I just found this over on Tech-Talk
If you stick this driver in the 0.4x Karlsonator, it actually looks pretty good. Here is sim wihthout room walls nearby.

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They are the Vifa 4" coaxial and are available at Apexjr. It is about half way down the page. It looks like a great little driver but need a crossover. For 14 bucks a pop, it is worth a try.
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That looks like a nice driver - never seen a Vifa coax before. You can probably just use a simple cap for a super tweeter maybe for 10kHz and above.
i have played these little ones for some time. nice and smooth. good for desktop. can't expect much bass though. however in Karlsonator, they may sound betterThat looks like a nice driver - never seen a Vifa coax before. You can probably just use a simple cap for a super tweeter maybe for 10kHz and above.
Soundnovice,
About how high can the main cone reach without the tweeter? It looks very similar in size to the 3.5 in Vifa that I would imagine it gets pretty high.
About how high can the main cone reach without the tweeter? It looks very similar in size to the 3.5 in Vifa that I would imagine it gets pretty high.
Djn,
If you have a lot of various caps.resistors/inductors already lying around - but that is a full blown XO as far as I can tell - the parts cost will be at least 2x the cost of the drivers alone. I wonder what the freq response of the bare woofer is...
If you have a lot of various caps.resistors/inductors already lying around - but that is a full blown XO as far as I can tell - the parts cost will be at least 2x the cost of the drivers alone. I wonder what the freq response of the bare woofer is...
X, I did a look back for plans. Can't find them. You (and your clips) got me fired up so I went to the store for some board. They were out of stock - but I do have plenty of 1/4" plywood in the shed.![]()
Bob,
Have you started cutting wood (or foam) yet? Looking forward to seeing your build and listening impressions.
Effect of K-slot width
I just want to remind folks that there is a lot of room for experimenting with the K-slot and its impact on the sound quality/bass extension.
According to my model, if you use the default K-slot initial width (0.125 in) for the 0.4x Karlsonator with the Vifa you will get a response like this:
However, if you make the slot start as zero (a pinched off cusp), you get this:
Note the bass extension is deeper but the efficiency went down, but the discontinuity at 300 Hz is reduced.
What is nice about having a foam core front wing is that you can really play with this and go with what you like after hearing it. It is easy to change and easy to put back to however you like.
I just want to remind folks that there is a lot of room for experimenting with the K-slot and its impact on the sound quality/bass extension.
According to my model, if you use the default K-slot initial width (0.125 in) for the 0.4x Karlsonator with the Vifa you will get a response like this:

However, if you make the slot start as zero (a pinched off cusp), you get this:

Note the bass extension is deeper but the efficiency went down, but the discontinuity at 300 Hz is reduced.
What is nice about having a foam core front wing is that you can really play with this and go with what you like after hearing it. It is easy to change and easy to put back to however you like.
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Djn,
If you have a lot of various caps.resistors/inductors already lying around - but that is a full blown XO as far as I can tell - the parts cost will be at least 2x the cost of the drivers alone. I wonder what the freq response of the bare woofer is...
I've got boxes of old crossovers so there would not be a cost to me. THe only issue I have is time. Just not enough of it.
I just wanted to remind folks trying this build (0.4x) to put a layer of 0.75 in thick open cell foam (or wool felt if you have it) on the flat surfaces of the divider behind the driver and on the flat surface of the back wall that is exposed to the line of sight of the back of the driver and along the entire bottom panel of the box. This will really clean up some nasty cancellatipn dips around 1.5 kHz and 2.3 kHz. Finally, put a fairly dense packing of poly fill stuffing in the bottom of the enclosure surrounding the driver and into the stub above the driver. With this box being as small as it is, internal reflections making their way back to the driver cone can be a problem. I was able to do all this through the driver cutout.
Soundnovice,
About how high can the main cone reach without the tweeter? It looks very similar in size to the 3.5 in Vifa that I would imagine it gets pretty high.
the xover i guess is designed for around 4khz or more may be. i have played it full range and it played well the male vocals.
Bob,
Have you started cutting wood (or foam) yet? Looking forward to seeing your build and listening impressions.
It's been a vast conspiracy. Finally yesterday afternoon, I found some foam board at the dollar store farthest away from my house. I'm convinced they all got together to thwart my efforts.

Anyhoo - the two additional Vifa's were delivered Wednesday so I'm ready to go. Before I start I wanted to ask about a couple options. In the interest of time, what do you suggest is the top of several paths:
A. Single driver in foam.
B. Dual drivers in foam.
C. A or B in 1/4" plywood.
D. A or B in foam with plywood baffle and wings.
As I read I get the impression you feel the single driver build provides the most impressive results considering size and number of components. Do I have that right.
Hi Bob, if you have to tools and are comfortable working in wood, I'd go with the plywood but 1/4" may be hard to glue up without bracing. The single in foam seems right from my POV and will let you do a good evaluation of them. Then you can make cabs later.
How will you use these? I am building mine for my computer desk so the small size is important to me. I have subs to fill in the low end.
How do those drivers look and feel. Are they quality built?
How will you use these? I am building mine for my computer desk so the small size is important to me. I have subs to fill in the low end.
How do those drivers look and feel. Are they quality built?
.....How will you use these? I am building mine for my computer desk so the small size is important to me. I have subs to fill in the low end.
How do those drivers look and feel. Are they quality built?
I'm afraid It's going to be like taking just a sip of ocean saltwater - once you start you can't stop.🙄
As mentioned I have some very good full-sized speakers that I like a lot. However, they are not sensitive enough to be a good match for the lowish power Pass amps in the collection. Beyond just having fun with the "K" technology, I can see myself scaling all the way up to a 10 or 12 inch full flown wood version to meet that need. I don't have experience with a full range driver that can provide the upper end sparkle and transparency of two or three way designs, but the "K" technique appears promising.
My computers are all tied into an audio-video home studio and terminate at a set of DIY all Vifa 2-way BR boxes. There is an 8" sealed sub under the desk. So I don't have any specific need for more speakers, but X made me drink that first sip of saltwater and here I am.

The driver build quality is fully consistent with the first pair I bought - great metal basket and super clean construction.
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I know what you mean Bob. I have a pair of Paradigm MK 3 for computer speakers but the foam finally gave out and I am thinking I would rather build the .4 K-ator than refoam....which a hate doing. If you ever get down to Waterford, give me a call.
I just want to remind folks that there is a lot of room for experimenting with the K-slot and its impact on the sound quality/bass extension.
According to my model, if you use the default K-slot initial width (0.125 in) for the 0.4x Karlsonator with the Vifa you will get a response like this:
![]()
However, if you make the slot start as zero (a pinched off cusp), you get this:
![]()
Note the bass extension is deeper but the efficiency went down, but the discontinuity at 300 Hz is reduced.
What is nice about having a foam core front wing is that you can really play with this and go with what you like after hearing it. It is easy to change and easy to put back to however you like.
I like graph #2 best. If I didn't have subs, I may change my mind, but the reduced 300hz canyon is appealing to me.
Its great that you can model this stuff so quickly X. I sure appreciate it.
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