# LCR multimeters for XO design



## Jason Schultz (Jul 31, 2007)

Hi 
I'm still gathering vital info before i plunge into building speakers from scratch.
Question: Does anyone use LCR multimeters for design and testing of cross overs. How useful are they. I came across one which seems to (in catalogue)
measure the value ranges commonly encountered with xo Design. I'm sure there are issues with these. Can anyone tell me please

Jason


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## Bill Fitzmaurice (Jun 14, 2008)

Jason Schultz said:


> LCR multimeters for design and testing of cross overs. How useful are they.


Not useful at all except when impedance testing. The most useful tool for crossover design is an RTA, which allows you to view the effect of component value swapping.


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## drf (Oct 22, 2006)

you'll get better milage out of a multi meter that does inductance and capacitance.


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## JCD (Apr 20, 2006)

Bill Fitzmaurice said:


> Not useful at all except when impedance testing. The most useful tool for crossover design is an RTA, which allows you to view the effect of component value swapping.


Agreed.. but wouldn't you want to test the various components to be sure that the value on the part is correct? 

I would also think it would be kind of necessary if/when you need to get to a specific inductor value by unwinding some of the turns.



drf said:


> you'll get better milage out of a multi meter that does inductance and capacitance.


I'm really not being facetious, but isn't that what an LCR multimeter is? Or is there a difference?

JCD


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## Bill Fitzmaurice (Jun 14, 2008)

JCD said:


> Agreed.. but wouldn't you want to test the various components to be sure that the value on the part is correct?


 I buy 5% or better parts and don't kvetch about it.



> I would also think it would be kind of necessary if/when you need to get to a specific inductor value by unwinding some of the turns.


 Few meters will read the high inductance values used in crossovers. The way to do this is by comparing the measured Le and DCR of the coil to that of a coil of known Le and DCR values, using standard speaker impedance measuring gear.


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## looneybomber (Sep 20, 2006)

LCR = Left Center Right?
What does LCR mean in this case.


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## Jason Schultz (Jul 31, 2007)

L stands for impedance , C- capacitance and R- resistance. I was thinking to use the inductance measurement to measure a coil as i unwound it to get target value. And to use the capacitance to make sure any capacitors i wired in parrallell were in fact the correct value before inserting them into the the XO. also you could measure the dc resistance of part of a XO to work out any insertion losses from inductors (I bet there's already a formulae for this ?) The meter I am looking at is thisage 37 of the pdf file LCR 9053:http://www.wagner.net.au/catalogue/14_Tools.pdf would this be useful?


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## Bill Fitzmaurice (Jun 14, 2008)

Just be sure it will go to at least 100uF and 10mH. As for insertion loss just be sure the DCR spec is less than 10% of the load impedance.


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## Jason Schultz (Jul 31, 2007)

Thanks Bill !


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## drf (Oct 22, 2006)

JCD said:


> I'm really not being facetious, but isn't that what an LCR multimeter is? Or is there a difference?
> 
> JCD


My bad, there is no difference, only in my head!! :dumbcrazy: 

No, back when I studied EE (just before valves made a comeback in audio) an LCR meter was a device used to measure two values of the one component; I.E L+Q, R+Q, C+R, phase angle etc. To call a device that measure L, C or R individually an LCR meter was the same as calling my DMM a VARFTLTDC meter because it does volts, amps, resistance, frequency, temp, inductance, transistor, diode and capacitance.

But ignore my rambling becasue my post was made assuming Jason was refering to an $800+ device that has limited use in Audio.


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## DrGeoff (Dec 27, 2007)

Jason Schultz said:


> L stands for impedance , C- capacitance and R- resistance. I was thinking to use the inductance measurement to measure a coil as i unwound it to get target value. And to use the capacitance to make sure any capacitors i wired in parrallell were in fact the correct value before inserting them into the the XO. also you could measure the dc resistance of part of a XO to work out any insertion losses from inductors (I bet there's already a formulae for this ?) The meter I am looking at is thisage 37 of the pdf file LCR 9053:http://www.wagner.net.au/catalogue/14_Tools.pdf would this be useful?


L = Inductance
C = Capacitance
R = Resistance

Most meters tend to do this at 1kHz, which is OK for audio work. Measurement tolerance might not be great though, depending on the meter.

If you have a CRO and signal generator you can simply use parallel resonance to measure the inductance value using a known value capacitor and watching for the current/voltage phase relationship.


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## Aaron Gilbert (Nov 12, 2008)

Bill Fitzmaurice said:


> Not useful at all except when impedance testing. The most useful tool for crossover design is an RTA, which allows you to view the effect of component value swapping.


I disagree. I use an LCR meter to test crossover components on occasion. It's by far the easiest tool for that task. Most of the time, inductors are not marked with a value, unlike capacitors, and it's a very useful tool when dewinding. Clip on a couple leads and you're done in seconds. Now as for crossover _design_, I agree, they're not much use at all.


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