DMD latency — out of sync with metronome

[amnestic]

Hey all!

I’m experimenting with Live Loops in LP for iPad, and I programmed a basic 4/4 beat that is being used as a kind of bed track. However, while creating the pattern in Drum Machine Designer, I kept realizing that the drum track was slightly off the click, like with a heavy swing or latency, but no swing setting is turned on. It’s enough to sound really out of time with other elements I’ve programmed into the track. Everything else (MIDI, recorded sounds) is perfectly in time. But no matter which samples I choose, DMD is slightly off the beat.

I verified that it’s properly programmed “on the grid” in the Pattern region, and I even made sure to edit the drum samples themselves in case there was any silence before the sample plays. I then transferred the loop into the arrangement, converted the pattern to a MIDI region, quantized, and it’s still playing with a latency.

I’m using an iPad Pro 11-inch, 2nd generation, pre-M1. I began to assume that my iPad was just unable to process everything, hence the latency. But it doesn’t explain why every other track is able to be perfectly in time.

Has anyone come across this before? Any help would be greatly appreciated!

[oscwilde]

Haven't encountered anything like this.
Would you be able to Airdrop/zip attach the project here?
I'll give it a spin on my M1 iPad Pro and see if I have the same playback issues.

[amnestic]

Thank you for the reply and offer to check the project!

I'm attaching it here. I also have an arp-type sound playing, which is muted, but it's always in time, and the DMD drums never are.

Let me know what you hear on your end. Thanks again! 🙏

Edit: I actually just opened the file in Logic on my M1 Mac, and the same thing is happening, so I'm not sure what's the cause of the issue. It really does seem like a DMD-specific thing.

EOTP - Clouds.logicx.zip

Edited November 29, 2023 by amnestic

[oscwilde]

Thanks for the file.
Yep, the timing with the metronome was out - iPad and Mac.
Went looking and noticed that quantize was active (for the drum part) in the Piano Roll editor as well as at the Main window/region level.
Disabling this (Quantize Off) in the Piano Roll changes the way things "sit" audibly (doesn't change visually).
Can you try this and see if you're hearing this as well?

[amnestic]

On 11/30/2023 at 12:50 AM, oscwilde said:

Roll changes the way things "sit" audibly (doesn't change visually).
Can you try this and see if you're hearing this as well?

Hi @oscwilde!

My apologies for the delayed response (pun not intended!); I was unfortunately sidelined by COVID-19.

I sincerely appreciate your assistance with this issue, and I'm relieved to know it's not just on my end.

I investigated the issue on my iPad and discovered that Quantize appeared to be enabled (using the "i" button that opens the Region settings); I disabled Quantize. However, there seemed to be no option to adjust quantize within the Piano Roll Editor on my iPad. I subsequently opened the file on my Mac, disabled Quantize, and the beat remains out of sync with the metronome, just as before.

I'm perplexed as to why it didn't work for me. Would you be able to re-send the file with the fix so I can investigate why it didn't work for me?

In the meantime, I've found a workaround by creating multiple Quick Sampler tracks of drum hits and placing them in a summing stack, which functions perfectly. It's not the most elegant solution, but it'll do for now. Additionally, I tested a Drummer track, and it played in perfect sync. Therefore, it appears to be a DMD-specific glitch.

Speaking of glitches, I suddenly recalled experiencing DMD issues in Logic on Mac around 2021. I even posted about it here:

 

Apart from creating my own Drum Bus with Quick Samplers or Drum Synth tracks (as I've done again on my iPad), I never found a solution. However, it seemed to resolve itself after some PDC issues were addressed. Perhaps this PDC issue persists in the iPad version of Logic Pro?

I'll keep digging into this issue and see if I can find a more permanent solution. Thanks again for your help and your willingness to assist me!

 

Edited December 6, 2023 by amnestic

[oscwilde]

1 hour ago, amnestic said:

Perhaps this PDC issue persists in the iPad version of Logic Pro?

Maybe just hold off until the next release before expending more energy on what seems to be buggy behaviour - particularly now that you've found a workaround?
While it may well be specific to DMD, it leverages the QS/Drum Synth engines....which are both fine, but does make use of auxes/mix busses....and I think this may be the relevant factor, based on your comments above (and the general level of weirdness).

Given the Logic 10.8.1 PDC changes at the audio engine level on MacOS, I'd imagine the underlying audio engine of LP4 iPad will receive these same changes - or project latency issues would happen when transferring between platforms (along with the outta sync stuff).
Not sure of when the next iPad release is planned, though, so might need to wait until early in the New Year (watch it get released tomorrow, now I've run my mouth off 😂)

[amnestic]

1 hour ago, oscwilde said:

Maybe just hold off until the next release before expending more energy on what seems to be buggy behaviour - particularly now that you've found a workaround?

Yes, you're right. Good idea! I tend to want to figure things out when they're not functioning, but I realize that this will not have a very clear solution until an update.

1 hour ago, oscwilde said:

 (watch it get released tomorrow, now I've run my mouth off 😂)

Now, that would be amazing, in more ways than one! 😂

Thanks again for your help! 🙏