PB posted a reply on RETROCENGO Youtube clip "We think that the bass cable and the right loudspeaker cable might be switched. The sound should be pretty good - especially with the fat bass speaker you have in the cabinet’s bottom And as an advanced tip: remove the backglass and find the bass boost knob below the screen, left of the speaker cables..."

David Thiel also commented "I finally watched the entire video. couple things.... looking at the cabinet speaker, that is a good looking driver and should be able to deliver good bass. Having talked with the Pinball Brothers I know that they have a commitment to audio so this is a big surprise. I suspect that it is an assembly problem with switched wires.... Hopefully soon , I will be able to hear a PB Alien in the Northwest so I can evaluate it. The PB audio system was designed to kick ass better than the original. If it is not, there is a problem."

Hopefully a simple fix and can't wait to check out one in person