If Smaart cannot communicate with an audio device or the device driver, you may see an error (pictured below) when you try to start a measurement or configure the SPL meter.
Causes and Solutions
If you're on Windows, open the Sound Control panel (mmsys.cpl) and make sure "Enable Audio Enhancements" is disabled. Check out this support article for more information on how to do this.
Device driver is not installed. Please check the device manufacturer's website and install the latest driver for each audio device being used. Keep Smaart closed during driver installation.
Device driver is corrupt or has crashed. Try reinstalling the device driver or update to the latest driver from the device manufacturer's website.
The selected measurement is trying to access a device that is physically disconnected from the computer. Please check the measurement's configuration and ensure that you have the correct device selected. Also confirm that the device is actually connected to the computer. Most audio devices do not come with a wireless failover ;-)
Sampling rate mismatch (rare). Smaart tries to match the sampling rate of the connected audio device. Rarely there will be a mismatch and you'll need to change either Smaart or the audio interface.
If all else fails, go to Options -> Audio Device Options and click the name of the device that is having problems. Now click the "Remove" button. Do the same for Input and Output devices. Finally restart Smaart (with the device connected) and try starting the measurement again.