silent_riot wrote:Let's see it, Brian, I have a pair of 12s I can play with.
Here's what I was fiddling with:
1. Atomic does not quote Le. I used 1mH for my sim, but it's likely higher than that. Once it's between 1mH and 2mH it should not affect the performance too much. Above that the parameters of the horn should be adjusted. Best to measure Le (and the rest of the t/s parameters) before committing to building one of these.
2. The compression ratio is a bit high, at just over 1/4. If the ELE12's cone is tough, this should not be an issue. However special care will need to taken to ensure that the cross sectional areas between S1 and S2 are kept as close to the model as possible (go even a little bit larger and performance suffers). A throat adapter should be considered if you plan to build this, to compensate for the effect of the driver's cone on S2.
3. You'll still need to come up with the folding. Have a look at the THAM15 or POC TH page for folding ideas. Alternatively, you could go for a "Cyclops" type fold (particularly if you can't come up with a fold that can accomodate the speaker's magnet in the mouth of the horn), but that would mean adjusting the model a bit.
4. Based on my experience with the POC TH, I suggest going with a larger mouth, to compensate for the driver shading it a bit. You can go up an additional 100 cm^2 easily without significantly impacting the frequency response.
5. About 6 inches or so of lightly stuffed polyester fiberfill between S1 and S2 should cut down the resonances above 150 H a bit.