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Question:

How inexact can I be with inductors when designing a crossover?

I have been searching for inductors for a 2nd order crossover and can't find exact matches, only close matches. How much will my crossover be affected if I use a 3.3 mH inductor instead of a 3.2 mH inductor? What about using a 5.0 mH inductor instead of a 5.2 mH inductor for the second one? Will it be that noticeably and undesirably affected?

Answer:

The tolerance on the inductors is likely to be ±5%; the tolerance on the capacitors is more likely to be ±10%. 3.3mH is out by +0.3% from 3.2mH and 5.0mH is out by -4% from 5.2mH. It'll probably sound fine. You could even add a few extra turns (1 more for every 50: the inductance is proportional to the number of turns squared, so increasing turns by 2% will increase inductance by double that, i.e. 4%) on the 5mH inductor, or stick a piece of ferrite rod down the middle if it doesn't.

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