design 2 way crossover

Procedure: Design a 2-way crossover

Choose your mid-bass driver based on lowest frequency (F3) desired, and cabinet size desired; Obtain the Thiele/Small parameters of the driver, its frequency response graph and impedance curve, either from the manufacture or measure yourself.
[ To measure drivers: Download ARTA: ARTA http://www.fesb.hr/~mateljan/arta/download.htm, Make this simple jig: ARTA Jig - http://zobsky.blogspot.com/2008/01/s...t-jig-for.html
]
Calculate the box size and port dimensions.
(use Winisd : http://www.linearteam.dk/default.aspx?pageid=winisdpro
or Unibox: http://audio.claub.net/software/kougaard/ubmodel.html )

Choose the crossover point based on cone break-up point
(More on choosing xover point: http://www.speakerbuilder.net/web_fi...xpointmain.htm, http://www.troelsgravesen.dk/Design_criteria.htm)
Decide the crossover order based on smoothness of driver roll off
Decide whether Zobel required (usually required only if the impedance curve is very steep, or you’re too lazy to tweak the crossover)

Choose a suitable tweeter based on the crossover point of the mid-bass driver
(usually resonant frequency of driver (Fs) less than approx half crossover freq)
Obtain its frequency response graph and impedance curve.
Decide crossover order (usually at least 2nd order for power handling unless F >~4Khz and not played too loud)

Re-evaluate the crossover point in terms of it’s suitability for both drivers

Calculations:
Calculate BSC frequency based on cabinet width (115/width in m.)
(more on Baffle Step Compensation: http://sound.westhost.com/bafflestep.htm (good explanation but ignore his line level solution,
http://www.quarter-wave.com/General/BSC_Sizing.pdf )
Calculate crossover parts values: http://ccs.exl.info/calc_cr.html#second
Don’t forget – use the ACTUAL value of driver impedance at the crossover frequency
Calculate L pad values: http://www.sengpielaudio.com/calculator-Lpad.htm
(more on understanding crossover calculations: http://sound.westhost.com/lr-passive.htm (You've got to understand the rules before you can break them :-)

Examples from the designs of others can be quite instructive:
http://www.zaphaudio.com/
http://www.troelsgravesen.dk/Diy_Lou...r_Projects.htm
http://www.rjbaudio.com/projects.html
http://www.humblehomemadehifi.com/