Raise crossover point?

[billfitzmaurice]

Problem is I've never come up with a 3rd order filter where the 2 capacitors are of the same value before and after the inductor.

It's not one of the standard alignments, but it can be done. If you do it right results are similar to a 2nd order Chebyshev but with 3rd order slope. Standard calculators won't help you on this one. I'd peg the crossover frequency of this versus the original about 1kHz higher.

 

[David Jayne]

I'd peg the crossover frequency of this versus the original about 1kHz higher.

Yeah, that 'sounds' about right. Of course it was driving a tweeter it wasn't designed for as well, so who knows. I'll see if Epi will give me specs on the tweeter.

 

[BassmanPaul]

I knew it was just a matter of time before someone said that. But I'd like to fix it, because no one else makes a cab like this, you see. I may swap the crossover out of my Goliath and see how that works.

No one else makes a cab like this??? BUT you want to change it!!! Swapping a crossover and expecting it to work with a completely completely different set of drivers is naive. As others have posted and you have experienced, it just doesn't work that way.

The bottom line is that there is nothing to "fix". You have tone goals that differ from how the Epi cabinet was designed. Just throwing different, fairly expensive parts at a perceived problem is never going to get you where you want to go.

I guess my main reason for this is that someone down the road is going to buy this cabinet thinking it is a stock Epi cabinet. He/she will not know that it is no longer so and will judge other Epi products by that example. Another reason is the Kern IP777 that I bought via Ebay. I discovered that someone had been into it and "fixed" it. I'm still trying to get the schematic so I can put it right.

Paul

 

[David Jayne]

If I find a way to mod it successfully, I will make the mod reversible. If I sell it I will certainly disclose what I've done, and offer to revert it to factory if desired. No big deal.