Audio quality (bass notes) not good enough?

[itsAlex]

After comparing my setup in my 2016 FR-S vs. my setup in my other vehicle, I came to the conclusion that either the audio coming from the stock Pioneer head unit just isn't good enough, or my line out converter isn't good enough.

In my other vehicle I had an aftermarket Pioneer FH-X700BT that had dedicated RCA outputs for an amplifier. I found that the audio signal coming from the RCA outputs to my amp sounded "cleaner" due to the fact that you could set the head unit to output only low frequencies through the RCA outputs. The FR-S head unit doesn't have such functionality so I am currently using a PAC LP7-2 line out converter.

Even after adjusting the various filters on my amp, the output just doesn't sound as clean. It's not distorted or clipping, it just that the bass notes don't sound as "pure" and I feel that it's cause of a lack of digital filters/equalizing.

Does anyone have solutions other than replacing the stock head unit? Do I have a crappy LOC?

[TOLM]

I have a 2017 brz with stock navi. Using a high level signal to feed to my subwoofer. No complaints about the lack of low end range. My amp has hi livel inputs, not using a separate loc