P-Bass humbucker modification

First thing's first: That split pickup in your P-bass already is a humbucker. Are you looking at something more like a dual side-by-side coil pickup?

Are you thinking that you want to put another pickup between the split pickup and the neck, or are you saying that you want to replace the split coil pickup with something different?

Edit: Also, what amp, cab, and pedals (and any other equipment) are you using?

 

Why not go for a hotter pickup? The Duncan SPB-2 goes very deep.

 

Dimarzio DP145 Will Power.

 

Have you try .1uf cap yet ?

 

Try the DiMarzio Model P in lieu of what's there now. It'll be heavier, and a little too loud even.

I have a bass with a mudbucker smack up against the neck, it's honestly too much. Now, that's *not* what you're asking for in your words, but it's just too much.

 

Look up Billy Sheehan's bass "the Wife." Same philosophy.

 

An alternate way of getting lots of deep tone is to install an onboard preamp, and cranking up the bass knob. John East (BTB-01) and Aguilar (OBP1) both have thick, deep bass boosts.

 

Have you tried simply plucking right at the end of the neck? That’s where the thickest sound lives. Plus if you ever need a percussive sound you can (finger style) play ON the neck and smack the strings down on the frets with your fingers.

 

Cool.

Have you tried flats or half rounds? Gets rid of a lot of high overtones and focuses on the fundemental pitch.

 

Do you have an octave-down pedal? It seems to me that would be the simplest (and probably least expensive) way to get the "insane heavy and deep, dark sound" you're hearing in your head.

 

I really think (know) your idea will not deliver the results you are looking for. The only thing a bridge pickup will bring is a slightly more defined attack and some brightness to the sound. And that will be after shelling out $300 between the pickup and the installation.
First of all, make sure you have top notch amp to handle those low frequencies. That is the MOST important and it is where you need to start. After that, there is an after-market split-coil that works fantastic to handle low frequencies and that would be just a swap with your current pickup, it is the Delano Big Pole Split-Coil. But honestly I heard some stock standard PBasses that sounded fantastic once tuned in C. Just make sure you use something like a .115 or .120 E string set or you'll get a muddy sound.

 

Sounds great, but I seriously doubt that a new bridge is going to change your tone (despite what the marketers will tell you...).