Car audio home audio ?

First of all, thanks Dyon for the information on the ribbons.  It was most enlightening.  I kept my comments more open ended as I wasn't sure if I was fully correct.  Your comments definitely clarified the parts I did not know.

That will depend on your intended application.  For music listening, a full range tower works great as you only usually need extention down to about 30 Hz.  But for theater you need some serious bass to really give that "movie theater" experience.  The Extremis driver will have as much extention and impact as our AV8 that is used in the Kit 281.  Those kits are well known for their extention, and the Extremis drivers should have similar performance.  For music listening, a ported MTM design should work just fine, giving you that extention.  Match that with a Shiva and you will get a good balance for music and movies.  But if you really want the ultimate HT, then I recomend either a Shiva/Tempest in a large ported enclosure, or better yet step up to the Tumult.  I'm willing to bet with that setup you could easily blow away the sound at any movie theater.

The Koda 8's will definitely have more extention.  But I don't think they add anything to the design.  They will greatly complicate the crossover design and the Extremis drivers will play plenty low to match up with a sub.  I think for your first attempt it would be wise to go with a two-way setup (mids,tweet).

Uh oh, we are getting into one of those popular misconceptions here.  The speed and accuracy of a driver is not based on the size or mass of the driver.  Transient response is effected by inductance.  Here's a very informative tech paper on this topic: http://www.adireaudio.com/Files/TechPapers/WooferSpeed.pdf

The Extremis mid uses a pretty short coil for the excursion it has (one of the benifits of XBL^2) and also has copper in the gap (you can see this in the pictures on our site).  This greatly reduces inductance.  in fact the inductance of the Extremis mid is a tiny .13 mH.  Tweeters usually have about .08-.09 mH, so you can see how low this really is. 

Steven Kephart

Adire Audio

My very first set of speakers were ESS Tempest with the Heil Air Motion Transformer tweeter.  It was a 2-way configuration, and they had 3 sizes of cabinets, each with the same tweeter but 8", 10" or 12" woofers, sealed.  Wonderful highs... this was in '75 and my Air Force buddies all said they liked the sound from that set.  I had the small pair first, then traded for the larger model (there may have been only 2 sizes).  The ESS Tempests had this rediculous foam grill on them, though, that had a velcro-backed aluminum bar that stuck onto them, and it would always fall off or get crooked.  I have no idea at all what happened to those speakers....like a lot of things they just became a memory.  They would be a lot more valuable to me nowadays.  DYohn, you jogged my memory.

And oh yeah, jeffchilcott......thanks!

Mine is kind of lazy.  All I can manage is to get it to walk fast.

Steven Kephart

Adire Audio

Steven, thanks for your input.  I've ruled out doing a 3-way with Koda's bringing up the bottom.  The article on inductance was fascinating, I'm even more sold on the Extremis than I was to begin with.

I'll let you all know if I have more questions as I get closer to building this thing.

check out my stereo that i built from some stuff i ripped out of my sister's car. it was just a boring day and i tried something new. it was great until my mom told me to turn it down cause her wall was vibrating. now obviously you wouldn't want this set up like the way it is, but for me it's pretty cool, not to mention it flippin rocks my dorm room and pisses off the RA's.

 i hope that picture works. it's too big to upload

anyways, it's 2 12" infinity reference subs with some lame-o 4 inch kenwood speakers.