[rocketpop]

I just picked up a 2017 M2 about a week ago. I found a loose large gauge speaker wire in the trunk and a large power cable. I also found a rj11 connector by the center console. (Bass Knob‽)

Here is what I found in the truck after removing that side panel

What exactly do I have here?

[marcw]

is your friend

The previous owner used a 2 channel line out converter. The RJ11 cable is used for remote bass control. The other part appears to be a JL Audio XD300/1v2 mono sub amp to drive a subwoofer.

[rocketpop]

So do you think this disabled the factory subs?

Do you think I can just purchase new sub for the trunk?

[marcw]

Originally Posted by rocketpop

So do you think this disabled the factory subs?

Do you think I can just purchase new sub for the trunk?

It's hard to tell from the pics. If the previous owner left the oem amp alone then the under seat woofers would still play. I'd wager a guess that yes you could add a sub to the JL amp. I'd recommend getting either a MusicarNW or Visual Ice fiberglass enclosure. These fit behind the driver side rear wheel well so you don't lose any trunk space. These enclosures are designed to run a 10" sub. The one in this pic is the Visual Ice enclosure with a JL 10" sub.