This is an image for Photos.

Guess what? My family came up to visit me this past weekend! It was awesome, and is part of the reason I didn’t get a post written sooner (my apologies). How does this relate to the photo above, you ask? Well, it doesn’t *really,* but they brought me the parts I ordered from Parts Express (apt name, I know) last week to make a Zobel Network for my speakers’ crossovers (the circuits that split the high and low frequencies for the two different speaker drivers).

Basically, for those of you with some knowledge of electronics, a speaker’s voice coil is just a bunch of windings of copper wire, like an electromagnet (or inductor). Because the coil acts as an inductor as well as the speaker’s motor, at a certain frequency the impedance of the coil begins to rise (remember that inductors block high frequencies). The impedance of the speaker driver, as a result, can rise from its rated 8 Ohms past 30 Ohms at the upper range of the frequencies it can reproduce. This is bad, and can contribute to ugly spikes in the driver output at high frequencies. Because I’m using a 4” full-range driver to handle the high frequencies in this design, this is more of a problem than with a dedicated tweeter – the voice coil is bigger, and therefore has a higher inductance. The drivers actually sound pretty heavenly up to a certain point, but are a bit harsh on-axis above that (past 15k Hz the frequency response plot gets rather rough). So, I’m installing Zobel Networks (a series combination of capacitor and resistor connected in parallel with the crossover circuit) to equalize the impedance of the loudspeaker over its entire frequency spectrum. Hopefully it will help with the slight harshness on the high end.