Anyone tried adding a stock subwoofer to a car that didn’t originally have one?

I have a 2010 Ford Focus S that didn’t come with the “SE” stock subwoofer. I actually have the OEM sub now, but I’m not sure if it’s plug-and-play or if I need to do some serious work to install it. Has anyone done this before?

Why not just go for a good aftermarket sub instead of sticking to the OEM one? The price difference might not even be that big.

Oli said:
Why not just go for a good aftermarket sub instead of sticking to the OEM one? The price difference might not even be that big.

I’m trying to keep the car as close to factory as possible. I’d consider swapping the head unit, but I’m not a fan of touch screens. They just look out of place for me.

Wait, the SE had a subwoofer? Where did they put it?

Vale said:
Wait, the SE had a subwoofer? Where did they put it?

Yeah, I think on the 2009 models in the US, it was optional on the SE, and it’s mounted on the left side of the trunk.

Vale said:
Wait, the SE had a subwoofer? Where did they put it?

Actually, the SE didn’t come with a sub.

Justice said:

Vale said:
Wait, the SE had a subwoofer? Where did they put it?

Actually, the SE didn’t come with a sub.

I’m not exactly sure which model had the OEM sub, to be honest.

@Micah
It was the RS and ST models that had the sub options. They usually installed it in the hatch area.

Justice said:
@Micah
It was the RS and ST models that had the sub options. They usually installed it in the hatch area.

I have the S model, and there’s a speaker in the middle of the dashboard.

@Ray
Are you saying there’s a sub in the dash?

Micah said:
@Ray
Are you saying there’s a sub in the dash?

Nah, it’s just a center speaker for filling sound. It’s part of the 6-speaker Sony system on the 2013 Focus S, not a sub.

Ray said:

Micah said:
@Ray
Are you saying there’s a sub in the dash?

Nah, it’s just a center speaker for filling sound. It’s part of the 6-speaker Sony system on the 2013 Focus S, not a sub.

Yeah, that’s just a center speaker, not a subwoofer.

Justice said:
@Micah
It was the RS and ST models that had the sub options. They usually installed it in the hatch area.

You’re probably thinking of the newer models. OP has the American 2008-2011 model, which only came in S, SE, SES, and SEL trims. Premium audio back then was usually part of the ‘Moon N’ Tune’ package with a moonroof.

Justice said:

Vale said:
Wait, the SE had a subwoofer? Where did they put it?

Actually, the SE didn’t come with a sub.

Ah, that clears it up. Thanks for the info!

@Vale
Does anyone have an idea of what’s involved in installing this?

Vale said:
Wait, the SE had a subwoofer? Where did they put it?

I’m not sure if it’s the SE or which exact model, but I know it’s mounted in the trunk for the 2008-2011 Focus.

Adding a stock sub setup is complicated and expensive. Here’s the best way to figure it out: check the manufacturer’s website for parts or go to a dealer. You’ll need to match your car’s audio part numbers with those from a model with the factory sub. This could mean needing the factory radio, harness, amp, amp harness, and any speakers with special plugs. That alone could run you hundreds, maybe even close to a thousand bucks.

Or, you could go the simpler route: get a small aftermarket amp, an amp kit, speaker wire, and a small subwoofer. Even a powered sub might work, and this would cost you around $250. Plus, the sound quality will likely be way better than the stock sub.

I added a factory-style sub box to my Focus MK3, and it was awful. Ended up using an adapter ring and swapping the sub, but still wasn’t great. Built my own box and put in an old sub from 20 years ago, and it sounds way better now.