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Paul[_13_] Paul[_13_] is offline
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Default 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....






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geoff geoff is offline
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Default 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

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Chuck[_12_] Chuck[_12_] is offline
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Default 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.

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Scott Dorsey Scott Dorsey is offline
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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

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Richard Kuschel Richard Kuschel is offline
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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.



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Paul[_13_] Paul[_13_] is offline
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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!!



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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!


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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
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PStamler PStamler is offline
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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
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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




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Phil Allison[_4_] Phil Allison[_4_] is offline
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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
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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

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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
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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?


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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


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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
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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.
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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
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This was the worst case, but several electrolytic caps had resonances within the audible range.

Peace,
The Other Paul
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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

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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



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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!!!


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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.
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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.
--
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John.


Wonder if they use anodized aluminum to rid of any insulating film?

Jack
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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

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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

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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.

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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.


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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.

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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



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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

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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."
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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."
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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
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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

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Output coupling caps on a power amp ? I haven't seen those for decades !


geoff



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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


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PStamler PStamler is offline
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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

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PStamler PStamler is offline
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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....


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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

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Output coupling caps on a power amp ? I haven't seen those for decades

!


geoff



It's decades old, too.

david

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