Vifa Coaxial Project Page

The Vifa coaxial drivers were originally used in several M & K home theater speaker systems. We have some very creative customers who have put these drivers to good use. This page is dedicated to showing off their designs. If you have a design you would like to share with our customers, please email it to us.

Hi Steve,

A little while ago I bought a pair of the Vifa coax drivers you have for a project and thougth I'd share it with you.

I wanted to make a boombox. I used a similar volume to your suggested one but left them sealed. I put the guts of a Sonic Impact T-amp in it and used your crossover (sometimes I just get lazy). I took some pictures of it and a friend dubbed it the "Boomboxa Rustica" so I left it unfinished. I have added a 1/8" stereo jack in the front so I can plug in a CD player, MP3 player or whatever catches my fancy. It sounds great and I take it everywhere.

Thanks!

Ray Wagner

I built these speakers for a friend of mine to be used as rear channel speakers. It is truly amazing how good they sound for such a small price. My Friend Ryan is really happy with them. They are used with Dennis Murphy designed CAOWI's in the front channels. The two design's pair up well. One note......I glued the drivers in with a paste glue since there are no screw holes. The glue holds well enough to keep the drivers secure, but I can still remove the drivers if I ever needed to. Steve Schenkel Webmaster

 

The "tubes":

I made a set of simple tubes, 37" long. The drivers are apparently only good for 80Hz (well Fs is 80 Hz AFAIK). Using the basic calculation for a non-taperd TL (if that is what they are). results in:

L=c/(4*f), c:=1133ft sec^(-1), L:=37" or 3.083 ft ----> f=c/(4*L), f=91.87HZ

into 1/2 space, there would be a boost of 6dB, using the "field" equation: dB (referenced to "0" dB):=20*log(2)

Because of the speaker playing into 1/2 space, it is capable of creating a frequency much lower. I suggest that it is capable of something like 1/2 of "f", so 45.94 Hz. This corresponds well to my listening observations. I have no means for measurements. Perhaps I was just lucky? The tube is lightly stuffed with Dacron and lined with some thin blue foam used to dampen the PVC pipe. Cross-overs are 2nd order Polk salvaged crossovers purchased over the internet. The values are similar to your provided schematic.

 

The TEAC "retros":
Basically I just pulled the original small driver out of the speakers from an old TEAC Reference 100 mini-system. I disconnected the existing tweeter, but left them in the enclosures. The stock cross over provides signal to the tweeter and mid-woofer (if you can call a 3-1/2" or 4" driver a "mid-woofer"). These easily better the stock speakers with more apparent bass. The boxes are only 4-1/2"X 6-3/4"X 7-1/2" and are ported. I did not change the box tuning. (1" diameter port, 2" long). The box is made of 1/2" "hardboard". These are very good for so little money. Great on the desktop, as home theatre surrounds or as a small speaker package to play music as originally intended (as long as not too loud). New enclosure could be built using better material. If I do I'll report the improvements (if any).