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stuck.wilson wrote:

having seen the benefits of first orders in my own application tonally AND dynamically

It's never was my experience. A never seen any tonal distinction between first and second order and I don't think that I experienced are any differences dynamically.

stuck.wilson wrote:

regardless though--   i do have a question about implementing the '1.5 order' crossover... how would one implement such a thing?

The 1.5 order is very easy.  The “1.5 order” is not the order itself but rather it is a hype-name that I use. However, it is very simple to implement and very effective. The 0.5 order crossover based upon a phenomena that I discover that if I have at first-order crossover and then, for instants, after one octave another first-order crossover, then I of course have a second order crossover, however this type of  “distributed” first-order crossover does less impact to Sound (imaging) then when I use full second-order crossover (I used religiously Bessel curve on second orders). That distributed crossover is a very interesting fruit, as it is allows a lot of flexibility. For instants you have the bass section that you would like to low-pass at 60 cycles with first-order. That frequency you'll found is necessary to integrate your base with your upperbass channel. The integration of bass is fine but you have an excessive HF “tail” from your low-frequency driver. If you go at 60 cycles with sharper order then you'll my gain some “issues” in imaging, so here is where you might employ the “distributed” first order. You'll keep your first order crossover at 60Hz and put in play and other first order crossover at, let say, 200Hz. The channel begins to write a full second order at 200 cycles, and does all typical for a second order phase spinning. However, the key in it is that subjectively, listening with that playback, this type of the arrangement screw up imaging less. The additional beauty is that you can move the second first-order crossover from (for instants) 100 cycles to 500 cycles, finding how much you would like to truncate the bass driver’s tail. There is even more very important benefit in this approach: the second first-order crossover might be not the actual crossover but rather roll-off from other means: enclosure, amplification, magnetics or whatever. The interesting part in that case is that if in place of the second first-order crossover is used a pure second-order crossover then the entire channel does not sound (imaging-wise) as a third order crossover.

stuck.wilson wrote:

also-  the higher DCR of the filter configured this way-- especially in the mids-- can do some damage to efficiency numbers and transients, wouldn't it?  i have noticed a significant slowing down of transients with air cores that i don't have as much of an issue with inductors like madisound sledgehammers (which are laminate iron cores).  any thoughts?  i know there's definitely a traditional bias against iron cores-- but i've definitely appreciated the 'lessening of the reins' below 1k!

Yes, the iron-core coils are OK as have fewer turns and consequentially lower DCR. In my past is I have used Erse Super Q Inductors with quite pleasant results. Steel being a snob I have paid a lot the money, perhaps stupidly, to wind 8-10 gauge high-inductively air-core inductors. It was a huge, it was heavy, it was outragesly expensive. If I had at a little brain during that time then I would buy for the money I spend for those inductors a separate amplifier and went bi-amping.

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