Originally Posted by Powerlifter405

This post then should only be reflective of the Sony systems w/ DSP?
https://www.f150forum.com/f30/head-u...3/#post6474731

I just listened to Phiso Jotaro and Rick Ross Purple lambo and faded to rear and according to my iphone app i'm seeing fr as low as 42hz. Does that seem correct?

Originally Posted by ponchorage

So, is there any way at all to eliminate the 80hz high pass filter on the rear channels for a 2015+? I'm going to be adding a 4 channel amp soon to power the front and rear speakers and using speaker level input. I'm assuming that will pass the filter on to the amp in the signal for the rear speakers. I also already have a sub in the back, so maybe it's not a big deal that the filter is there? I really would like to be able to have the full signal for the rear speakers. I'm a novice, so please excuse if there is a simple way around this. I wasn't sure if I could just not use the speaker lines from the rear speakers from the head unit into the amp but then still have the signal go to the speakers themselves out of the amp. Thanks!

Originally Posted by jdunk54nl

Forscan can change it to flat for basic systems. Upgraded (Sony or b&o) need an interface device.

Originally Posted by ponchorage

But is that true with 2015+ or only 2014? That was unclear to me from this post.