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History of the mightiest horn speaker - the Shearer Horn


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PWK references Harry Olsen's work many times in the Klipsch Audio Papers.

What I find interesting is if you look closely at the bass horn sections, one quarter of it kind of looks like a LaScala bass section turned on its side.

EDIT: haha, I just noticed mung said the same thing.

Hey Dave, how's that Revox working out?

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"PWK references Harry Olsen's work many times in the Klipsch Audio Papers."

Harry F. Olson, a pioneer in the field of 20th century acoustical engineering, was born in Mount Pleasant, Iowa to Swedish immigrant parents. Olson went on to earn a bachelor's degree in Electrical Engineering from the University of Iowa then continued to earn a Master's degree with a thesis on acoustic wave filters in solids and a doctorate in Physics. Immediately after completing his course of study in 1928, Olson moved to New Jersey to work for RCA Laboratories.

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Totally different that a LaScala.

Woofer faces forward, and is not in a sealed chamber.

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Artto, I hope to sort it out this weekend. It powers up, but powers down again when you try to open the drawer. Hoping the tracks need cleaning and some new silicone grease . If it is as simple as that I'll be very happy.

I have recently seen W bins and Altec batwing 210s, and they are huge. It is stunning to realize you could have a thousand seat theater in 1940 listening to concert levels with these speakers and may 15 wpc amplifiers. Talk about quality!

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That article is great I've read it a few times this year. I was thinking about the larger horns like MWM. The klipsch museum has some nice RCA horns Shearer and1428 compression drivers.

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RCA corner horn but the hf horn is missing the rest of the horn cells but we can see how many there would have been.

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The Jubilee audition at Coytees led me to the JBL forum which exposed me to the Shearer horn. I then had a premonition that one of these things was still in the old theatre in my hometown in Ky. I had my buddy go to the theatre and sure enough they had just unhooked the original complete 1939 RCA speaker system. He told the owner that he wanted the speaker and would be back the first of the week to get it. This is a picture of how he found it.

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He went back 3 days later to find that the third owner had decided to throw away the field coil midrange drivers ( going for 3k or so nowadays), and the top horn. My buddy sped off to the county trash site to start looking for them. An old fellow said, " I saw a lady put that into the back of the trash truck and it was compacted and taken to the landfilll.....unfrigginbelievable.[:@] We ended up getting the bass bin and the original amp that drove the speaker. There was only one speaker all those years I was growing up listening to movies, filling up the whole theatre with the (2) 15" RCA field coil woofers and the horn setup on top. This is a pic of it upon removal

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My friend delivered it with a 7 hour drive to NC last weekend. It still had the 70year old dirt on it.

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I got it all cleaned up and painted it now and it will reside below the 110" projection screen in my garage.

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I've done alot of research on it and found some original drawings that were posted in a recent Ebay auction. I have found several people who have experience with these things and they are supposedly some chest slamming, mid-bass monsters that give some of the tightest, punchy bass from about 40hz on up. I have gotten (2) JBL 2226 15" woofers to put in it (recommended by a Roadie who used one of these touring Austrailia back in the 80's).

I'll be firing it up soon and will be taking measurements with a laptop PC measurement system we recently got ahold of. I'll try to report back how it sounds.

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This is the final resting spot, although I have the bass bin on a carpeted dolly for now until I get the JBL drivers mounted, then I'll install the funiture "sliders" since they are only 1/2" high.

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I'm looking forward to the day when I can fire up the system with the front mains consisting of dual Audax PR170MO high-eff drivers which will be 105db and then mated up to some Italian Ciare TW 1.38 tweeters which are also 6" in diameter and also 105db/1 watt. The mains will run from 300hz on up and the Shearer will run from 300hz down to 50hz where they will cross over to 2 separate Electrovoice 18" subwoofers in the loft area. You can see one subwoofer in the loft on the LH side near the cabinets.

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Amplification will be Crown Macro Reference which should be about 760 watts to each woofer with a damping factor of 20,000 on the RCA cabinet.

I'll have a Crown Micro Tech 1200 watt amp on the front mains, and a Crown K2 on the 2 EV subwoofers. I'll use the amps in my HT processor for the side axis and the rear Clements surround speakers which have (2) 6 1/2" and (2) dome tweeters per cabinet.

Coytee will be proud when I am watching the Blue Man Group DVD on the 110" screen through a system of 105 db efficiency...I might even match his level of slam his system has.[:D] I want that big-*** drum they haul off and whack with that big sledge-hammer mallet to be in the room with me or seem like I'm hugging the thing.[<:o)]

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About the Fletcher horn, I have the original paper by Snow (thanks to PWK himself) but I have never seen a cross-section of that beast. I have always wondered if the large central plug held the woofer, and the four corner boxes were there to reduce the taper rate, or if the four corner boxes held a driver, or what...

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That sounds about right. Steve posted them on Oswald's mill archive and a few other places. Very cool document.

SOOOooooo how do they sound!!!!!!!!!!!!!!!!!!!! What JBL drivers are you using? Your cabinet is among the nicest I've seen. Good job cleaning them up.

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