iOS Audio Optimization Guide

When streaming audio through an interface connected to your iOS device, there are many factors that can cause performance problems such as:

  • audio artifacts such as pops or clicks, stutters, or dropouts as you play or record
  • bit crushed robot-like audio sound
  • excess latency
  • distortion in previously recorded audio
  • distortion in recorded files that was not heard on hardware input monitoring
  • performance issues, or other strange behavior
  • device disconnects 

In iOS it can be more difficult to troubleshoot these issues compared to a full macOS or Windows computer, because there are fewer places to make adjustments.  However there are some general procedures you can follow to keep a clean iOS device and reduce the potential for performance issues.

Before each recording session:

  1. Start with a freshly restarted iOS device

  2. Turn off WiFi and BlueTooth

  3. Make sure no other Apps are open except your recording App

  4. Increase Buffer Size:  If you are using an App like Auria which has a Buffer Size selection try turning it up to increase performance.  On other Apps like Garageband for iOS Buffer Size is chosen automatically, there is no way for the user to adjust it, so you will have to close the App and take more steps to improve overall system performance so that Garageband can choose a lower Buffer Size the next time you use it.

If you are having continued glitchy audio or performance issues:

  1. Delete as many Apps as you can!  Many Apps that seem harmless can be a strain on the OS, even if they are not open.  It is very common users will download more and more Apps as times goes on, but never delete them.  Going through your iOS devices to remove as many excess Apps as you can will dramatically increase performance.  Look out for Apps like games, or anything from a less well known developer.  Unfortunately many Apps that seem harmless like a random cute game could be "PuPs" or Potentially Unwanted Programs that are actually running in the background, gathering data, using up CPU performance you need, or even a true virus.  Even Apps distributed through the App Store CAN be malicious, or if not malicious still be using up the CPU power you need to record!
    More about PuPs in the iOS environment can be found here:

  2. Make sure your iOS and Apps are Updated.  If there have been any iOS updates be sure to check the individual App is still compatible with your new iOS version.  Sometimes App Developers will not update their Apps anymore and thus there can be bugs in a new iOS version.  Test a different recording App to see if the issue is specific to only one App or the entire system.

  3. Make more space.  Offload as many photos, videos, and old recordings to your computer as you can, to free up space for new recordings and optimal OS function.
  4. Do a Factory Restore.  Over time of using your iOS device files are always moving and changing in the background of the system.  So even if it doesn't feel like you made any specific changes there can be corrupt system files, or left over system changes previously installed Apps have made, which decrease performance.  You may have tried doing a "Backup and Restore" but usually this does not work, as it creates an image of the entire system, then restores to exactly the same state.  This can recover the same software problems again, because it is not a clean install.  It is just a duplicate of the previous state.
    Before doing a full Factory Restore to default be sure to back up your data on the iOS device in more accessible ways than with the backup button in iTunes or iCloud.  These create a single encrypted Backup file, which can only be used by restoring it on to an iOS device.  Thus the files are inaccessible without also recovering any problematic system files.  You will want to import photo/video/audio files to your computer directly, as individual files.  Same with any sessions in your Audio recorders, or other personal data you need.  Make sure you have everything backed up in another device, where you can access it as a individual file, not all locked in a single "iPhone Backup" file which you cannot access without restoring it to an iOS device.
    How to Factory Restore to Default:

  5. Test another iOS device.  If you are still having trouble with glitches after a Factory Restore it could be the actual Audio Hardware is faulty, or the iOS device itself is faulty, or just too old and low on CPU power and RAM for the Apps you are trying to run, and real time audio recording.  Testing a totally different iOS device will help you narrow this down.

    If another iOS devices works fine you know that the problem iOS device may be too low on specs for what you are doing, or faulty.  Check the minimum requirements of your App versus your model and specs of iOS device.  If needed contact Apple to have the iOS device checked out for hardware issues.

    If another iOS device has the same issues please Contact Apogee Support so we can help further!