Latency issues in GarageBand X

Hi all,

I'm relatively new on this forum, but have lurked a little since GarageBand X came out and I started contemplating a move towards Logic Pro X. I haven't messed with GBX much until recently, as the Amplitube plugin that I use heavily hasn't been supported in it, but was still working fine in GB 6.0.5. Still, I figure that GB 6x will probably cease to be supported by Apple at some point (conceivably with Yosemite!) and I should get used to the new GBX/LPX world. I recently got a new late-2013 27" iMac , and after some effort got most of my plug-ins and stuff (even Amplitube, via a slightly kludgey workaround from the maker's support team) up and running on GB 6.0.5 and GBX. I decided take an old demo project from GB 6x and work it up into something more polished in GBX to start getting the hang of things.

However, I've been running into significant latency issues in GBX that I don't seem to get when running GB 6x. I laid down 2 guitar tracks in my imported project (which had consist basically of half-a-dozen Software Instument tracks), and stuck in a GBX/LPX drummer track to see how that worked (pretty cool stuff, actually).

So far, so good -- but when I went to add bass as a third real instrument, I ran into insurmountable latency issues. Switching the Input source in and out via the Preferences has usually solved temporary/minor latency issues in the past when working in GB 6x, and it initially seemed to work here. However, then doing anything else -- play, record, select a different tracks and then go back, whatever -- reintroduced the latency issue. No matter how many times I switched the audio driver, or restarted the machine, any attempt to play/record the real instrument input alongside the already recorded tracks reintroduced the latency issue in GBX.

I thought it might be because I was using the "semi-supported" Amplitube plugin via the manufacturers workaround, but running instruments through GBXs own amp simulation effects had the same latency problems. I read somewhere online that imported pre-GBX projects might have latency issues in GBX, so I started a whole new project, but couldn't get more than a couple of real instrument tracks down before the same latency issue started popping up.

Curiously, I don't seem to have the same problem in GB 6x! I went back to the original GB 6x version of my project, and was quickly able to add several new tracks of real instrument audio without any significant latency issues. (I think one latency problem popped up, but I made it go away with the usual "switch drivers in/out" trick, and carried on.) Then, heading back to GBX, the latency problem was immediately there again.

So I'm not quite sure what the problem is, except that it seems to occur particularly when using GBX. My new iMac still has only the stock 8GB of RAM that it came with and probably needs more, but again the problem seems to affect GBX particularly. I have a slightly aged MOTU Microbook (version I) for my interface, but again it works reasonably well for running into GB 6x, and I have the latest drivers installed. OSX and GBX are likewise fully up-to-date. I'm not trying to record more than one instrument at time (which I gather GBX doesn't allow) or anything weird. I don't think it's necessarily the Amplitube plugin playing badly with GBX, but I will confess that I haven't been able to exclude 100% of all the variables yet.

Still, it's kind of weird that I get the problem in GBX but not in GB 6x. That makes me think its more a GBX problem than a problem with any of my other hardware or software (or simply a RAM issue or something). I had been thinking I could get accustomed to GBX as a path to LPX, maybe moving to Logic later this year after installing more RAM and stuff, but not being able to record more than a couple of real instrument tracks in GBX (when GB 6x still works OK, if a bit grudgingly once you've piled a dozen or so track on it! ) is kind of a show-stopper ... in that it has literally prevented me from moving forward with the recording project.

Any ideas?

OK, I think I may have figured this out on my own.

I had inserted the Ozone 5 plugin on the Master Track as I often do while working on a piece, just to be able to hear how it might sound with different mastering settings as a go along. Of course, I tend to turn off the plugin while tracking since it introduces a lot of latency.

However, while simply turning off (i.e. clicking off the little blue "light" next to it) the plugin was an effective way to avoid latency issues in GB 6.0.5, the plugin seems to continue introducing latency in GBX even while turned off. That is, if the plugin is present on the Master Track in GBX, even if it is temporarily "disabled" via the little on/off button next to the AU, it still seems to cause latency just as if it were enabled (though not affecting the sound of the playback).

The issue seems quite reproducible in GBX: high-latency plugin inserted on Master Track = tracking latency even when plugin is turned off, high-latency plugin absent from Master Track = no significant latency problems when tracking.

I'm not sure why the resultant behavior appears to be different in GB 6x and GBX -- but it so it seems, nevertheless!

On a different matter, I am bemused to see that my Master Track in GBX appears equipped with a Lock icon. I don't quite understand what that's about. I understand the purpose of locking individual tracks (to reduce the load), but ... what's the function of locking the Master? Presumably that would mean you were actually doing anything else with the rest of the tracks anyway!

GB (and Logic) uses latency compensation for plugins, meaning that tracks get shifted in time to compensate for latency. This shifting stays when a plugin is bypassed, because otherwise the track would jolt when it is bypassed/unbypassed during playback. It would also lead to other problems with plugins on buses. So it is by design, and not an "issue". Here's plugin latency compensation explained:

http://documentation.apple.com/en/logicpro/usermanual/index.html#chapter=41%26section=3%26hash=apple_ref:doc:uid:TempBookID-ReplacedWhenAssociatingWithMessierRevision-43984LAT_SC_1107-1008102

Though it is the Logic manual, the principle also goes for GB (same audio engine as Logic).

I must admit and disclaim that I haven't fully read your two posts. You should really try to restrict any post to one question, make different topics for different issues ( Forum rule #4: one question per topic

It would also help if you could add your setup info to your signature:

click this link to your signature and add your system information:

• Logic version and sub-version (e.g. Logic 10.0.3)

• OS X version and sub-version (e.g. OS 10.8.4)

• Computer (e.g. MacBook, Mac Pro, iMac)

• Processor (e.g. 2 GHz Intel Core 2 Duo)

• Memory (e.g. 2GB)

• Audio interface manufacturer and model (e.g. Presonus AudioBox USB)

(most of that information can be found by choosing Logic Pro X > About Logic Pro X, and  > About This Mac)

Please also list whatever you own of those:

• MIDI controller(s), (hardware) synths, soundmodules, other MIDI-using hardware, external processing equipment, etc.

Sorry for violating the Forum Rules! I meant no harm --

Signature updated now in what I hope is an acceptable way.

Thanks for the link to latency info, though I don't think it actually addresses the issue I was seeing. Nevertheless, I believe I have figured out a way around the problem, so hopefully all is now well.

Hi Guys,

While we're on the latency subject, I just laid down big bucks for a set of Bose QC 35's. They are wonderful. However, the main reason I bought them was to monitor my soloing over rythmn tracks in Garage band. So I hit a note and 10 minutes later I get to hear it through the headset. OK, slight exaggeration...it's about a third of a second which is just unbelievably frustrating. Please help me someone.