Not that I recall, it was just the cap itself making the noise. I should have done further tests, but did not. Pinging the cap might not generate enough current to be heard in the woofer, but would it modulate a signal passing thru it? Easy enough to test - alas I did not.
And playing with darts on a loudspeaker can be a challengeI guess I have never smacked my caps with a hammer when listening to music.
They seem very solid to me. I've used the film/foil and the oil bath. No Ping! noises. Jantzen the same.
FWIW I DID actually test a ceramic capacitor as a microphone/pickup, in my case as a Bass Guitar string pickup.
I simply removed the bridge which holds strings in place and put the .047 or .1uF capacitor (don´t remember exact value but it´s irrelevant) between string and Bass body, using a couple plastic shims so string stayed at the proper height, applied 9V from a battery to cap through a 47k resistor and wired cap to a guitar cable, adding a series cap to keep 9V DC from preamp input.
And yes, it worked very well, loud clean signal.
I should have patented/manufactured it.
Now back to idle/empty endless non facts arguing, who am I to introduce facts and testing in a DIY Audio discussion?
I should feel ashamed for the rule breaking.
Oh well.
I simply removed the bridge which holds strings in place and put the .047 or .1uF capacitor (don´t remember exact value but it´s irrelevant) between string and Bass body, using a couple plastic shims so string stayed at the proper height, applied 9V from a battery to cap through a 47k resistor and wired cap to a guitar cable, adding a series cap to keep 9V DC from preamp input.
And yes, it worked very well, loud clean signal.
I should have patented/manufactured it.
Now back to idle/empty endless non facts arguing, who am I to introduce facts and testing in a DIY Audio discussion?
I should feel ashamed for the rule breaking.
Oh well.
Please give us your results. I would welcome to be proven wrong that a Dayton is completely adequate with some actual facts. All I have seen up to now is pure placebo ( well meaning) or plain old snake oil. Some talk about ESR in a circuit with an L-Pad or in a notch with an added series resistor. There are differences in termination which can effect parasitic inductance, not compared to the rest of the circuit, it seems like it is just something to be included, not a justification for a $50 cap when a $7 may work the same if properly designed.
Of course, I would be more inclined to isolate the crossover rather than spend cubic dollars. Funny isn't it. We built these small bookshelf speakers and then put them up on big stands. Same floorspace as if we went ahead and made use of the stand space. Not everyone has a spousal mandate to use Vietnamize elephants as stands. Long live the good old three way monkey coffins!
I have a bunch of caps I hoarded at the beginning of my foray into this hobby. Many of these I would not purchase given what I know now. That said, on a few occasions where I’ve had DATS running on my laptop after doing driver measurements, curiosity has compelled me to run tests on my hoard of capacitors for the sake of baseline comparison. Of course small differences are observable given the varying values of capacitance but one thing that did surprise me was that Mundorf metallized “foil” capacitors and the Russian teflon foil caps had consistently (slightly) higher Q values vs metallized film caps of virtually the exact same value. I have a lot of Dayton (Bennic) and Solen (SCR) capacitors, so these comparisons were of caps matched within .1% of each other. My WAG is that this is due to the higher voltage rating (thicker electrodes) of the Mundorf and Russian Teflons vs the lower voltage rating Daytons and Solens. Among the Solen, Dayton, Auricap and Obbligato caps nothing really stood out measurement-wise.
I will grant that Mundorf capacitors are well-made, regardless of whether one considers them a poor value. The communist caps are also well-made value champs that love to eat up real estate.
I will grant that Mundorf capacitors are well-made, regardless of whether one considers them a poor value. The communist caps are also well-made value champs that love to eat up real estate.
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Yes, ceramic capacitors are well known to cause - in certain situations - significant distortion due to the piezo-electric effect. The well-known example would be the output filter in a class-D audio power amplifier.
Which is why other types are preferred in this application...
Higher voltage would be thicker dielectric. Thicker electrode would be lower ESR. Both mean physically larger device, but that is not usually an issue in a crossover. The first is two thin foils separated by a film, the later film with vapor deposited metal.
ESR, leakage, DF, capacitance, inductance and variation of all parameters with voltage and temperature. Lots of things go wrong with a cap. They seem simple but are really hard to do. They get ugly.
https://www.electrocube.com/pages/capacitors-dissipation-factor-technical-bulletin
This does not even touch failure modes. Differences in termination, be it contact or sputtering, and behavior of micro shorts differs.
Good point about dielectric thickness with regards to voltage rating. I should have known better. Electrode thickness is typically specified in cap datasheets (microns).
A 250V rating for a capacitor is more than sufficient for a crossover, so I agree higher voltage caps aren't of concern here.
A long-standing critique of boutique capacitors is that despite being an incredibly poor value, many of them are also more poorly made and/or measurably worse than mass- produced, inexpensive alternatives. It’s worth knowing the instances where this isn’t actually the case, though your point that there’s more to it than meets the eye and I can’t disagree with that.
A 250V rating for a capacitor is more than sufficient for a crossover, so I agree higher voltage caps aren't of concern here.
A long-standing critique of boutique capacitors is that despite being an incredibly poor value, many of them are also more poorly made and/or measurably worse than mass- produced, inexpensive alternatives. It’s worth knowing the instances where this isn’t actually the case, though your point that there’s more to it than meets the eye and I can’t disagree with that.
THIS thread? Sure!!!
I am referring to capacitor threads in general.
Add cable threads to the menu
And for dessert, audibility of resistor distortion
Well, yes, but I did NOT use it as a Piezo nor relied on that effect, BUT biased it instead (9V).
A not-so-distant cousin of a conventional capacitor microphone, and relying on the same principle: capacitance variation cause by varying pressure, only in "voice" microphones membrane is flimsy and air pressure is enough, while on my experimental pickup, capacitor is heavy and hard, but it was pushed by a heavy roundwound Bass string which was directly plucked, so pressure was orders of magnitude higher.
Signal was strong and clear, and way higher than what the raw Piezo effect could produce.
Way back then (late 70´s) I did not dare invest an important amount of $$$$ into necessary dies so I left it as a curious experiment but today, given the availability of CNC machining for metal parts (brass? ... aluminum? ...) or plastic 3D printing I "should" build a couple prototypes and retest.
Stay tuned
I wonder what would happen if the 9V was disconnected - that would leave the piezo-electric effect as sole contributor. But I can well believe that you're seeing mainly capacitance modulation here.Well, yes, but I did NOT use it as a Piezo nor relied on that effect, BUT biased it instead (9V).
A not-so-distant cousin of a conventional capacitor microphone, and relying on the same principle: capacitance variation cause by varying pressure, only in "voice" microphones membrane is flimsy and air pressure is enough, while on my experimental pickup, capacitor is heavy and hard, but it was pushed by a heavy roundwound Bass string which was directly plucked, so pressure was orders of magnitude higher.
Signal was strong and clear, and way higher than what the raw Piezo effect could produce.
Way back then (late 70´s) I did not dare invest an important amount of $$$$ into necessary dies so I left it as a curious experiment but today, given the availability of CNC machining for metal parts (brass? ... aluminum? ...) or plastic 3D printing I "should" build a couple prototypes and retest.
Stay tuned
I could imagine electrolytics being the most susceptible, but who knows?