This goes out to those who know more than I do. Another thread for passive XO gurus and RTi A7 owner/modifiers.
Bottom line: I don't see a series cap much less a shunt inductor on the Mid to provide the HP filtering suggested on Polk's site. 12dB/octave HP&LP for all drivers.
Read what I saw upon inspection of XO; I hope it makes sense:
Tweeter: 2 caps* paralleled**, shunt inductor, 2 caps* paralleled** - 18 dB/oct, right?!!
* in series w/tweeter
** w/each other; under 20 micro farads total
Mid: series inductor, shunt cap & resistor - 12 dB/octave LP, right?
NO SERIES CAP or SHUNT INDUCTOR on the mid
Sub: BIG series inductor, shunt cap 12 dB/octave LP, right?
This also suggests 4 ohms below 125hz. If I did the math right, 125hz HP series cap should be about 2500 microfarads.
Polk Tech spt stands behind the web site specs. How can Polk claim any Mid HP filtering w/out a series cap?
Unless they know something I don't, the site's not accurate.
anyone's comment please?!!
thnx for bearing w/me; tony