Our pianist is beginning to dabble with MIDI. We hope to use Auria Pro to mix his MIDI tracks with several 48 kHz strings tracks for CDs and web demos. Our pianist loves the sound of Lyra's C7 grand piano, xylophone, and other sampled instruments in Auria Pro. The problem is that whether MIDI files are recorded directly into an Auria project or added later, there are lots of random pops and crackles in the audio playback. It is quite distracting. Below are a series of observations regarding 48 kHz playback pops/crackles, which also happens on my iPad Mini in iOS 10.3.1 (i.e., not a single defective iPad):
MacHound wrote:I have been doing experimentation about this popping / clicking issue on the 48 kHz MIDI tracks and I found highly reproducible observations which, despite how bizarre they seem, are present across multiple projects involving different combinations of MIDI and non-MIDI instruments. Here are my observations regarding MIDI tracks in Auria Pro 2.10 beginning with three NEVER statements:
(1) 44.1 kHz projects: MIDI tracks NEVER pop for me regardless of changing instruments, track position or anything else... 44.1 kHz projects always sound fine (so far).
(2) 48 kHz projects: MIDI tracks NEVER pop when they are in the first or second track position (top).
(3) 48 kHz projects: MIDI tracks NEVER pop in any track position when the non-MIDI audio tracks above them contain no audible sound (i.e., the non-MIDI tracks have been trimmed or moved not to overlap with the MIDI track in the vertical orientation.)
(4) 48 kHz projects: MIDI tracks begin to have popping issues when there is more than one non-MIDI track with audio above a MIDI track. A single non-MIDI track above a MIDI track is not enough to produce popping / clicking. It takes two or more audio tracks with sound located above the MIDI track to elicit popping.
(5) 48 kHz projects: Dragging a MIDI track from the bottom of a project's track list to the top or second-from-top track position eliminates MIDI popping. Dragging the MIDI track back down the track list restores the popping (most of the time but not always). Sometimes an instrument change or two is needed to get the popping to start again.
(6) 48 kHz projects: The severity of the popping depends on the instrument being played. For instance, among the Lyra sampler pianos, Classic Grand piano tends to pop more often than C7 Grand, which itself pops more noticeably than Salamander Grand. Even within a single instrument some pops are more obvious than others.
(7) 48 kHz projects: Popping can go away for a while when a project is exited and reentered depending on factors I have yet to identify. I wish the pops would stay away, but they eventually start back again after the fourth or fifth listening.
(8) 48 kHz projects: Even with a single MIDI instrument loaded and everything else unchanged, the clicks always happen in different and apparently random time locations during playback. It's not like a scratched vinyl record where the click always happens in the same spot, though the popping sound is otherwise somewhat reminiscent of a scratched vinyl record or one that developed a static charge.
(9) 48 kHz projects: Three non-midi audio tracks above a MIDI track seems to produce worse popping than only two non-midi audio tracks above a MIDI track. This observation is only partially confirmed. Beyond three consecutive non-MIDI tracks, I cannot hear any difference.
(10) It doesn't seem to matter if processing is present or absent on the non-MIDI tracks... popping occurs either way when a MIDI track lies below two or more non-MIDI tracks.
(11) It doesn't seem to matter whether non-MIDI tracks are muted or playing audibly.
(12) It doesn't seem to matter whether the non-MIDI tracks are stereo or mono... either way, the above observations apply.
(13) Adding one or more empty tracks between a MIDI track (say track 14) and multiple non-MIDI tracks (1-10) does not seem to prevent popping, though it may lessen it somewhat.
If the above observations sound like shaking chicken's feet to make continents drift, that's how it feels. I would not be writing these bizarre observations if they weren't so reproducible.
In summary, I can get Auria Pro's popping / clicking problem to go away by putting our pianist's MIDI recording in track 1 or track 2, but not in track 3 or lower - unless there's pure silence in the top tracks. For our youth strings group, that is a satisfactory solution. It doesn't explain the popping / crackling nor voodoo necessary to make it go away. Thanks.
[Edited 4/22/17 to remove a broken link]