Need help with DIY speaker project

My first time posting here. Looking for some advice before I begin another project. I need new speakers to be used for diverse rock & roll music listening. They’re going into a 12’ x 22’ family room. My goal is to get the highest quality sound reproduction possible with just two constraints: #1) a budget of max $500 for drivers and crossover (cabinet materials and other supplies would be extra and are not included in the $500.) and #2) wife does not want “big bulky” floor standing speakers but likes the “narrower” MTM floor standing tower speakers. So given this background, I’m leaning toward building two MTM (6.5”, 1”, 6.5”) tower speakers, each with an amplified 12” side woofer built in. Q1: Do you think getting the bass through a built-in side woofer will provide a better listening-quality than having a separate sub-woofer? The sub-woofer would end up being located at least 6 feet away from the towers?

I also have a second question. Today I listened to a bipolar Definitive BP2002TL (retail $999 ea) for the first time and actually liked it slightly better than comparably priced ($999 to $1399) Boston Accoustics, Snell and Klipsch, which were the other brands that this particular dealer had on the floor. My mind tells me that the bipolar sound effects should actually detract from the sound quality, but my ears liked it. Q2: What is the general feeling towards this bipolar concept? Is it a good thing or a bad thing? Can the bipolar sound effect be reproduced by other means e.g. electronically or by simply adding additional speakers? Do you know of any successful DIY projects that incorporated this bipolar concept into their design?

Thanks for the help
If you really want a lot of bass power, a powered subwoofer is generally a good thing if you use a reciever (rather than a reciever/preamp and an EQ and separate amplifiers). I drive my speakers using a Sherwood reciever, and I notice that the output from the reciever doesn't have that much bass, it's only the sub output that really carries the bass. So if you have a reciever like I do, then make a pair of ported towers with a pair of the Axon 6.5" midbasses at Parts Express (part number 297-500) and a Dayton 1 1/8" silk-dome tweeter (part number 275-070, nice tweeter in my opinion)

Even hard rock and roll music can benefit from well-made speakers. The Axons only need 1.38 cu. feet, so a pair of MTM bookshelves on stands seems to be the best option. You will enjoy the detailed sound provided by the lightweight diaphragm of the Dayton tweeter. The Axons will provide nice bass down to 55 Hz (thanks to their relatively long cone excursion) and they have an impedance of 4 ohms, so that when wired in series, they will present your amplifier with an 8-ohm impedance to match the tweeter.

Get a velodyne subwoofer. You will not expect much from those unassuming little cubes until you play some music with hard-hitting, low bass. Since Velodynes use servo feedback loops, they have unparalleled cone control, and they do go LOW. The servo loop makes sure the cone is exactly where it needs to be when it needs to be there. Available at your local Circuit City or
I have to admit, velodynes sound nice for my father owns one. But I'd say to go with an amplified 12" woofer in each speaker. First of all you get stereo bass, which I find sounds much nicer. Although the parts for the active crossover for the woofer as well as an amplifier (DIY or pre-made) would rise the total cost.

What should work pretty well for you is to make a 3-way speaker with the 12" woofer passive crostover power by the same amp as your midranges and tweeters. That is, if you don't want to spend the extra cash for the active route.
Well given a $500 budget I would look at a Vifa or Vifa/Peerless combo. Using 10" woofers and 6" midbass drivers.

4 Vifa 6" woofers = $150
2 Vifa D27TG45 tweeters = $50
2 Peerless 831727 or Vifa M26 woofers = $ 150
2 Crossovers = $100

The 10" works well in a 1.8 cu. ft sealed box
The MTM would require a 1.2 cu. ft. sealed box (or more preably 2 0.6 cu. ft sealed boxes).

Assuming the internal dimension are: (W x H x D)
6" x 18" x 20" = 1.2 cu. ft.
6" x 24" x 22" = 1.8 cu. ft.

You have the boxes that can sit on top of each other.
There are other combinations that I can think of too but this is the simplest.

Another combination could use Audax 6" drivers instead of Vifa or if you can spend more Vifa PL series drivers. If you can have a bigger sub box (2.5-3 cu. ft) then a variety of 12" drivers (Shiva, Audio Concpets, etc... are available.)

Obviously any extra options, like biamping (needs an active crossover and a spare amp) will cost more.

Hope this helps

Another idea that brings you in under $500 is the Kit 281 from Adire Audio. For your budget, you could get the kit for a pair of speakers and one Shiva driver (also from Adire) to use as a sub. A single sub would probably meet your needs for bass, but you would need an external amp for it. I'm currently using an old stereo receiver for my sub amp.

Many people have built the 281's (I am not one of them, however) and use them for both music and home theater. The nice part about the kit is that it comes with all of the crossover parts. Often the hardest part of building your own from scratch is designing a good crossover - an impossible task without good software to start with, expensive measuring equipment, and LOTS of spare parts to swap in and out until its fully tweaked to your liking.

Of course, looking at the date of your original post, you probably already have a new set of speakers by now...