I have 16 Ga laminated core inductors in my speakers. I am considering upgrading them to an alpha-core 12 Ga. inductors. The 12 Ga. alpha-core inductor has the same DCR as the 16 Ga. laminated core does. Maybe a 12 GA hex wound aire coil. Maybe a 12 Ga laminated core inductor with lower DCR and a lower Mh.
I have been told to upgrade and have been told I am wasting my time.
These inductors are in series with my woofer in a second order two way system where the crossover is appox. 2K.
I don't want to waste money the inductors are appox. $60.00 each.
Any comments?
I have been told to upgrade and have been told I am wasting my time.
These inductors are in series with my woofer in a second order two way system where the crossover is appox. 2K.
I don't want to waste money the inductors are appox. $60.00 each.
Any comments?
I think it depends on everything else. High resolution mid/bass and tweeter drivers? Associated electronics?
I do prefer the foil inductors, but if the system is not capable of reproducing the difference, then obviously it would be a waste of money.
One possibility would be to sum the two channels to mono, or use a mono source, and modify just one unit. Breakin, and compare. If no difference is heard, then you're only out half the money.
Rule of thumb for breakin is 40 hours. I prefer not to listen during the breakin period if possible, to avoid acclimation.
I do prefer the foil inductors, but if the system is not capable of reproducing the difference, then obviously it would be a waste of money.
One possibility would be to sum the two channels to mono, or use a mono source, and modify just one unit. Breakin, and compare. If no difference is heard, then you're only out half the money.
Rule of thumb for breakin is 40 hours. I prefer not to listen during the breakin period if possible, to avoid acclimation.
I don't see how an air-core inductor could possibly make an audible difference in a real circuit.
Out of experience with almost all types of inductors, light gauge, heavy gauge, ribbon, air, typically cored, heavily and specially cored etc, in maybe 100 hi-fi and pro audio projects in my life I must admit that inductors do sound different. Reality is that heavy gauge and copper quality do reduce audible distortion and bring slam and 3D into the recipe. Main thing is to estimate correctly their application taking into account the resolution and power class that the speaker is going to cater for. Just because a non compromised crossover can outcost many driver combinations its a matter of budget vs quality factor. The class of components must be specified early and all designing and testing must be carried out with specified class of components. Arbitrary upgrading changes for completely tested speakers with originally lesser gauge coils and inferior caps changes the intended balance. Sometimes for the better in most areas, sometimes not. Its a matter of what the designer has done. Because if the losses are counted in, its easy to unbalance. Harbeths for example. UK monitors are the most sensitive in that respect. Danish are less difficult but be careful there too. American and German or French loudspeakers are almost always going for the better without surprises with coil / cap upgrades.
12gauge Alphacores and toroidal core in big values are among best choices. Don't underestimate the distortion reduction that a heavy coil brings into tweeter circuits too. After all, coils are just many metres of copper (or exotic) wire and sound like it. If budget allows choose heavy.
12gauge Alphacores and toroidal core in big values are among best choices. Don't underestimate the distortion reduction that a heavy coil brings into tweeter circuits too. After all, coils are just many metres of copper (or exotic) wire and sound like it. If budget allows choose heavy.
454Casull said:
Better to try hearing than seeing, little cricket...🙂
Steel or ferrite core coils have two disadvantages; the seriousness depends on the application. First, a core will saturate at some level; more likely at low frequencies, and current dependent of course. A good large core won't saturate in actual use, a small one can. Secondly, all cores have some hysteresis. Not audible with steel cores in a woofer, or in any event, not to me. With a 2 kHz XO, I'd listen to see if there is an audible effect.
The advantage of a core is that the inductance is quite a bit higher for a given number of turns, so resistance is lower. Useful in woofer circuits where you may not want the loss or change in Q.
Of course you take into account the real resistance...
EDIT: I didn't see that he was using steel-core inductors. What I meant was that there should not be any difference between air-core inductors.
EDIT: I didn't see that he was using steel-core inductors. What I meant was that there should not be any difference between air-core inductors.
I find a mild improvement from using foil inductors. Greater resistance to magenetostriction effects? Metal purity? No idea. Try it with a high resolution (real resolution) driver. If you hear a difference, or not, you'll have the answer for yourself.
I have found that foil inductors are good if your design is first or second order and when the inductor has pretty good influence from 1KHz up. Otherwise normal air core or C core are good.
Foil inductors are said to have lower interwinding capacitance which could make a difference, at least in theory.
They also have much lower mechanical resonances. A few years ago a German DIY magazine showed measurements for a number of different types of inductors which they tested. All inductors had mechanical resonances somewhere around 2 kHz (if I remember correctly), except the foil inductors which showed vanishingly low resonances. I would assume that the impedance is going up at the resonance frequency.
They also have much lower mechanical resonances. A few years ago a German DIY magazine showed measurements for a number of different types of inductors which they tested. All inductors had mechanical resonances somewhere around 2 kHz (if I remember correctly), except the foil inductors which showed vanishingly low resonances. I would assume that the impedance is going up at the resonance frequency.
My speakers are Merlin VSM-M. They are using Hovland 16 Ga laminated care inductors in series with the woofer in a second order design. I was considering the Alpha-core 12 GA inductor that would raid my DCR .01 ohm. I am also considering the 12 Ga Erse Super Q coil that would reduce my DCR by .12 ohms. My coil is 2.20 Mh.
If a coils don't sound differant then how can speaker wire?
If a coils don't sound differant then how can speaker wire?
454Casull said:
Note to self: do not post after 10 pm!
AFAIK, the foil inductors tend to be high grade purity copper; wire varies all over the place from generic magnet to OFHC.
I am leaning toward the 12 GA Goertz Alpha-core 1.20 Mh foil inductor. The DCR on the Alpha-core is .141. My 1.225 Mh 16 Ga laminated core inductor (from what I can guess) is .131 ohm. These should be an almost perfect swap. The woofer is a Scan speak 18W/8545 and is crossed over at 2150hz.
I can't get the Erse super Q in 1.2 Mh at 12 Ga or 14 Ga.
I could go with a 10 Ga air coil inductor, but the cost is $20.00 more each. The DCR of the 10 Ga inductor is .09.
I can't get the Erse super Q in 1.2 Mh at 12 Ga or 14 Ga.
I could go with a 10 Ga air coil inductor, but the cost is $20.00 more each. The DCR of the 10 Ga inductor is .09.
I don't know if it is worth the extra money for the 10 Ga air coil.
I am torn between the Northcreek and the Alpha-core.
$40.00 for the Alpha-core 12 Ga or $68.00 for the Northcreek 10 Ga air core.
Thanks for the link to the Northcreek music foil inductor Q and A. I didn't see that before.
I am torn between the Northcreek and the Alpha-core.
$40.00 for the Alpha-core 12 Ga or $68.00 for the Northcreek 10 Ga air core.
Thanks for the link to the Northcreek music foil inductor Q and A. I didn't see that before.
I could see that for an equivalent inductance, the foil inductor MIGHT have a lower DCR (I doubt it), but does that mean OFC speaker cables sound better than plain copper cables? 😀Curmudgeon said:
As for mechanical resonance, dunking it in silicone or something might get rid of it.
So I found this web page: http://www.goertzaudio.com/foil.html
1 - Negligible skin effect below 100 kHz; many orders of magnitude below conventional wire-wound types.
2 - High winding tension and vacuum fusing of faces provide high dimensional stability, effectively locking the conductors in place. Wire-wound inductors, which allow relative motion of conductors due to electromagnetic forces, will exhibit FM distortion by the process of reactance modulation.
3 - Flat inductive reactance from 5 Hz to 50 kHz.
4 - No saturation distortion due to air-core design.
5 - Reduced power loss. Highest space factor (ratio of conductor cross area to total cross-section) means lower DC resistance within comparable dimensions. Negligible power loss due to skin-effect.
6 - Extremely low stored charge.
7 - Cool operation even during prolonged high output power operation. The high space factor and winding density results in improved heat dissipation.
1 - Maybe I'm stupid or something, but why would you want an inductor to have low resistance at high frequencies?
2 - Fill the air space in a wirewound with something.
3 - Formula for inductance - I don't see frequency anywhere
4 - Not exclusive to foil inductors.
5 - Maybe. I don't know any measurements off the top of my head.
6 - Same as 5.
7. Wouldn't a lower winding density increase heat dissipation?
1 - Negligible skin effect below 100 kHz; many orders of magnitude below conventional wire-wound types.
2 - High winding tension and vacuum fusing of faces provide high dimensional stability, effectively locking the conductors in place. Wire-wound inductors, which allow relative motion of conductors due to electromagnetic forces, will exhibit FM distortion by the process of reactance modulation.
3 - Flat inductive reactance from 5 Hz to 50 kHz.
4 - No saturation distortion due to air-core design.
5 - Reduced power loss. Highest space factor (ratio of conductor cross area to total cross-section) means lower DC resistance within comparable dimensions. Negligible power loss due to skin-effect.
6 - Extremely low stored charge.
7 - Cool operation even during prolonged high output power operation. The high space factor and winding density results in improved heat dissipation.
1 - Maybe I'm stupid or something, but why would you want an inductor to have low resistance at high frequencies?
2 - Fill the air space in a wirewound with something.
3 - Formula for inductance - I don't see frequency anywhere
4 - Not exclusive to foil inductors.
5 - Maybe. I don't know any measurements off the top of my head.
6 - Same as 5.
7. Wouldn't a lower winding density increase heat dissipation?
Do inductors have a sound?
Yes, they do. Always a bad sound!
Since my first try on active xover at the woofer in my 3-way, I never go back to passive, ever, not in this life.
For a 2-way, it's also preferable to get a midbass with smooth rolloff on top & use minial passive xover. (the kind with only a small cap on tweeter... )
Inductors & heavy attenuations always suck the life out of speakers. Avoid them as much as possible, please.
In a 3-way, try active on the bass portion at least. That won't cost you very much, since we all have surplus amps lying around, don't we? And those exotic coils don't come cheap.
Yes, they do. Always a bad sound!
Since my first try on active xover at the woofer in my 3-way, I never go back to passive, ever, not in this life.
For a 2-way, it's also preferable to get a midbass with smooth rolloff on top & use minial passive xover. (the kind with only a small cap on tweeter... )
Inductors & heavy attenuations always suck the life out of speakers. Avoid them as much as possible, please.
In a 3-way, try active on the bass portion at least. That won't cost you very much, since we all have surplus amps lying around, don't we? And those exotic coils don't come cheap.
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