wow that's a kinda weird conclusion given that background > all big electric machines use lots of big iron and Cu for eff. and economy. IMO if anything goes bang it's system / operator error. Also insulation lifetime is often overlooked for most failures. job satisfaction backlash
when the passive network approaches cost of drivers time to re-boot.
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Ok..
Meaning I understand that hysteresis and saturation curves make iron cored inductors less desirable for speakers...you choose what material suits the application and cost is always a factor.
Besides insulation failure is not often overlooked...(in electrical machines)
Meaning I understand that hysteresis and saturation curves make iron cored inductors less desirable for speakers...you choose what material suits the application and cost is always a factor.
Besides insulation failure is not often overlooked...(in electrical machines)
so does mean you have "insider" data that we should avoid iron laminated cores with large air gaps for woofers?
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Nope
I'm not a design engineer. Those guys are smart.
But someone said (Timpert?) that saturation characteristic curves are defined in design. Entirely correct. Although the same techniques are used to minimise harmonic distortion (air gap) as well as other techniques which are not generally applicable to static devices. (or maybe they are, though ive never seen a inductor core with corebars 😉)
But back OT, the only reason I have personally used ferrite cored coils, is cost. Otherwise I would have used air cored - though once you need more than say 3mH you have little choice to use a cored coil.
I used to see folks here using EI mains transformers as high inductance chokes, and I was never really convinced it was a good idea since theyre designed for 50/60Hz and without testing them the user would have no idea whatsoever how, when or to what degree they saturate.
I'm not a design engineer. Those guys are smart.
But someone said (Timpert?) that saturation characteristic curves are defined in design. Entirely correct. Although the same techniques are used to minimise harmonic distortion (air gap) as well as other techniques which are not generally applicable to static devices. (or maybe they are, though ive never seen a inductor core with corebars 😉)
But back OT, the only reason I have personally used ferrite cored coils, is cost. Otherwise I would have used air cored - though once you need more than say 3mH you have little choice to use a cored coil.
I used to see folks here using EI mains transformers as high inductance chokes, and I was never really convinced it was a good idea since theyre designed for 50/60Hz and without testing them the user would have no idea whatsoever how, when or to what degree they saturate.
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What if they took out the Is and stacked the Es?
Otherwise inductance would be high (for speakers). Some applications with DC can be used straight with a PT as they can handle small amounts of it as is.
Otherwise inductance would be high (for speakers). Some applications with DC can be used straight with a PT as they can handle small amounts of it as is.
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A good idea, I would imagine (not an expert myself), and it would seem a simple approach, given the availability of core kits where you build your own core from laminations and a plastic sleeve.
Someone who knows about this could answer regarding suitability of the specific type of steel used.
My only concern would be loss of mechanical strength by removing the interleaving I's. Could be easily cured with thinned down resin....
That happens:
Lautsprecher Intertechnik - Shop
A little difficult to see, but at the botttom of these inductors, the Is are missing
Thanks timpert for the example.
I have used power transformers as chokes in choke input power supply filters. The fact that a swinging choke can be used in this kind of position justifies that an interleaved power transformer of appropriate properties can be squeezed into duty. Though my preferred choke for this duty is one with a gapped core whose inductance sans the core meets the minimum (critical value), I see value in having a core here.. even though I normally use an air core if I can for the second choke if there is one.
Maybe also clamps/brackets/wedges. I keep a box of transformer mounting and assembly hardware, bells, insulators and so forth for these things.
I have used power transformers as chokes in choke input power supply filters. The fact that a swinging choke can be used in this kind of position justifies that an interleaved power transformer of appropriate properties can be squeezed into duty. Though my preferred choke for this duty is one with a gapped core whose inductance sans the core meets the minimum (critical value), I see value in having a core here.. even though I normally use an air core if I can for the second choke if there is one.
Is here anyone here equipped with distortion analyzer ? who can make compression of distortions of the air core and ferrite core.
So we just replace coils in the crossover and check the difference in distortions.
So we just replace coils in the crossover and check the difference in distortions.
Fuixing the inductor position
Ok is all right but is impossible to made a vibration free cabinet .
There are many small movements between woofer and the cross over inductor .
I think is so difficult to tell exactly the interaction from woofer and his inductor by
simple measurement of THD on woofer coil .
Ok is all right but is impossible to made a vibration free cabinet .
There are many small movements between woofer and the cross over inductor .
I think is so difficult to tell exactly the interaction from woofer and his inductor by
simple measurement of THD on woofer coil .
What was the voltage at the output of the amplifier? If you aren't dropping a significant voltage across the inductor then you won't be able to observe the effects of the inductance changing as it goes in and out of saturation, which is the mechanism that causes the distortion.
Fwiw I've tested an Erse 5mh and saturation was in the 10-20A range iirc.
how did you manage the test?
Erse are really nice inductors , super Q series at the top
ERSE - THD Test Drive
I'm without a spectrum analyser (old works HP was chucked a few weeks back and I wish I had tried it out and recycled it).
I wonder....would a power analyser work, with a power amp, shunt and sig gen?
I think it could, but id have to take many many single frequency points.
When I look over at Erse webpage, I have this warm sensation
in my guts that tells me this is a serious manufacturer which
won't disappoint although I've never had any business with them.
in my guts that tells me this is a serious manufacturer which
won't disappoint although I've never had any business with them.
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everyone here is equipped with the core of a high resolution audio spectrum analyzer - your PC soundcard is fine on resolution for loudspeaker XO component measurement
what you need is interface hardware - dividers, input protection, amplifiers, reference current shunt R and free software
what you need is interface hardware - dividers, input protection, amplifiers, reference current shunt R and free software
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Programmable current/voltage/power source I have, up to 400 Hz. Dividers and isolation amps I have. Interface....think I am.lacking anything suitable.
But power analyser can measure the up to 250th harm, if I use with calibrator source. Just very long-winded.
I just wonder if measuring change in Z with current source variation at say 400 hz would be a good indication. And following on, what deviation would be acceptable?
Need to think lol
oh and something to push out gobs of current at high fidelity.
small details i'm sure LOL don't break jcx's amp
small details i'm sure LOL don't break jcx's amp
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Which is the main issue for me. A 40amp current source 40-400Hz I have access to. I just doubt that 400hz is anything like enough.
96k sample rate gets you 2x conventional audio bandwidth
really no need for 250th harmonic - by the time that high an order harmonic is above the noise you have low order harmonics making even the idea of linear component value meaningless
aren't audio power amps are a given too for speaker builders?
soundcards have output and inputs, generate test signals and analyze http://www.sillanumsoft.org/prod01.htm
although I've used LTspice .wav output and SciLab math software with Audacity in between to play/record
really no need for 250th harmonic - by the time that high an order harmonic is above the noise you have low order harmonics making even the idea of linear component value meaningless
aren't audio power amps are a given too for speaker builders?
soundcards have output and inputs, generate test signals and analyze http://www.sillanumsoft.org/prod01.htm
although I've used LTspice .wav output and SciLab math software with Audacity in between to play/record
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Yes this is true, and I realise there is no need for 250th, BUT I reckon O could rig something up, just very longwinded without a sweep function sig gen and bigggg amplifier.
That being said, wouldn't distortion manifesting itself be apparent with a single frequency point, increasing current until it presents itself?
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