Quoted from smokedog:
ull Throttle audio issues ..
Turned it on one day and all you could hear was bass, and it was super loud. Drowned out everything. I have the volume now at 1, and it's still pretty loud. I had to basically turn the bass completely off. It was way to 'bassy '.
Plus a high pitch tone. Barely audible, but really bothersome. It would probably be louder if I turned the volume past 1.
Alien Amplifier Settings http://www.heighwaypinball.com/wp-content/uploads/2017/12/AlienAmplifierSettings.pdf
As a first step try these settings.