Left/Right Channels

The left and right speakers are electrically identical, so no damage.  Even if you mixed the speaker type you'd be OK, they are close enough. :)

The worst that can happen is a left to right inversion of instruments in the sound field.

Now, if you invert the Red/Black (i.e. plus and minus) connections on only one speaker you'll suffer a variety of acoustical effects, but again, no damage.

Thanks Erik, just what I was hoping to hear. Didn’t realise I had them plugged the wrong way.  The red and black were connected properly.  
After I switched them up, I find the quality of bass has slightly improved and vocals are bit forward and centered. I could be imagining but that’s what I experienced. 

anyway, I’m glad that I didn’t end up damaging my gear. 

Only classical nutcases suffer conniptions over reversing the channels, because orchestras and chamber ensembles always sit a certain way onstage. Of course, it might twist your brain a little if you have a balance control. This is because when you move the slider/knob to the right everything will go left, and moving it left will send things right.

One time by accident I reversed the channels on the cartridge pins, phono stage, amp, and speakers. Everything sounded just fine, except the sound stage had moved three feet further back, behind me, and upside down.

My balls got twisted once. My pitch went three octaves higher!

Lol

LoL

LOL miller & iso. 

Lol millercarbon and isochronism 

If you are a percussionist in an orchestra, you are used to hearing the channels reversed.