Saturation will make a steel core inductor in a crossover less good than an air coil.
But when happens the saturation?
Is this only at high currents? So then a steel core inductor gives alway good sounds at low volume levels.
When saturation is only dependend of the current then we can use an air coil in series with woofer because the current is highest. So there is no need to use air coils in notch filters and low current tweeter filters?
At what power or current will saturation be audible? And what is the effect on sound? Harmonic distortion only at high volume levels?
But when happens the saturation?
Is this only at high currents? So then a steel core inductor gives alway good sounds at low volume levels.
When saturation is only dependend of the current then we can use an air coil in series with woofer because the current is highest. So there is no need to use air coils in notch filters and low current tweeter filters?
At what power or current will saturation be audible? And what is the effect on sound? Harmonic distortion only at high volume levels?
If the core saturates, the inductor will loose the inductance. Compare a toroid transformer under startup conditions.
You should pick a core which can handle the current you'll have in mind. The other more obvious side effect is maybe unlinearity and hysteresis.
You choose iron core (of some kind) when you want high inductance and rather low resistance.
You should pick a core which can handle the current you'll have in mind. The other more obvious side effect is maybe unlinearity and hysteresis.
You choose iron core (of some kind) when you want high inductance and rather low resistance.
Use air core if you can accept the higher cost or resistance. It will have less distortion.
Use cored if you have to have low resistance.
Larger cores will handle more current before saturation. Cores for inductors usually have large air-gaps, like rod cores and such. The will saturate gradually, gradually increasing distortion.
Use cored if you have to have low resistance.
Larger cores will handle more current before saturation. Cores for inductors usually have large air-gaps, like rod cores and such. The will saturate gradually, gradually increasing distortion.
Thanks for the aswers.
But at what power or current has saturation effect?
Is the distortion bad?
Many people use tube amplifiers to create some kind of distortion.
When saturation creates second and third harmonic distortion it will be good? Tube amps create also distortion and sound more natural.
But at what power or current has saturation effect?
Is the distortion bad?
Many people use tube amplifiers to create some kind of distortion.
When saturation creates second and third harmonic distortion it will be good? Tube amps create also distortion and sound more natural.
Typical budget iron cores will begin to saturate during normal to slightly loud listening.Jonasa said:
It can be. By losing the inductance you may hear parts of a driver's range that sound bad. By using two saturating iron cored inductors you may notice interactions between them.
My point is that the distortion is not consistent.
.No.
Oh-oh!!!!
In home audio I would ascribe the subjective superiority (to some including me) of tube amps to the several benefits they could have; the higher harmonic distortion being a backdraw and NOT the reason for their good performance (besides, measured distortion patterns of tube and transistor amps do not necessarily differ much). Some benefits of a minimalistic set amp versus a typical commercial transistorised amp (push-pull) that come to mind:
- minimum component count in signal path
- much better phase behaviour due to the absence of negative feedback
- no crossover region distortion
- ??????
...which mainly translates into better midrange. Needless to say there are many backdraws much greater than the slightly higher harmonic distortion that go with sets.
To answer your original question :
The way I understand it is that the 'distortion' you'll get with a saturated X-over coil is simply that the crossover won't work as planned but e.g. in the case of a first order low-pass filter the woofer crossover point will shift upwards = subjectively more midrange + break-up resonances will come through with more bite (especially in the case of alu-cone // kevlar etc. woofers). Iron-cored coils are only used because they are cheap, small and have low DCR for a given price.
Groets -- Simon
If you're referring to guitar-amps you're right.
In home audio I would ascribe the subjective superiority (to some including me) of tube amps to the several benefits they could have; the higher harmonic distortion being a backdraw and NOT the reason for their good performance (besides, measured distortion patterns of tube and transistor amps do not necessarily differ much). Some benefits of a minimalistic set amp versus a typical commercial transistorised amp (push-pull) that come to mind:
- minimum component count in signal path
- much better phase behaviour due to the absence of negative feedback
- no crossover region distortion
- ??????
...which mainly translates into better midrange. Needless to say there are many backdraws much greater than the slightly higher harmonic distortion that go with sets.
To answer your original question
:The way I understand it is that the 'distortion' you'll get with a saturated X-over coil is simply that the crossover won't work as planned but e.g. in the case of a first order low-pass filter the woofer crossover point will shift upwards = subjectively more midrange + break-up resonances will come through with more bite (especially in the case of alu-cone // kevlar etc. woofers). Iron-cored coils are only used because they are cheap, small and have low DCR for a given price.
Groets -- Simon
Jonasa said:Does anybody know what the difference in sound is between air and non air inductors.
What is the effect on woofer, tweeter or in case of notch filters?
There isn't any until the iron core saturates. With good iron core or ferrite this will not hapen until the speaker is so stressed you wouldn't notice anyway. Buy cored inductors when they are more than 1mH, it only makes sense. Cored inductors have lower DCR, better "Q".
I've used Erse iron core coils; the best I've seen.
http://www.erse.cc/coils/ov/coils.asp I used the Super Q hammerheads as I needed lowest possible DC resistance in series with the woofer.
In general, air cores are preferred. I prefer to use foil inductors, but unless you're pretty picky they're not necessary. A coil in series with the woofer especially, and to a lesser extent the mid, should usually be as low in resistance as possible.
In a series trap (L-C-R) you can use a small gauge wire for the L. For example, if the trap calls for 5 ohms, just subtract the coil resistance from the R; 5-1.- 1.4 Ohms, for a 3.6 Ohm resistor, and a total of 5 ohms.
When mounting the coils on the XO board, if they are close (within 2 inches?) mount them at right angles to each other to minimize coupling. One flat, and one on edge for example.
By all means stay away from ferrite cored inductors. I remember a system a friend had with those in it, and when he played it loudly, the core would saturate and collapse, making a "crack" noise. That's a big reason why I tend to be very conservative on the size of the steel core coils.
http://www.erse.cc/coils/ov/coils.asp I used the Super Q hammerheads as I needed lowest possible DC resistance in series with the woofer.
In general, air cores are preferred. I prefer to use foil inductors, but unless you're pretty picky they're not necessary. A coil in series with the woofer especially, and to a lesser extent the mid, should usually be as low in resistance as possible.
In a series trap (L-C-R) you can use a small gauge wire for the L. For example, if the trap calls for 5 ohms, just subtract the coil resistance from the R; 5-1.- 1.4 Ohms, for a 3.6 Ohm resistor, and a total of 5 ohms.
When mounting the coils on the XO board, if they are close (within 2 inches?) mount them at right angles to each other to minimize coupling. One flat, and one on edge for example.
By all means stay away from ferrite cored inductors. I remember a system a friend had with those in it, and when he played it loudly, the core would saturate and collapse, making a "crack" noise. That's a big reason why I tend to be very conservative on the size of the steel core coils.
http://www.northcreekmusic.com/COILS.html
This webpage addresses amongst others the issue of ferrite core inductors
This webpage addresses amongst others the issue of ferrite core inductors
Thanks for the answers there are real specialists on this forum.
For several months i'm busy with a design of a crossover.
I looks realy nice now. I use lspcad for simulation.
But before I order components I must know it for sure about the inductors.
So it would be good to use a coil for the first order filter that I'll use for woofer.
But to flatten the frequency response I've used several noth filters in my design. Because I want to keep the Q factor high I need to use large L.
The crossover design is for realy small speakers so I have not much space for big inductors.
The inductors in the notch filters are between 1 and 2 mH.
Current in noth filters is not so high. (correct me if not)
So would it give a difference in sound when I only use steal core inductors for the notch filter? With good luck they never reach the saturation level.
But will the hystersis of the inductors be audible in sound? Are there some tests that I can do with a functiongenerator and oscilloscoop???
For several months i'm busy with a design of a crossover.
I looks realy nice now. I use lspcad for simulation.
But before I order components I must know it for sure about the inductors.
So it would be good to use a coil for the first order filter that I'll use for woofer.
But to flatten the frequency response I've used several noth filters in my design. Because I want to keep the Q factor high I need to use large L.
The crossover design is for realy small speakers so I have not much space for big inductors.
The inductors in the notch filters are between 1 and 2 mH.
Current in noth filters is not so high. (correct me if not)
So would it give a difference in sound when I only use steal core inductors for the notch filter? With good luck they never reach the saturation level.
But will the hystersis of the inductors be audible in sound? Are there some tests that I can do with a functiongenerator and oscilloscoop???
Hi,
Is there a way to calculate the DCR of an inductor from its value and wire gauge or something?
I have been getting to grips with passive Xover simulation using the FRD consortium tools and Speaker Workshop. I have what seems to be a good Xover design but when I remembered to add some DCR to each inductor (I tried 1 ohm for each inductor?) it got pretty messed up. Some things I couldn't seem to compensate by changing other values.
So, what is a common DCR for good air-core inductors? For something small like 0.5mH and something bigger like 1.5mH? Just to give me an idea...
Do foil inductors have lower DCR? What are their negatives/advantages, high capacitance, low resistance maybe?
Is there a way to calculate the DCR of an inductor from its value and wire gauge or something?
I have been getting to grips with passive Xover simulation using the FRD consortium tools and Speaker Workshop. I have what seems to be a good Xover design but when I remembered to add some DCR to each inductor (I tried 1 ohm for each inductor?) it got pretty messed up. Some things I couldn't seem to compensate by changing other values.
So, what is a common DCR for good air-core inductors? For something small like 0.5mH and something bigger like 1.5mH? Just to give me an idea...
Do foil inductors have lower DCR? What are their negatives/advantages, high capacitance, low resistance maybe?
Under normal listening condition Iron Core inductors sound better due to its low DCR. Loudspeaker will sound bright and harsh if air core inductor is used in low pass circuit in 2-way system designed for flat response. If you use air core you need to pad down the tweeter by a db or a half and you need more powerful amplifier.
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Unfortunately - or fortunately - different ferromagnetic
core materials behave fairly different.
Also dimensions of the coil and the core play a
significant role.
This supplier provides some distorsion measures
for his "iron core" coils.
Unfortunately in german, maybe you can find
an english version too.
http://docs.ts-audio.de/a/ax/svqxmzqwnjaw/ite/it_grundlagen_drosselspule.pdf
There are some cores which come somewhere near
to an aircoil, at least from upper bass upwards.
When weighting the pros and cons
my personal limit for an aircore might be
1 ... 2.2 mH depending on the application.
For significantly higher inductance i would look
for a good core material.
You need lots of wire in an aircore for larger values
if you want acceptable Rdc. *
Independent from the core material, the windings
of a coil should be very tight and either
backed enamel should be used or the coil should
be vacuum drenched to keep it "silent".
I want to try this grain-oriented dynamo sheet
"I" cores, in the next weeks:
Lautsprecher Shop Intertechnik - I130/3.3/132 | I Kern :: Drosselspulen :: Frequenzweichenbauteile ::
---
* On the other hand, if you have reasons to increase effective Qts
of a woofer, a higher Rdc in a series inductor might be useful,
which may call for an aircore even with higher inductances as an
exception to the rule.
core materials behave fairly different.
Also dimensions of the coil and the core play a
significant role.
This supplier provides some distorsion measures
for his "iron core" coils.
Unfortunately in german, maybe you can find
an english version too.
http://docs.ts-audio.de/a/ax/svqxmzqwnjaw/ite/it_grundlagen_drosselspule.pdf
There are some cores which come somewhere near
to an aircoil, at least from upper bass upwards.
When weighting the pros and cons
my personal limit for an aircore might be
1 ... 2.2 mH depending on the application.
For significantly higher inductance i would look
for a good core material.
You need lots of wire in an aircore for larger values
if you want acceptable Rdc. *
Independent from the core material, the windings
of a coil should be very tight and either
backed enamel should be used or the coil should
be vacuum drenched to keep it "silent".
I want to try this grain-oriented dynamo sheet
"I" cores, in the next weeks:
Lautsprecher Shop Intertechnik - I130/3.3/132 | I Kern :: Drosselspulen :: Frequenzweichenbauteile ::
---
* On the other hand, if you have reasons to increase effective Qts
of a woofer, a higher Rdc in a series inductor might be useful,
which may call for an aircore even with higher inductances as an
exception to the rule.
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Steel core coils sold for audio use have what amounts to a very large air gap, which linearizes the coil, so that hysteresis is not a factor. I have never seen saturation in a steel core, and because the currents are so limited in a notch filter due to the narrow bandwidth, I am sure it would never be a problem. As mentioned several times above, DC resistance is an issue, which steel cores minimize, but in a Series notch (R-L-C) part of the R can be in the coil, just so long as the discrete R and the coil R add to the desired value. In the parallel notch |-L+Rc|
o-|-C-|-o
|-R-|
it's a little trickier, but your optimizer/simulator will get you through. Tape wound air core coils are my preference, then steel core, then wire.
Don't spend a lot of concern on the issue, as your use in notch filters will minimize the sonic impact in any event.
o-|-C-|-o
|-R-|
it's a little trickier, but your optimizer/simulator will get you through. Tape wound air core coils are my preference, then steel core, then wire.
Don't spend a lot of concern on the issue, as your use in notch filters will minimize the sonic impact in any event.
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