200-300 cost is common, solid build, excellent value, can be updated

I have the SDA-2 with the 3 woofers and 2 tweeters per cabinet, there are other SDA-2 speakers that have 1 tweeter, and just 2 woofers. With my speakers, what is most impressive is the bass reproduction,they do indeed reproduce bass to specifications when set up correctly in the room. With the cable connected between the speakers in back, another dimension is created which elevates the sound experience, you have to hear it to appreciate it. I have had to rebuild the internal crossovers, because there are protection devices Polk incorporated that may now either not work at all or are adding distortion. If they don't work at all, you will loose sound from your drivers because the signal has to pass through them.Polk now advises removing them from the crossover boards. The SDA effect really only works well in the stereo mode, so if you are listening to FM stations in mono because of a poor signal you will not hear the SDA at its best, if at all. The drawbacks of this speaker is the large size, the heavy cabinets.You will need to have a large room for these to sound their best, and space between and in back of the cabinets. Some say the tweeters are not accurate, these can be updated with more accurate tweeters from Polk. Woofers have advanced through the years, with more modern materials and computer aided developments. But we are talking about a vintage speaker here, and as such it shouldn't have to compete with modern designs. The woofers designed for this series of speaker is special if you look at the specs,for a 6.5" speaker the frequency is low,finding a more accurate replacement is difficult.For me, a step up from these would be a Heil or ribbon speaker, or electrostatic design. But I wouldnt want to give up my bass extension or SDA effect. And I am not willing to part with a couple thousand dollars...or more.

Great older speaker, huge low end

Great older speaker
Sounds as good as many new models
When driven by a good amp
Will work fine without the interconnect cable
Great product from the past

Wow, the sound

Incredibly accurate speakers. They will distort if driven too hard but are extremely clear and crisp.