These ADS are different, but many modern 2 and 3 way speakers have two sets of binding posts with a bridge between them. Most of them retain the internal crossover network even when removing the bridge and using seperate inputs, which simply isolates the bass driver(s) and bass crossover network from the mid/tweet drivers and their network. In that case no external crossover is requried when using two amp channels per speaker. To bypass the internal x-overs on those you need to open up the speaker and rewire things.
Any speakers wired like that benefit from bi-amping primarily due to the increased power reserve of using two amps. One larger amp would pretty much do the same job. Bi-wiring mostly decreases wire resistance by using twice as much conductor. Either way the internal crossovers still do the frequency dividing work, regardless of whether they are connected together at the binding posts or not. They just do it together or independantly.
Less commonly, some speakers have a provision to bypass the internal crossover network completely on 2-way speakers, or bypass a portion of it on 3-ways like these ADS which retain the internal mid/tweet internal x-over even when the lower x-over is bypassed. I suppose there are some 3-ways with three sets of binding posts designed for external x-overs but that's rare. I think these ADS speakers have switch on the back that bypasses the lower crossover network, and with that switch thrown you'd need an external two way stereo x-over for the woofer/mid baton handoff.
Here's a question: Is there both a switch and also removable conductor bridges between the binding posts? or simply the switch? If there are both, you may be able to remove the conductor bridges but not throw the switch, allowing you to bi-amp with your existing amps to increase the available power, while retaining the internal crossovers. If there is only the switch that isn't an option. But check with the ADS forum experts and don't blow up your speakers by listening to me!
Confused yet? My current speakers are the more typical 3-ways featuring two sets of bridged binding posts which retain the internal crossovers when the bridge is removed. I do have the L/R pair biamped, mostly because I'm using fat 4 conductor welding machine power cable as speaker cable so I have the extra conductors there already, and I've set my multi-channel amp to internally switch to L/R bi-amp mode to double up the available amp modules when listening in two channel. If I only had one set of wires to each speaker, I could set the amp to bridge the availabe amp modules instead of bi-amping, and that would achieve basically the same thing power wise except the four modules would not be driving the woofers and the mid/tweets independantly. When switched to multichannel mode they become simply bi-wired as the extra amp modules are re-routed to other channels.
I also have a pair of ADS speakers, though not big ones. I have the L10 bookshelf speakers, which are great speakers in their own right; just not large scale speakers.
You ever find the tweeter you were looking for a few years back? I finally cleared out the trunk I had those parts stuff stored in but no sign of 'em.