Have I got the wrong amp? or the wrong speakers?

What is the source? Maybe too much gain for the receiver.

Hello, 
I like the idea of the heavy copper speaker cables. 12awg should be enough. Before you do that check the output/ bias on the speaker connections.

I am amazed by the knowledge of this group.  I would imagine there are a few dealers who are part of this discussion.  Millercarbon you mention ditch the receiver because it is a receiver.  Why are receivers inferior to a 2 channel amplifier.  My dealer sold me my ARCAM AVR850 receiver because I wanted to use it for both TV and 2 channel listening.  Is my receiver good or bad and why?  At the time I would have liked to have gotten a 2 channel amplifier, but was not sure I could play it through my TV.  Right now I have left and right towers, a large center channel and 2 S2 SHO Rel subwoofers I have not yet added the two left and right rear surround speakers.  I looked at the Parasound Integrated.  Wish I had more clarity in the highs.

With 88dB efficiency, and an older Akai, I’m guessing you are clipping, or at least driving high distortion. Maybe a new Integrated Amp?

Take a look at Parasound’s options.

A good, smooth amp with those speakers would be nice. 
Also, take a look at a powered subwoofer like Rel T Series. Their T7i is $100 off for a while. 
A little dialing in (excellent docs and videos on their site, and lifetime support. 

Kudos to everyone's input. And to Larry's note, yeah. Doin' it since this stuff was made. And to the integrated amp: yes and no. There just as many bad integrateds as there are receivers. It depends on the brand, model and year it was made. I modify older pieces to do what they never did back in the day usually because there are now better parts and / or the designers back then weren't allowed the budget to do it right.

In any case one item that comes to mind here- try a BBE processor. Unlike an equallizer, it corrects time. It's a time correction equalizer that most any mid-end system can benefit. High end system don't need this as much because there are no (or few) time base problems to solve.
Most items in your system do not process all frequecies at the same rate of speed. Amps, cables,speakers, it all adds up. Even the room plays a part in this. Time arival equals clarity and usually flater smoother response.
I keep one on my own system (often in bypass) because audio recordings themselves have no standards in which they are recorded and often have time correction problems from the invironment and equipment where they were recorded.
Best of luck on the old gear. There's probably more to it than we know. Are the surrounds on the speakers dead? Are the pot on the amp cleaned, etc?