Select your input device (built-in microphone, external microphone) as the default recording device in the sound settings:
Access the sound settings. Select your input device as the default the playback/recording devices:
- Check the input level and raise if necessary
- Select the default output also as the speakers / headphones you have (some audio devices can dual as both input and out, so this is just to avoid the conflict)
On a Mac:
Go to System preferences-> sound
Select the correct Input device, strum a few times and check the input level -> raise if necessary
Select the default output also as the speakers / headphones you have (some audio devices can dual as both input and out, so this is just to avoid the conflict)
Disable the echo cancellation / tweak the ambient noise reduction
Both Windows and Mac have their default means of filtering mic / recording device input, which can affect the way the signal is delivered to the game.
On Windows :
Right-click the speaker icon from the bottom right corner of the screen, and from the displayed context menu click Recording devices.
On the opened Sound box, make sure Recording tab is selected and from the displayed list of recording devices, double-click the icon of the microphone.
On the opened properties box, go to Enhancements tab and uncheck Noise Suppression and Acoustic Echo Cancellation checkboxes.
Press OK button to apply the changes.
Tweak the "Use ambient noise reduction" setting (if present) on the "Input" tab of the "Sound" Preference Panel in System Preferences.