[Ardour-Users] MIDI workflow

Leigh Dyer lsd at wootangent.net
Mon Oct 17 16:48:42 PDT 2011

On 18/10/11 4:38 AM, Edward Diehl wrote:
> I've also been wondering about the best workflow for midi work.  I
> want to record solo piano using Pianoteq and possibly other sounds
> using Linuxsampler or Yoshimi.  That is, I'll use the same midi track
> to drive 1 or more sound generation programs.  I find that the CPU
> requirements of doing midi seem to be quite high so I've decided that
> the best approach is to do a 2 step process:
> 1)  Sequence my midi track using just A3 and Pianoteq and no effects.
>      do all the midi takes, editing.  Use low latency since audio is
> monitored.
> 2) "Bounce" midi to audio tracks (with Pianoteq, Linuxsampler, etc)
>     and then mix/master those.  Might even bounce to Mixbus since I own
>     it already.  Use high latency to minimize DSP demands.

Yep, that's what I've been doing, too. In my case I had no choice for 
most tracks -- I have multiple MIDI tracks going out to a multitimbral 
hardware synth that has just a single stereo output, so I had to bounce 
those to audio one-at-a-time. I think it's nice to have a separation in 
my mind between writing and mixing, though, so I bounced all of my other 
tracks, too, even those that used instrument plugins.

> Initially I tried working with a midi track + audio buses like this:
> a3 midi track ->  Pianoteq ->  a3 bus ->  a3 master
> a3 midi track ->  Linuxsampler ->  a3 bus ->  a3 master

FWIW, both of these instruments are available as plugins. LinuxSampler's 
LV2 plugin works just fine, and with the native VST support in current 
SVN (and hopefully included in the next alpha/beta Ardour release), the 
Pianoteq VST works well, too.

Using them as plugins makes things much easier: there's no need to route 
things manually, and all of your instrument settings are automatically 
restored when you load your Ardour session, which is particularly handy 
with LinuxSampler. I've written about using the LV2 plugin for 
LinuxSampler here:


> I could add fx to either the bus or the master.  The above set up
> requires routing midi and audio externally of Ardour using Jack,
> though I don't think that is a big issue.  I'll automate the setup
> using a scripts start all the programs I'm using and use aj-snapshot
> for the Jack connections.  One issue is that when recording midi you
> need to use low latency (I'm running at 8.7 ms) so you can monitor
> properly.  The low latency makes the DSP problem worse.

I was actually surprised recently at just how much extra DSP load having 
a low latency can add, while mixing a track. At 8ms latency, I was using 
around 130% CPU while playing my track; increasing the latency to 32ms 
reduced it to something like 30%. After seeing those numbers, I'd 
definitely say that it's worth bouncing your MIDI tracks to audio before 
mixing, just to reduce the CPU overhead.


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