drmcclainphd
August 8th, 2012, 03:24 AM
It was suggested that I offer some of my expertise gathered from 50 years of building loud stuff Now, I grew up waiting for solid state amps to become common and built my own tubers out of such as Teac reel to reel decks with built in amps. I can't say I'm much inclined to discuss tube vs. tube. But now, when it comes to designing and building speakers for a given area/power situation, then I got things to say that I, at least, think might be helpful. If you see anything that sparks your
plug, and makes you want to glue wood and solder wire, give a shout.
For my main guitar amps I own two Fender Frontman 65R's. The amp is adequate. But the box is quite the hack. The single 12" driver (part # 0062679000) is the most efficient driver I've ever used (est. SPL 104dB 1w/1m). I suspect Fender thought it was maybe too good and wouldn't sell the driver except as a replacement part. Then they cancelled the 65R, again, I suspect because it was too good in comparison to the other amps, at least in terms of volume. You can buy these through a Fender dealer. Make sure you're getting the part number above. Price is $57.99 MSRP. If they want more they're selling you the wrong thing or ripping you off. I built two extension cabs for my Frontmen, one of these in each. The two 65R's could fill a concert hall. With the cabs on them, they can fill a stadium. These are my most preferred instrument drivers. Get them while they're still available.
Now for some of the large scale stuff I've built recently. Here's the main towers for my PA. Detuned port ("open back" facing front) design twelve (2 x 6) Sony "dynamic bass" low/mid driversplus two piezo tweeters (4kHz to 27kHz). 250 w handling, each.
http://dl.dropbox.com/u/52918987/tower1.jpg
http://dl.dropbox.com/u/52918987/tower2.jpg
Center unit, a "Sweet 16" (4 x 4) array of the same Sony's, plus two piezos. The rear panel in this 2 foot cube holds four 10" woofers with response down to 39 Hz, effectively subs. 600 w handling.
http://dl.dropbox.com/u/52918987/16top.jpg
http://dl.dropbox.com/u/52918987/16side.jpg
Not enough bass? This multiply folded horn is a 2 foot cube with 2 10" SAS Bazooka subs, an effective
length of 6 feet with a 10:1 expansion. 400 w handling.
http://dl.dropbox.com/u/52918987/Cubebass.jpg
Alternate towers are my pair of "Peavish" stacks. One Peavey Pro 12" low range, four Peavey 8" Blue Marvels, two piezos and an RCA heavy duty 4" full range. 350 w handling.
http://dl.dropbox.com/u/52918987/tower-PV.jpg
Now, put together these make for a PA of 1500 to 1700 w capacity. If you think that's impressive, someone has sold you on simplistic specs. All the drivers and designs were chosen for maximum efficiency -- the most decibel bang per watt. I push these with 400 - 600 w of amp. I'll stack (ahem) them against a 1000 watt system from any commercial manufacturer.
They were also chosen for cost. The Sweet 16 and Peavish towers cost less than $150 every other unit cost less than $100. That's drivers, MDF, glue, sealant, wire, screws, and paint.
I also experiment with different speaker designs. One of my favorites is the Karlson. As regular cabs, they are typically single driver boxes with am inverted parabola opening (shaped like the Eiffel Tower).
These are frequency dependent acoustic lenses. They focus the lower freqs and add some phase shifting to the upper, making these highly localized and therefore exceptoinal for stereo imaging and projection.
An alternate design is the K-tube, essentially the same, built into a cylinder matching the driver's diameter and a length about 6 times that. This waveguide design is widely used in microwave transmission,
and is the bsis of the ability of the B2 bomber to fly right up to you unheard, even at 100 feet, until directly over you. As speakers, these are essentially sonic cannons. Here's a 3 way system with a woofer,
three mids and a tweeter. The output tested to be 11 to 14 dB greater than the drivers alone. Just from some cardboard tubes cut in a certain way.
http://dl.dropbox.com/u/52918987/cannon%20built.JPG
One of the drivers shown is not a K-tube. It's a De Laval nozzle, basically the "bell" of a rocket engine serving much the same purpose as the K-tube. It produces twice the amplification of the K-tube.
http://dl.dropbox.com/u/52918987/overthruster.JPG
And, to feed my tube based beast, a Gretsch Electromatic, I built a reversable cab. I put a baffle down the center to cut it in two. One one side I put four TA Weber signature series (two 6", two 8")
http://dl.dropbox.com/u/52918987/Webers.JPG
On the other I put two Wurlitzer organ full range instrument drivers (and a little cone tweeter for luck)
http://dl.dropbox.com/u/52918987/Wurlitzers.JPG
Lastly, my Pignose needed a bit more mouth. This extension cab has eight 2" square full range drivers, like they put in large flat planel TVs with real good sound, plus a 4" metal cone woofer that will scare the
neighbors. Built in an old clarinet case, weighs less than 5 pounds, and is almost wasted on the Piggy because it has a 100 w capacity. The most expensive item on this page, in dollars per decibel, but sometimes
cool is far more important than cost.
http://dl.dropbox.com/u/52918987/Piggy%20Too.JPG
plug, and makes you want to glue wood and solder wire, give a shout.
For my main guitar amps I own two Fender Frontman 65R's. The amp is adequate. But the box is quite the hack. The single 12" driver (part # 0062679000) is the most efficient driver I've ever used (est. SPL 104dB 1w/1m). I suspect Fender thought it was maybe too good and wouldn't sell the driver except as a replacement part. Then they cancelled the 65R, again, I suspect because it was too good in comparison to the other amps, at least in terms of volume. You can buy these through a Fender dealer. Make sure you're getting the part number above. Price is $57.99 MSRP. If they want more they're selling you the wrong thing or ripping you off. I built two extension cabs for my Frontmen, one of these in each. The two 65R's could fill a concert hall. With the cabs on them, they can fill a stadium. These are my most preferred instrument drivers. Get them while they're still available.
Now for some of the large scale stuff I've built recently. Here's the main towers for my PA. Detuned port ("open back" facing front) design twelve (2 x 6) Sony "dynamic bass" low/mid driversplus two piezo tweeters (4kHz to 27kHz). 250 w handling, each.
http://dl.dropbox.com/u/52918987/tower1.jpg
http://dl.dropbox.com/u/52918987/tower2.jpg
Center unit, a "Sweet 16" (4 x 4) array of the same Sony's, plus two piezos. The rear panel in this 2 foot cube holds four 10" woofers with response down to 39 Hz, effectively subs. 600 w handling.
http://dl.dropbox.com/u/52918987/16top.jpg
http://dl.dropbox.com/u/52918987/16side.jpg
Not enough bass? This multiply folded horn is a 2 foot cube with 2 10" SAS Bazooka subs, an effective
length of 6 feet with a 10:1 expansion. 400 w handling.
http://dl.dropbox.com/u/52918987/Cubebass.jpg
Alternate towers are my pair of "Peavish" stacks. One Peavey Pro 12" low range, four Peavey 8" Blue Marvels, two piezos and an RCA heavy duty 4" full range. 350 w handling.
http://dl.dropbox.com/u/52918987/tower-PV.jpg
Now, put together these make for a PA of 1500 to 1700 w capacity. If you think that's impressive, someone has sold you on simplistic specs. All the drivers and designs were chosen for maximum efficiency -- the most decibel bang per watt. I push these with 400 - 600 w of amp. I'll stack (ahem) them against a 1000 watt system from any commercial manufacturer.
They were also chosen for cost. The Sweet 16 and Peavish towers cost less than $150 every other unit cost less than $100. That's drivers, MDF, glue, sealant, wire, screws, and paint.
I also experiment with different speaker designs. One of my favorites is the Karlson. As regular cabs, they are typically single driver boxes with am inverted parabola opening (shaped like the Eiffel Tower).
These are frequency dependent acoustic lenses. They focus the lower freqs and add some phase shifting to the upper, making these highly localized and therefore exceptoinal for stereo imaging and projection.
An alternate design is the K-tube, essentially the same, built into a cylinder matching the driver's diameter and a length about 6 times that. This waveguide design is widely used in microwave transmission,
and is the bsis of the ability of the B2 bomber to fly right up to you unheard, even at 100 feet, until directly over you. As speakers, these are essentially sonic cannons. Here's a 3 way system with a woofer,
three mids and a tweeter. The output tested to be 11 to 14 dB greater than the drivers alone. Just from some cardboard tubes cut in a certain way.
http://dl.dropbox.com/u/52918987/cannon%20built.JPG
One of the drivers shown is not a K-tube. It's a De Laval nozzle, basically the "bell" of a rocket engine serving much the same purpose as the K-tube. It produces twice the amplification of the K-tube.
http://dl.dropbox.com/u/52918987/overthruster.JPG
And, to feed my tube based beast, a Gretsch Electromatic, I built a reversable cab. I put a baffle down the center to cut it in two. One one side I put four TA Weber signature series (two 6", two 8")
http://dl.dropbox.com/u/52918987/Webers.JPG
On the other I put two Wurlitzer organ full range instrument drivers (and a little cone tweeter for luck)
http://dl.dropbox.com/u/52918987/Wurlitzers.JPG
Lastly, my Pignose needed a bit more mouth. This extension cab has eight 2" square full range drivers, like they put in large flat planel TVs with real good sound, plus a 4" metal cone woofer that will scare the
neighbors. Built in an old clarinet case, weighs less than 5 pounds, and is almost wasted on the Piggy because it has a 100 w capacity. The most expensive item on this page, in dollars per decibel, but sometimes
cool is far more important than cost.
http://dl.dropbox.com/u/52918987/Piggy%20Too.JPG
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