The PA1+ has an 8ohm 6.5 watt amp. We have 70V horn speakers which is why we need the 70V external amp.
I figured out I could download the XML config file, edit it, and upload it. The volume is now at 15 which is the max. It’s made it louder, but it still seems less than my phone.
I have this setting at 15 which is the max audio.
https://preview.redd.it/q8vyt1m4vlwb1.png?width=491&format=png&auto=webp&s=2acedd46fdd6aac4a34807ecad856749473d0efe