FabFilter User Forum

iOS Pro-L2 Latency..

Hi FF,

I get latency with various (not all) projects in AUM.

One project it causes latency on the master channel I created.

Another project (still on the Master) it creates latency when using the mic. So I have to left swipe the L2 node (off) whilst using the mic.

Because it’s not all project it’s not something I’ve tried to debug ‘as yet’.

Have you had any other reports of this? If yes, it will save me some writing..




P.S. Apart from the Pro-Q3 not responding after a project reload (which has now been fixed! - cheers! for that) so far, this is the only other ‘noticeable’ issues (i) have come across with the suite.



This is happening with Pro-L2’s default state.

And the latency is a fraction of a second - just enough to know it’s there.






I think I'll start using your email addy from now on, this place is a bit too open, for no reply..




Hi King,

Well, Pro-L 2 introduced latency; it does not offer a zero-latency mode. It needs the lookahead to perform proper, transparent limiting.

Of course, our plug-ins correctly report latency to the host, also on iOS, which can be compensated by the DAW in mixing situations.

When placing Pro-L 2 on the master bus, the latency will of course introduce a short but inevitable delay.

Floris (FabFilter)

Hey Floris,


Not sure why, but it seems it’s mainly when an IAA app is used. (Please test!) in (AUM)

So everything else AUv3 is in sync within the host (synths, drums etc) but the IAA is out ‘only’ when L2 is initiated. (But like I said, some project is ok)..

This issue is also includes when using a headphone mic (out of sync only with L2).

Haven’t found this issue with any other plugin FF or other.

Hope this info helps!
If not, what would be the solution? As it can’t be used as is.
Also I can provide a project if needs be..



I may try n do some debugging this week..



Ok guys,

Think I may be getting somewhere.

I just tested it with my mic.

In ‘STYLE’ if I use Aggressive, Modern, Bus or Safe, then the latency is introduced.
‘Transparent’ to ‘Allround’ is fine! = (Styles 1-4)

The main issue is the ‘Default Setting’ for the plugin is - ‘Modern’.

Please look at this!



P.S have not checked my other projects yet, but hopefully it is the reason for all affected. Maybe the projects not affected, were ones where I had changed the Style..


That seems to me to be expected behavior. The styles introduced in L2 (vs Pro-L, 5-8) have slightly more latency then the older ones (1-4). So that’s what you’re hearing. But they all have latency. Like Floris said, this is by design and inevitable byproduct of look ahead limiting.
And since you’re using it on the master it doesn’t even matter if the host is compensating correctly.



Not sure about “expected behaviour” but..

.. now that I have sussed out the issue, and a workaround (if necessary) I’m golden.

When it’s not working :(
Now that it is working :)

I can just create and save a different Default.

But as I will ‘99% of the time’, only use it on the Master, it is simple to change/select a different Style.

It’s all good!



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