Problems with freezing AU on iPad Pro

as written on
I have massive problems freezing AUs with Cubasis on my iPad Pro 9.7 with latest Cubasis and iOS 11.4

In the screenshot, I tried a regular freeze with both mood and Ravenscroft and after that, the same with the AU compatibility modus.

And as last resort, I tried to send MIDI to mood loaded as IAA on an audio track, which looked most strange.

Using those settings, it got better:

Sample rate 44.1 kHz
Bit resolution 16
“Hardware Latency” Low
“Large Recording Buffer” Off
“Real-time Mixdown Freeze” Off
“Audio Unit Mixdown Capability Mode” Off

Hi tja,

I’ve already replied to your current similar threads in the Audiobus forum.
Please find the copied message below.


Hi tja, Hi all,

After exchanging with our development please allow me to reflect on this topic.
Since tja has published the similar topic in a different thread, you will find this answer copied there as well.

In general, using third party instruments and/or effect plug-ins always bears the risk for issues, that are often unrelated to Cubasis - as already mentioned by other users here.
The same applies for other DAW’s, no matter if mobile or desktop. In this context, running into issues, also can lead to consequential errors, when the iPad/apps in use aren’t restarted, once a problem arose.

We’ve tried our best to state the limitations of Cubasis’supported third party standards in the following articles:

Limitations of Audio Unit

Limitations of Inter-App Audio

Limitations of Audiobus 3

In commenting your topics, Rodolfo sums it up quite well (Thanks Rodolfo!):
“There are two different problems, one is related to the volume level and eventual clippings (I insist it has nothing to do with Cubasis/Auria but the volume level of the sound source app), the other is related to the freezing feature in Cubasis introducing longer audio tracks as if they had been streched out. The latter has been discussed in this forum and other forums and Cubasis was fixed in some way to avoid the problem, but it seems there are still some issues pending. The problem is related to apps that make intensive use of the CPU during the freezing operation and the way Cubasis handles this feature.”
(1) Track freeze and audio file length
Depending on the third party app instrument/effect plug-in and its associated values, the use of track freeze can lead to long files in some cases, making sure to prevent audio file signal loss.

(2) Audio file clipping
So far, we are not aware of any audio related problems related to Cubasis, when using track freeze.
Therefore we expect issues such as distortion or similar to be related to either, the third party app in use, the chosen format (IAA, AU), consequential errors or other problems.
If the problem persists and is reproducible, please provide the individual instrument developer and us with the steps, to allow the evaluation.

(3) Track freeze settings and further options
In a nutshell, working with third party apps and Cubasis works best with regular 44.1 kHz projects and ultra low latency.

Furthermore, if track freeze fails with specific effects or instruments using the standard setting, Cubasis provides additional real-time rendering options located in the setup (Mixdown / Share section).
Please make sure to have a look at the relevant articles that explain the limitations of AU, IAA and AB3, that are linked above.

In our opinion, Apple’s Audio Unit format can be more or less seen as the successor of Inter-App Audio.
In general, IAA seems more unstable, compared to Audio Unit, which provides more options and has recently updated by Apple (CPU time out bugfix in iOS 11.3).

If you experience issues, please make sure to send reports to the individual instrument and/or effect plug-in developers. As we did in the past, of course we’re at hand and willing to exchange with them, if required.


@LSlowak Dear Lars,
at first: Cubasis is my one-stop for everything in regards to music and audio on the iPad!
I love that thing greatly.

The situation

But there was now quite some time, where Cubasis had some problem, esp. in regards to freezing tracks.
This got much better with the last update.

But as you can see, there are still very strange effects and problems in this regard.

Using the recommended settings did indeed help with this and i could finally render the audio.
But others may not be in the forum or do not ask, they will just run into those problems and come to the conclusion, that Cubasis is just too buggy.

So, it may be worth to fix those issues.

Of course, i understand that not always Cubasis was the sole cause, but then, i did not see such problems when trying Auria Pro!



So far, i did not yet read the links you provided, but i will do so!

And about what Rodolfo wrote, i used Ravenscroft and mood in this example, both of which are not CPU intensive.

About your additional recommendations: I am aware of the real time freeze and the compatibility mode, both of which were tested and did not solve the problem!

I cannot say, that AU is more stable for me than IAA.
And IAA has the possibility to be loaded into an audio track and feed MIDI from another track, which is great!


Terms used

One last thing, you “hardware latency” settings are not realy “hardware” settings, as it seems.
This may confuse people!
It would be better to just use the term “latency” as others also do.

And then, PLEASE, don´t write “Ultra Low”, “Low” and “Medium” - what shall that be? Are we forced to read this up somewhere?
In a setup, you normaly want to apply a certain latency, which is formulated as milliseconds, “ms”.
Please, allow us to choose or set milliseconds instead of that arcane terms that are just not concrete.



I will try the recommended settings from Littlewoodg with different Synths and Samplers.
I realy hope, that i can then render audio in a stable way.

One thought about those real time and compatibility settings:

When using Cubasis, i may very well render the most different things with a list of Synths or Samplers, just to try out variants and compare things.

But that means, i will not even noticed that there was a problem and that i should try one of those options! If the problem was not directly visibly apparent, i will only learn this, when it is already too late - as happened with the Piano Poll.

So, that Freeze should work stable.
Or is there any other way to render audio from an AU?

In both Auria and BeatMaker, there is just an “export” or “mixdown” button for any type of track.

Going to post this also to the Steinberg topic, and create a link within the Piano Poll topic.

Hi tja,

Thanks for your message.

As stated before, track freeze and mixdown should work fine straight out of the box for many instrument and/or effect plug-ins apps.
For those failing (e.g. due to not having update for some time, other issues) there is the real-time mixdown option.

If you run into track freeze/mixdown issues, please make sure to file a proper bug report to inform the instrument/effect plug-in vendor and us about the problem.