Steven Kephart

I just upgraded to an HD projector as well. I built a screen with this material: http://www.dazian.com/cgi-bin/page.pl?acti...d=339&group_id= It is acoustically transparent, so you can put your center channel behind it. I basically built a frame and stretched the material with great results. It only cost me about $30. I had previous experience with the stuff after building a 16' by 9' screen at Adire. I did make one change after talking to Kevin at DIY Cable. I stretched some black grill cloth behind it which masks any framing from being viewed through the material, and improves the blacks a little bit. Hopefully that gives you some ideas.

Dan kept his comments to the facts about each type. There was no "bad mouthing" about it as everything he said was true and unopinionated. But just because you don't like his conclusions doesn't mean you need to take cheap shots at him. Or maybe you could prove factually that his conclusions are wrong?

Ah, I see what he is talking about now. Those actually aren't "Adire" drivers. Those are drivers Adire is designing for an OEM client.

They aren't out yet if I remember correctly. <{POST_SNAPBACK}> I believe he's talking about these surplus drivers: http://forum.soundillusions.net/showthread.php?t=56323 But IMO I would choose the Extremis over that surplus driver as it has more excursion. After all it was designed to out-perform the Revelators and Excel's.

Dan Wiggins just did a run-down of different motor designs on the Adire forum that should give you what you even more information. Here's a link: http://forum.soundillusions.net/showthread...3755#post583755

Hello vladd. You can find a couple technical papers in the tech section on Adire's website about XBL^2. Here's a link to them: http://www.adireaudio.com/Files/XBL2TechPaper.pdf http://www.adireaudio.com/Files/XBL2DetailsPaper.pdf It's easier to draw pictures than to try to explain how it functions, but I will try. Think of having 2 "gaps" of magnetic flux with a certain height, and the space between the gaps being the same height. Now picture a coil twice as long as one of the gaps. Now picture the top of the coil filling up the bottom gap, and hanging down below it. Now picture the coil moving up toward the other gap to where now the bottom of the coil is completely covering the bottom gap, and the top of the coil is in the space between the two gaps. Now picture the coil moving up further still. Now the coil is starting to enter the upper gap, however it is leaving the bottom gap at the same rate. This means that the amount of flux the coil is seeing is staying the same as it transfers from one gap to another. Now it can continue moving up until the bottom part of the coil is in the top gap. As you can see, you get a great deal of excursion from a short coil. I drew a picture a long time ago that should help with your visualization. It shows the coil at it's peaks of excursion. Here's the link: http://memimage.cardomain.net/member_image...68_115_full.jpg

Just to let you guys know, it is also stickied in the Advanced Discussion Forum as well.

If you want a really good imaging CD, check out Planet Drum by Mickey Hart (ex Greatful Dead drummer). http://www.amazon.com/exec/obidos/tg/detai...=music&n=507846 The Fifth Element soundtrack is a pretty good one as well.

Ok, BL is made up of the B field; the magnetic flux effected by the coil, and L which is the number of turns (length of wire) effected by the magnetic flux. When you change the number of turns (changing BL), you change Re. Now on to dual voice coils. Think of each voice coil as seperate. Each voice coil has it's own Re that will multiply by two when seriesed and divide by two when paralleled. Well BL is effected because when in series there is twice the length of wire, therefore higher BL. In Parallel you in essence double the thickness of the wire. Steven Kephart Adire Audio

One thing I like to do when building enclosures is when the edges of the MDF are going to be exposed, cut that piece 1/4" large. Then when you build the enclosure, you should have 1/8" of wood sticking out in those areas. Now use a flush trim bit on a router to cut the excess off and you are left with professional looking edges. Steven Kephart Adire Audio

I wouldn't recommend the equipment and software for the DIY'er. It is extremely expensive and difficult to learn how to use. That's why I suggested the kits to you since the design work is already done. In fact if you want some killer sounding kits for cheap, check out Exodus Audio's offerings. They are by far the best performance per dollar I've heard. Steven Kephart Adire Audio

Each vehicle/system is so different it is very difficult to say. It also depends on the persons abilities to set the time alignment properly. Keep in mind that custom pods are generally aimed, so they are more on axis. This could be a benifit if falling into what I described earlier. I guess the point of my comments isn't to completely rule out kick pannels. It's just to help people get a realistic idea of what the benifits/weaknesses are. My plans for my car is to put the mids in the lower doors, and put the tweeters up in the A-pillars. But then I've got some pretty crazy processing available with 72 dB per octave digital slopes on the crossover which will greatly reduce comb filtering and allow me to run the tweeter much lower. I'm also going all active so I can adjust the time alignment on the tweeters and mids seperately. And finally to tune everything from there I have a pretty crazy parametric equalizer. The results should be pretty amazing, I hope. Steven Kephart Adire Audio

That's what beaming effects is the off-axis response. If you are crossing the driver over before the off axis is rolling off then aiming probably won't help any. I kept my comments mainly to actual speaker positioning and really didn't mention time alignment. Changing time alignment in intervals smaller than 3 miliseconds will make a difference in the frequency domain, which is most likely what you were hearing. If you noticed, I mentioned that the new speaker locations would also have a change in the frequency domain. There are several ways this is effected. The main one I remember Dan telling me was that you change the spectrum of comb filtering. I guess what I learned from all this, and I hope others do as well, is that kick pannel positioning isn't always THE BEST solution. Generally speaking, the easiest and best way to set things up is to use the stock, lower door locations and utilize proper processing. Steven Kephart Adire Audio

High BL is not necessarily a good thing. You want just as much BL as needed, and that's it. To understand why, you must understand what happens to the parameters when you change one thing like BL. Here's a quote Dan Wiggins once posted that explains how they interact with eachother: "Vb is proportional to Vas (double Vas, double Vb). Vb is proportional to Qes squared (halve Qes, quarter Vb). This is for the same Qtc/alignment... And since Qes is inversely proportional to BL squared, if you double BL you cut Qes by a factor of 4, meaning the box volume for a given alignment is cut by a factor of 8. Now, that is all well and good, but consider what Fb does in relation to Qts/Qes... Fb is inversely proportional to Qts, thus as you raise the BL, and lower the Qts, you raise the Fb accordingly. Double BL, cut Qts by a factor of 4, meaning Fb just jumped up 2 octaves!" As for BL and Re, when you double Re you double BL. So two subs with the same BL and different Re's have different motor forces. That's how they interact. I'll try to get more information to explain why. I hope that helps. Steven Kephart Adire Audio

We use LspCad for a lot of things as it is a great program. But I believe Dan mainly prefers and uses Praxis for crossover design. I believe he also likes MLSA and Speakeasy as well, although the latter is less user friendly. I know he doesn't like Lms as it isn't as accurate and doesn't have nearly the functionality. It's really neet to watch him do it. First he has me build test cabinets and mount the speakers. He then tests the frequency response of each speaker, and then uses the program to design a crossover to match his own response curve (this is something he and Dr. Hyre spent thousands of hours of testing and listening to come up with). He then hooks up the speakers to his computer and listens to the crossovers, using the software to simulate the new design. He can then make changes to the crossover based on available values, and tweak the sound for the clients tastes. Once we have a good sounding crossover, we order the parts, put them together, and take a listen again. Steven Kephart Adire Audio