This project came about as a going away gift for my best friend. He is not an audiophile by any means, he had a pair of budget monitor speakers that I recommended to him about 5 years ago sitting on the floor for the past 5 years... Sure I could have just gotten/built him some stands, but where is the fun/cool factor in that? My friend listens to a large varied collection of rock and electronic music, similar to me but even more varied. Absolute flat, "reference" quality response was anything but a consideration for this design. An overtly flawed Cerwin Vega style sound was also not going to happen, as I have to draw the line somewhere :). My goals were a true full range tower that sounds good with lesser quality recordings, but still has all of the audiophile qualities of a high end speaker. Size also needed to be kept in check, as my friend has always lived in apartments, and I cant just expect him to all of a sudden except monkey coffins in his living room. He only has a cheap HT receiver, so a true 8 ohm design was needed. Oh yeah, this had to be done on a fairly tight budget to keep my wife off my back.
Crossovers come out to $60ea using NPE's for any value over 20uf, bringing the parts total to $300.
The bass requirements immediately got me looking at subwoofers, which lead me to the Infinity for small box, deep bass potential at an acceptable price, with an 8 ohm option. I had a very short period of time to finish this design before my friend leaves, so testing out all of the drivers first wasnt in the cards.The breakup on the Infinity is actually very well dampened, and other then having slightly high HD due to a basic motor design, it is perfectly capable of handling woofer duty. Not knowing that before hand, I wanted a mid that was capable of crossing as low as needed if the Infinity fell flat above 80hz. My senses told me there wasnt going to be a cheap tweeter that will work well with this peerless woofer, and that assumption was true. The breakup on the peerless shows through as a high level of 3rd HD between 1-2khz, the driver also has a honking sound if played to high. I have wanted to try a "cone" tweeter (full range driver) for a while now, and the potential of the Vifa TC drivers for extremely low prices was irresistible for this project. The TC7 is every bit as good as Zaph's data indicates, extremely clean and extended. Since this gave me wide driver overlap potential, I figured I might as well go for LR2 slopes, which is how I came to the baffle arrangement..
(1/48 octave, 1 meter) Reverse null showing excellent wide LR2 phase tracking, at least for the TM portion. The woofer/mid section is properly summed, but you can see how much the room gets in the way with a low crossover. The driver measurements used for the design work were properly summed/spliced. This is not a reflection of system sensitivity, which is closer to 83db 2.83v. The rise in the TC7's response to 10khz gave the design a sort of BBC dip on axis.
This speaker really does like some juice on it, it handles power with ease thanks to the highly capable drivers. I designed it to run on a cheap receiver, it will beg you to keep turning it up. I am really pleased with the final result of this design. In a small room the bass capability, and lack of excessive high frequency content give an immensely pleasing sound.
This is the woofer box layout, with 1" square dowels, and a 3" long sweep elbow fitting.
The chamfers were cut on my table saw at a 45 degree angle