Tom Adams Posted December 26, 2005 Share Posted December 26, 2005 That horn had a 12' square mouth, was made from 1/2" plate, with stiffening ribs. It was written up in the JAES. Used a 4" coil on the throttle valve, and a 100W amplifier. The pressure was no where near 3000psi, it was a low pressure, high volume device. The self-noise was only about 30dB down, IOW it made about 120dB of noise with no signal! The JAES had pictures of structural damage done in test with this device. You can download from JAES for $5 or so. Thanks djk. Like I said....in those days I was more interested in girls than horns. [] As for the pressure, I just remembered what the supply pressure was because I also did a summer working at the high pressure gases facility and knew what we supplied to various areas of the entire NASA facility. BTW, can you point me in the right direction for that JAES article?? I've searched the AES website and come up empty (probably don't know what to search on - duh). Tom Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted December 26, 2005 Share Posted December 26, 2005 But at a measley 138dB it isn't the loudest horn system out there.... One that comes to mind is installed below this fountain thing in Michigan (I wanna say Grand Haven or around there). It plays music that has to shoot across a big river and still be loud and full range - those bass horns are pumping over 145dB at "normal" listening levels. (and there are signs and fences and warning bells all over the place to keep people away from the bass of this fountain...at least the side shooting out over the river). I bet this is impressive to hear. Hope I get a chance to hear and see this. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted December 26, 2005 Share Posted December 26, 2005 Speaking about loud noises, don't cruise ships use some sort of directional loud noise to ward off bandits. The military may use something like that too.......? A horn like that would be great for quieting down the neighbors dogs....[6] I remember that too... I think though it was above 5000 hertz at 150 decibals. Quote Link to comment Share on other sites More sharing options...
pauln Posted December 28, 2005 Share Posted December 28, 2005 Building 49 (Vibration and Acoustic Test Facility) at NASA JSC uses huge generators to produce the electricity to power huge pumps that drive the horns used to test things going into space. The huge horns go up to 180dB and go down to 8Hz. I'm trying to image what this does to the air inside the test chamber when this is going on... Quote Link to comment Share on other sites More sharing options...
djk Posted December 28, 2005 Share Posted December 28, 2005 "But at a measley 138dB it isn't the loudest horn system out there...." For those of you that don't understand these things, a bit of help is in order. 138dB at 100' is over 174dB at 18", you're welcome to go stick your head in it. To put things in perspective, the 'beeper' that goes off at McDonalds when the fries are done is about 85dB at 18". The Victory is about the same volume level at 4 miles. Quote Link to comment Share on other sites More sharing options...
djk Posted December 28, 2005 Share Posted December 28, 2005 You will probably want to visit the library, the JAES has instituted BOHICA pricing. They now want $20 to download the pdf file. High-Power, Low-Frequency Loudspeakers Volume 13 Number 3 pp. 229-231; July 1965 This paper discusses the generation, propagation, and detection of acoustic energy over a wide frequency and power level range. In particular, it describes an electro-pneumatic sonic generator which develops several kilowatts of acoustic energy. The photographs and charts illustrate several applications for this sonic generator; e.g., facilities to measure low frequency propagation and examples of metal fatigue and building structure damage criteria when exposed to high-level acoustic energy. Author: Hilliard, John K.It is also in this collection, $40 for non-members.LOUDSPEAKERS VOL.1 edited by Raymond E. Cooke. Sixty-one papers, covering the years 1953 to 1977, written by the world's greatest transducer experts and inventors on the design, construction, and operation of loudspeakers. 448 pages Quote Link to comment Share on other sites More sharing options...
Myhamish Posted December 28, 2005 Share Posted December 28, 2005 Nice little thread and link, Speedball, Thanks. Relics of the Cold War that are being preserved and restored. Way back in the college days, our neighbours downstairs kept on complaining about our stereos being too loud. (I had double Advents and a quad HK 900 - my roomie had ESS Heils and a Marantz 1120). Anyway, after months of bickering with them, our buddy Roger, showed up in his Ford Cortina pulling a small trailer. He was able to get the rig into the back yard nice and tight against the house. It was a smaller version of the sirens shown in the link - about the size of a modern generator. The horn section was just a huge open box on the one end. The whole thing sat on a huge metal plate. He was able to use a pull rope to start the engine and then it would fill some kind of pressure tank. After a few minutes, the siren would start with this really low pitch that increased in volume and would start to climb. This thing was so loud that we wussed out and he released the air through some kind of valve and it stopped. Our ears would have bled if it had done the whole cycle - probably broken some windows too. Anyway, we ended up down at the hotel, and later, Roger left with the siren. Never knew where he got it or why he had it - but that was an interesting day. Quote Link to comment Share on other sites More sharing options...
oscarsear Posted December 28, 2005 Share Posted December 28, 2005 O.K. Story time. My great uncle was a pack rat. He'd grown up in the depression and decided that there was value in everything so he gathered it all. He owned 4 house and rented 3, but not the garages. Those he kept for himself for storage space. When he died me, my brother and my cousin got the duty. Amongst that collection was an old air raid siren. It was big but nowhere this big. My uncle was a newspaper dealer. He had all of us young folk working on the papers doing all sorts of stuff. His business was based in a separate service garage of a Phillips 66 gas station. Also in that service space was the air compressor that supplied the gas station with it's needs. We knew the siren used compressed air because it said so right on its labelling and we knew where we could get compressed air from. We always worked every Saturday day and all Saturday night getting out about 6 thousand Sunday papers...and we were alone up until around 3:30 A.M. Sunday. During the day we figured out what we needed to connect the horn to the compressor. At around 1:30 that Sunday morning we got everything set it all up and cut 'er loose. Holy crap was that a mistake..... 1st we set it off inside the garage, a steel garage building. 2ndly the compressor access port we used was it's manual emergency relief valve. It wasn't regulated and wouldn't stop blowing until the damn resevoir was empty. We figured we could just turn the valve off if we needed to. We did a really good job of hooking it all together cuz nothing blew out and the horn worked perfectly. We instantly HAD to leave the building. It screamed at maximum volume and ran for about 4 minutes at that volume. After about 6 minutes we were able to get in and shut it off. Shortly after that the police (3 cars) arrived at the station. Of course we heard that siren too but had NO idea of it's source directing them off to the south of us. The lieutenant's car came back about 45 minutes later and he had a nice visit with us. Our ears were now ringing for more than one reason. He put us on "patrol probation" meaning that he let us off but routinely had a car come by to make certain we behaved. Later tha same year my Uncle commented on how smart we were for making friends with the police as they all seemed to know our names. Ah adolescence...... Quote Link to comment Share on other sites More sharing options...
Speedball Posted December 28, 2005 Author Share Posted December 28, 2005 Great little story..........the "good" old days. Quote Link to comment Share on other sites More sharing options...
fletcherkane Posted December 29, 2005 Share Posted December 29, 2005 But at a measley 138dB it isn't the loudest horn system out there.... One that comes to mind is installed below this fountain thing in Michigan (I wanna say Grand Haven or around there). It plays music that has to shoot across a big river and still be loud and full range - those bass horns are pumping over 145dB at "normal" listening levels. (and there are signs and fences and warning bells all over the place to keep people away from the bass of this fountain...at least the side shooting out over the river). I bet this is impressive to hear. Hope I get a chance to hear and see this. I make several trips a summer with my kids to hear the Grand Haven "Musical Fountain" I've seen and heard it so many times is doesn't impress anymore, but the kids love it. That being said, you can hear concert level, orchestral accompaniment with pretty fountains synced to it from across a pretty wide expanse of water. I've never met someone who wasn't impressed at their first viewing of this thing. (The people of Grand Haven get sick of hearing it every night at dusk throughout the summer though....) This summer, at the Coast Guard Festival, the whole thing was in danger of going up in flames. We had a very dry summer here in West Michigan, and the Festival firework show (always very impressive...the only rule for the people putting on the show each year is that it has to be better than last year...) had a few of the fireworks go off too low. The hill that the fountain is on went up like a tinder box. It burned about Ten acres. Fireman got their in quick fashion, and focused most of their energy on preserving the area surrounding the musical fountain. It is truly a land mark. See it if you can... Quote Link to comment Share on other sites More sharing options...
DrWho Posted December 30, 2005 Share Posted December 30, 2005 But at a measley 138dB it isn't the loudest horn system out there.... One that comes to mind is installed below this fountain thing in Michigan (I wanna say Grand Haven or around there). It plays music that has to shoot across a big river and still be loud and full range - those bass horns are pumping over 145dB at "normal" listening levels. (and there are signs and fences and warning bells all over the place to keep people away from the bass of this fountain...at least the side shooting out over the river). I bet this is impressive to hear. Hope I get a chance to hear and see this. I make several trips a summer with my kids to hear the Grand Haven "Musical Fountain" I've seen and heard it so many times is doesn't impress anymore, but the kids love it. That being said, you can hear concert level, orchestral accompaniment with pretty fountains synced to it from across a pretty wide expanse of water. I've never met someone who wasn't impressed at their first viewing of this thing. (The people of Grand Haven get sick of hearing it every night at dusk throughout the summer though....) This summer, at the Coast Guard Festival, the whole thing was in danger of going up in flames. We had a very dry summer here in West Michigan, and the Festival firework show (always very impressive...the only rule for the people putting on the show each year is that it has to be better than last year...) had a few of the fireworks go off too low. The hill that the fountain is on went up like a tinder box. It burned about Ten acres. Fireman got their in quick fashion, and focused most of their energy on preserving the area surrounding the musical fountain. It is truly a land mark. See it if you can... Funny you should bring it up because one of the coworkers was a volunteer fireman putting out those fires too [] Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted December 30, 2005 Share Posted December 30, 2005 wow... THE MUSICAL FOUNTAINAUDIO SYSTEM (32) 18", 600 watt JBL subwoofers(12) High-frequency JBL horns(30"x 30"x 6' deep) (14) Power amplifiers (35,000 watts total)(4) Independent zones of control: Equalization Electronic signal distribution Frequency dividing Power level attenuation About a mile and a half of cableTotal system output (at the shoreline) in excess of 130dB Quote Link to comment Share on other sites More sharing options...
mike stehr Posted December 30, 2005 Share Posted December 30, 2005 There's a victory siren still sitting up on it's tower here in Spokane next to a fire station on north division. (Painted yellow, and just sitting there rotting away.) I want that thing..... They used to fire that thing up and all the electronic sirens every Wednsday at noon back in the '70's. Back then you would get blasted by sonic booms quite often as well. Kinda like Gregg mentioned, I wanna pull one on a trailer cranked up through a major metropolitan area at about 4 AM. Talk about getting in some serious trouble........ http://www.victorysiren.com/x/wav/chrysler2.wav Quote Link to comment Share on other sites More sharing options...
fletcherkane Posted December 30, 2005 Share Posted December 30, 2005 Thanks for looking that up Ray! I had no idea that it had that impressive of a layout. I just know it sounds good from across the river...[8-|] Quote Link to comment Share on other sites More sharing options...
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