Noob DIY crossover question Inductor values

[Spuddywuddy]

I want to build my own crosover for the KEF Q350's. Oh boy! I found a link on this forum to a website from a guy named Alex who made a network for them. You can find it here

As I am trying to order the parts I came across a problem. The inductors have 2 values, Henry and Ohm. My problem is that when I search in an online store I can't find the inductors with those exact values. For example, one of the inductors needs to be 220 micro-Henry and 330 Milli-Ohm. The web store that I'm looking in is called soundimports.eu (I'm in Belgium) and when filtering on inductors that are 220 micro-Henry (or 0.22 Milli-Henry) I get 3 results, but none of them are 330 Milli-Ohm.

What do? Can I deviate slightly from one of those values and if so, which value is most important? Or should i find another store where they do have the exact same value inductor?

 

[iMickey503]

https://www.unitconverters.net/inductance/millihenry-to-henry.htm

This may help.

 

[Spuddywuddy]

https://www.unitconverters.net/inductance/millihenry-to-henry.htm

This may help.

I don't think you read my post

 

[Renato]

I want to build my own crosover for the KEF Q350's. Oh boy! I found a link on this forum to a website from a guy named Alex who made a network for them. You can find it here

As I am trying to order the parts I came across a problem. The inductors have 2 values, Henry and Ohm. My problem is that when I search in an online store I can't find the inductors with those exact values. For example, one of the inductors needs to be 220 micro-Henry and 330 Milli-Ohm. The web store that I'm looking in is called soundimports.eu (I'm in Belgium) and when filtering on inductors that are 220 micro-Henry (or 0.22 Milli-Henry) I get 3 results, but none of them are 330 Milli-Ohm.

What do? Can I deviate slightly from one of those values and if so, which value is most important? Or should i find another store where they do have the exact same value inductor?

Henry is the unit for setting the inductance value...and this is the value responsible for filtering your crossover.

But every coil has a small resistance and so this second value you have in the unit stipulated in Ohms.

In practice, buy the coil with the same value as Henry and partially ignore the value in Ohms.

The better the coil, the lower the resistance and the better for the filter...

A coil with 12AWG wire will have a lower resistance than another coil with the same value but with 18AWG wire....

English is not my native language and I had to ask Google Translate for help... rsrsr

 

[sergeauckland]

The inductance value sets the crossover frequency together with any capacitance, but the coil's resistance matters as it sets the amount of attenuation and how steeply the filter acts, at least initially. An inductor in series with the bass driver will also affect the amount of damping, so lower resistance is generally preferred.
If you want to replicate the exact crossover, you'll need to use the correct values, if you can't get those, then the crossover will be different, but how much that matters will require measurements.

In general, if the inductors have a lower resistance, then that's likely to be less harmful than higher resistance, but it will require measurements to ascertain how much difference there is.

One more reason for preferring a DSP-based active crossover....

S

 

[Adam_M]

The better the coil, the lower the resistance and the better for the filter...

A coil with 12AWG wire will have a lower resistance than another coil with the same value but with 18AWG wire....

I wouldn't go that far. If it is in series with a woofer, sure - the lower the better. I'll often use laminate core inductors in that location. If it is in series with the mid, it can affect the padding to a certain extent, although there's probably also a resistor in series and perhaps in parallel to help with attenuation that will more or less overwhelm the inductor resistance. ...And it's pretty rare to see an inductor in series with a tweeter, although I have seen a TINY inductor used to slow the rising response in the top octave.

Where inductor resistance matters most is in the shunt sections of the XO, as small changes in resistance can change the shape of the knee and the ultimate slope of the rolloff - which while important for proper frequency response, also significantly affect the phase response and matching around the crossover frequency. I've found that swapping from 16ga to 20ga inductors of the same value can significantly affect the phase coherence of the 2 drivers at the design axis.

With that said, if you are +-5% of either component, there's absolutely no cause for concern, and I'd probably be happy with +-10% on the resistance.

 

[Jim Matthews]

In practice, buy the coil with the same value as Henry and partially ignore the value in Ohms.

The better the coil, the lower the resistance and the better for the filter...

English is not my native language and I had to ask Google Translate for help... rsrsr

As a native English speaker, I could not have said this better.

Kudos

 

[Spuddywuddy]

Thank you all for the replies. I have learned a lot.