PA Speaker Sound Quality

I have a JBL Professional IRX108 Powered Portable Speaker with Bluetooth. Last night for a block party I played music through the Bluetooth and it sounded great. I tried to run it through CH1 using a headphone jack. The headphone jack was connected to a USB DAC connected to a raspberry pi. The music sounded good, but the audio was quiet and kind if tinny.

Does anyone have any suggestions?