I've been using Infinity RS 2.5s in my main system for over a year. One year may not seem all that long, but for me it's an eternity. Before the Infinities, B&W 801s, Martin Logan Aerius i, JBL SVA2100 (a real sleeper BTW), ADS L1530, Pioneer HPM-150, ESS AMT 1, Walsh 2 and many many, more cycled through my system, all within the course of two years. I know the Infinies aren't perfect, but they're damn good.
The Infinity 2.5s are so good in fact that I've decided to track down a pair of the ridiculously low WAF 4.5s or build some clones.Twice the fun! No WAF issues here, (just ex-WAF issues). To further that goal I have decided to sell my beloved 2.5s. I moved them out of my main system yesterday to prepare them for shipment, and did my best to suppress my tears. I happened to have a pair of RT25's on hand so I popped them on a pair of nice Mission stands and prepared for the worse.
I'm a bass junkie, so the lack of bottom end would not be an issue, after all, that's what subs are for, right? I even use subs with the Infinities. After playing with positioning and the sub/main interface with electronic crossover and eq adjustments I settled into my sweet spot.
I have one deal breaker for speakers; if they can't float a believable human voice (I use NPR) between the the two speakers, they are politely asked to leave. The B&W 801s (first gen w/textile tweeter) were astoundingly good at this test, besting even my beloved Infinities. The tiny Polks sounded good on NPR, REALLY good. There is no chestyness on male vocals, a malady almost small small ported speakers suffer from. Overall balance was fine, with no zippy highs or overly forward or snarling midrange. Very nice indeed. Were they better on the NPR test than the Infinities? Well, in some ways yes. The Infinities dipole setup can add some space on a voice that I suspect isn't really there, but the overall balance was similar.
It was time to play some music. Here's where it became evident Infinity wasn't trying to build a big LS35A. They just have an uncanny ability to sound real and alive. The Polks get snarly when pushed, but their main flaw is dynamic compression, especially in the mid bass. Even with an excellent sub and a THX rolloff, the Polks sound strained when pushed. I had to turn it down.
To sum up, the Infinities win this one, and it really wasn't close on music, but if you don't listen loud, and have a good sub, the RT25s are an excellent choice. I prefer them to other small speakers I have owned:JBL L1, Kef Coda7, Goodmans EE-10, RS Minimus 7, the slightly larger Polks with the big port in the front, Infinity SM60 and a few more I can't remember. The only better mini I've heard is my buddy's little Sonus Fabers. The silk dome tweeter is very smooth, as are the mids if you keep it under 95 dB or so. For $10 a pair I don't think you beat them.