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Crossover Thoughts


Dave A

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I have been working on a passive crossover for a two way for some time now and the major problem was the mismatch of driver efficiencies. Along the way I was using the common crossover calculators online and I got to thinking about how the OEM crossovers are often rounded off to even numbers both in capacitance and resistance. The calculators would give a number like say 4.56 UF or 5.17ohm and I thought "OK why not try to do just this and not round things off". So I built the 2nd order Linkwitz–Riley and an L-Pad doing just this and the results were really good. It took up to three capacitors to drill in as close as I could to calculated values as nothing out there was dead on like I wanted. With the resistors it was different and I found some really close without having to add some together.

 

  The end result is that the precise calculated values gave a much better sound then rounding off to the nearest whole number value. Not an expert by any means but I know what my ears tell me and has anyone else tried this?

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46 minutes ago, Dave A said:

... has anyone else tried this?

 

Absolutely! For my last crossover I measured dozens of capacitors, inductors, and resistors. (At one point I even contemplated winding my own inductors, but it turned out that I had appropriate values on-hand.) I fine-tuned with SPICE simulation. My results agreed with yours.

 

If you really want to put the final touch on your results, implement Zobel networks, too.

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1 hour ago, Edgar said:

 

Absolutely! For my last crossover I measured dozens of capacitors, inductors, and resistors. (At one point I even contemplated winding my own inductors, but it turned out that I had appropriate values on-hand.) I fine-tuned with SPICE simulation. My results agreed with yours.

 

If you really want to put the final touch on your results, implement Zobel networks, too.

OK would those go in after the L-Pad?

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26 minutes ago, Dave A said:

OK would those go in after the L-Pad?

 

Yes. I typically mount them directly to the driver terminals. That way everything upstream of the driver (and Zobel) see nearly constant impedance.

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On 7/6/2022 at 3:37 PM, Dave A said:

I have been working on a passive crossover for a two way for some time now and the major problem was the mismatch of driver efficiencies. Along the way I was using the common crossover calculators online and I got to thinking about how the OEM crossovers are often rounded off to even numbers both in capacitance and resistance. The calculators would give a number like say 4.56 UF or 5.17ohm and I thought "OK why not try to do just this and not round things off". So I built the 2nd order Linkwitz–Riley and an L-Pad doing just this and the results were really good. It took up to three capacitors to drill in as close as I could to calculated values as nothing out there was dead on like I wanted. With the resistors it was different and I found some really close without having to add some together.

 

  The end result is that the precise calculated values gave a much better sound then rounding off to the nearest whole number value. Not an expert by any means but I know what my ears tell me and has anyone else tried this?

 

I don't know how familiar you are with circuit simulations, but if you were to post the exact values you used, I'd be happy to simulate the voltage transfers.  Then, I could substitute common capacitor/inductor values and run a new simulation.  It might be interesting to see the difference.

 

Mike

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On 7/6/2022 at 5:37 PM, Dave A said:

I have been working on a passive crossover for a two way for some time now and the major problem was the mismatch of driver efficiencies. Along the way I was using the common crossover calculators online and I got to thinking about how the OEM crossovers are often rounded off to even numbers both in capacitance and resistance. The calculators would give a number like say 4.56 UF or 5.17ohm and I thought "OK why not try to do just this and not round things off". So I built the 2nd order Linkwitz–Riley and an L-Pad doing just this and the results were really good. It took up to three capacitors to drill in as close as I could to calculated values as nothing out there was dead on like I wanted. With the resistors it was different and I found some really close without having to add some together.

 

  The end result is that the precise calculated values gave a much better sound then rounding off to the nearest whole number value. Not an expert by any means but I know what my ears tell me and has anyone else tried this?

Yes. Quite successfully.

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