Definitive Technology

For bookshelf speakers that have quite an impressive weight of bass output.

They are not Bipolar either, like alot of the other Deftech speakers are.

Small, compact, clean tight bass that a speaker that size should not be able to reproduce.

I like them. I think they image well, they do not require a subwoofer.

Definatly take a listen if you can find a retailer.
For the price, in my opinion, they are a pretty good deal.

Personally, i think these would make an excellent 2ndary system, like a nice bedroom system. They would also be superb for Home Theater usage.
They are good budget speakers too, the depths they can hit eliminates the need for a subwoofer. Perfect for a dorm system or such.

For a main system, if i wanted to use monitors, i would probably go with KEFs

If you do not mind buying an additional subwoofer, i think you could get speakers that might sound a little bit better.

Remember, with these speakers you are paying extra for the subwoofer and such. If you already have a subwoofer, then spend that money on some good monitors without built in subs, then more of your moneyw ill be going to the actual driver and enclosure.

Ive always liked DefTech stuff. I used to have some of thier 2004tls, holy crap, talk about soundstage. The Imaging is not as crisp as i like, but for HT i dont think DefTech's done right can be beat.

that is one thing that all Deftech powered speakers have, is one wicked soundstage for the price. Very commanding.

Yeah, actually I have tried both. I gave my parents a pair of PM500. OK. This was overkill for the stuff they listen to, but they are getting on, and they do enjoy listening to their music. After I set the PM500's up by the TV, we were watching the movie "Waking Ned Devine" (OK, OK, not really exciting HT stuff, but hey, my folks are in their 70's and it sure beat watching Lawrence Welk). The scene with the thunderstorm had my old lady was up looking out the window! I could not convince her that the thunderclap came from those little speakers! The soundstage was incredibly wide and transparent. Just a wonderful stereo image.

I don't have a lot of room in my little log house, so as much as I would love a set of powertowers, I just can't do it. So for myself I needed small speakers with a separate sub. The SM450's fit the bill. I bought the SM450's first. They have a built in bracket for hanging on the wall. Looks weird, but it sounds great- and I listen with my ears, not my eyes. My 6 year old who likes to play drums to CD's cranks them and you can feel the upstairs floor vibrate. These are really nice musical speakers. Lots of bass. But for deep bass, I added a Supercube 1 subwoofer later. I can't say enough about this setup- except that this year I upgraded the Supercube 1 to a Supercube Reference. Absolutely amazing. They blend seamlessly. Put on the Neville Brothers "Live From Planet Earth" and it is sheer heaven.
My answer- the PM500 and the SM450 are both great choices, especially for small to mid sized rooms (up to 300 square feet). When you close your eyes the PM500's sound like much, much larger speakers. It is totally unbelievable how much bass comes out of them. And they are well balanced, smooth and tonal. However, if you like it really loud, but still don't have a lot of room, use the SM450's. My impression is that you can drive the SM450's a lot louder than the PM500's, probably due to that nice 6 inch mid-bass driver in the SM450's. (The PM500's have a much smaller midrange - maybe 4") To go really deep, use the SM450's with a good clean amp and a killer subwoofer like the Supercube 1 or Reference. (You can always add or upgrade the subwoofer later- I used the SM450's for months without the sub and thought they were wonderful. )