error while trying to synchronize Audio and Midi (Logic Pro)

T

ThinkingMetal

Active member
Good evening,

This error pops up if I try to record a synth (running on a Teensy 3.5) in Logic Pro. I'm also sending Midi down the same USB cable. Theoretically, it should cope with the load.

I've tried searching the forum but can't find anything obvious. Am I pushing the Teensy too hard? [Yes, I know I should be using a Teensy 4.1.]

Any ideas?

Screen Shot 2023-07-13 at 20.55.54.png

Thanks
David
 
I assume you also did this, but when I googled for "error while trying to synchronize Audio and Midi (Logic Pro)", most of the hits point to a sample-rate issue. For example this page.
At what sample-rate does your synth output audio?

Paul
 
Hey,

I'm using the normal 'Serial + Midi + Audio' option in the Tools->USB drop-down coupled to the standard Teensy audio library. Hence, the sample rate should be 44.1 kHz.

I've programmed the same board (Teensy 3.5) to function as a bi-directional sound card so I know that works in that I can record into Logic as usual. However, adding the Midi + Serial option makes me wonder if some of my debugs are breaking the flow.

I'll try that first thing in the morning.

Cheers
David
 
Some additional information - it's a four oscillator poly synth. The oscillators are the usual waveMod oscillator generating band-limited waveforms. The synth architecture is very vanilla - single oscillator into the SVF. Two envelope shapers and one LFO, feeding into a couple of mixers and a delay line for effects.

I'm wondering if the band limited waveforms are hogging the CPU. Memory usage calculations give this result:

AudioProcessorUsage : 56.89
AudioProcessorUsageMax : 76.15
Memory: 186,202
 
Yet another update:

1. I've removed several of the debug messages that the instrument generates in the background and I can record into Logic without the error message
2. That said, the audio that is recorded is incredibly crackly. It's not what I heard on the phones coming out the back of the audio card.
3. I'm running Logic Pro 10.3.2 on a MacMini (2.3 GHz Intel Core i5) under OS 10.13 (High Sierra) with 8GB of RAM

I'm wondering if this little development system just can't cope with the load.
 
Did you try to increase the AudioMemory(numberBlocks); ? Perhaps it's useful to check what AudioMemoryUsageMax(); returns.
Another cause of crackling audio could be (interval)timers that run at the same priority (128) as the audio chain update.

Paul
 
Hmm, it could indeed be your Mac Mini not keeping up with the pace.
I'm not familiar with Logic Pro and/or a Mac Mini, but is there an option to adjust the latency of the audio coming in? I recall from playing with Ableton Live that setting a too short latency also introduced crackling audio.
Perhaps other forum members can chime in that have more experience with Mac Mini/Logic Pro?

Paul
 
Wondered if it was a Logic thing and recorded a brief passage into Audacity. The result was the same, lots of crackles and pops. When I look at the recorded data, there seem to be samples missing. Not many, but enough to mess the recording.

I tried changing the latency of Logic - made no difference.

Hey ho. Will keep soldiering on.
 
You may want to check your cable. Try a new, short, high quality USB cable and see if that changes anything.
 
JayShoe said:
You may want to check your cable. Try a new, short, high quality USB cable and see if that changes anything.
Click to expand...

Yeah, tried that. Not the highest quality cable but it's reliable. I use it to transfer movie footage off my phone so I know it works.

Pretty sure this is down to the MacMini. It dates from 2011 so... yeah... not the zippiest of machines.
 
In your post #3 you stated that you programmed the Teensy 3.5 to function as a bi-directional sound card without MIDI. Did you experience crackling audio then?
If not, it's just the addition of MIDI data over USB that causes the audio to break up?
By the way, is it MIDI data to the synth or data from the synth to the DAW?

Paul
 
PaulS said:
In your post #3 you stated that you programmed the Teensy 3.5 to function as a bi-directional sound card without MIDI. Did you experience crackling audio then?
Click to expand...

No crackling at all but then the test was not exhaustive i.e. I set it running and it worked as a proof of concept. The intention was always to migrate the project over to a Teensy 4.1.

PaulS said:
If not, it's just the addition of MIDI data over USB that causes the audio to break up?
Click to expand...

Looks very much like it.

PaulS said:
By the way, is it MIDI data to the synth or data from the synth to the DAW?
Click to expand...

It's Midi data from Logic to the synth - Midi Clock for syncing and Midi Notes for the synth engine. There are no Midi CC's or Midi Aftertouch that I can see, unless Logic is injecting them.

I plan on upgrading to an M* Mac shortly anyway. Using a 2011 device for testing current generation kit is not a good test. :)
 
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