I've read a lot of debates in these forums about the value of bi-amping and bi-wiring. Most of these debates have been from a theoretical perspective. I just wanted to offer my experience. Note that I am not attempting to settle this question nor am I encouraging everyone to believe me and do what I did. I just want to relate my isolated experience to provide a point of reference for those considering bi-amping.
My original setup was using inexpensive 16AWG copper wire ($25 per 100ft roll) with a single amp. The sound was good, I thought.
Using the same 16AWG wire, I bi-amped the front speakers. There was a very noticeable increase in the clarity and power of the base. The kind of difference that even a non-audiophile would notice. I'm not a bass enthusiast, but the improvement was very enjoyable.
I then bought moderately priced 10AWG copper wire ($70 per 100ft roll). Without bi-amping, the sound was somewhere between the other two setups, quality-wise. It was an improvement over the original setup, but not as dramatic as the bi-amped arrangement.
Upon the recommendation of several people in these forums, I removed the cheap gold-plated metal shorting bars which join the conductors on the bi-ampable speakers and replaced the shorting bar with a piece of the 10AWG wire. The sound now is incredible, without bi-amping. I feel like I'm getting the full value of my speakers/amp for the first time. The sound is a lot more accurate and crisp and the bass is strong and clean.
I ran out of 10AWG wire, so I'm not able to test the bi-amped configuration with the new wire. But I'm very very happy with the quality of sound I'm getting now without bi-amping.
I make no claim that this will work for everyone. But my strong recommendation would be to replace your cheap wire and replace the shorting bars before going the bi-amp route. You may find (as I have) that this cheaper alternative to bi-amping satisfies your ears quite well. If you've already spent more on wire than you would on a second amp, then you can ignore everything I've just said.
How did you accomplish the Bi-amp function? What amplifiers did you use for the high pass and low pass sections of the speaker? What crossover did you use? Did the crossover comply to the original specs of the speaker or did you alter the filter order or frequency location? Those facts would be far more influential than merely the choice of 16 AWG vs. 10 AWG cable.