A paper mache horn for class A audio.
Whether you own a three watt, class A triode, a 10 watt mosfet follower--or anything in between--it is critical to compliment your sound system with high-efficiency transducers and horns if you desire realistic, powerful sound. Over the years, I've developed a paper mache, tractrix horn that coaxes every nuance these amps can deliver, thus enhancing the musical presentation as if the musician were in your home.
Fabricated with a thirty inch mouth and a body that's twenty-three inches deep (two inch throat version), this horn can carry five-plus octaves of lush, silky music and harmonics, and with a dozen layers of paper mache for support (think ultra density, high grade plywood), it's well dampened--no ringing, or metallic ilk to jar the nerves. The best part: everything sounds good, whether it be home theater, jazz, folk or rock. This horn also works well with one inch compression drivers -- you might have noticed the TAD 2002 on the horn, above.
In the picture, below, you can see the RTA frequency range of a pair of two inch throat paper horns with stock JBL 2446 compression drivers operating in stereo format. This test was taken at the listening position, eighteen feet from the horns, with my Behringer Ultra Curve EQ using a calibrated ECM-8000 test microphone running on a thirty-five foot XLR cable. You'll notice that I have decent performance from 315hz to 8000hz with a gradual falling off thereafter due to room anomalies. The sub-harmonic noise on the left of the screen is from the road construction taking place a mile down the road (we're getting a new overpass!).
I enjoyed the privilege of auditioning Mark Wilson's TAD 2002 one inch compression drivers (as displayed in the opening picture at the top of this page), and I'm absolutely sold on the concept of lighter diaphragms. The highs are extremely transparent, the distortion just vanishes, and my ability to be transported to another place in space and time is all that seems to exist.
Now, if you're a Diyer,
Diy projects are fine and dandy, but if you find yourself drooling over the thought of ownership, and fabricating isn't your bag, then I can build a pair for you.
Fabrication: due to their extreme complexity, it takes me about one month per horn + stand/perch, so you're still going to have to manifest patience :^)
JBL 2446 drivers are available, new, for $550.00. If you're naturally lucky, you can always purchase a pair of 2445, or 2446 drivers, used, off eBay for about half the cost. I've never encountered a problem with used compression drivers--a testament to JBL quality.
I've recently learned that beryllium diaphragms are being marketed as: Truextent, and are available for around $600.00 (that was awhile back), which means you can have the equivelent of a TAD driver for half the cost.
I can build you a custom bass horn.
It took me about three weeks to complete the prototype you see in the pictures, above. The horn's outside dimensions are 45" x 45" x 25.5" and it's stained "red-mahogany", then sprayed with shellac (the warehouse was unheated and shellac will spray with no problems down to 40º F -- typical working temperature during most of the fabrication process) The grill fabric, dual speaker terminals, and LAB 12 drivers, I purchased from Parts Express. The grill frame is solid oak, stained black. When the weather warms up, I'll wet sand the horn with 400 grit, wipe it down with acetone, then spray several coats of urethane.
Testing this brute gave me more joy than a kid with a jamb packed Christmas stocking. Loading up a CD designed to deliver bass response effects (the kind of music you test automotive subs with), I held my breath and hit the "start" button. With a mere 125 watts of input, the entire warehouse came alive with the punch from this horn. Best part yet, the first octave came through loud and clear. I heard the synthesized bass note roll from 50 Hz to 20 Hz without out losing steam. Needless to say, my brother and I were beyond surprised! Hornresp helped me to accomplish a fantastic job.
A few days later:
My neighbor, the owner of the warehouse that I borrowed to fabricate this beast--and also the fellow for whom I fabricated two Jensen Imperials with 21" B&C subwoofers, asked for a demonstration. He's running 2400 watts per channel verses my piddly 125 watts there at the shop. Curious of his reaction, of course I had to fire her up. He jumped back, eyes big and round, looking like he'd just got his first kiss. "This sounds better than my system!?! My god you've got the whole building shaking!!" he shouted.
I grinned and shouted back, "Front loaded horns are more efficient than rear loaded horns. We could always use the Imperials for the rear channel. I'll build you a pair of these to replace the Imperials."
Oh, let me tell you, he looked tempted. "My wife wouldn't appreciate my doing that," he said, then smiled. Now there's one heck of a man, and devoted to keeping his marriage on the right track.
An old memory:
In the early days of the Internet, many years ago, and some of you may recall, I fabricated a goose neck horn similar to Nelson Pass'. I posted it and the plans on my web site back when I used Earthlink as my ISP. Unfortunately, Earthlink was implementing new software (which wasn't Mac friendly) and destroyed my website. Feeling defeated, I gave up on everything I posted.
Where was I? Oh yeah:
My goose neck horn was front loaded with a single driver (I experimented with everything from an 18" JBL 2240 to an 8" JBL 2118. And when it became available, I tried out a Lab 12 driver--I think I played with an 18" PAudio "blue monster" as well. In my case, the goose neck was bent over the backside of the horn's mouth and fit nicely into a corner. It was a breath taking experience to have this instrument of divine audio reproduction in my system. I kept it for many years until, one day, I couldn't tolerate the size, and like a hundred other projects, it met it's fate on the burn pile. The point I'm driving at is this: my new, folded horn does everything the old goose neck horn did and does it with a much smaller foot print. Eventually, it will replace the tapped horn and bass reflex enclosure in my primary system.
Should you be interested in ownership, a basic version of my newest folded horn design (no fine finish, putty, or drivers) is valued at $1000.00. Moonlighting, it takes me about two weeks to fabricate a roadworthy unit.
I'm offering enough schematic information on my DIY folded bass horn page to get you up and running, should you be interested in fabricating this beast.
If you're interested in owning a pair of paper horns, or my bass horns -- or anything else on this web site, for that matter, please check out my Products page.
One final thought:
In the quest for quality sound, I've discovered there's more than one way to approach a problem. That's why I feel compelled to share many audio topics on this site. We DIYer types seem to have a burning passion, an itch that can't be scratched, and as long as there's another day in our future, another sheet of plywood in the garage, another idea sparking, clawing for life in our brains, our unique social construct will flourish.
Peace, my friend,
John Inlow
