Audio recording glitches. Need help

actuel

Hi, I'm using an iPad Air 2 iOS 10 to record apps and hardware synth (through audio interface) on cubasis. When I switch between apps (audiobus remote or home button) there is some glitches. I cannot record anything properly. Do you have any solution to solve this problem please?

telecharge

Have you attempted to optimize your iPad for recording? If not, have a look at this thread...

https://forum.audiob.us/discussion/comment/205058/#Comment_205058

wim

A few suggestions:

• Make sure background audio is turned on in Cubasis audio settings
• Set latency to Medium
• Try changing "Large recording buffer"
• Make sure no other apps that you don't need are running. Mute any running tracks in Cubasis that you don't absolutely need while recording.
• Shut down all apps, then reboot your iPad at least once and / or clear ghost apps by holding down the power button until the slider comes up, then the home button until you get back to the home screen.
• Detail what audio interface you're using. Someone may recognize whether it's a known issue with that interface.
• Try narrowing down the problem by starting with Cubasis and just one of the apps you switch to. If it happens, then close that and try another to see if the same thing happens. Basically try to see if it's just one particular app that's causing the problem through process of elimination.

actuel

Thank you for the fast reply. I also have the same issues recording just an app (no hardware) + only one effect. It seem that I got more glitches with klevgrand's effect. I keep searching..

actuel

i followed previous advices (stop modification, refresh ram, airplane mode, etc) and tried different configuration (record on audioshare, IAA without audiobus) but still have these "pop" when i switch apps.

telecharge

@actuel said:
i followed previous advices (stop modification, refresh ram, airplane mode, etc) and tried different configuration (record on audioshare, IAA without audiobus) but still have these "pop" when i switch apps.

Have you tried reinstalling the Klevgrand effect or Audiobus? Does it happen with multiple apps?

actuel

It happen with almost any app. Even on a basic input>effect>output

telecharge

@actuel said:
It happen with almost any app. Even on a basic input>effect>output

But have you tried reinstalling anything? I remember @Sebastian stating the most problems are cleared up by uninstalling, rebooting, then reinstalling. Maybe he has some fresh ideas for you.

actuel

Well, i think it's a CPU issue but i have no idea why..

Only 1 track on cubasis with 1 IAA app (e.g. Borderlands granular) and 1 IAA effect (e.g. Klevgrand vandelay) and the CPU meter is already at 50%. When i switch from app to app i can see the CPU spiking and that's why i can hear glitches.

I tried every advices (reboot ipad, refresh ram, turned of notification, airplane mode, wifi, reinstall apps, etc...) but same issue.

wim

@actuel said:
Hi, I'm using an iPad Air 2 iOS 10 to record apps and hardware synth (through audio interface) on cubasis.

Does this happen with the hardware interface disconnected (specifically, with only headphones or with just the ipad speaker)?

actuel

I tried with and without interface. On interface headphone out OR Ipad headphone out.

telecharge

I just tested this and it looks like Vandelay does not play well with Cubasis 2. The CPU was jumping between 30% and 40% with just Vandelay on a MIDI track and nothing else going on. I tried several other FX apps and none of them performed this way.

EDIT: Wow, Vandelay hasn't been updated since 2014.

actuel

Thank you for the feedback.

It reach 100% CPU and glitch when i switch app only. with different apps and effect too.

telecharge

At this point, I'm thinking you should contact Apple support.

You could also test your iPad's performance and compare the results.

From http://www.anandtech.com/show/9605/the-ios-9-review/8:

"Since Apple’s default apps are so lightweight, it’s difficult to set up an actual CPU test for multitasking right now. During this test I had Photos in a 50/50 split with Safari, along with a video playing using picture-in-picture. Since nothing was going on in Safari the CPU usage was very low. Decoding video occurs on its own fixed function blocks as well, so there’s very little CPU usage there. If you decide to try and play Hi10P or HEVC files in another application then you might see CPU usage rise very high during video decoding, but that’s a very limited set of users.

I found that editing in the Photos app seemed to be the most intensive task that you can do with Apple’s default apps, and even it only uses 50-60% of a single core on A8X. Backboardd is also using an additional 24% of a core as it handles information coming from various device sensors and input. As far as Apple’s apps go, A8X is more than fast enough to handle running two applications at once.

Once you consider some more intensive third party apps things get a bit more stressful for the system. While I can’t test this with a split view due to the fact that no third party apps support it yet, you can see above that Adobe’s Photoshop Express application can use an entire CPU core and 65% of another simply by applying photos to filters and rendering the changes in real time. If you were to run two apps of this intensity you would still likely not saturate A8X’s CPU capabilities as you would need to be interacting with both apps at the same time, but it does highlight the possibility that if one application is doing any sort of intensive work on its own it could end up having a negative impact on the performance of the other active application. However, I think for 99% of use cases there’s nothing to worry about as far as CPU performance goes when multitasking on the iPad Air 2."

actuel

Thanks again for your help.

I have better results with some apps i try. I think Klevgrand effects are not well optimized yet. I will contact them.