I'm trying to learn more about how passive filters work by modelling a speaker crossover (using Qucs), and as a starting point I'm using a crossover from a speaker I've built as an example, since I'm familiar with it.
What has me really scratching my head about this circuit is that unlike pretty much every example crossover and filter diagram I've seen online and in textbooks, the series components are all placed between the negative terminal of the driver and Ground instead of between Vin and the positive terminal.
Taking the woofer circuit as the simplest example since the driver isn't inverted, this means that Vin = Vout for any input V, doesn't it? So a couple questions:
1) Am I missing something obvious here? Can the diagram be flipped or rewritten in an equivalent (more standard) way and I'm just not seeing it?
2) If not, how does this filter work with this layout? And where would you place a probe to measure Vout in a sensible way?
3) The inversion of the tweeter makes this even more confusing to me, how does that fit in? (or is it unrelated?)
Thanks in advance for any tips to help understand this!