Has anybody come across an Altec 5 or 7 type front loaded plus vented design for 12 inch drivers.I was hoping to mate this to my Edgar midrange horn at around 500-600Hz.
There are plenty of designs for 15 inch but not 12s.I have a pair of Fostex FW 305 woofers to use.
If not a back loaded type with the horn mouth firing at the back might be an alternative-something like the Frugal horns but they all seem to be designed for smaller drivers.
There are plenty of designs for 15 inch but not 12s.I have a pair of Fostex FW 305 woofers to use.
If not a back loaded type with the horn mouth firing at the back might be an alternative-something like the Frugal horns but they all seem to be designed for smaller drivers.
I know of no Altec 12" horns. FYI/FWIW, the small VOTT are quarter size 55 Hz expo flares, so assuming the horn for a 12" needs a higher BW horn loaded one can just scale it, though obviously better to design based on the driver's specs.
Do you adjust the scale by reducing the width and height and hence horn cross sectional area by the percentage of the difference in cone diameter or the difference in cone surface area?
Technically, neither, though DIYers historically just scale horn throat area (St)/driver effective piston area (Sd) or use the diameters; Altec's were designed based on their various 15" driver's (Sd) = 128"^2/~12.76".
Here is a build that uses a pair of EV 12" drivers in front horns. http://wp.volvotreter.de/projects/pics_plans/traxtrix-midbass-fronthorns/
"these horns measure 140Hz to 700Hz within a range of ± 2dB. Below 140Hz these horns rolls off with approx 12dB/oct."
You could use his hornresp model as a starting point for a "front loaded plus vented" design.
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"If not a back loaded type with the horn mouth firing at the back might be an alternative-something like the Frugal horns but they all seem to be designed for smaller drivers."
The Big Fun Horn is a design for a 8" driver. It has been built / copied / measured by various people.
Scoop PA horns are usually for 15" or 18" drivers.
The folding / horn path for these are very similar... so the same folding should work just as well for a 12".
http://www.parow.no/Lowther/bigfunht.html
The Big Fun, as described in the link above, is just a truncated tractrix horn. You can model these in hornresp.
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If it were my build, I'd probably take a 3rd option, and split the task up. I'd run the Altec-type front horn down to 140Hz (or whatever), then use different drivers (+DSP + amp) to cover the LF.
"these horns measure 140Hz to 700Hz within a range of ± 2dB. Below 140Hz these horns rolls off with approx 12dB/oct."
You could use his hornresp model as a starting point for a "front loaded plus vented" design.
---
"If not a back loaded type with the horn mouth firing at the back might be an alternative-something like the Frugal horns but they all seem to be designed for smaller drivers."
The Big Fun Horn is a design for a 8" driver. It has been built / copied / measured by various people.
Scoop PA horns are usually for 15" or 18" drivers.
The folding / horn path for these are very similar... so the same folding should work just as well for a 12".
http://www.parow.no/Lowther/bigfunht.html
The Big Fun, as described in the link above, is just a truncated tractrix horn. You can model these in hornresp.
---
If it were my build, I'd probably take a 3rd option, and split the task up. I'd run the Altec-type front horn down to 140Hz (or whatever), then use different drivers (+DSP + amp) to cover the LF.
http://wp.volvotreter.de/projects/pics_plans/traxtrix-midbass-fronthorns/
These might be a good starting point.
These might be a good starting point.