I've hunted round and not really got an answer, the low end limit of a horn, does the area of the horn mouth or the circumference of the horn mouth dictate the lowest frequency the horn will support? I'm playing with horn designs for in the car, for those who don't know these are very flat and wide, and traditionally positioned under the dash using the roll up off the dash as an extension of the horn mouth. Now if the circumference is the deciding factor its not important to make the horn very high as most of the circumference is found in the width, BUT if the mouth are dictates the lower cut off, then doubleing the height of the horn should have a very pronounced effect.
I've looked around and found argument stating circumference is the deciding value, and I've found arguments stating mouth area? I know the likes of Hornresp use mouth area but they also assume an axially symetric horn which this is not.
any help or advice? (I put this in 'full range' as I guess these are more horny types in here
)
thanks
I've looked around and found argument stating circumference is the deciding value, and I've found arguments stating mouth area? I know the likes of Hornresp use mouth area but they also assume an axially symetric horn which this is not.
any help or advice? (I put this in 'full range' as I guess these are more horny types in here
)thanks
First stop: www.quarter-wave.com
Martin has lots of white papers etc on horns that you can read. Pretty technical in many ways, but that's a good thing. Hifi is ultimately about science. You can implement it in an artistic way, but the laws of physics don't change.
Martin has lots of white papers etc on horns that you can read. Pretty technical in many ways, but that's a good thing. Hifi is ultimately about science. You can implement it in an artistic way, but the laws of physics don't change.
Hi,
the circumference of the horn mouth applies to circular mouth horns only.
If you convert your mouth area to an equivalent circle of the same area, then the circumference can give a good correlation.
A second rule determines the lower bass extension. The flare rate will fix the high pass frequency of your horn.
A third rule suggests the horn length must be between a quarter wavelength and a half wavelength of your lowest frequency.
Some suggest that after you have applied these three rules you can truncate your horn by upto 40% with acceptable response ripple in the passband.
To get bass you need big mouth area, a slow flare rate and a long horn.
Below the passband the driver is effectively unloaded and "in car" amps have some pretty big powers that are liable to damage your expensive driver, especially if you try to show off the bass response of your new speaker.
the circumference of the horn mouth applies to circular mouth horns only.
If you convert your mouth area to an equivalent circle of the same area, then the circumference can give a good correlation.
A second rule determines the lower bass extension. The flare rate will fix the high pass frequency of your horn.
A third rule suggests the horn length must be between a quarter wavelength and a half wavelength of your lowest frequency.
Some suggest that after you have applied these three rules you can truncate your horn by upto 40% with acceptable response ripple in the passband.
To get bass you need big mouth area, a slow flare rate and a long horn.
Below the passband the driver is effectively unloaded and "in car" amps have some pretty big powers that are liable to damage your expensive driver, especially if you try to show off the bass response of your new speaker.
thanks for the info, this is for mid and highs, not bass. My current designs are good down to 650Hz and use 1.4" throat radian compression drivers, I want to go lower and change CDs. My aim is to get 300Hz up to 20kHz, I'm looking at the new BMS 4594 compression driver.
so designing in hornresp and then 're-shaping' the conical horn into the shape I want would not be a bad way to go about it.
so designing in hornresp and then 're-shaping' the conical horn into the shape I want would not be a bad way to go about it.
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