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inductor differences

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  • #61
    Re: inductor differences

    Originally posted by DDF View Post
    This is the closest I could find to a characterization, but the test conditions seemed overly aggressive and there was no indication that the inductor was appropriately targeted for the application:

    One thing about u-core inductor distortion is that it rises only at much higher SPLs where your ability to hear the distortion is far less. At high SPLs, your own ear is distorting as biological non linearities kick in as a self protection mechanism (inner ear hair cells tighten, middle ear muscles tighten).
    Yes I posted that link earlier. A shame nothing else is showing up online.


    • #62
      Re: inductor differences

      Any comments on inductor microphonics due to winding movements, and vacuum impregnation & baked varnish?


      • #63
        Re: inductor differences

        Originally posted by timw View Post
        Any comments on inductor microphonics due to winding movements, and vacuum impregnation & baked varnish?
        Take your inductor, put zip ties around (4 will do), reef them tight, there is no way they'll be microphonic.

        The MLSSA system will measure inductive reactance over frequency. It gives a "correlation factror" to pure actual inductance, after removing the real resistive part. You can then investigate the pure inductive reactance at any frequency. If the coil was not a true pure coil (capacitive interwinding, mechanical resonance etc), then the pure inductive reactance part would vary over frequency.

        For a sloppy, starting to unwind coil, you do indeed see the inductive reactance have some small variance over frequency. Reef on the zip ties, its a perfect inductor again. I've measured dozens of coils myself, from half a dozen manufacturers. No need to spend more than 5 cents for some zip ties.



        • #64
          Re: inductor differences

          Pretty good discussion going....

          Couple of things to throw in:

          Cap thru coil. Yep, you will do some amount of induction heating.. likely only an amount hard to measure due to low freq and low currents... But, as was mentioned, how big will the "single turn transformer" effect of the cap going thru the inductor be? Being one turn vs the # of turns of the inductor, would it be enough to put a voltage into that node that shouldn't be there, to an amount that would be noticeable? Good question...

          Saturating/Hysteresis effects. Wish I had a classic hysteresis graphic to show. It is a non linear, and non abrupt effect, and how different core materiel will behave will vary. Also, the current density makes a difference, and different differences (;)) with different core materiel. I'd think like has been said, most current levels are low for big effects. But, laminated iron vs lossy ferrites will have a difference in how low, low would be. Saturation OTOH, is pretty abrupt, and kind of like amp clipping, when you reach that maximum magnetization strength of the materiel, there ain't no more...

          Special case: certain circuit configurations, like a LC parallel trap, can have much higher circulating current at resonance (flowing back and forth betwixt L and C) than the current applied to them, and possibly saturate at a much lower power level than expected.

          On the vibration/microphonics factor... After reading a commercial speaker manufacturer's statements on keeping their crossovers outside of the enclosure, to prevent vibration/pressure from altering the components, I wanted to build a test fixture and see just how big of an influence, or if any, it could be. Still haven't done it, but pictured a small, tight box, with a strong, long throw driver that I could put some parts in and measure them while pumping some serious SPL. I'd guess it's not all that huge, but would be interesting to do someday... might contribute some knowledge to the DIY collective... Hmmm... got a W6-1139 and a lot of spare BB pieces laying around....


          • #65
            Re: inductor differences

            On the issue of inserting a capacitor inside an inductor ... When performing duty as part of a crossover circuit, within the capacitor there's a changing electric field. Within the inductor there's a changing magnetic field. Changing magnetic fields create changing electric fields, and vice-versa.

            So, my first thought was that the capacitor would interfere with the inductor. Let's say you have a coil connected to a meter and you're measuring its inductance. You take a capacitor that's connected to a source, say for example it's acting as a simple filter for a tweeter, and you've got it hooked up to an amplifier and sound is coming out of the tweeter.

            Now, insert the capacitor into the center of the coil. Will the reading on the inductance meter change? Will the voltage and current flowing through the capacitor change? I doubt it. There might be a small effect, but my guess would be it's undetectable. It would make an interesting experiment, though.


            • #66
              Re: inductor differences

              Here you go Herman:
              "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche



              • #67
                Re: inductor differences

                Interesting. Those caps with nonmetallic housing that had no effect? What if you were running a signal through them, as if they were functioning as part of a xover circuit?


                • #68
                  Originally posted by pixelgarden
                  What dB gain I will see on my woofer (1st order crossover) if the DCR from my series inductor is changed from 0.92 ohm to 0.15 ohm ? The driver is 8 ohm rated Hivi B4n.
                  You might have been better off starting a new post. But you did get me to read the first few pages of this old one!

                  This is easiest to sim in an program like Xsim. WinISD can also should you how it will effect your speaker.


                  • LOUT
                    LOUT commented
                    Editing a comment
                    I think that's a copy/paste of a 2011 post from the first page. Probably a Spambot waiting to add its spammy link.
                    Whoops, nevermind...the first-page post was a recent comment from the same poster. My mistake.
                    Last edited by LOUT; 08-09-2022, 10:13 AM. Reason: I was wrong.

                • #69
                  Oh, you MIGHT gain almost +1dB, but only between about 200 and 600Hz.
                  The B4N doesn't really like a single 1.1mH coil very much.
                  It will flatten out it's (rising) response a bit, but it'll still roll off near 6kHz (not 2k, not w/out a Zobel - or a parallel cap) and retain its metal-cone "ringing" above 10k.

                  What 're you up to?


                  • #70
                    Originally posted by 1100xxben View Post
                    Re: inductor differences

                    Capacitors work by storing electrical charge, and should not affected by magnetic fields generated by the inductors in a crossover. Also there shouldn't be any iron in capacitors, therefore placing a capacitor in the center of the inductor would not affect the inductance of the cap. If you place a capacitor next to a coil, there is still a significant magnetic field present, just not as strong as the middle of the coil.
                    Placing a capacitor within the inductor coil, since there is metal inside the capacitor you'll induce eddy currents in the capacitor, just like induction cooking, though the effect will be much smaller.


                    • #71
                      Large gauge wire on a large core, saturation will not be a problem.

                      Click image for larger version

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