What is latency?
When you begin recording you may experience a delay between the time you perform and the time you hear the playback. This can occur when using MIDI to trigger a virtual sound on your computer/iOS device or when recording a live instrument, like guitar or vocals. This delay is referred to as Audio Latency and is quite common when recording in the digital world. What you are typically hearing is the time it take to process the audio from digital to analog or from analog to digital. Other times you may be experiencing an audio delay when the computing device is using many synth engines/virtual instruments or other CPU demanding plugins.
How to Control Latency
There are many ways to overcome audio latency depending on additional equipment being used in your signal path, but here are the most common tweaks to help you get the best performance when recording MIDI and audio.
Adjusting the playback buffer through the Recording Software
Many DAWs will have latency adjustments for playback in the Preferences > Audio section. You can always do a keyword search in the PDF of your software's manual for "latency" if you are not sure where the menu is.
- Larger audio buffer values - allow your computer look ahead when processing playback. Larger values will assist when a session has many tracks or if a session is heavy on plugins or processors. Using the highest playback buffer may be recommended when finalizing your mix, but it is typically not used when tracking because of the latency it creates.
- Smaller audio buffer values - allow your computer to process audio playback as quick as possible. Smaller values will assist when recording or performing live. Using the lowest playback buffer may be required while recording. Do not worry if you hear pops or clicks, as these are normal and will not record.
TIP: This will typically overcome latency caused by the digital to analog conversion made by audio interface or sound card connected to your monitors or headphones. Feel free to toggle back and forth from different buffer values as you work, but often you will find a happy medium for playback and recording.
Adjusting the playback buffer through the iOS App
Many iOS apps will also have audio latency adjustments that can be found through the app's preferences. This may be something as simple as a Hi/Lo switch, but you should see some reference to "Latency" or "Audio Buffer".
TIP: This will help overcome small amounts of latency caused by sending the digital signal from the iOS device to the other computing device(s). Although, you should not experience much latency when sending signal between computing devices using iConnectivity's Audio passThru technology, since it sends the audio digitally (Digital/Digital). This is one of the best features of Audio passThru.
Adjusting Audio passThru buffering through iConfig
Within iConfig, there are two adjustments that will affect the performance of Audio passThru's digital signal bussing. Through iConfig > Audio Info, adjust the following two settings:
- Number of Buffered Audio Frames - refers to how many USB frames of audio the interface will buffer between the two USB ports. Each frame is 1 millisecond of data. Lower values yield lower latency but at the risk of distorted sound (lost data). Higher values yield higher latency but less likelihood of distorted sound due to lost data. User should select the lowest value that works best for their system.
- Sync factor Value - used to calculate the frame rate for synchronization between the two USB ports. Lower values yield higher jitter, high values yield lower jitter. User should select the value that works best for their system.
TIP: This will help overcome latency when sending audio digitally between computing devices using iConnectivity's Audio passThru technology. Although, you should not experience much latency when sending digital signal between computing devices.
Other Latency Tips
- Try another USB port - Some USB ports may perform better than others, resulting in better USB buffering. Make sure your interface is connected to a USB port on the computer directly (without a USB hub).
- Turn on Airplane Mode on your iOS device - If you are using an iOS device that has a service provider, you can turn on Airplane Mode to ensure the device is not wasting resources searching for towers, running push notifications, etc.
- Bypass or remove CPU intensive plugins - Some plugins are more demanding than others, like reverbs and mastering multiband compressors. Bypassing a few may free up the resourced needed for your playback buffer.