Hi there,
does anyone know at which frequency the inductor values are measured?
In all these calculator for cross overs are values for the inductors. But the value of an inductor differs a lot over the frequencies right?
does anyone know at which frequency the inductor values are measured?
In all these calculator for cross overs are values for the inductors. But the value of an inductor differs a lot over the frequencies right?
At the crossover frequency, or more accurately the filter resonance frequency, the inductor reactance is the same as that of the capacitor.
Primarily the impedance of a single inductor goes up with frequency. This impedance will be a straight line on a linear scale.
Primarily the impedance of a single inductor goes up with frequency. This impedance will be a straight line on a linear scale.
Just an example as in the attached picture
Is the value of the inductors mentioned here for 250 Hz or - as inductor values are mostly measured - at 1 khz?
Is the value of the inductors mentioned here for 250 Hz or - as inductor values are mostly measured - at 1 khz?
They are always given at the specified frequency & for the specified (flat, resistive) impedance, since that is what the user is interested in.
The inductor value is measured in mH. This is not a measure of impedance. Your question of frequency is therefore irrelevant.
The inductance can be considered pretty much constant within the audible frequency range, it's the reactance that is a function of frequency according to the formula Xl = j*2*pi*Freq*L.
re:'at which frequency the inductor values are measured" - the inductance value and DC resistance are independent of frequency, the AC Impedance varies with frequency, and needs to be measured for the apllication, i.e. for a loudspeaker crossover, you would use the impedance value at your chosen crossover frequency.
