speakers and cables

this looks also cool (but $ already too high

Okay, so that’s a low pass filter, which, if I’ve got this right and your sub is the same as mine, is the adjustable part that sets where the frequency that the sub reproduces will be cut off at..

"A low-pass filter (LPF) is a circuit that only passes signals below its cutoff frequency while attenuating all signals above it. It is the complement of a high-pass filter, which only passes signals above its cutoff frequency and attenuates all signals below it."

"I hooked them up was I went from the SUB SPEAKER OUT from both subwoofers"

You want to go to the sub INPUT not the output. Unless that was a misprint in your original post, using the output on the subs would blow a fuse.You would be directing the sub amps back into your stereo amplifier.

Grizzly, I am confused (but that doesn’t take much) picture 1.

I’ve never hooked my sub up via speaker wire, but I save all my manuals, so I just went to my M&K sub manual and looked at it, and it appears as if they are saying to hook up as you show in picture 2.

Left + & - out of amp goes into left + and - i "from sub" inputs in subwoofer.

Right + & - out of amp goes into right + & - "from sub" inputs in the sub.

At the sub, in my manual, it shows two sets of (one for L and the other for R) TO SPEAKER outs.

I am not understanding how you wired it in pic one.

I could scan the diagram in my manual and attach it to a reply if that would help?

But on edit: being computer illiterate, I don’t see how to include an attachment on this site?

@jtcf yes it was a typo, I went to the sub INPUT as shown on the pictures

@immatthewj I understand your description. It makes sense. What I did was duplicating the output (that I used to have for ONE sub). I should just treat the subs and the speakers, as left and right channels. 

I tried. Few bucks of fuses are not the end of the World. I will try your suggestion tomorrow.