External MIDI Audio Playback/Recorded Late

[Nibiru]

Hey All!

Stumpt.

The other day I connected and powered up all my old killer "real world" MIDI synths and sampler of yesteryear. Loaded up some old MIDI files, played em back, everything worked great and was having so much fun! Until I wanted to add a VI kick drum to one of the songs. I quantized the VI kick to a quater note to layer it with a kick from my Emu E4XT sampler (amazing still!) which is also doing quarter notes. I notice they do not line up perfectly at all. There is quite a bit of audible "flamming" going on. I recorded the audio from the sampler and discovered the external MIDI is about 390 or so samples late. I tested with each port on my crappy M-Audio MIDISPORT 4x4. (I've tried this with my MTP/AV with the same results btw). I've tried changing the buffer settings as well, to no avail.

I understand I can use the Time Shift plugin to move the MIDI data earlier, which works great. Thank the stars. However, I'm just really needing to know...is anyone getting sample accurate playback, i.e., VI's lining up with external hardware synths, near perfectly?

Edit: Typically I work with buffers set to 512, work priority low, host mult 1, using an Apogee Rosetta 200 via Firewire.



Any input is greatly appreciated!! Thanks!

On 10.6.8., DP8.01.

[kgdrum]

From my understanding because the sampler & synths are external and not itb software based there will always be some type of delay,it takes time for MIDI data to go back & forth between the hardware and your Mac.

[Nibiru]

Hey kg!

Thanks. And totally. Just could have sworn way back when, I was able to get pretty spot on in terms of the recorded audio being near sample accurate, all with my motu 1224 and my mtpav. Anyhoo, thanks again.

[kgdrum]

Well it might have seemed that way because everything was external and you weren't using soft-synths/vi's, now when you're trying to mix external with software based itb vi's the timing differences are more apparent.

[Radiogal]

There is a way to optimize the MIDI timing in DP. It's a Motu plugin, if I remember it correctly. Check out the manual. It should be there in the MIDI section.

[Radiogal]

It's for timing of external MIDI instruments.

[DPINCGK]

duplicate

[DPINCGK]

390 samples at 44100 is about 8mS.

MIDI is 31.25 kBaud, 3125 bytes per second can be sent and it's serial, so one at a time. A realtime note on event is only 3 bytes long, I think it's somewhere around 320 microseconds to send a single MIDI byte due to the transfer speed, so you figure 1 millisecond for 3 bytes. That's just the time for your note on to get from one end of the cable to the other.

It still takes time for the keyboard controller to process your keydown event, and to send the right value. Once the message is delivered, it takes time for the destination hardware (Emulator) to process the input data and play the sample.

I'd assume somewhere between 5 and 10 mS might be typical MIDI hardware response time (but I could be wrong on that). Seems like I remember hearing somewhere that a MIDI hardware system could have response times as long as 20 mS. It would be very difficult to play drum parts and certain rhythmic things with a long response time like that, but 5 mS is almost impercetible.

[stephentayler]

Is this what needs to be addressed?

Setup>Configure Audio System>Fine Tune Audio I/O Timing

Always used to use this to calibrate for recording external MIDI modules

Cheers

Stephen

[Nibiru]

390 samples at 44100 is about 8mS.

MIDI is 31.25 kBaud, 3125 bytes per second can be sent and it's serial, so one at a time. A realtime note on event is only 3 bytes long, I think it's somewhere around 320 microseconds to send a single MIDI byte due to the transfer speed, so you figure 1 millisecond for 3 bytes. That's just the time for your note on to get from one end of the cable to the other.

It still takes time for the keyboard controller to process your keydown event, and to send the right value. Once the message is delivered, it takes time for the destination hardware (Emulator) to process the input data and play the sample.

I'd assume somewhere between 5 and 10 mS might be typical MIDI hardware response time (but I could be wrong on that). Seems like I remember hearing somewhere that a MIDI hardware system could have response times as long as 20 mS. It would be very difficult to play drum parts and certain rhythmic things with a long response time like that, but 5 mS is almost impercetible.

Hey all1! Sorry for the late response...

Thanks for the break down DPINCGK!! I always knew it took some time for everything to process, but, I just remember back when (on a blue a white G3 mind you) recording with DP (god knows what version), and my 1224, recording with all the same MIDI hardware, that the sample accuracy was pretty much spot on. I remember zooming in to see it bc I would layer drums from my Emulater with drums from other hardware, and remember checking to see visually if it was on point, and it was. Enough that I didn't ever need to nudge all recorded tracks back to zero start point.

[Nibiru]

Is this what needs to be addressed?

Setup>Configure Audio System>Fine Tune Audio I/O Timing

Always used to use this to calibrate for recording external MIDI modules

Cheers

Stephen

Hey Stephen!

Thanks for that! I always felt weird messing with those settings bc I felt they were temporary and needed to be changed back to the default if one were to go back to recording non-MIDI hardware whilst using VI's and Audio. I could very well be over thinking it all, but I messed with those settings in trying to get everything lined up, and felt like I had to be aware of those settings when I open a different project where this wasn't an issue, and change them back to default.

On the other hand...yes Radiogal, that freakin Time Shift plugin, once again, saved me. I love the functional simple things in life that just do their job. Man. I put the plugin on all external MIDI tracks, set it to samples, move it 390 samples earlier, problem solved. So freakin cool! Thanks for all the input from everyone!

[tommymandel]

I would agree with Stephen T, that you do that calibration once for your studio setup, and then leave it; no need to 'turn it off.' It's been a while since I did that myself, probably before VI's got so important; so I'm going to do that now. I'll be back with any interesting results.

[tommymandel]

1. Create MIDI Sequence with 4 quarter notes playing C2, one measure total.
2. Instantiate Model 12 Motu VI drum module. Assign that MIDI Track to Model 12.
3. Assign Model 12's audio output to bus 13-14.
4. Create Audio Track. Assign its input as bus 13-14.
5. Record on that audio track. Model 12's audio performance gets recorded.
6. Assign the same MIDI Track's MIDI output to external module Yamaha Rack XS.
(MacPro's USB MicroExpress USB feeding a Syco-Logic MidiPatchBay (no processors.))
7. Create 2nd Audio Track. Assign Yamaha Rack XS's audio output to this track's input.
8. Record the audio track.

RESULTS 1:
Model 12 (VI)'s audio track starts at 414 samples.
(External MIDI Instrument) Rack XS's audio track starts at 709 samples.

9. As per Stephen Taylor's suggestion, Setup/ConfigureAudioSystem/FineTune i/o timing...
Set Playback to +400. Set Record to +300.
10. Repeat all earlier steps.

RESULTS 2:
Model 12 (VI)'s audio track starts at 267 samples
(External MIDI Instrument) Rack XS's audio track starts at 100 samples.

Comments? Advice?