Problem connecting MiniDSP to PA

My MiniDSP 2x4 has just arrived and iv downloaded the 2/4 advanced software and done all the necessary set up.

i have my source (laptop) connected to the DSP via a 3.5mm to RCA cable into inputs 1 & 2,
The DSP is then connected by RCA to 3.5mm from channels 1 & 2 too the 3.5 input of my 2 channel digital amp (i use this amp constantly and would normally connect it by 3.5mm cable to my laptop and it works fine) The amp is connected to a passive PA speaker which obviously has an inbuilt cross over.

i have done all this, changed absolutely nothing in the DSP settings but when i connect it all up and hit play all the signal is being sent to the woofer of the PA and nothing to the tweeter so it obviously sounds worse than rubbish and i cant figure out whats wrong.

The speaker runs off one channel of the amp correct, same as i always have when using it before and it works perfectly, i bought the DSP because i am building a sub (not done yet) and i wanted to apply a high pass filter to the PA at 120Hz and send the rest to the sub.

since i am only running the one speaker not left and right am i doing the right thing by having the 3.5 connected to both inputs or should i just be running a 3.5 to single RCA on one output and same out the other side?

Swap the red and white RCA connectors on the MiniDSP end.

I tried swapping the cables around on both the in and the out and it didn't make a difference so I'm not sure that's it unfortunately

Swapping the inputs round won't make a difference assuming you have a valid signal coming into both L+R of the MiniDSP.

Time to go back to basics. Something must be wrong in the MiniDSP settings. Set up output one with zero processing, no filters, 0db gain. Then connect just output one to one of your amplifier channels, and the output of the amplifier channel to a cabinet.

If you can't get a full range signal out of the cab something is wrong with the MiniDSP settings, or the caninet crossover. You can eliminate the cab crossover by plugging your source direct to the amplifier channel. If that works your issue has to be with the MiniDSP settings.

Yeah, assuming both L+R signals are going into the MiniDSP ok you only really need to plug in on each end. To cover all bases if you like plug the output lead into both output one and output 2 of the MiniDSP, and set up both outputs to have no filtering and 0dB gain. Then at least whatever channel of the amplifier you plug the speaker into it should be seeing a signal.

Tbh it shouldn't be that hard to get working, there must be something fairly basic wrong. I have never used the software myself but  I'd also be very carefully re-reading the manual just in case something got missed.