Ever since I first designed and built the V-Trac horn, I have had customers ask about using their stock K55 drivers on them so they could do the upgrades in steps, and stretch out the cost.  Until now, I didn't have a way to do that.

Now, not only can you use these adapters to save money when you first upgrade your horns, but the sound quality of the K55 drivers with these adapters is so good, you may not ever buy the expensive 2" drivers!  Well ok, that might be stretching it a bit, but read on.

After many hours of work designing these adapters, building prototype throat adapters and listening to them, I came up with two different designs that work extremely well with the full line of 2"-throat Volti Audio horns.

The V-120 is the one I would recommend for most customers.

It offers a very good balance between a warm sounding midrange and a sharp/clear sound.   I voiced it specifically to be like the BMS 4592ND driver in it's tonal characteristics

$99 per pair

The V-121 is a larger version that is voiced deeper and softer sounding, with a dull high end (2500Hz to 6000Hz).  Please note: The V-121 will not fit inside a stock Klipsch Cornwall cabinet, please use the V-120.

This adapter blew me away when I first listened to it.  I thought it sounded better than the BMS drivers!   I was initially being fooled by the soft, warm sound, but after listening for a few minutes, I realized that it didn't have the clarity and detail of the BMS, or the V-120 for that matter.  But it's still an interesting choice that I bet a lot of people would love to listen to.  I have one customer who ordered these because he listens to older rock and roll music at very high volume levels!   That is probably the perfect use for these over the V-120's.

$99 per pair

Here's a couple of pictures showing the size difference between the V-120 and the V-121.

The adapters are made with solid hardwood, painted with black paint.   They have the 1" screw-thread adapters attached, a gasket where the adapter contacts the horn, and brackets to hold the adapter to the horn.

It's important to note that these adapters do not simply turn the 2" tractrix horn into a 1" tractrix horn.  It is a completely different design.  The expansion of the adapter is much quicker than if it were made like a standard 1" tractrix horn throat.   Technically, the expansion of this adapter is not "correct", however, the design incorporates just the right compromise to provide a nice new "voicing" to the K55 driver, and incorporates extremely well with the full line of Volti Audio horns.

Check out this photo:

This shows two horn designs with identical Fc and mouth size, but one has a 1" throat and the other has a 2" throat.  First question - just by looking at the horns and using your own intuition, which do you think will sound better?  It's obvious that the larger throat, shallower horn will sound more natural, while the long skinny throat of the 1" horn will sound more like a cheap megaphone, or the Klipsch K400, take your pick!

In designing the adapters, I wanted to stay away from that long throat, and keep the desirable tonal qualities that you get from larger-throat horns.  This is what caused all the hours of experimentation, and resulted in something much more unique than simply a 1" to 2" adapter, or a really long throat to make the 2" horn into a 1" horn.   This adapter is carefully contouring the sound of the K55 driver so that it is compatible with the V-Trac horn, and very close to the performance you get with the 2" outlet drivers.

Here's a few more pictures:

V-120 pair

Throat of Fc260

V-120 on Fc260

V-121 on Fc260

The throat shape of the V-120 is a dual flare with a very neat round to square transition

The throat of the V-121 is a single flare, but longer, and with the same neat round to square transition

When I first listened to the big BMS 4592ND driver, with it's large diaphragm and 2" throat, I was impressed with how clear and nice sounding it was listening at low volume, right up close to the driver.  For years I had been used to the K55 compression driver, and listening to that driver without a horn attached is painful.  With one sitting in your hand, with music playing, the K55 spits the sound at you with a crunch.   It is really unpleasant, and it's the way I thought all compression drivers sounded.

But when I got the BMS drivers and listened to them without a horn attached, the sound was very different, very nice, with no unpleasantness.  They sounded almost like a dome midrange to me.  I thought that it was solely because of the higher quality construction, new technology, new materials, etc... But just recently I've realized that there is another, much more important reason why the BMS driver, and other large compression drivers sound so much better, and that is because of the throat that is built into the driver itself.

The diaphragm on these big drivers is deep in the driver towards the back, and the sound is funneled through a throat that is about 3" long, with a phase plug in the middle.   This throat is responsible for much of the tonal quality that you hear from the driver.   The manufacturer can change the shape of this throat and completely change the tonal characteristics of the driver.  In fact, I believe that the throat shape, size, and phase plug have much more to do with what we perceive as quality of sound from the driver than any other aspect of the construction of the driver.

I was making 1" to 2" adapters to fit the K55 driver onto my 2"-throat horns, but what I discovered during the process of designing and building these adapters provided me with information that extends far beyond what a simple adapter can do.  I learned very important information about how the throat of a horn, or the throat of an adapter, or the throat built into a driver can effect the overall sound of the driver and the horn that it is attached to.  I learned that I could make a throat for the K55 and completely change the tonal quality of the driver, just like the throat that is built into the BMS driver does.

Adding a throat extension onto the K55 completely changes the tonal quality of the driver.   When designed and built properly, this throat makes the K55 sound like a much more expensive driver than it is.  The V-120 and V-121 throat adapters essentially turn the 11/16" outlet of the K55 driver into a 2" outlet driver, much the same way that BMS takes their diaphragm and contours the sound with the built in throat and phase plug to a 2" outlet.

I built at least fifteen different throat adapters to test with the K55.  I tried every combination of hole size, length of adapter, flare rate of the mouth of the adapter, and even dual flares (which is what I ended up using on the V-120).  I was able to contour the sound in many different ways with these various adapters.

I did two different test sessions with these adapters.  The first test rig consisted of a single Klipsch La Scala, two Fc260 horns, and an A/B switch box.  The second setup was with my Khorns at my house.  I put the Fc260 horns on top of my Khorns, with the K55/adapters on them.  With this second test session, having two horns for each of the drivers, and bringing into play the imaging, really made the differences between the two drivers more evident.

My old beater La Scalas

I made a couple of these switch boxes, which work great!

First test session - I had the two Fc260 horns hooked up through the switch box, one of them had the BMS driver and the other the K55 with one of the adapters.  I used all kinds of different music and could instantly switch between the adapter and the BMS driver.   I also set it up so I could switch between two different adapters, each with K55 drivers on them.  It was actually pretty funny.  I would go into the wood shop and in 20 minutes or so I would make another adapter with a modification of some kind, and then walk back out to my test rig and hook up the adapter and listen to it, then go back in the shop, make another adapter and come out and listen to that one!   I basically spent an entire week doing this!  But the end result is worth it, the sound quality from the K55 driver on these adapters is wonderful.

The second test session with my Khorns really made it clear how much better the larger BMS drivers really are.  Not only did the sound quality of the driver really shine over the K55/adapter setup, but the presentation is bigger, and imaging improved greatly.

But I got to tell ya, the K55's with these adapters are way, way ahead of using the stock K55/K400 setup, and they are better than just a simple 1" tractrix horn with the K55.   The V-120 adapter doesn't just make the V-Trac or Fc260 horn into a 1" tractrix horn, it does more than that.  The sound quality that results from using this adapter on the K55 is much better than you'd ever expect to get from a standard 1" throat horn.

Installing the adapters:

The adapters screw onto the V-Trac horn, or Fc260 horn with metal brackets.   For the smaller V-120 adapters, the brackets are bent to fit over the larger throat end of the horn.  What I did to attach them, is to put the horn on it's mouth, and I carefully centered the adapter on the horn throat and pressed down hard with one hand to compress the gasket, and then used a magnetic tip on a screw gun to drive the screws in.  This does take some strength and coordination, and it may not be that easy for everyone to do, so you may need to first mark the hole locations and pre-drill the holes.  The two pictures below show how I installed them.  Please note how I started the screw at the bottom of the hole in the bracket so it would help draw the bracket down when the screw tightened up.