Hi,
Do you pay attention to the quality of the coils with good loudspeakers enough ?
Is it better for instance in a treble 24dB filter to have the two coils of the high pass in parrallel with the tweeter to be air coil VS feritte core coil or foil ones, or foil waxed and so on ? Especially if the drivers are typical hifi drivers with low efficienty ?
As for the mid, should one swap a serie ferite core coil by a waxed foil air coil for better something ??? And idem for the low pass in // with the mid driver ?
Of course being attentive to the serie Z and power dissipated, so mmore or less at iso perimeter.
If yes, are you aware of the quality difference and precision between brands and models : Mundorf, Jantzen, Intertechnik, ... ?
Do you pay attention to the quality of the coils with good loudspeakers enough ?
Is it better for instance in a treble 24dB filter to have the two coils of the high pass in parrallel with the tweeter to be air coil VS feritte core coil or foil ones, or foil waxed and so on ? Especially if the drivers are typical hifi drivers with low efficienty ?
As for the mid, should one swap a serie ferite core coil by a waxed foil air coil for better something ??? And idem for the low pass in // with the mid driver ?
Of course being attentive to the serie Z and power dissipated, so mmore or less at iso perimeter.
If yes, are you aware of the quality difference and precision between brands and models : Mundorf, Jantzen, Intertechnik, ... ?
Have you been reading that parallel components are not as important as series ones? Both of course contribute to the source impedance seen by the driver. Parallel components can affect the voltage across the driver.
Either way, parallel or series, a distorted waveform from a distorting component should have some effect everywhere else in the circuit, so for treble I'd advise Air coils. Simply because they don't have magnetic hysteresis from a core material, I wonder how effective litz wire coils are for HF applications as well.
Thanks,
So at iso Z between a solid core and air coil, better air coils are for the treble. So I assume the same for midrange or woofer driver.
But the Z difference and power dissipating between different air coils, do the exotic foil types or even more exotic foils type with wax and paper isolation beneficiate of a soyndimg improvement over the simpke bajed round wire ones according your experience, please?
@AllenB ,
Yes despite I know this is AC and parrallel components are important, some are daying though the quality of the Parralel components resistors, caps, coils, is indeed not as important than the ones in serie with the signal source (amp) ? Hence the question
So at iso Z between a solid core and air coil, better air coils are for the treble. So I assume the same for midrange or woofer driver.
But the Z difference and power dissipating between different air coils, do the exotic foil types or even more exotic foils type with wax and paper isolation beneficiate of a soyndimg improvement over the simpke bajed round wire ones according your experience, please?
@AllenB ,
Yes despite I know this is AC and parrallel components are important, some are daying though the quality of the Parralel components resistors, caps, coils, is indeed not as important than the ones in serie with the signal source (amp) ? Hence the question
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Example of coil assymetrie quality between the serie and parralel to the driver
https://www.humblehomemadehifi.com/Nova-Andromeda/Nova-Andromeda-crossover.jpg
What to think ? BS?
https://www.humblehomemadehifi.com/Nova-Andromeda/Nova-Andromeda-crossover.jpg
What to think ? BS?
Not necessarily for the midrange because by having an air core you have a lower magnetic permeability than with a ferrite core, so you need more turns for the same inductance value, this causes the resistance to go up alot from a cored inductor, so it becomes a tradeoff between distortion, resistance, size and cost, the best inductor for mid is low distortion, and low resistance so you need alot of copper or silver if you have bottomless pockets.
hahaha, yes monney matter... looking for trade off here ! Curious about that exotic foil coils !
Is the lower resistance is also causing less distorsion or is it just important for magnitude level ? Cause after all some resistor are often needed in serie to shape the magnitude ?
So if I have say : a feritte square core air col of low resistance, say 0.1 ohms and I swap it for an air coil being 0.5 or 1 ohms for instance, as far I substracte it from the serie resistor before, I'm ok and willl have iso resistance but less distorsion ?
Seems to me logical for the serie low pass coil of the bass and mid drivers, but I prefer to ask.
Although, yes, another story I assume if serie resistence of the // air coils are bigger than the ferrite ones they are planned to swap. Putting air coils with higher Z in // will change the filtering behavior of the filter, so the sound (AllenB input above).
Is the lower resistance is also causing less distorsion or is it just important for magnitude level ? Cause after all some resistor are often needed in serie to shape the magnitude ?
So if I have say : a feritte square core air col of low resistance, say 0.1 ohms and I swap it for an air coil being 0.5 or 1 ohms for instance, as far I substracte it from the serie resistor before, I'm ok and willl have iso resistance but less distorsion ?
Seems to me logical for the serie low pass coil of the bass and mid drivers, but I prefer to ask.
Although, yes, another story I assume if serie resistence of the // air coils are bigger than the ferrite ones they are planned to swap. Putting air coils with higher Z in // will change the filtering behavior of the filter, so the sound (AllenB input above).
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I'm not sure about foil and don't have in person experience unfortunately, but the idea behind wax is that it viscoelastically dampens out coil whine where the magnetic field produced in the coil causes the wire to move, and the wax dampens the movement.
I'd hazard a guess that for dynamic/instantaneous peak compression, a cored inductor would be able to move the heat out of the coil quicker conductively than an air coil, but for long term power compression, an air core should have more airflow, resulting in better heat dissipation. TBH power compression should be negligible compared to a VC, much more mass of copper in inductor.
Yes (resistor + cored inductor) should be poorer performance wise than a pure air core, distortion wise, really what you need is a core material that is paramagnetic and an insulator, so no eddy currents, it would be more inductive than air core but also have the non-hysteresis properties, but most paramagnetic have very small responses unfortunately and so would have minimal effect. I've thought about using gadolinium but it's far too conductive.
This is not the question I would ask. I would ask is it a problem? Maybe both are a problem and maybe both are not.
At iso Z parameter (coil) for the woofer, between less distorsion and more hysterisis, should I go for an air coil for the mid too, so ?
It is about 1.2 mH, 300W proof, cut-off high pass second order (so a coil in // that should has 0.1 ohms) or simply target less hysterisis and keep in lieu the ferrit core ? I see one foil air coil type with the same Z, just the size is enormous and it costs 50 euros. (I just used DVM ohms function to measure my coils in serie)
Is there a problem with the original design with ferrite core ? I do not think, I just wonder if it will sound better with air coils in the mid and treble. Same for future DIYs. So about the distorsion if I understand what you both are saying.
It is about 1.2 mH, 300W proof, cut-off high pass second order (so a coil in // that should has 0.1 ohms) or simply target less hysterisis and keep in lieu the ferrit core ? I see one foil air coil type with the same Z, just the size is enormous and it costs 50 euros. (I just used DVM ohms function to measure my coils in serie)
Is there a problem with the original design with ferrite core ? I do not think, I just wonder if it will sound better with air coils in the mid and treble. Same for future DIYs. So about the distorsion if I understand what you both are saying.
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I have found sintered cores to sound bad and distort readily, steel laminates to have an emphasis in the 70 to 80Hz region, and air cores to be the most neutral. Foils, and ive tried several, sound no different crom each other, IMO. I actually prefer a good large gauge round wire air core to the foils. Litz on tweeters does not always work well due to the capacitive characteristics of the litz coil. On midbasses/woofers I find it can reveal a little more texture or detail in the music.
Yes, I definitely pay attention to the quality of coils.
On mids and tweeters I only use air cores, waxed or baked.
On woofers I-cores or transformer cores.
Ferite cores only in LCR notch filters.
All from Monacor, Jantzen or Intertechnik.
No transformer coils from Monacor, I once compared them to Mundorf I-cores and the Monacors had much higher distortions.
Some measurements of different types of coils can be found on the Dutch forum zelfbouwaudio
On mids and tweeters I only use air cores, waxed or baked.
On woofers I-cores or transformer cores.
Ferite cores only in LCR notch filters.
All from Monacor, Jantzen or Intertechnik.
No transformer coils from Monacor, I once compared them to Mundorf I-cores and the Monacors had much higher distortions.
Some measurements of different types of coils can be found on the Dutch forum zelfbouwaudio
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Thanks Danny,
I also seen lower Mundorf cost were not so precise in H value: L and BL serie.
I also seen lower Mundorf cost were not so precise in H value: L and BL serie.
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So what constitutes a coil?
- Some L
... and losses:
So most probable the only thing to really think about is R - and that can be dimensioned to substitute wanted R or if not needed, just pay to make it as low as possible.
The L in x-overs are the lest worry I have but by all means - mount them Ls orthogonally and if you have more than 3 - place same direction Ls as far apart as possible.
Pay for (air) L and low R - nothing else.
L is L - no matter boutique golden text....
I bet there is a least one error or omission in the above 🙂
//
- Some L
... and losses:
- Some R. Depends on wire dimension.
- Some C. Negligible in any reasonably decent implementation.
- Some magnetic friction in the core - 'hysteresis'. In an air coil there is no core - but I suspect there might still be a tiny fraction of this due to wire impurities. Negligible.
- Some electric currents induced in the core - 'eddy currents'. In an air coil there is no core - but I suspect there might still be a tiny fraction of this due to wire impurities. Negligible
- Some Self-induction. Negligible
- Some permeability. Negligible
So most probable the only thing to really think about is R - and that can be dimensioned to substitute wanted R or if not needed, just pay to make it as low as possible.
The L in x-overs are the lest worry I have but by all means - mount them Ls orthogonally and if you have more than 3 - place same direction Ls as far apart as possible.
Pay for (air) L and low R - nothing else.
L is L - no matter boutique golden text....
I bet there is a least one error or omission in the above 🙂
//
If you have a good LCR meter then wind your own out of heavy gauge magnet wire on a wooden former. Dip in varnish to control movement. Large inductors for lower frequency use very heavy gauge wire to limit resistance unless desired. 18ga is good for tweeters, 16 mids and 12 or 14 for woofers. It’s cheap and you get the exact value you want. Boutique inductors are a great way to waste money as they all are just coils of wire in the end. If you must have flat wire just buy a huge one and use it as the spool of wire to wind smaller units from it. I use a jig of a dowel with a long screw through it to mount on a drill to spin the coil. Go slow to maintain tension and layer evenly. Slide it off and zip tie and dip in varnish.
The losses listed are the reason for distortion - so, yes. It's not a list of what evil is created.
And as usual - distortion from non faulty, well dimensioned passive items (R,L,C - large or small signal) are very very low. Forget about them.
//
And as usual - distortion from non faulty, well dimensioned passive items (R,L,C - large or small signal) are very very low. Forget about them.
//
Quite interresting input as I believed it was huge disto there VS the one of the amp or a good source. I also notice you use active setup if my memory serves me well. Have you tuned loudspeaker with passive parts ?
Indeed, a trap could be : you change a passive parts (say for an exotic one without having in mimd the RLC parameters) for illustration an expensive one, the sound is changed because the inductance is not exactly the same or the Z not exactly the same, so sound is changed because filter and magnitude sligthy affected and you may think it is better (or worse).
So let rephrase it à la AllenB : you have a design that works without problem (with a ferite core) and (again at iso Z) you change for air dielectric, you objectivly do not notice an improvement, or at least there is a change you believe to be an improvement ?
Let continue to dig more then : people and litterature for mid and treble, air dielectric is better, but just sligth improvement over ferite coil
I just add the discussion is for a low efficienty loudspeaker (typical around 88 dB/2.83V and below) not sensible high efficienty ones with tube amps with H2 disto.
I also notice, noone is using foil core coil. So big enough wire with air coil seems enough.
Indeed, a trap could be : you change a passive parts (say for an exotic one without having in mimd the RLC parameters) for illustration an expensive one, the sound is changed because the inductance is not exactly the same or the Z not exactly the same, so sound is changed because filter and magnitude sligthy affected and you may think it is better (or worse).
So let rephrase it à la AllenB : you have a design that works without problem (with a ferite core) and (again at iso Z) you change for air dielectric, you objectivly do not notice an improvement, or at least there is a change you believe to be an improvement ?
Let continue to dig more then : people and litterature for mid and treble, air dielectric is better, but just sligth improvement over ferite coil
I just add the discussion is for a low efficienty loudspeaker (typical around 88 dB/2.83V and below) not sensible high efficienty ones with tube amps with H2 disto.
I also notice, noone is using foil core coil. So big enough wire with air coil seems enough.