Hi Folks,
This is something we see and think about when designing and building crossovers. We try to separate inductors as far apart as possible and we align them so their B fields are perpendicular. But have you wondered how effective this is and just how much of an effect it is?
Well I found out by accident when I was testing two identical crossovers for my FAST TL’s. I had one connected to the speaker drivers and no amp. I had another one connected to an amp (playing music) and no speakers. To my surprise, I heard quite audible music being played! The boards were about a foot apart. I suspected it was vibrations in the crossover that made noise at first (caps or inductors can mechanically vibrate). But I was not playing that much signal. I finally realized it depended on the separation distance of the boards and that the sound d was not from the XO board but from the speaker which was right next to it. So I moved the XO board around and checked orientation etc. it helps to cross the axis perpendicularly, but doesn’t eliminate it.
Something to keep in mind when laying out your coils on your crossovers.
Here is a video of what I saw:
Demonstration of Inductor Crosstalk in a Crossover - YouTube
The crossovers I was testing for basic functionality before packing them up to ship to my cabinet builder:
If you guys have similar stories or experiences I would love to hear them. I wonder how much worse iron core ones are? I think worse if laid side to side or end on end.
This is something we see and think about when designing and building crossovers. We try to separate inductors as far apart as possible and we align them so their B fields are perpendicular. But have you wondered how effective this is and just how much of an effect it is?
Well I found out by accident when I was testing two identical crossovers for my FAST TL’s. I had one connected to the speaker drivers and no amp. I had another one connected to an amp (playing music) and no speakers. To my surprise, I heard quite audible music being played! The boards were about a foot apart. I suspected it was vibrations in the crossover that made noise at first (caps or inductors can mechanically vibrate). But I was not playing that much signal. I finally realized it depended on the separation distance of the boards and that the sound d was not from the XO board but from the speaker which was right next to it. So I moved the XO board around and checked orientation etc. it helps to cross the axis perpendicularly, but doesn’t eliminate it.
Something to keep in mind when laying out your coils on your crossovers.
Here is a video of what I saw:
Demonstration of Inductor Crosstalk in a Crossover - YouTube
The crossovers I was testing for basic functionality before packing them up to ship to my cabinet builder:
If you guys have similar stories or experiences I would love to hear them. I wonder how much worse iron core ones are? I think worse if laid side to side or end on end.
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Troels has a page with some measurements on different inductor placements:
Placement of coils in crossover networks
Placement of coils in crossover networks
Thanks, Scott.
I see that the one orientation I twisted it to was the bad one. The orientation diagram from TG is very helpful.
I see that the one orientation I twisted it to was the bad one. The orientation diagram from TG is very helpful.