I'm at a crossroad right now. I'm looking to purchase a pair of floor-standing speakers in the Polk Audio line. I'm considering either the RTi A5 or the RTi A7. Price is not so much a factor and other than the 7s having a slightly larger woofer, 7 inches compared to the 5s 6 1/2 inches, they are similar except that the 7 has a midrange frequency driver. What I need help in is deciding is it better to spend a little extra and get the speaker with the midrange or not? Is a midrange an important feature in a speaker or not? Please somebody help me out. Thanks.
You should really try to get a chance to listen to them.
In many respects a one-way speaker has advantages (imaging and phase coherence come to mind), but of course, it will struggle with the upper treble and/or the deeper bass..
Every addition of another crossover point invites problems which must be dealt with by the designer.
Dennis has proven very good at this, but part of his being good at it involves deciding not to use certain driver because they just won't work well with the other driver(s). It is a complex problem to address all of the concerns without letting one get out of sorts.
Generally, the main benefit of a three way is to relieve the mid-woofer in a 3-way speaker from having to produce such a wide frequency range by splitting it into a mid and a woofer.
As Lovinthehd pointed out, if you are using a sub, you are relieving your mid-woofer of most of the bass, so part of the benefit of the 3-way is already taken care of!
As a subjective anecdote, I compared the Energy RC-70 (3-way tower) against the Energy RC-10 (2-way bookshelf). The RC-70 could play louder and had more bass, but the RC-10 was clearer through the all-important mid-range!
A major factor is where the crossover needs to fall. If it falls in the mid-range (we evolved to have the most acute hearing in the mid-range), extreme care needs to be taken to avoid any audible artifacts from the crossover. If the crossover gets into lower frequencies - like 400Hz in the case of where M-L crosses their electrostatic panel to a standard (sub)woofer driver, a small glitch in the crossover is not as likely to be noticable.
If you are not using a sub and want real bass, there is good reason to covet a 3-way, but once you add a sub, the benefit a 3-way becomes less compelling and it all depends - on the quality of the design.
Try to A-B them side by side even if you need to buy both then return one...unless you can find someone who knows those specific speakers!
