kenti

fader8, just wanted to thank you for helping so far. I think it's an issue many users could also benefit from. My CoreMidi Framework is 1.6.1 I'm on 10.5.8 In the case of RME AIO's own midi port there's no USB sharing the port, it's PCIe, by default that's my midi interface of choice for external devices.

I'm not using an external instrument plug-in. I'm using a regular external midi track, and recording to an audio track. The round-trip latencies are of no concern to me as I'm aligning the recorded result manually to be in perfect alignment with the 1st bar. If you check my screenshots you will see exactly what I mean. If the problem were round-trip latencies or predictable/constant offset, well then there would be no "problem". The actual problem is the wildly varying offset, as in -30/+125 samples between 3 quarter notes. If I record a simple 4/4 bassdrum it's galloping like a retarded drummer. EDIT, here are the screenshots so you won't need to scroll through all the previous posts: 0) Overview of recorded external device http://img138.imageshack.us/img138/1992/picture3ib.png 1) recorded audio aligned to Bar. http://img69.imageshack.us/img69/8245/picture6kr.png 2) recorded audio fluctuation at 2nd Bar: http://img268.imageshack.us/img268/9894/picture4ou.png 3) recorded audio fluctuation at 4th Bar: http://img232.imageshack.us/img232/631/picture5cd.png

Logic 9.1.1, Logic 8.0.2 Midi Interfaces: RME AIO, Midisport 2x2, Motu Traveller Mk3, E-Mu Xmidi Audio Interfaces: RME AIO, RME 9632, Motu Traveller Clocks: Lavry AD-10, UA 2192, RME AIO, RME 9632 External Devices: Moog Voyager, Poly Evolver DS, PC with V-stack and Cubase 5 as sampler

Excellent acceptable values. I'd be happy with those as well. What Logic version were these recorded on?

David, that would be perfectly acceptable if the offset was "constant" or at least unidirectional. In my of recording of 16th single-hit notes it went from (after first 16th aligned to 0 or 1st bar) -30 samples on 2nd hit, to -70 sample on 3rd hit, to -100 samples on 4th to +(PLUS)125 samples on the 5th. This is the very definition of inconsistency and randomness. Of course were I to go on counting offset for the next 20, 40, 100 bars the effect is the same. You can check my screenshots (posted above) for a visual representation of what I'm talking about.

Thank you for the reply Minimoog. If it were a matter of 1 sample I wouldn't be worried about it at all. We've just established (on another forum) that the minimum latency is 80 sample. you can check out the following screenshots to see that the fluctuation is random and a note will sometimes trigger and record even before it is meant to be "played" via midi but also much later, and all within a single bar. 0) Overview of recorded external device http://img138.imageshack.us/img138/1992/picture3ib.png 1) recorded audio aligned to Bar. http://img69.imageshack.us/img69/8245/picture6kr.png 2) recorded audio fluctuation at 2nd Bar: http://img268.imageshack.us/img268/9894/picture4ou.png 3) recorded audio fluctuation at 4th Bar: http://img232.imageshack.us/img232/631/picture5cd.png Also this has been tested with various recording devices, I do not even use an all-in-one audio card in the classical sense. In this example it's an RME AIO clocked via a Lavry AD-10.

believe me I've tried 32, 64, 128, 256, you name it, I've tried it. Has nothing to do with Midi interface: Fact. Nothing to do with Audio Interface: Fact. Nothing to do with natural round trip latencies, it's a random fwd. backward. fraction fluctuation: Fact. Nothing to do with Studio-clock: Fact. I'm not sending out any kind of midi sync signals, no MTC, sequencing or the like. Notes/velocity only. This applies to any type of external gear, be it a synth or ANY other midi receiving device controlled via logic. Logic's internal midi is in perfect sync as usual. here's another ongoing discussion, I've started on another forum, I'm not alone on this anomaly as you'll see: http://www.gearslutz.com/board/music-computers/482777-logic-pro-midi-fluctuation.html

Dear fellow Logic friends, here's the thing.. Lately I've noticed something weird when playing back external instruments via midi. The midi is constantly fluctuating around a given tempo. Say I record a 4/4 rimshot at 123bpm then align the recorded track to be in sync with the bar/metronome. The first aligned wave is of-course in-sync, but the rest fluctuates randomly around the needed values, sometimes forward sometimes backward. It's never really noticeable like a +/- 1bpm galloping fluctuation, it's a tiny but very annoying fluctuation especially on drums. And it's not just ONE particular midi instrument or audioInterface or Midi Interface. Tried 4 different midi interfaces, 4 different clocks. Tried Logic 8. Erased logic preferences, audioMidi preferences, restarted twice, updated Interface drivers... wtf?