Heresey II Crossover

[sbcoffey42]

I opened up my H2 to take a peek what was going on inside, out of curiosity, because today I found out that there was an H2 to H3 upgrade kit you could buy. When I looked at the crossover I noticed a  10nF cap across the 68uF cap, this is not on the schematic I found, and was wondering this. Would a cap that small in parallel just be there to improve the tolerance of the larger cap? 

[Marvel]

I found this on a PE forum thread. It's from the Speaker Design Cookbook, vol 7:

 

Choice of capacitor type is usually determined by consideration of loss factor and costs. This generally means using plastic film capacitors (such as Mylar and polypropylene) for values of 20uF or less in midrange and tweeter sections, and non-polar electrolytics in most other applications. This is not a hard-and-fast rule, as certain high-quality, nonpolar capacitors are quite adequate for most applications. This does not always apply, however, since the majority of readily available nonpolar capacitors intended for loudspeaker design are only moderate-quality Asian products. One way to improve the "sound" quality of these cheap, nonpolar capacitors is to bypass them with small-value (0.1-1uF) polypropylene types. Another technique is to parallel multiple smaller values rather than use a single large value of capacitance. This way, the resistive and inductive components are also paralleled together, and the net resistive and inductive effects of such a component will be smaller than would be the case with one large capacitor.

[sbcoffey42]

Thank you for that explanation.