Unless your budget is infinite, there will be compromises. So the question becomes, what are you willing to give up ?
A single driver can deliver deep bass, lifelike midrange, extended treble, but not at the same time. It is physically impossible to create a single driver that can deliver 90db of distortion free 30hz bass, AND deliver 90db of non directional, undistorted 15khz treble at the same time. So what are your preferences ?
The majority of musical content lies in the upper bass to low treble region....about 100hz to about 5khz. That range should be achievable using a single driver system. One can add loading to extend bass response another 25-30hz, and an outboard tweeter for anything above 5khz. This would technically become a 2 way system, but the vast majority of sound, including the human voice and almost the full range of a piano, will come from a single driver.
The famed Western Electric / Altec 755a excels in this application, and many say that modern drivers still do not come close. Caveats are the fragility of the driver....15w is too much power. That said, the driver is very efficient and can deliver room filling sound powered by a SET amp.
Single driver systems sound different than mulit driver systems. There is merit in point source reproduction. (This is one of the reasons why people like small monitors also). Some have gravitated to coaxial drivers as a way to get past inherent limitations. Vintage Altec, Jensen, Tannoy drivers are valuable and held in great esteem because of the clarity of their sound. But to get the best sound one has to invest in a precise outboard crossover, careful amplifier selection, and construction of a cabinet well matched to the characteristics of the speaker.
Be prepared to experiment, and think seriously about what you want to accomplish.
