7 meter horn
Hi!
I saw my 7 meter "Gjerstad horn" on this forum and thought I owed you some information about it.
The history behind the horns started last year when they did not have enough low bass on the Mølla festival in Gjerstad (Norway).
The festival boss Knut Magne Valle contacted me and said he had bought two P Audio BM 18LF and wanted to have high fidelity and high efficiency bass cabinets at a maximum length of seven meters. Not quite the dream driver for a large horn, so I used three full days modelling and calculating a special horn for these drivers.
To compensate for the weak motors I ended up with an open back sideloaded design where the horn does all the damping. A closed box behind the driver in such a big horn is not nescessary as long as you use your hp filter correct.
Frequency response is pluss minus 1 dB in the bandpass from 23-250 Hz, and the phase response is pluss minus 10 degrees in the intended bandpass from 23-80 Hz (but it still has quit good efficiency at lower frequencies than 23 Hz
The horns was built by Jarle Grimsland and Knut Magne Valle, it took the brave boys a full week to build them. They used 100 meters of 2”x4” to brace each horn, and they are planning to fill sand in each cell of braces.
Just to get an idea of how loud these monsters can play, they made ripples on the ponds just like in Jurassic Park.
Best regards
Rune Skramstad
Hi!
I saw my 7 meter "Gjerstad horn" on this forum and thought I owed you some information about it.
The history behind the horns started last year when they did not have enough low bass on the Mølla festival in Gjerstad (Norway).
The festival boss Knut Magne Valle contacted me and said he had bought two P Audio BM 18LF and wanted to have high fidelity and high efficiency bass cabinets at a maximum length of seven meters. Not quite the dream driver for a large horn, so I used three full days modelling and calculating a special horn for these drivers.
To compensate for the weak motors I ended up with an open back sideloaded design where the horn does all the damping. A closed box behind the driver in such a big horn is not nescessary as long as you use your hp filter correct.
Frequency response is pluss minus 1 dB in the bandpass from 23-250 Hz, and the phase response is pluss minus 10 degrees in the intended bandpass from 23-80 Hz (but it still has quit good efficiency at lower frequencies than 23 Hz
The horns was built by Jarle Grimsland and Knut Magne Valle, it took the brave boys a full week to build them. They used 100 meters of 2”x4” to brace each horn, and they are planning to fill sand in each cell of braces.
Just to get an idea of how loud these monsters can play, they made ripples on the ponds just like in Jurassic Park.
Best regards
Rune Skramstad
After receiving an email from the owner of those horns,Ive updated the page which shows them.
Cheers!
"audio systems"
http://www.geocities.com/xobt/index2.html
Cheers!
"audio systems"
http://www.geocities.com/xobt/index2.html
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