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    June 20th, 2012

    Inspired by Linkwitz's Orions and Jens Rasmussen active filters...

    Ok, i've got loads of speaker drivers lying around, but that's it - they are just speaker drivers, not a speakers...
    In the other hand, i've had a really good experience in trying out actively crossed speaker systems which sounded good, even with mediocre/bad drivers... 
    In addition, the active system is easy to tweak, faster in bringing it up alive, and not much pricier than passive one.
    I'll leave out the pros and cons... Actually i'll put some pros :) That may sound weird, but i belive they are true...

    1. Active crossovers are cheap. The more drivers you try to cross, the more passive components you'll need, more lower the woofer will play, and therefore, the required components for woofer/midwoofer circuit will get enormous and costy.
    2. Active crossovers are easy. No impedance to measure/keep in mind, no large caps/coils to search for in specific values, and full precise control of signal filtering.
    3. Time. 
    4. No change in crossover required if you decide to swap some of drivers. Drivers alone, transfer functions of crossovers alone. Great for endless research for the best-driver-ever.

    Gerbers from first batch, have the errors listed in the last image on this page (errata).
    Micro-Cap 9 files with topologies from this filter, for the simulations.
    Schematics in PDF

    So, what do we get in this tiny /100x100mm/ package? Let's see a picture :)

    * All the high/low pass sections are Sallen-Key topology.
    ** All the parametric EQ's could be used as notch or hump filters by selection of a jumper.
    *** 2-way jumper is there to switch between 3-way and 2-way presets of inbuilt traces.

     - Large selection of components to put in, available in every DIY'er drawer (LM337/317 regs, 0803/1206/thru-hole resistors, large film caps, and some electrolytic caps around the chips and in the PSU). All the parts are generic and available in every bakery down the street.

     - Ability to re-route the signal around the sections/use these sections in different order, giving ability to build up to 5-way systems, yet with 2-nd order filter stages.
     - 2-way with 8-th order filters are possible too.
     - Even fullrange speakers will benefit from bafflestep and 4 parametric EQs...

    Model Vs Real. Real is much more sexier :) rrr

    And the PCBs: (hint: use mouse scrool wheel in viewer).



     - LM317/337: i've used 337 instead of 317 and vice versa. So, their 2 and 3 pins have to be swapped on each regulator prior to mounting.

    Errata in pictures :


    By s3t © 2011