDI messages. The two systems are separate. VST automation uses a 32 bit floating point value, IIRC, not a 14 bit value. So yes, it's a lot more fine-grained.

[Libertine Lush]

VST automation uses a 32 bit floating point value, IIRC, not a 14 bit value. So yes, it's a lot more fine-grained.

That's wonderful to know. Thank you.