"LTD02!!! Love the Limey model! Thank you so much for putting the time into designing something like this. I really appreciate it!"
no problem. once you spend all the time to learn how to design and fold a horn, it doesn't take very long to cook something up. it can also become a little challenge to see what can be done/what is possible.
"What program/method do you use to fold the horn anyways?"
hornresp is the program that most everyone uses to design the horn in order to see how it will perform. if you know that you have 20 cubic feet per horn to work with, you design a 20 cubic foot horn as a start. from there, i use a little bit of intuition and mock up in microsoft word of all things and perform the calculations manually in excel. it's just geometry to translate the hornresp model into physical dimensions. my problem is that all my intuition is in inches and feet and hornresp is in cm and cm^2, so i spend half my time converting back and forth between units! it is a little bit of an iterative approach between the hornresp specs and the physical model until they are in harmony with the objectives and constraints of the plan.
others have spreadsheets that will calculate everything, but i haven't taken the time to learn them.
"Could you either touch on or point me somewhere that explains the pros/cons of Front Loaded vs. Tapped horns?"
i looked around quite a bit on that one and there isn't a strong consensus one way or another. there are people with both designs that report that they are better, cleaner, or whater, than the other. tapped horns are tricky because they tend to have more resonances and frequency suckouts to deal with. that said, they tend to do a little better on the low end for sensitivity. front loaded horns tend to have a much cleaner frequency response toward the top end. so there are advantages to each. it seems that tapped horns work a little better with stronger motored drivers, while front loaded horns seem to have a little more flexibility.
"Looking at the FLH and TH designs I wonder if it is easier to get a low tuned/little bit more gain on a single sheet of MDF with a TH because you're not sacrificing physical space to the sealed volume behind the FLH."
that is probably right in theory, but other aspects are more important.
"I've tried modeling several drivers with the TH, but have found nothing flat as the model you provided or that Volvo's design achieves with a no longer manufactured Eminence driver."
you have to be really careful when comparing horn designs for 'flatness' and sensitivity. if you model in something less than 2 pi space, the response will appear flatter than in 2 pi space. volvo's model is in 1 pi space. that also makes the spl higher than a 2pi space model.
then you have sensitivity. i always use 1w1m in model, while many others use 2.83v, which if your driver has something other than exactly 8 ohms resistance, will generate more power, so it is not a fair comparison. volvo used 2.83 volts and has a driver with an re of 5.27, so he is modelling 1.5 watts.
finding a flat response is a lot of trial and error with different drivers. i can sometimes get a sense for a driver that may work in a particular design, but sometimes i can be surprised, but that may just be me.
volvo has one mistake in that his s1->s2 length is 1cm. s2 is area in front of the center of the cone, so s1->s2 lenth can't be less than 1/2 the diameter of the driver. shortening up that length will make the response appear flatter. i'm not taking shots at volvo's design, just pointing some things out to look for in any design.
the flatness of the frequency response in what i posted was also "cheating" because i clipped off only up to 200hz and then scrunched it down to fit on the page. the peaks and dips appear much greater on my screen. in practice the peaks and dips won't be as bad as in the hornresp model. what the room does to your frequency response will almost always dominate.
some people suggest using "par" for the flaring, but in this case the difference is a db here and a db there. not practically significant.
i'm pretty sure a few folks put together a quick tutorial for what each s1 s2 s3 et al are in hornresp. if you search around, you can probably find it or ask lilmike.
bracing is also required. something like in this picture will work fine.http://imageshack.us/photo/my-images...aklz7.gif/sr=1
one brace every 16 inches or so should help keep the cabinet from resonating too badly.