Latency and External effects

Hi,
just wanted to know whether Logic NOW correctly
handles latency on external effects, and by correct I
mean is it automatically compensated for?

Blessings and Love

Beya

Since nobody has the same external devices, Logic could never
do this completely automatic. As soon as you know what size of
delay you have in samples, (this can be caculated) just insert
this figure into the core audio preference area and Logic
will compensate for it.

The short answer is no, Logic doesn't have this feature (like Cubase and Nuendo do). But the I/O plugin DOES apparently take into account the buffer latency and will automatically compensate for that.

In other words, if you know the latency of the external device, you don't need to add it to the buffer latency in your calculations. Contrary to what the post above says, this is probably NOT something to take care of in your preferences settings.

The best solution is a freebie plug called "Latency fixer", which doesn't process the audio at all, it just lets you specify a latency amount in samples, which it reports to Logic so that it can compensate accordingly.

The best way to use it is to make two copies of your audio track, one with no plugins, and the other copy with lantency fixer, and a 'gain' plugin set to reverse phase, and Logic's I/O plugin sending your audio to the external effect in question. You adjust the values in latency fixer until phase cancellation is as close to perfect as you can get. What I then do is create a channel strip preset for that amount, making it fairly easy to plug in your various bits of outboard gear and 'automatically' take care of the latency.

Clear-ish?

I cant argue with you when you put it that way,

Beya Beya.
I think that many LogicPro users are aware of other DAWs than Logic. I am very familiar with CubaseSX since it´s first "edition". I do use outboard effects a lot in my workflow and I do know that "Ping" function that SX offers through it´s External Plugin. Truly, it is very nice. However this one advantage will not make SX my favorite DAW. I have to work with SX time to time, but for one reason and another I always prefer to work in Logic Pro if I can choose. The fact I have to compensate for the latency of External devices manually isn´t really a problem that big that I would think even 5 seconds about switching the project to CubaseSX.
Sorry, no way 🙂
With Love,
Mark

Timkerboy, that is really good idea-to save a Channel strip with predefined Latency fixer and I/O plugin, thanks for that!
One question: do you think there is a difference if Latency fixer plugin is inserted before or after I/O Plugin?

Since I invented the "Latency Fixer" plugin, I think I should answer this post.

I use outboard gear rather than plugins. When routing audio out through the converters and back, latency is a serious problem. I found that using the track delay parameter to compensate for this latency was worthless, since it is tied to the song tempo, it is too time consuming to set up for each song. It is also not sample accurate.

I theorized that since all AU plugins need to report their latency to the Core Audio driver, a simple plugin could be created to do nothing more than to report a certain amount of latency which was specified by the user, thereby causing the Core Audio system to read that track ahead by this fixed amount. I contacted three programmers aboout coding this simple plugin. All three said it was impossible, but OS from the OS collective actually responded with questions and arguments, and we started a dialog. After a few permutations we came up with the current incarnation. In Logic 6 is was not possible to set up a different compensation for each instanciation, but in Logic 7 it is.

In my work I require absolute sample accuracy, and I much prefer to know precisely that my interfaces are compensated to this degree.
I recently sent off one of my MOTU HD192 to MOTU for repair, and the unit they returned back was a different hardware revision. It had a ONE sample difference in latency from my other HD 192. MOTU took a rather arrogant stance, telling me that I cannot hear one sample difference. Trust me, when you are parallel processing using outboard gear, one sample causes a serious phase problem.

Despite what the above poster said, there is NO means to adjust for insert latency in Logic. There is a recording delay parameter , but that has no effect on this problem.

Also, the latency changes with each Logic version and OSX revision. You need to re-test your system using the method outlined above each time you update any part of the software.

If you are using a firewire interface, you may find that it is impossible to accurately compensate for latency due to Apple's firewire driver issues.

ZMIX, thanks for that great plugin and for joining this thread.
I'd like to ask a few questions:
1) as I already asked, should there be a difference if Latency Fixer plugin is inserted before or after I/O Helper plugin in the chain? (I guess not...)

2) I am very familiar with the buggy aplle FW driver and whenever I need sample accuracy ( for paralell compression for example) I need to calibrate my system and set the recording delay offset in Logic preferences. My mLAN system from Yamaha can be calibrated-thanks god- in 2-3 minutes. All I need to do is send a signal from one track over firewire cable to my mixer and record it back to another track in Logic. The "signal" is a clip that begins exactly on a sample value (I gues 9600 samples). The clip that is recorded back to Logic is offseted in time so with recording delay offset I compensate for this issue of bad streaming in apple's FW driver. Now-when I calibrate my system this way, I guess that also Latency Fixer should working fine, don't you think so?
Ofcourse, as the offset is random , I need to calibrate everytime I start new session...

1) The latency fixer plugin works in exactly the same way as any plugin, it tells the system to read the audio file from the disk earlier by the amount requested by the plugin or plugins. The value calculated is the TOTAL of all plugin latencies. Order matters not.

2) The Latency Fixer plugin has nothing to do with Logic's recording delay compensation parameter. None.

The 'random' offset is specifically due to Apple's Firewire driver issues. I use a PCI based system and the recording delay is constant.

EXCEPT WHEN USING BUILT-IN AUDIO IN AN AGGREGATE DRIVER.

I cannot express how dissapointed I am that apple have dropped the ball on this. Who in the 'professional' audio community will put up with such an UNPREDICTABLE placement of newly recorded audio?

This forum software does NOT allow editing, so here is an addendum:

USING BUILT-IN AUDIO IN AN AGGREGATE DRIVER.

In this case the 'recording delay' compensation is worthless, and newly recorded audio is not positioned accurately. This means that there can be no rhythmic certainty. In simple terms, the groove is busted. The best musicians will sound out of the pocket, like amateurs. Thanks Apple!

I cannot express how dissapointed I am that apple have dropped the ball on this. Who in the 'professional' audio community will put up with such an UNPREDICTABLE placement of newly recorded audio?

It should be noted, however, that the issue is not with ALL Firewire audio devices, but rather only with those that rely upon Apple's FW audio driver. FW interfaces that rely upon proprietary drivers (e.g. MOTU, RME, and others) are not affected by the 'random latency' and CPU spike bugs.

That is true, Michael. However, the "family" of devices that rely on apple's FW driver is pretty big: Presonus, Focusrite, TC electronics, Yamaha, Apogee and others... Especially in case of Apogee Enssemble, which was massively promotioned by apple as a perfect Logic solution it seems to be a bad joke from apple 😟 And zmix is really right about sample accuracy and core audio-this issue makes Coe Audio a marketing ballast as well...
Zmix, thanks for the answers. Be sure you are not the only dissapointed one...
Some of "dissapointed ones" do not call apple apple any more.
Just iPod factory.
iPod doesn't have to know what sample accuracy is.

Thanks for that information, Michael.

However, it should be further noted that even a stable, reliable, professional driver like the MOTU PCI-424 becomes unpredictable when used in an aggregate driver with the built-in audio. Using an input from the PCI-424 while monitoring the built in audio introduces a random latency in the monitoring chain. This value is random and dynamic. It cannot be compensated by the recording delay parameter. I consider this to be a serious OS bug, and apparently it is impossible to contact apple with these professional concerns without paying an extortion fee called 'Apple Pro Care".

Can someone please relay these concerns to Apple?

These issues are the sort of things we saw in early computer music software, where 'fixes' were tacked onto existing code, eventually creating an unworkable mess known as 'spaghetti code'. The only solution is to re-write Logic from the ground up. The problem is, as you have pointed out, there are many other programs for the professional to choose which have worked out these basic issues. In my interactions with apple's support staff I have found that their response is to condescend by saying that nobody has ever mentioned these issues, implying that they are certainly not a priority, or even a small concern.

I was a bit furious when EQ, an international recording magazine, mentioned in the October 2006 issue that I use "Apple Logic Pro" without even asking me if I want to give endorsement to apple. Apple have been nonexistant in solving my very real concerns. Not a happy camper.