Acoustic Zen Crescendo speaker crossover capacitors ... who makes them?

Mapman and Granny,

The type of capacitor used depends on where in the crossover it is used, in some cases the only reasonable solution is to use a Electrolytic capacitor.

http://pbnaudio.com/speakers/speaker-kits/scanspeak-b741

Use the above speaker design as an example, in the bandpass for the midrange driver there are two series capacitors and two shunt capacitors, the two series capacitors certainly in a speaker this quality needs to be metalized poly propylene 100uF is a standard value and the 180uF is made up by paralleling 2 each 90uF capacitors, the two shunt capacitors both are 27uF, since this is a relatively small size it only makes sense to use polypropylene here too and luckily 27uF is a standard size too with a pretty tight tolerance too as compared to an Electrolytic capacitor. Now for the Impedance correction network in parallel with the midrange driver, here a 820 uF capacitor is needed - the only reasonable choice is an electrolytic capacitor, in this case to get the 820uF, 320uF uF is paralleled with 500uF and then I typically use a small value polypropylene to bypass with, something like 3uF

Good Listening


Peter

I understand completely Peter. Thanks for sharing that link. I love the idea of building a nice kit like that. Great idea. I think the designer of my speaker did what was reasonable with the bass board. No doubt about it.

I like thinking and planning on ways to improve what is reasonable and done with perhaps more cost constraints in place for the builder. 

@pbnaudio and others. The two 8 inch woofers are parallel wired. I have drawn out the circuit and taken photos of the board. Please take a look. The 1000uf caps, smaller inductor, and 8 ohm resistor all seem to be included parallel to the amps output to raise the impedance of the bass filter. Two 8 ohm woofers in parallel would deliver a net impedance of 4 ohms. The builder wanted to keep the speaker friendly to tube amps and thus implemented this impedance filter. The speaker is 6 ohms nominal.  I am not sure if this impedance filter reduces the impedance peaks of the vent/port and drivers or raises the nominal woofer impedance the amp sees? Or both? 

Question. Will the quality of the parts in this impedance filter impact bass quality? On paper it seems like no, but I know from experience they can very well have an impact on sound quality. Thanks in advance.

http://s1097.photobucket.com/user/grannyring1/library/Bass%20board%20crossover

Looking at your schematic, you have a impedance correction network across the positive and negative, not knowing the value of he inductor is impossible to tell, you where it corrects, you could disconnect it measure the impedance and see where you get a raise in the impedance.  Changing the caps or bias them in this circuit will not do much to SQ but you could certainly try.

The woofers are connected to a standard 18dB/Oct electrical filter consisting of two coils in series and a 200uF capacitor as a shunt via a 12 Ohm resistor between them, pretty standard stuff. However parts seems to be a extraordinarily high quality. 

Best

Peter

Peter thank you so much. I will leave all alone except upgrading the sandcast resistors.