Bass Cabinet Crossover?

[CarpathiART]

Hello all!

I recently took my time to dig out the insights of a Hartke VX115 that I have lying around with no woofer in it. Discovered it being abandoned a while back. I already own a Hartke 2x12" bass cabinet that right now needs to have some new speakers put in since the original aluminum coned ones are pretty much shot.

I came to think of an idea about doing a crossover for the two cabinets in the manner of running the lower sub frequencies to the 15" and the rest to the 2x12".

So I dug out the the HF driver and the internal Crossover setup from the VX115 and here´s a photo of the PCB. The first thing that got my attention was my low level of knowledge when I took a look on the "ohmage" of this thing. The VX115 is rated 8 ohms (300W) and the woofer used in the cabinet is 8 ohms (300W) and the driver is 8 Ohms (50W). So how is it connected to make the total load 8 ohms?

I´ve also gone through some Xover circuits to make any sense of how they work and it occured to me that they actually are pretty simple. So this would be my first in order to run the low register of my bass signal passing the effects chain untouched to keep that low end clear as possible.  http://sound.westhost.com/project123.htm And this would go in one channel of my amp. The effected signal would then go to another channel. There the table of values for different crossover frequencies. Suggestions anyone? I play mainly a 5-string. I was thinking the crossover at about 120 - 130hz. And as these signals would be ran to their own channels I would have good control over them.

I thought I´d then run the signal to the V115 which would have another crossover modded inside that would guide at least the most of the "sub channel" to the 15" woofer inside and the rest to the 2x12" cab. The 2x12" also has a driver in it. I though I´d mod the existing crossover board (the attached image) and the new board behind a switch to flip depending on the occasion. Since I don´t think the HF driver in the VX would be neccesary to have in the circuit when just low frequencies are driven though the speaker.

And if anyone could guide me through this existing PCB too in a sense of what is the crossover point in this circuit approximately. It doesn´t show the "traces" all that clearly but it´s pretty simple all together. The red and black leads go to the woofer and blue and white to the HF driver.

I hope I´m being clear enough. And I gladly try to put out more information if anyone is interested in the subject