Hi all. I had a friend of mine ask me to do a system for her. She wants to use my 2 Sundown Audio SD1-v.2 subwoofers and my Sundown Audio 100.2 to power them. Her car is a 2009 Ford Fusion, which leads me to my issue. It has Microsoft Sync, and she would like to retain the stock head unit if possible. I know the only way to do this it to use a LOC, but I've never used one, as I always upgrade the HU. I have read that if you use one the factory system will turn down the bass automatically to protect the other speakers, thus making the subwoofers not serve their full purpose.

Is this true? Would it be a waste to use a LOC? Am I best off convincing her to spend money on a new HU? If she does get a new HU, will the Sync still work?

Not sure on the subwoofers being turned down by the stock HU but my GF runs a LOC in her explorer so she could keep the 6 disc changer and theres no problems at all. Subs sound fine.

I thought the same thing, but it's what I've been reading. Does she have Sync? What kind of LOC is she using?

No sync, and the Scosche LOC.

bump for a new day!

Any general input on a LOC?

ALL stock HUs, no matter the make have some sort of attenuation build in as volume increases. It will cut the bass level. The only possible way to avoid this is if the unit had a factory subwoofer as most will not cut the level on this, but I have seen it done on cars from the 90s, so it may still be practice.

Try the LOC and if it's a problem, you know you'll need to go with another implementation device.

Does that car have separate amps or are they built into the h/u. The reason being is some stock units have a flat output to amplifiers where the attenuation occurs. *note I haven't seen this in a Ford yet, but haven't looked lately either