DCR of a coil is constant, it's the resistance that you measure with a multimeter, you mixed up with impedance
No, for mids and tweeters the DCR of the coil is not important, the distortion of the coil is much more important.
So for mids and tweeters: aircore, you don't want the distortion of an iron core in the mid and high freq.
DCR of a coil has a big effect on the damping factor of the woofer, here you want the lowest possible resistance.
It is not only the saturation distortion, iron cores have in the mids&highs more distortion than air cores without being saturated
It's how they are positioned that matters, see Troels guide on placement of coils
Thanks dannny,
the ohms number given for a coil model is the DCR or just the impedance at a given frequency ?
Which number is giving Arta or REW when measuring the resistance in the audio band, please ?
the ohms number given for a coil model is the DCR or just the impedance at a given frequency ?
Which number is giving Arta or REW when measuring the resistance in the audio band, please ?
Jantzen, Mundorf, intertechnik,... always specify the DCR resistance for a coil.
They measure the inductance of a coil mostly with 1v at 1khz
With REW you can measure the impedance of a speaker, driver or just a coil.
You then get an impedance graph (ohm - Hz)
They measure the inductance of a coil mostly with 1v at 1khz
With REW you can measure the impedance of a speaker, driver or just a coil.
You then get an impedance graph (ohm - Hz)
Ok, thanks for that, I didn't know the number they give was the continuous, and not the frequency one at 100 hz or 1 khz
No need to involve frequency to define L.
L = (0.2 x d2x N2) / (3d + 9l =10b)
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L = (0.2 x d2x N2) / (3d + 9l =10b)
- L = Inductance (in μH)
- d = Diameter of the inductor coil (Inches)
- l = Length of the indutor coil (inches)
- b = Diameter of the coil winding wire (inches)
- N = Total turns of wire.
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The resistance DCR is stated in ohm.
An inductor is not usually specified/described by an ohm figure for its impedance. Rather, its the inductance that is specified.
Like:
Indictor: 0,2 ohm, 1 uH. this means DCR is 0,2 ohm (not impedance).
I have never seen an inductor descried as e.g.: R=0,2 ohm, Z=13 ohm@1kHz. (but nothing wrong with it...)
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Yes TNT is correct again, but exceptions are sometimes seen (I seem to be finding many exceptions in this thread 🙂 ) when you specify an inductor using Ohms at several frequencies because you're describing either core variations or parasitic capacitance which can cause it to vary from being a simple inductance.
So to be sure, as it is ultimatly a vocabulary problem also for the basic enthusiast with low electricity understanding:
- What I add to the attenuation resistor to have the total Z to level the spl when having a coil as a low pass, so midrange cell, is the DCR of the coils.
illustration : 4 ohms attenuation resistance +0.5 DCR (given by the brand) of the low pass coil must be read 4.5 ohms.
- I don't mid the ESR at frequency given by the LCR function of LIMP or REW, but only look at the Henri value at 1000 hz when using an impedance/frequency tool as LIMP/REW. 1K hz being what most brands use for loudspeaker voice-coils datasheets.
- The DCR is what I enter in the Z option of the coils tunning in software like XSim. DCR is took by continuous current measurement, so the Z after is constant whatever the frequency. It is the internal loss of the coil and not its ESR (this last always related to a frequency)
If having a coil with no DCR marking, is it possible to find it without expensive precise DVM à la Fluke as the ESR given at 1 k hz is useless ? Or maybe the ESR at 10 hz from a sine wave would be close enough to the DCR number ?
- What I add to the attenuation resistor to have the total Z to level the spl when having a coil as a low pass, so midrange cell, is the DCR of the coils.
illustration : 4 ohms attenuation resistance +0.5 DCR (given by the brand) of the low pass coil must be read 4.5 ohms.
- I don't mid the ESR at frequency given by the LCR function of LIMP or REW, but only look at the Henri value at 1000 hz when using an impedance/frequency tool as LIMP/REW. 1K hz being what most brands use for loudspeaker voice-coils datasheets.
- The DCR is what I enter in the Z option of the coils tunning in software like XSim. DCR is took by continuous current measurement, so the Z after is constant whatever the frequency. It is the internal loss of the coil and not its ESR (this last always related to a frequency)
If having a coil with no DCR marking, is it possible to find it without expensive precise DVM à la Fluke as the ESR given at 1 k hz is useless ? Or maybe the ESR at 10 hz from a sine wave would be close enough to the DCR number ?
When you write "but only look at the Henri value at 1000 hz", it sound as if you think that the "Henri value", L, is dependent on frequency - it is not. The inductance of a coil is a fix value (in Henry) and it does not change with frequency. What is changing with frequency is its impedance Z. The ESR part R don't change with frequency.
"The DCR is what I enter in the Z option of the coils tunning software like XSIM." - are you sure its called "Z" option in XSIM - this is how mine look:
DCR is to be entered as ESR. You write "continuous current" - its called direct current or DC - hence DC R 😉
"DCR is took by continuous current measurement, so the Z after is constant whatever the frequency. It is the internal loss of the coil and not its ESR (this last always related to a frequency)"
->
Z is the letter to describe Impedance - and impedance could be R only and that impedance would not vary with frequency - an impedance with a reactive part (L or/and C) would vary its impedance with frequency. You measured an inductor and therefore the Z will NOT be constant. It's (ES)R would.
- "It is the internal loss of the coil and not its ESR" - vocabulary again - the reactive part (the pure L part) of a coil that varies with frequency is a desired property, not a loss - what is actually/usually seen/described as a loss in an inductor is the ESR 🙂
- "not its ESR (this last always related to a frequency)" - the last (ESR) is what is not related (dependent) to frequency.
The ESR part of an indictors impedance don't change with frequency. The reactive part of an indictors impedance (the "pure" L part) change with frequency.
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"The DCR is what I enter in the Z option of the coils tunning software like XSIM." - are you sure its called "Z" option in XSIM - this is how mine look:
DCR is to be entered as ESR. You write "continuous current" - its called direct current or DC - hence DC R 😉
"DCR is took by continuous current measurement, so the Z after is constant whatever the frequency. It is the internal loss of the coil and not its ESR (this last always related to a frequency)"
->
Z is the letter to describe Impedance - and impedance could be R only and that impedance would not vary with frequency - an impedance with a reactive part (L or/and C) would vary its impedance with frequency. You measured an inductor and therefore the Z will NOT be constant. It's (ES)R would.
- "It is the internal loss of the coil and not its ESR" - vocabulary again - the reactive part (the pure L part) of a coil that varies with frequency is a desired property, not a loss - what is actually/usually seen/described as a loss in an inductor is the ESR 🙂
- "not its ESR (this last always related to a frequency)" - the last (ESR) is what is not related (dependent) to frequency.
The ESR part of an indictors impedance don't change with frequency. The reactive part of an indictors impedance (the "pure" L part) change with frequency.
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Yes, ESR is only from inherent resistivity of the wire excluding inductive effects and is the same regardless of the current type (AC or DC), so DCR is ESR on the otherhand impedance Z (occurs from the inductive effects) is frequency varient and so the total resistance at a specific frequency is the ESR + Z (generated by inductive effects).
I purchased this 2 weeks ago : https://www.ebay.com/itm/261114892135?hash=item3ccba90f67:g:CUEAAOSwDN1UTTmg
Performing a sine from 15k hz to 750 k hz is then useless for checking our (loudspeaker) filter voice coils ? The owner told me that is acurate for low values, mostly in the nH and pF range.
@danny66 told loudspeaker coils makers measure mostly at 1 k hz/1V to give the Henri value, which seems not correct at reading TNT #51 post.
So what is the technic brands perform to give the "fix" H value of the coils?
What the way to do to have the Henri and DCR of a loudspeaker coil with no marking for an audio enthusiast ? Needs several tools ?
Performing a sine from 15k hz to 750 k hz is then useless for checking our (loudspeaker) filter voice coils ? The owner told me that is acurate for low values, mostly in the nH and pF range.
@danny66 told loudspeaker coils makers measure mostly at 1 k hz/1V to give the Henri value, which seems not correct at reading TNT #51 post.
So what is the technic brands perform to give the "fix" H value of the coils?
What the way to do to have the Henri and DCR of a loudspeaker coil with no marking for an audio enthusiast ? Needs several tools ?
It's fine. Your question means you'd did not get all what was written earlier.
You dont measure L at a certain frequency. You can measure at 100, 1k, 10k or 100k and you will come to the same inductance. Remember this now! 😎
Say after me please: An inductor has a certain impedance at a certain frequency but the inductance (the L value) is the same at all frequencies.
Use you meter that you showed above - its fine. If you dont trust it - take an inductor and measure it and compare with the inductor specification. If its within 5-10% its OK and now you can trust it for any other measurement.
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I like to plot inductors vs frequency, at least look at them on a scope while increasing the frequency. This way I can determine the self-resonance frequency where they resonate with their parasitic capacitance, or other variations which signal the region where they become unusable.
..... The ACSEL is not fine as it is up to 20% difference in relation to Mundorf coils marking I do trust more. So there is something wrong meanwhile it measures capacitance below 1 uF (it has both capacitance and inductance measurement options) with great precision, something is wrong with inductance then, because :
"An inductor has a certain impedance at a certain frequency but the inductance (the L value) is the same at all frequencies."
I got it, what has decieved me is the inductor vs frequency performed with the resistor jigg test method gave me at 1K hz with the RLC function button (LIMP) exactly the measurement marked on the Mundorf coils, hence the beginning of my questions and confusion (plus the lack of basic knowledge of course).
Whatever the frequency/impedance is not giving the fix/only-one H value I see there is a good concistency at 1 khz between Limp result and what is marked on coils... ok, i understand now it is in such Limp tool, related to an unusefull impedance/frequency ratio for the need to have the Henri -fix- coil value I am looking for. As said someone elswhere iirc : such a tool will give you just an idea to know if two coil are paired enough. The way i understand it, is the Z value frequency related is low enough in coils with some layout like iron i-core at very low frequency below 1 k hz and something like 20 to 50 hz to give a good idea enough of the "true' fixe H value... something like that at least mixed up in my basic ununderstanding.
@AllenB , you mean after the resonance peak it becomes more and more capacitive ?
"An inductor has a certain impedance at a certain frequency but the inductance (the L value) is the same at all frequencies."
I got it, what has decieved me is the inductor vs frequency performed with the resistor jigg test method gave me at 1K hz with the RLC function button (LIMP) exactly the measurement marked on the Mundorf coils, hence the beginning of my questions and confusion (plus the lack of basic knowledge of course).
Whatever the frequency/impedance is not giving the fix/only-one H value I see there is a good concistency at 1 khz between Limp result and what is marked on coils... ok, i understand now it is in such Limp tool, related to an unusefull impedance/frequency ratio for the need to have the Henri -fix- coil value I am looking for. As said someone elswhere iirc : such a tool will give you just an idea to know if two coil are paired enough. The way i understand it, is the Z value frequency related is low enough in coils with some layout like iron i-core at very low frequency below 1 k hz and something like 20 to 50 hz to give a good idea enough of the "true' fixe H value... something like that at least mixed up in my basic ununderstanding.
@AllenB , you mean after the resonance peak it becomes more and more capacitive ?
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If a "cheap" measurement instrument can be forced to do its L measurements at different frequencies I can very well see that a difference could come up due to measurement or calculation errors.
You are nit the measurement close to some iron? Or other strong magnetic field? That could skew the measurement?
It's the same with capacitance - it doesn't get "more and more" capacitive with higher frequency - it's impedance changes - but C is fixed.
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You are nit the measurement close to some iron? Or other strong magnetic field? That could skew the measurement?
It's the same with capacitance - it doesn't get "more and more" capacitive with higher frequency - it's impedance changes - but C is fixed.
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If speakers can have lossy semi-inductance, giving X mH @1kHz and some other value at 10kHz, I can imagine something similar happening with other coils. This is why ferrite cores are often optimised for some set of frequencies. For ferrous materials the losses really do change with frequency, so the idea of a single inductance value as a lumped element is just a simplification.