Most home theater systems consist of a subwoofer & a bunch of small satellite speakers. The trouble with these systems is that the small speakers are unable to produce bass so they rely on the subwoofer for this. They sound great & this is fine until you add surround sound to the mix.
The problem with most surround sound systems that use small satellite speakers is they employ subwoofers that produce sound well up into the directional frequencies. They need to have the subwoofer do this to compensate for the no bass small speakers. This results in a diminished 3D sound stage & a subwoofer you can locate blindfolded.
To avoid needing my subwoofer to play anything close to directional bass-midrange I wanted a speaker capable of producing its own bass. A mid sized ported speaker using two woofers was the answer. The Mid-Tweeter-Mid (MTM) design has become quite popular. With two woofers & a tweeter these speakers can produce excellent fullrange sound without having to work too hard when the bass starts pumping. So I did some research & came across the following design by a guy in the Netherlands.
by Tony Gee - The Netherlands
This cool looking DYI design had me hooked from the moment I saw it. I instantly fell in love with the cool angular faceplate. The ingenious double slotted port built around the tweeter enclosure was a big selling point also. She had the ported MTM layout that I wanted too.
There where a few problems however. Both the tweeter & two woofers were Seas models. VERY nice drivers but a little out of my price range. Also these high quality low impedance drivers when wired together result in a pretty serious load for an amplifier to handle. I would not be able to turn up the volume much using these. My amp just wouldn't take it. Also the design called for some fairly fancy electronics that went way over my head. Still I liked the design & wasn't willing to give up on it yet.
You can view Tony's design in detail here...
Continuing my research I came across this more amp friendly design by GR Research:
GR Research A/V-3
GR Research make a really nice 16 oHm woofer that when wired together in a pair produce a comfortable 8 ohm load. Something that my amp can handle.
Their A/V-3 speaker, although an attractive design, didn't compare to Tony Gee's Proteus as far as pure looks goes. At least that's my opinion. So I decided to see if I could make the A/V-3's drivers & electronics work with the nifty Proteus enclosure design.
The only complication with this approach is that the A/V-3's electronics are tuned for the A/V-3's enclosure design. The Proteus has its drivers spaced further apart & also has the two woofers sitting an inch or so ahead of the tweeter. Minor differences but they do effect the sound slightly. How slightly I was to find out later on.
You can check out the A/V-3 here...
Using my computer's 3D software & my audio programs I reworked the Proteus to work with the GR Research hardware. The ports were tuned to 47.18 Hz with an internal volume of 1.487 square feet. This was the predicted curve for the woofers.
The resulting enclosure was a nice manageable size. Neither huge & bulky nor small & wimpy looking.