Logic Pro - Audio Sync issues

[alexdingley]

This is just doesn't make sense to me...

I setup a logic studio for a friend with the following gear:

new iMac 27" with an external USB 3.0 drive (for audio... might switch it to FW)
Logic 9
Apogee Symphony I/O (connected via USB) (Driver buffer = 512samples & no audio delay compensation adjustment)
external pre's / yaddah yaddah.

On the first day that I was testing the system:
- I tracked some audio, then overdubbed more on top...
- On playback, the second audio track was lagging behind (uniformly) the initial track.
- Tried it a couple of times and it was the same every time.
- Changed the Driver Buffer setting up and down... no change in the lag (very slight)

The next day
- I turned off "universal track mode" (realizing that it shouldn't have any effect)
- recorded overdubbed audio...
- played it back perfectly.
- scratched my head, then turned-on "universal track mode"
- Recorded audio overdub & played it back perfectly...

Since then...
- It has been fine (to my ear & the ear of the client)

...till Today...
- Now it's the original problem. Overdubs are delayed ever so slightly.

... So I'm testing some variables on my machine after reading the following (albeit old) troubleshooting article:

I've got my own Logic studio at home and I'm using an older Apogee Symphony64 system. I've got my machine setup with a buffer of 512 samples (for this test) and no audio delay adjustment. So, I setup some audio on a track and routed it out (analog) and back in (analog) to another audio track... No matter what I do on my machine at home the tracks are perfectly in sync without making any adjustments to the audio delay adjustment.

I can't find a ton of recent (last year or two...) articles or any articles with people talking about issues like this in Logic 9...

Does anyone else suspect (as I now do) that it's some weird delay brought in by the USB bus not handling the real-time audio very well?

Hopefully my many hyphens and ellipsis make sense.

[Nick Sevilla]

Try with a FW drive, although it should not matter, as USB3 is plenty fast.HOWEVER... if you have the audio interface also connected to the same USBs, it may be bumping down the speed to USB2.0 or worse. What USB spec is the interface?

It is 2.0:

http://www.apogeedigital.com/products/s ... ration.php

USB High-Speed 2.0

So, you may only be using all USB as 2.0 speed, and that may be causing trouble.


From what I recall:

I have Logic Pro 9.1.8 ... opening it... (scanning too many plugins...)...

Audio preferences pane (not the settings, but preferences, I know that is so confusing in Logic):

I have Core Audio (on a Mac) enabled. No other types of drivers are on mine.

I have the IO set up to "built in digital" from the mac to a Motu 828mkiii.

Buffer set to 512,
roundtrip latency number is at 25.2 mS.

Universal Track Mode On
24 bit on
Software monitoring on
Independent monitoring level on

Processing threads automatic
Process buffer range medium
ReWire behavior : playback mode (less CPU load)
Maximum scrub speed double
Scrub response fast

Recorded a couple of mono audio tracks, they came back fine.

Cheers.

[alexdingley]

I'm heading over to his studio after work today... (thank goodness for half-day fridays in the day-job world) and I'm gonna try thunderbolt-to-FW800 for the audio drive.

I really wouldn't be surprised if it's the USB bumping down... but the audio I/O and the HD are on different USB ports. I don't know if each USB port is its own different bus, or if one can get bogged down by the other.

Regardless, it's worth a test. Thanks for testing and posting Nick!

[trevord]

One thing to check if you have tried all and its not that
----
Did you run anything else audio related on the DAW?
The reasoning is - some programs (usually web-y crap ) re-configure the system audio settings to suit themselves and others (DAW) just use those settings and only change settings when told to do so.

The culprits are usually FLASH media crap but Apple should have protected you from that, but it could also be cheap (er.. non standard) software to even playing strange media as part of your system setup - movie desktop - fancy system sounds

anyway
check if something is reconfiguring your system audio setup when you weren't looking

trevor

[alexdingley]

well... this was interesting.

I went back to the studio today... saw the problem in action. every newly created song was getting out of sync overdubs. almost 300ms late. it was bad.

So, I dismounted the Hard drives, then used a thunderbolt-to-fw800 adapter to hook the audio drive up via FW instead of USB 3.0

... and then the audio overdubs were getting recorded perfectly. Strange, but I almost felt better.... thinking it was fixed.

So, to be sure, i switched back to the USB 3.0 for a (hopefully) final test... and damned if it wasn't still recording in perfect sync.

... so now I'm scratching my head again. The problem went away, even when I'm back on the USB again. WTF!!?!?!?!??

So, I called Apogee's support team.

Low and behold, they have heard of the issue... rare, but it's out there. They said they've got a beta firmware, and they emailed it over within minutes of the call.

I followed the directions provided, and installed the new firmware + maestro software and then rebooted.

... so far, it seems rock-solid... but time will tell.

[tjcasey1]

Stick to firewire, even if it's thunderbolt to firewire. Why troubleshoot USB 3.0/2.0 if you don't need to?

[alexdingley]

Yeah... I'm heading over there this week to change out the data cable for the t-bolt to fw800. Thankfully, the system has been rock-solid since the firmware update, but I'm on board for not risking anything and staying with fw.