WMcD Posted February 16, 2007 Author Share Posted February 16, 2007 At the risk of offending Roy (not my intent) I'll point out that Voight (sp) designed for a curved wavefront, Keele designed for a curved wavefront, and Roy designs for . . . the bubble curved wavefront. Great minds think alike. I think PWK did too. - - - - - - Let's change the subject to one suggested by Maron. What about the dry ice? It reminds me of ripple tanks we had in high school. There the waves in the water acted as lenses and a they would focus a stong overhead light onto a wihite panel below, making them more visible. A Wilson cloud chamber uses an atmosphere which is just near saturation. One way of doing this is with dry ice to chill a mass of moist air. The shock wave of a small particle causes the atmosphere to condense into a cloud, like a contrail, and thus small particles and their path can be detected. And we see some jet aircraft where the low pressure on the top of the wing, or in the votex, causes condensation clouds. These visually show the low pressure area. This is because low pressure air is less able to hold water vapor (or there is some adiabatic cooling), it flashes to a visible cloud. My thought is that if a sound pressure wave is travelling down the axis of a horn, there is a rarification area as part of the wavefront, and the wave, maybe, could be seen as a cloud. Of couse you'd have to cut the horn in half and glue it to a piece of plexiglass. (Were have we seen that?) It could show whether there is an arcuate wavefront at various frequencies. = = = = My wacky alternative is to set up a horn mouth up. Put a spark plug in the throat. Then dribble in some butane (like from a lighter). The butane being heavier than air would settle in the throat. Then we light it with the spark plug. Maybe the flame would gush out in a bubble. It would be tough to do this at different frequencies. Impulse response? Unfortunately, I'm not able to do that in my apartment. Smile, Gil Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 16, 2007 Share Posted February 16, 2007 At the risk of offending Roy (not my intent) I'll point out that Voight (sp) designed for a curved wavefront, Keele designed for a curved wavefront, and Roy designs for . . . the bubble curved wavefront. Great minds think alike. I think PWK did too. actually, i don't how one designs for a curved wavefront. it comes down to what the equations assume. in webster's equation, it assumes that the wave is a plane wave traveling down the length of the horn. as a result the expo equation, is the one that offers the greatest power transfer. but if you assume the wavefront starts to curve, then the tractrix is the one that offers the greatest power transfer. this is part of dr. post results. - - - - - - Let's change the subject to one suggested by Maron. What about the dry ice? It reminds me of ripple tanks we had in high school. There the waves in the water acted as lenses and a they would focus a stong overhead light onto a wihite panel below, making them more visible. A Wilson cloud chamber uses an atmosphere which is just near saturation. One way of doing this is with dry ice to chill a mass of moist air. The shock wave of a small particle causes the atmosphere to condense into a cloud, like a contrail, and thus small particles and their path can be detected. And we see some jet aircraft where the low pressure on the top of the wing, or in the votex, causes condensation clouds. These visually show the low pressure area. This is because low pressure air is less able to hold water vapor (or there is some adiabatic cooling), it flashes to a visible cloud. My thought is that if a sound pressure wave is travelling down the axis of a horn, there is a rarification area as part of the wavefront, and the wave, maybe, could be seen as a cloud. Of couse you'd have to cut the horn in half and glue it to a piece of plexiglass. (Were have we seen that?) It could show whether there is an arcuate wavefront at various frequencies. = = = = My wacky alternative is to set up a horn mouth up. Put a spark plug in the throat. Then dribble in some butane (like from a lighter). The butane being heavier than air would settle in the throat. Then we light it with the spark plug. Maybe the flame would gush out in a bubble. It would be tough to do this at different frequencies. Impulse response? Unfortunately, I'm not able to do that in my apartment. Smile, Gil have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
bhendrix Posted February 16, 2007 Share Posted February 16, 2007 Hi Roy, Is there greater resistance (drag) nearer the wall of the horn (less in center on horn) that causes the wavefront to curve to form a bubble? Thanks, Roy, for sharing your genious with us. This is a rare treat for us to get to learn!! Blessings, Bill Quote Link to comment Share on other sites More sharing options...
WMcD Posted February 16, 2007 Author Share Posted February 16, 2007 "actually, i don't how one designs for a curved wavefront." Awww. Come on. Tell us all about "the bubble". Smile, Gil Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 16, 2007 Share Posted February 16, 2007 Roy, Sent you a PM. Jordan back at ya! have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 16, 2007 Share Posted February 16, 2007 Hi Roy, Is there greater resistance (drag) nearer the wall of the horn (less in center on horn) that causes the wavefront to curve to form a bubble? Thanks, Roy, for sharing your genious with us. This is a rare treat for us to get to learn!! Blessings, Bill hi bill, i would not say genious; if anything, i was blessed to hear, interact, work, watch geniuses (sp?). i call myself a tinker..... does the wave curve because of friction on the wall? well right at the wall, the velocity should be zero so it would dictate that wave would bend. kinda of like looking at flowing water in pipe; if you look at the model, one of the assumptions is that at the wall the velocity is zero. have i ever seen it? no. i have thought of trying to figure out a way to actually see how waves travel down a horn....have some "tinkering" ideas in mind.... have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 16, 2007 Share Posted February 16, 2007 "actually, i don't how one designs for a curved wavefront." Awww. Come on. Tell us all about "the bubble". Smile, Gil well first you need the finest bubble making stuff money can buy. me i prefer the stuff that whamo makes..... have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
bhendrix Posted February 16, 2007 Share Posted February 16, 2007 Hi Roy, Is there greater resistance (drag) nearer the wall of the horn (less in center on horn) that causes the wavefront to curve to form a bubble? Thanks, Roy, for sharing your genious with us. This is a rare treat for us to get to learn!! Blessings, Bill hi bill, i would not say genious; if anything, i was blessed to hear, interact, work, watch geniuses (sp?). i call myself a tinker..... does the wave curve because of friction on the wall? well right at the wall, the velocity should be zero so it would dictate that wave would bend. kinda of like looking at flowing water in pipe; if you look at the model, one of the assumptions is that at the wall the velocity is zero. have i ever seen it? no. i have thought of trying to figure out a way to actually see how waves travel down a horn....have some "tinkering" ideas in mind.... have a blessed day, roy delgado Would this harken back to the days of fluid dynamics? How about a clear plastic horn submerged in a clear liquid with the ability to inject a dye or color into liquid flowing through the horn? OK, now I'm the pain . . . . .Sorry . . .[:$] Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 16, 2007 Share Posted February 16, 2007 Roy, It would be a royal PITA to setup but how about taking probably dozens of something like an impulse response measurement (strictly to see the propagation delay) at very specific points across the horn. Maybe all the exact same distance from the driver (to get rid of path length differences) at various points across the horns dispersion. Then by graphing any propagation differences between the mic positions you could get an approximation of wave shape at the measurement points? Shawn Quote Link to comment Share on other sites More sharing options...
Speedball Posted February 17, 2007 Share Posted February 17, 2007 horn design......that's heavy stuff.... continue on all you engineering wizards......... Quote Link to comment Share on other sites More sharing options...
DizRotus Posted February 17, 2007 Share Posted February 17, 2007 Gil said, . . . It reminds me of ripple tanks we had in high school. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Someone else remembers those. When I asked my 17-year-old son if they used ripple tanks in his high school physics class, you would have thought I was speaking Russian. After I described them he laughed and said no. Quote Link to comment Share on other sites More sharing options...
pauln Posted February 18, 2007 Share Posted February 18, 2007 Thanks, interesting article and comments. For those keeping score at home, my only quibble is your mention of the rule of 70... should be 72. 72 divided by the interest rate is the number of years to double your money. 5% doubles in 14.4 years, 10% in 7.2 years, etc. Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 18, 2007 Share Posted February 18, 2007 Hmmm, we had ripple tanks in my physics classes....I'm only 22 (man I feel old....) Thanks bunches Gil, nothing better than a lengthy 'white pages' read! I'm considering changing my Cornwall horns out to Tractrix design. Do you have any experience on this mod or know anyone who has done it successfully? It might also take changing out the mid driver and possibly crossover points, so I don't want to get in over my head. Michael Next time I'm in town I'll bring my Chorus II squawkers and we can play around with them and the cornwall bass bin. Maybe we can play around with your forte squawkers too? I would love to hear a pair of the new K-510 horns in a cornwall - you could even convert it to a 2-way! Same thing for the Heresy. Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 18, 2007 Share Posted February 18, 2007 HELLO! wow, this one died. have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 18, 2007 Share Posted February 18, 2007 Hello Roy - lol Actually, do you happen to know what driver was being used in that article? Does it imply the squawker drivers in the chorus and forte are actually good up to 20kHz? So really all that's needed is a better horn and you could go 2-way? Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 18, 2007 Share Posted February 18, 2007 hey doc, no for the data in the article (which most of it was written by a marketing guy,,,,,eh, go figure), we used a driver that went up to 20 kHz; not the one in the forte II and chorus II and quartet......the driver in that mid is strictly a mid driver.......dies at about 8 kHz if i remember correctly or selectively, whichever suits me at the time.... have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
ZAKO Posted February 19, 2007 Share Posted February 19, 2007 ROY....Mike Klementovich sent me 165 pages of a study by John T Post and Elmer L Hixson....A Modeling and Measurment Study of Acoustic Horns. (May 1994) from the Electroacoustic Reasearch Labratory..Dept. of Electrical and Computer Engineering..University of Texas at Austin.....Its heavy in math & formulas..Right up your alley.....Have you read it? I can send it your way if interested. Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 19, 2007 Share Posted February 19, 2007 Roy, Sent you another PM. Jordan Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 19, 2007 Share Posted February 19, 2007 ROY....Mike Klementovich sent me 165 pages of a study by John T Post and Elmer L Hixson....A Modeling and Measurment Study of Acoustic Horns. (May 1994) from the Electroacoustic Reasearch Labratory..Dept. of Electrical and Computer Engineering..University of Texas at Austin.....Its heavy in math & formulas..Right up your alley.....Have you read it? I can send it your way if interested. yes sir in my collection along with another student that continued john's work with dr hixson (who just happened to be my supervising professor when i went to school!) with a guy named............thinking...........geesh it's crowded in here...............how did THAT get in here..................crap i forgot. i will find out. have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 19, 2007 Share Posted February 19, 2007 ROY....Mike Klementovich sent me 165 pages of a study by John T Post and Elmer L Hixson....A Modeling and Measurment Study of Acoustic Horns. (May 1994) from the Electroacoustic Reasearch Labratory..Dept. of Electrical and Computer Engineering..University of Texas at Austin.....Its heavy in math & formulas..Right up your alley.....Have you read it? I can send it your way if interested. yes sir in my collection along with another student that continued john's work with dr hixson (who just happened to be my supervising professor when i went to school!) with a guy named............thinking...........geesh it's crowded in here...............how did THAT get in here..................crap i forgot. i will find out. have a blessed day, roy delgado MCCLAIN....i think... have a blessed day roy delgado Quote Link to comment Share on other sites More sharing options...
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