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#1
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
GO AHEAD AND TAKE TURNS SAYING: "I TOLD YOU SO, DUMB MOTHER-****ER!" **** YOU ALL FOR BEING RIGHT! HAHA! IN MY DEFENSE, I'M NOT STUPID....JUST CHEAP, FRUGAL, AND STUBBORN AS HELL! THERE IS A DIFFERENCE! HAHAHAAA!!! This was apparent after comparing A/B NON-CROSSOVERED piezos with one of my Yamaha HS80Ms. The incriminating test song was Pink Floyd's "Time"! As soon as the vocals come in, it's SCREECH CITY with the piezo! BOY THAT SOUNDS BAD! I mean, it depends on where you are listening wrt the horn, but if you are right in front of it....UUUUGGGHH!! In contrast, you can listen anywhere in front of the Yammies, and although they may sound bright, and have tons of "presence", they never get HARSH like the piezos! So then I experimented with adding a crossover, and settled on series 2uF non-polarized cap, and shunt 22 Ohm resistor before the piezos in parallel (a series 0.1uF after the shunt resistor, for -6dB, was too much, and almost killed off the signal completely). The crossover makes it more tolerable, but I can't say it sounds good delivering high fidelity music. For some reason, just singing through it with an SM58, makes the harshness less noticeable, so it could still be useful for that usage. I'll probably sell this for a few bucks to a poor garage band, telling them exactly what I did. I DIDN'T WASTE MY TIME AND ENERGY WITH THIS EXPERIMENT: I LEARNED QUITE A BIT, AND THAT MAKES TINKERING WORTH DOING! Thanks for the feedback, everyone.... |
#2
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 15/02/2017 6:31 PM, Paul wrote:
I DIDN'T WASTE MY TIME AND ENERGY WITH THIS EXPERIMENT: I LEARNED QUITE A BIT, AND THAT MAKES TINKERING WORTH DOING! Thanks for the feedback, everyone.... So a positive outcome after all that ! ;-) geoff |
#3
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Tue, 14 Feb 2017 22:31:54 -0700, Paul wrote:
GO AHEAD AND TAKE TURNS SAYING: "I TOLD YOU SO, DUMB MOTHER-****ER!" **** YOU ALL FOR BEING RIGHT! HAHA! IN MY DEFENSE, I'M NOT STUPID....JUST CHEAP, FRUGAL, AND STUBBORN AS HELL! THERE IS A DIFFERENCE! HAHAHAAA!!! This was apparent after comparing A/B NON-CROSSOVERED piezos with one of my Yamaha HS80Ms. The incriminating test song was Pink Floyd's "Time"! As soon as the vocals come in, it's SCREECH CITY with the piezo! BOY THAT SOUNDS BAD! I mean, it depends on where you are listening wrt the horn, but if you are right in front of it....UUUUGGGHH!! In contrast, you can listen anywhere in front of the Yammies, and although they may sound bright, and have tons of "presence", they never get HARSH like the piezos! So then I experimented with adding a crossover, and settled on series 2uF non-polarized cap, and shunt 22 Ohm resistor before the piezos in parallel (a series 0.1uF after the shunt resistor, for -6dB, was too much, and almost killed off the signal completely). The crossover makes it more tolerable, but I can't say it sounds good delivering high fidelity music. For some reason, just singing through it with an SM58, makes the harshness less noticeable, so it could still be useful for that usage. I'll probably sell this for a few bucks to a poor garage band, telling them exactly what I did. I DIDN'T WASTE MY TIME AND ENERGY WITH THIS EXPERIMENT: I LEARNED QUITE A BIT, AND THAT MAKES TINKERING WORTH DOING! Thanks for the feedback, everyone.... Motorola sent a sample of these tweeters to a speaker company I worked for in the 1970s. We tested it then smashed it with a hammer and threw it in the trash. Dahlquist used one in a very good sounding speaker but they crossed it over above 10 khz. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#4
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
In article , Paul wrote:
In contrast, you can listen anywhere in front of the Yammies, and although they may sound bright, and have tons of "presence", they never get HARSH like the piezos! Okay, you saw that 4kc peak on the piezos. Now, assuming you're using a 12dB/octave filter, if you crossed over at 8kc then the peak would only be 12dB down. You'd probably want to cross over at 16kc in order to really control the problem, or use a sharper filter. Which kind of makes it useless. You'd think maybe you could use a Zobel network like you would with an electrodynamic tweeter to control the peak, but really nobody has ever been able to make that work well. It might not be minimum phase. It MIGHT be possible to use an acoustic network in order to deal with the problem, but it's hard to do that and not screw up the pattern. In the 1980s some grad student built a PA speaker system using a horizontal array of piezo tweeters and phase-shift networks, which somehow wound up in the EE department auditorium at gatech, probably because nobody else wanted them. They had oversized Motorola drivers with the worst of the ugliness around 1kc, and they were crossed over around 5kc using a conventional midrange driver. Even though the plot wasn't so horrible, there was still severe harshness due to the nonlinearities. Now... Jon Dhalquist with the DQ-10 actually did use a piezo tweeter and did actually get some benefit from it. But he was crossing them over at 18 KHz or so and using them only as a supertweeter in order to add a little more air. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#5
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Wednesday, February 15, 2017 at 9:13:13 AM UTC-7, Scott Dorsey wrote:
Snip Now... Jon Dhalquist with the DQ-10 actually did use a piezo tweeter and did actually get some benefit from it. But he was crossing them over at 18 KHz or so and using them only as a supertweeter in order to add a little more air. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." A friend on mine had a pair of those Dahlquists and they were a good sounding system. I knew that they had piezo tweeters, but wasn't awate that they were crossed that high. A piezo will respond to a 40kHz signal but all that is going to do is annoy the dog. |
#6
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 2/15/2017 3:16 AM, geoff wrote:
On 15/02/2017 6:31 PM, Paul wrote: I DIDN'T WASTE MY TIME AND ENERGY WITH THIS EXPERIMENT: I LEARNED QUITE A BIT, AND THAT MAKES TINKERING WORTH DOING! Thanks for the feedback, everyone.... So a positive outcome after all that ! ;-) Oh, completely! I didn't just learn new things: Many electrical engineering concepts are the same, no matter what the frequency range. So this was also a review for potential Radio Frequency job interviews that might be coming up. Also, this stuff is fascinating, and FUN! And you are never wasting your time if you're having fun! BWAAAHHAHHAAA!! |
#7
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 2/15/2017 9:13 AM, Scott Dorsey wrote:
In article , Paul wrote: In contrast, you can listen anywhere in front of the Yammies, and although they may sound bright, and have tons of "presence", they never get HARSH like the piezos! Okay, you saw that 4kc peak on the piezos. Now, assuming you're using a 12dB/octave filter, if you crossed over at 8kc then the peak would only be 12dB down. You'd probably want to cross over at 16kc in order to really control the problem, or use a sharper filter. Which kind of makes it useless. You'd think maybe you could use a Zobel network like you would with an electrodynamic tweeter to control the peak, but really nobody has ever been able to make that work well. It might not be minimum phase. http://www.wavecor.com/html/zobel_networks.html So when the cap becomes low impedance at higher frequencies, it essentially adds a shunt resistor to a dynamic speaker's voice coil inductance, attenuating the higher frequencies I assume. But maybe this wouldn't work on piezos since they look capacitive? It MIGHT be possible to use an acoustic network in order to deal with the problem, but it's hard to do that and not screw up the pattern. In the 1980s some grad student built a PA speaker system using a horizontal array of piezo tweeters and phase-shift networks, which somehow wound up in the EE department auditorium at gatech, probably because nobody else wanted them. They had oversized Motorola drivers with the worst of the ugliness around 1kc, and they were crossed over around 5kc using a conventional midrange driver. Even though the plot wasn't so horrible, there was still severe harshness due to the nonlinearities. Now... Jon Dhalquist with the DQ-10 actually did use a piezo tweeter and did actually get some benefit from it. But he was crossing them over at 18 KHz or so and using them only as a supertweeter in order to add a little more air. --scott So it appears piezos are only acceptable in the high fidelity world from 10kHz and above? Non-linearities implies clipping and odd order harmonic generation. What is it about the physics of the piezos that would cause such distortion below 10kHz? It appears piezo tweeters are everywhere! Obviously because they are cheaper to manufacture. MP3s and earbuds are also widely used by the public at large, but MP3s never made the high end unlistenable! |
#8
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
Capacitors, unfortunately, don't become low impedance at high frequencies; since they're made of rolled-up layers of foil and dielectric, they have an inductive component, and at high frequencies this becomes the most important; real-world capacitors show an impedance that falls with increasing frequency up to a point, then bottoms out, and rises as the frequency increases..
Peace, Paul |
#9
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
Capacitors, unfortunately, don't become low impedance at high frequencies; since they're made of rolled-up layers of foil and dielectric, they have an inductive component, and at high frequencies this becomes the most important; real-world capacitors show an impedance that falls with increasing frequency up to a point, then bottoms out, and rises as the frequency increases..
Glad you had fun. Watch out, though -- speaker building is addictive. Peace, The Other Paul |
#10
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 2/15/2017 12:42 PM, PStamler wrote:
Capacitors, unfortunately, don't become low impedance at high frequencies; since they're made of rolled-up layers of foil and dielectric, they have an inductive component, and at high frequencies this becomes the most important; real-world capacitors show an impedance that falls with increasing frequency up to a point, then bottoms out, and rises as the frequency increases. Well, of course I'm aware that all capacitors have parasitic inductances (and Equivalent Series Resistance, or ESR), which is the reason why we keep leads lengths short in the radio frequency world, when not using chip capacitors: http://sound.whsites.net/articles/capacitors.htm#s30 But in the audio frequency world, where we are only concerned about up to 22kHz or so, I we shouldn't see the impedance start rising again. Let's assume from the above link that we have about 5nH of parasitic inductance mainly due to lead length: XL=2*pi*f*L And using f=22kHz, and L=5nH, we still only get about 69 milli-Ohms! Glad you had fun. Watch out, though -- speaker building is addictive. No worries on that....as you can see, I'm shopping for an already built PA speaker now. Sometimes it's best to leave things to the professionals! Peace, The Other Paul |
#11
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
PStamler wrote:
Capacitors, unfortunately, don't become low impedance at high frequencies; ** Yes they do. since they're made of rolled-up layers of foil and dielectric, they have an inductive component, ** That is not true. The foil is connected along the whole length of one side, which cancels inductance completely. real-world capacitors show an impedance that falls with increasing frequency up to a point, then bottoms out, and rises as the frequency increases. ** Real world capacitors have no more inductance than a piece of wire the same length. This is so small, it never matters in audio circuits or even SMPS and the like. FYI, a typical value is 15nH for leaded types and about 2nH for SMD types. You have just trotted out a stupid myth that I really hoped had gone away. ..... Phil |
#12
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
At the risk of attracting one of Mr. Allison's personal attacks, I have measured the rise in capacitors' impedance at high frequencies -- in some cases they switch from being capacitative to inductive well within the audio band.
Peace, Paul |
#13
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range.
Peace, The Other Paul |
#14
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 2/15/2017 10:13 PM, PStamler wrote:
At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? |
#15
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 16/02/2017 8:07 PM, Paul wrote:
On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? ..... and what type of cap ? geoff |
#16
Posted to rec.audio.pro
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
Phil Allison wrote:
PStamler wrote: Capacitors, unfortunately, don't become low impedance at high frequencies; ** Yes they do. This depends a lot of what kind of capacitor it is. If you look at an electrolytic, they tend to become inductors down in the 100s of KHz range. On the other hand if you look at stacked film capacitors, they tend not to become inductors at all, just resistors. I have come to love stacked films. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#17
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote:
On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. |
#18
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 17/02/2017 8:21 AM, PStamler wrote:
On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote: On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. Maybe a little 'sweeping' to attribute the characteristics of that capacitor to all capacitors . Especially given the typical application of that type and value of cap. geoff |
#19
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
This was the worst case, but several electrolytic caps had resonances within the audible range.
Peace, The Other Paul |
#20
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Thu, 16 Feb 2017 11:59:47 -0800 (PST), PStamler
wrote: This was the worst case, but several electrolytic caps had resonances within the audible range. Peace, The Other Paul And the problem here is that the better the cap the sharper the resonance. Get a nice rubbish cap with a huge ESR and the effect is much diminished. d --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#21
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
so if your 3,300 uF cap had a series resonance at 5.3 kHz, that implies an
inductance of about 0.25 uH which has a Z of about 9 mOhms. The ESR will easily swamp that and Z is so low so as not to have any practical impact at any audiofreq. m |
#22
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 2/16/2017 12:21 PM, PStamler wrote:
On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote: On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. http://www.murata.com/~/media/webren...ow/12to14.ashx So resonant freq f=1/(2*Pi*(L*C)**0.5) So L=273nH. So you had 273nH of parasitic/lead inductance? BULL****. Also, where in the **** would you need such a large cap in a speaker crossover? IF DON'T WANT PERSONAL ATTACKS, DON'T MAKE STUPID **** UP!!! |
#23
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 16/02/2017 21:43, Paul wrote:
Also, where in the **** would you need such a large cap in a speaker crossover? In the PSU for an active speaker? He didn't say he used it in a crossover, just that he tested it and found the resonant frequency he mentioned. Incidentally, the tan δ for that capacitor is given in the maker's datasheets as as 0.16 at 120 Hz, so the ESR isn't fanstasic. There is no mention of self inductance values, but as it's an aluminium film type capacitor, the self inductance figures won't be all that low. -- Tciao for Now! John. |
#24
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Thursday, February 16, 2017 at 4:11:19 PM UTC-5, John Williamson wrote:
On 16/02/2017 21:43, Paul wrote: Also, where in the **** would you need such a large cap in a speaker crossover? In the PSU for an active speaker? He didn't say he used it in a crossover, just that he tested it and found the resonant frequency he mentioned. Incidentally, the tan δ for that capacitor is given in the maker's datasheets as as 0.16 at 120 Hz, so the ESR isn't fanstasic. There is no mention of self inductance values, but as it's an aluminium film type capacitor, the self inductance figures won't be all that low. -- Tciao for Now! John. Wonder if they use anodized aluminum to rid of any insulating film? Jack |
#25
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
In article ,
wrote: so if your 3,300 uF cap had a series resonance at 5.3 kHz, that implies an inductance of about 0.25 uH which has a Z of about 9 mOhms. The ESR will easily swamp that and Z is so low so as not to have any practical impact at any audiofreq. Right. Much more of a worry is nonlinearity when the ripple voltages get higher. However, the series resonances in the ultrasonic can be much more dramatic and those can lead to stability issues if you don't do the math right. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#26
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
John Williamson wrote:
Incidentally, the tan δ for that capacitor is given in the maker's datasheets as as 0.16 at 120 Hz, so the ESR isn't fanstasic. There is no mention of self inductance values, but as it's an aluminium film type capacitor, the self inductance figures won't be all that low. 270 nF does not seem out of the question to me, but it's kind of hard to look at this as a lumped-sum problem since you're dealing with both distributed capacitance and inductance across all the winds. I haven't personally seen resonances that low in capacitors, but I have seen some only a couple octaves higher. Thankfully not huge ones. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#27
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 16/02/2017 6:38 AM, PStamler wrote:
Capacitors, unfortunately, don't become low impedance at high frequencies; since they're made of rolled-up layers of foil and dielectric, Not all are made like that. they have an inductive component, and at high frequencies this becomes the most important; real-world capacitors show an impedance that falls with increasing frequency up to a point, then bottoms out, and rises as the frequency increases. Which is rarely a problem at audio frequencies though. Trevor. |
#28
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 16/02/2017 3:57 PM, PStamler wrote:
At the risk of attracting one of Mr. Allison's personal attacks,I have measured the rise in capacitors' impedance at high frequencies -- in some cases they switch from being capacitative to inductive well within the audio band. If you often use power supply filter caps etc. for audio coupling purposes, that's definitely something you'd would want to take into account I guess. :-) There is a reason why one selects components for purpose of course. Trevor. |
#29
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 17/02/2017 6:21 AM, PStamler wrote:
On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote: On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. Most people use those for power supply filtering etc. rather than audio. What was their inductance at 50-120Hz? Try using components for their intended purpose perhaps? Trevor. |
#30
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Thursday, February 16, 2017 at 3:43:15 PM UTC-5, Paul wrote:
On 2/16/2017 12:21 PM, PStamler wrote: On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote: On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. http://www.murata.com/~/media/webren...ow/12to14.ashx So resonant freq f=1/(2*Pi*(L*C)**0.5) So L=273nH. So you had 273nH of parasitic/lead inductance? BULL****. Also, where in the **** would you need such a large cap in a speaker crossover? IF DON'T WANT PERSONAL ATTACKS, DON'T MAKE STUPID **** UP!!! You know you stuff! Welcome to see someone with your knowledge here! Jack |
#31
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
Trevor said...news
On 17/02/2017 6:21 AM, PStamler wrote: On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote: On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. Most people use those for power supply filtering etc. rather than audio. What was their inductance at 50-120Hz? Try using components for their intended purpose perhaps? Trevor. My Dynaco ST120 channels use that value for output coupling to the speaker. david --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#32
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
In article , Trevor wrote:
On 16/02/2017 3:57 PM, PStamler wrote: At the risk of attracting one of Mr. Allison's personal attacks,I have measured the rise in capacitors' impedance at high frequencies -- in some cases they switch from being capacitative to inductive well within the audio band. If you often use power supply filter caps etc. for audio coupling purposes, that's definitely something you'd would want to take into account I guess. :-) There is a reason why one selects components for purpose of course. Sadly, that was the technology of the 1970s. People were designing with transistors but they were still thinking about tubes in their heads, so everything was capacitively coupled and electrolytics were needed in order to deal with the high values required due to the low impedances. I was at a mastering facility a few years back with some audiophile label guys who were looking at having some LPs cut. They asked the mastering engineer if there were any electrolytic capacitors in the signal path of the Neumann lathe amplifier and he about spit himself. "Millions of them!" he said. "Millions!" And so, because we live with a lot of older equipment designed in this regime, we have to deal with it and we have to find capacitors appropriate for the application. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#33
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
david gourley wrote:
My Dynaco ST120 channels use that value for output coupling to the speaker. Is mentioning an ST120 like mentioning Hitler? Is this thread closed now? --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#34
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 2/16/2017 5:49 PM, Trevor wrote:
On 17/02/2017 6:21 AM, PStamler wrote: On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote: On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. Most people use those for power supply filtering etc. rather than audio. What was their inductance at 50-120Hz? Try using components for their intended purpose perhaps? Trevor. +1 |
#35
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 17/02/2017 2:05 p.m., david gourley wrote:
My Dynaco ST120 channels use that value for output coupling to the speaker. david --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus Output coupling caps on a power amp ? I haven't seen those for decades ! geoff |
#36
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On 2/16/2017 4:48 PM, Scott Dorsey wrote:
John Williamson wrote: Incidentally, the tan δ for that capacitor is given in the maker's datasheets as as 0.16 at 120 Hz, so the ESR isn't fanstasic. There is no mention of self inductance values, but as it's an aluminium film type capacitor, the self inductance figures won't be all that low. 270 nF does not seem out of the question to me, So let's assume the leaded capacitor has about 15nH of self inductance. 270-15= 255 nH. And let's guesstimate 6nH of inductance per cm of lead length. 42.5 cm of added lead length??? THAT WOULD BE SLOPPY ENGINEERING!!!! :/ http://sound.whsites.net/articles/capacitors.htm I haven't personally seen resonances that low in capacitors, but I have seen some only a couple octaves higher. Thankfully not huge ones. --scott |
#37
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Thursday, February 16, 2017 at 2:43:15 PM UTC-6, Paul wrote:
On 2/16/2017 12:21 PM, PStamler wrote: On Thursday, February 16, 2017 at 1:07:31 AM UTC-6, Paul wrote: On 2/15/2017 10:13 PM, PStamler wrote: At the risk of incurring a personal attack, I wish to report that I have tested common commercially-available capacitors, looking for the resonant frequency (frequency at which the device's impedance bottoms out; the cap stops behaving like a capacitor above this frequency and starts behaving like an inductor). The lowest resonant frequency I found was 5.3kHz, well within the audio range. What was the capacitor value for that measurement? It was a 3,300µF/50V Panasonic Series NHG electrolytic. http://www.murata.com/~/media/webren...ow/12to14.ashx So resonant freq f=1/(2*Pi*(L*C)**0.5) So L=273nH. So you had 273nH of parasitic/lead inductance? BULL****. Also, where in the **** would you need such a large cap in a speaker crossover? I never said you would. A 3,300µF cap would more likely be found in a power supply, or perhaps in series with Rin in a noninverting opamp circuit.. IF DON'T WANT PERSONAL ATTACKS, DON'T MAKE STUPID **** UP!!! I am making nothing up; I'm simply reporting the result of aome tests I ran, no counter the assertion that inductance isn't an issue with electrolytic capacitors. Peace, The Other Paul |
#38
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
On Tuesday, February 14, 2017 at 11:32:09 PM UTC-6, Paul wrote:
GO AHEAD AND TAKE TURNS SAYING: "I TOLD YOU SO, DUMB MOTHER-****ER!" **** YOU ALL FOR BEING RIGHT! HAHA! IN MY DEFENSE, I'M NOT STUPID....JUST CHEAP, FRUGAL, AND STUBBORN AS HELL! THERE IS A DIFFERENCE! HAHAHAAA!!! This was apparent after comparing A/B NON-CROSSOVERED piezos with one of my Yamaha HS80Ms. The incriminating test song was Pink Floyd's "Time"! As soon as the vocals come in, it's SCREECH CITY with the piezo! BOY THAT SOUNDS BAD! I mean, it depends on where you are listening wrt the horn, but if you are right in front of it....UUUUGGGHH!! In contrast, you can listen anywhere in front of the Yammies, and although they may sound bright, and have tons of "presence", they never get HARSH like the piezos! So then I experimented with adding a crossover, and settled on series 2uF non-polarized cap, and shunt 22 Ohm resistor before the piezos in parallel (a series 0.1uF after the shunt resistor, for -6dB, was too much, and almost killed off the signal completely). The crossover makes it more tolerable, but I can't say it sounds good delivering high fidelity music. For some reason, just singing through it with an SM58, makes the harshness less noticeable, so it could still be useful for that usage. I'll probably sell this for a few bucks to a poor garage band, telling them exactly what I did. I DIDN'T WASTE MY TIME AND ENERGY WITH THIS EXPERIMENT: I LEARNED QUITE A BIT, AND THAT MAKES TINKERING WORTH DOING! Thanks for the feedback, everyone.... |
#39
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
(Scott Dorsey) said...news
david gourley wrote: My Dynaco ST120 channels use that value for output coupling to the speaker. Is mentioning an ST120 like mentioning Hitler? Is this thread closed now? --scott Wow, sorry didn't know it was THAT bad. I've used it for a guitar and bass amp. david --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#40
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APOLOGIES TO ALL: PIEZO TWEETERS DO SOUND LIKE ****!!!!
geoff said...news:Q8Gdnbn5apB0yDvFnZ2dnUU7-
: On 17/02/2017 2:05 p.m., david gourley wrote: My Dynaco ST120 channels use that value for output coupling to the speaker. david --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus Output coupling caps on a power amp ? I haven't seen those for decades ! geoff It's decades old, too. david --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
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