Revised technical question:

[Shawn Sutherland]

What is the best capacitor value for audio frequencies between 100 HZ and
6000 HZ into an impedance of 1K ohms?

Please let me know.

Shawn

 

[Richard Crowley]

"Shawn Sutherland" wrote ...

What is the best capacitor value for audio frequencies
between 100 HZ and 6000 HZ into an impedance of
1K ohms?

According to the RFC calculator online at
http://www.opamplabs.com/rfc.htm ...

1.5 microFarads has an impedance of ~1000 ohms
at 100 Hz. This would give you a 3dB down point
at 100 Hz.

To be honest, you will not likely get anywhere very fast
asking excedingly cryptic questions like this, however.

We have no way of interpereting what YOU mean by
"best" without significantly more context.

 

[Myron Samila]

1k ohm for audio? as in where in the circuit?? speaker? active part of the circuit?
passive crossover?

A capacitor cannot limit bandwidth on the top end, you'd need a bandwidth limiting
crossover network to limit frequencies between 100hz and 6khz.

We need the following information:

Application?
What you are trying to achieve??

--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19


"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:vvdk8unijd7711@corp.supernews.com...

"Shawn Sutherland" wrote ...
What is the best capacitor value for audio frequencies
between 100 HZ and 6000 HZ into an impedance of
1K ohms?

According to the RFC calculator online at
http://www.opamplabs.com/rfc.htm ...

1.5 microFarads has an impedance of ~1000 ohms
at 100 Hz. This would give you a 3dB down point
at 100 Hz.

To be honest, you will not likely get anywhere very fast
asking excedingly cryptic questions like this, however.

We have no way of interpereting what YOU mean by
"best" without significantly more context.

 

[Brian Oakley]

A cap cant limit on the high end?? Are you sure about that? If you take an
appropriate cap across a speaker, doesnt that short out some of the high end
freqs?

"Myron Samila" <myronx19@no.spam.sympatico.ca> wrote in message
news:NwBJb.19880$Vl6.3715141@news20.bellglobal.com...

1k ohm for audio? as in where in the circuit?? speaker? active part of the
circuit?
passive crossover?

A capacitor cannot limit bandwidth on the top end, you'd need a bandwidth
limiting
crossover network to limit frequencies between 100hz and 6khz.

We need the following information:

Application?
What you are trying to achieve??

--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19


"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:vvdk8unijd7711@corp.supernews.com...
"Shawn Sutherland" wrote ...
What is the best capacitor value for audio frequencies
between 100 HZ and 6000 HZ into an impedance of
1K ohms?

According to the RFC calculator online at
http://www.opamplabs.com/rfc.htm ...

1.5 microFarads has an impedance of ~1000 ohms
at 100 Hz. This would give you a 3dB down point
at 100 Hz.

To be honest, you will not likely get anywhere very fast
asking excedingly cryptic questions like this, however.

We have no way of interpereting what YOU mean by
"best" without significantly more context.

 

[Richard Crowley]

"Brian Oakley" wrote ...

A cap cant limit on the high end?? Are you sure about that?
If you take an appropriate cap across a speaker, doesnt that
short out some of the high end freqs?

Depends on whether the cap is in series in parallel.

Of course we are all guessing because the OP is provding
no useful detail about his/her question. I smell a troll.

 

[Myron Samila]

You wouldn't use a cap to limit bandwidth in parallel in audio.

You'd use a coil to limit high frequencies at a rate of 6db/octave, in series. A cap in
series with the speaker will filter low frequencies.

Passive crossovers are horrible anyhow, bi-amping or three way (active xovers) work best.

Yes, the OP won't get his question answered because it is too vague.

--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19


"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:vvtm69susa43bb@corp.supernews.com...

"Brian Oakley" wrote ...
A cap cant limit on the high end?? Are you sure about that?
If you take an appropriate cap across a speaker, doesnt that
short out some of the high end freqs?

Depends on whether the cap is in series in parallel.

Of course we are all guessing because the OP is provding
no useful detail about his/her question. I smell a troll.

 

[Brian Oakley]

It depends on his application. As I said in my post "across the speaker"
will roll off the top end. As you stated in your post, a cap in series will
roll off the low end. We dont know what kind of circuit application he is
using, hifi, mono, etc. He may be looking for a filter for his ham radio
reciever for all we know so a crossover may not even be what he needs.
Anyway, until he is more specific, we wont be able to answer.
Brian

"Myron Samila" <myronx19@no.spam.sympatico.ca> wrote in message
news:dpBLb.107761$BA6.2045358@news20.bellglobal.com...

You wouldn't use a cap to limit bandwidth in parallel in audio.

You'd use a coil to limit high frequencies at a rate of 6db/octave, in
series. A cap in
series with the speaker will filter low frequencies.

Passive crossovers are horrible anyhow, bi-amping or three way (active
xovers) work best.

Yes, the OP won't get his question answered because it is too vague.

--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19


"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:vvtm69susa43bb@corp.supernews.com...
"Brian Oakley" wrote ...
A cap cant limit on the high end?? Are you sure about that?
If you take an appropriate cap across a speaker, doesnt that
short out some of the high end freqs?

Depends on whether the cap is in series in parallel.

Of course we are all guessing because the OP is provding
no useful detail about his/her question. I smell a troll.

 

[Switch]

"Brian Oakley" <brianoakley@ispwest.com> wrote in message
news:btnhp002d51@enews4.newsguy.com...

It depends on his application. As I said in my post "across the speaker"
will roll off the top end. As you stated in your post, a cap in series will
roll off the low end. We dont know what kind of circuit application he is
using, hifi, mono, etc. He may be looking for a filter for his ham radio
reciever for all we know so a crossover may not even be what he needs.
Anyway, until he is more specific, we wont be able to answer.
Brian

How does a cap across the speaker roll off top end? I believe that is incorrect. Hifi,
mono, 5 channel, it doesn't matter. A passive filter is a passive filter, period, ham
radio or not (I have friends who are operators and I've built many bandwidth filters for
them. The only way to roll off high frequencies to a speaker is to put a coil in series
with the speaker or resistor across the speaker (high value resistance will absorb
frequencies at a specific attenuation, as 6db/octave typical). Putting a capacitor across
a speaker is the same as putting it in parallel. Trust me, it won't work, even when a
12db/octave filter is used, the cap goes in series with the load, the coil goes in
parallel to the load for low-pass applications, reverse for high pass applications.



A crossover is a filter, exactly that, highpass vs lowpass vs... bandpass..... all
crossovers (a term used in the audio field).

Top posting is bad, stop it.

 

[Richard Crowley]

"Switch" wrote ...

How does a cap across the speaker roll off top end?

A capacitor's impedance goes down as the frequency increases.

 

[Brian Oakley]

"Switch" <clubkidd_toronto@hotmail.com> wrote in message
news:mxWLb.2978$fM3.22056@news20.bellglobal.com...

"Brian Oakley" <brianoakley@ispwest.com> wrote in message
news:btnhp002d51@enews4.newsguy.com...
It depends on his application. As I said in my post "across the speaker"
will roll off the top end. As you stated in your post, a cap in series
will
roll off the low end. We dont know what kind of circuit application he
is
using, hifi, mono, etc. He may be looking for a filter for his ham radio
reciever for all we know so a crossover may not even be what he needs.
Anyway, until he is more specific, we wont be able to answer.
Brian


How does a cap across the speaker roll off top end? I believe that is
incorrect. Hifi,
mono, 5 channel, it doesn't matter. A passive filter is a passive filter,
period, ham
radio or not (I have friends who are operators and I've built many
bandwidth filters for
them. The only way to roll off high frequencies to a speaker is to put a
coil in series
with the speaker or resistor across the speaker (high value resistance
will absorb
frequencies at a specific attenuation, as 6db/octave typical). Putting a
capacitor across
a speaker is the same as putting it in parallel. Trust me, it won't work,
even when a
12db/octave filter is used, the cap goes in series with the load, the coil
goes in
parallel to the load for low-pass applications, reverse for high pass
applications.



A crossover is a filter, exactly that, highpass vs lowpass vs...
bandpass..... all
crossovers (a term used in the audio field).

Top posting is bad, stop it.

I will accomodate your wish about top posting. And dont be telling people

what to do.
A cap does roll off the frequencies when placed across the speaker. If you
study filter design, the coil in series does what a capacitor in parallel
does. The point is the capacitor needs to be the correct value to do so.
Granted, it may be a large capacitor, but it does work. Try it. Also, the
ARRL Handbook has some good theory on filters.'
Brian

 

[Brian Oakley]

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:1000esneck57laa@corp.supernews.com...

"Switch" wrote ...
How does a cap across the speaker roll off top end?

A capacitor's impedance goes down as the frequency increases.


Someone that understands!

B.

 

[Switch]

I will accomodate your wish about top posting. And dont be telling people
what to do.

Usenet rules.... read the FAQ and rules and regulations of usenet, it is in black and
white.

A cap does roll off the frequencies when placed across the speaker. If you
study filter design, the coil in series does what a capacitor in parallel
does. The point is the capacitor needs to be the correct value to do so.
Granted, it may be a large capacitor, but it does work. Try it. Also, the
ARRL Handbook has some good theory on filters.'
Brian

Brian, in my time of designing filter networks, reading books, using crossover/filter
design software, there is no where that suggests the use of a capacitor in parallel to a
speaker to limit frequency. If so, what is the predictable filter slope??

Anything less than 6db/octave is useless in audio.

 

[Richard Crowley]

"Switch" wrote ...

Brian, in my time of designing filter networks, reading
books, using crossover/filter design software, there is
no where that suggests the use of a capacitor in parallel
to a speaker to limit frequency. If so, what is the
predictable filter slope??

Keep studying.

Anything less than 6db/octave is useless in audio.

A remarkably rash pronouncement. We'll write it off
to youthful indiscression and inexperience.

"There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy."
-William Shakespeare, "Hamlet"

 

[Switch]

Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:1000psao8uku284@corp.supernews.com...

Anything less than 6db/octave is useless in audio.

A remarkably rash pronouncement. We'll write it off
to youthful indiscression and inexperience.

Why would that be considered rash? if you are trying to limit bandwidth (lets say low
pass) from 250hz up to 20khz, then at anything less than 6db/octave, you will still hear a
great deal of program material at the next lower octave. The slope is too great,
typically, in home audio filter networks employ a minimum of 6db per octave, and then
higher quality ones use 24db/octave, Butterworth, Linkwitz, Bessel, Bec... depending on
the desired Q.

Look, if you want to limit bandwidth in audio, I am simply suggesting that your method is
not practical and not used.

ie: 8ohm speaker, bandpass 500hz-6000hz, use a 40mF (non polarized) cap in series with a
coil of .212 mH, this will bandpass at an effective slope of 6db/octave on the upper and
lower end of the shelf.

What now?? Qualify yourself, otherwise your posts aren't of any use.

 

[Richard Crowley]

"Switch" wrote ...

Look, if you want to limit bandwidth in audio, I am
simply suggesting that your method is not practical
and not used.

You not only have a remarkably narrow view of the world,
but you seem unusually cock-sure that your's is the only
valid concept.

You clearly haven't studied many schematics if you think
that simple "1-pole" R/C filtering "is not pracical and not
used" it is used in virtually every AC-coupled circuit ever
made. Perhaps you don't recognize it because it is so pervasive.

ie: 8ohm speaker, bandpass 500hz-6000hz, use a 40mF
(non polarized) cap in series with a coil of .212 mH, this
will bandpass at an effective slope of 6db/octave on the
upper and lower end of the shelf.

What now?? Qualify yourself, otherwise your posts
aren't of any use.

Well, if you go back and read the original post, it wasn't
even detailed enough to mention anything about using it
in speaker crossovers (or any other identifiable application).

Did you even understand the concept of the Shakespear quote?

 

[Switch]

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10032s3id8uba93@corp.supernews.com...

You clearly haven't studied many schematics if you think
that simple "1-pole" R/C filtering "is not pracical and not
used" it is used in virtually every AC-coupled circuit ever
made. Perhaps you don't recognize it because it is so pervasive.

We are talking audio (AC), not any other type of AC coupled circuit. You are clearly (not
to you though) missing the point.

Someone suggested you can bandpass audio using only a cap, how?(bandpass passively on the
output of an amp) Where does it filter the low end? Are you going to put a 100,000 mF
capacitor at 200V to cut out frequencies at 8 ohms? Practical? ummmmmm.......

The suggestion of bandpass came up regarding ham radios........ that is why we are on the
topic of audio, nothing to do with the OP.

ie: 8ohm speaker, bandpass 500hz-6000hz, use a 40mF
(non polarized) cap in series with a coil of .212 mH, this
will bandpass at an effective slope of 6db/octave on the
upper and lower end of the shelf.

What now?? Qualify yourself, otherwise your posts
aren't of any use.

Well, if you go back and read the original post, it wasn't
even detailed enough to mention anything about using it
in speaker crossovers (or any other identifiable application).

I was responding to someone who said you can use a capacitor across a speaker to achieve
bandpass, not the OP.

Did you even understand the concept of the Shakespear quote?

We're talking electronics here.....I'm not in the alt.shakespear.chat.forum, his rants are

about as out of date as your theorems.


You're still incorrect unless you can prove otherwise. Show me an example using ONE
capacitor how you would filter frequencies between 100hz and 5000hz with an 8ohm speaker
load?? we are assuming the signal is audio, from an amp. That is what I was arguing, it
is incorrect and cannot be done, period......

Lets stop the misinformation here. I wasn't referring to the OP at all, all previous
posts have snips of the question I was answering.


Do you own a stereo? Do you understand what I'm talking about at all??!?! That is my
only question. If there is any other way of doing what I'm suggesting, why doensn't
anyone else do it?

Just like the thread about 50hz vs 60hz motors, oh my, don't even get me started on that
one. So much WRONG information, I only wish I jumped in on that one.

 

[Myron Samila]

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10032s3id8uba93@corp.supernews.com...


You clearly haven't studied many schematics if you think
that simple "1-pole" R/C filtering "is not pracical and not
used" it is used in virtually every AC-coupled circuit ever
made. Perhaps you don't recognize it because it is so pervasive.

Hate to say it Richard,

This person is right........ You cannot create a bandpass audio filter with just a cap
across a speaker load as was mentioned that you could in a previous post. If you put a
cap in series with the speaker load, you create a filter. (filtering out low frequencies).

I think you missed the initial point that I brought up in this thread a while back.

And you don't need to study schematics to understand how a speaker crossover or bandpass
filter works. Usually, there are no more than 4 components (in a 24db/octave slope
passive crossover), this is the only component between a speaker and an amplifier.

I think I also talked about the ham radio application and such, but whatever. Points get
missed, heheh.

All I do is live and breathe professional audio, have done so for the past 10 years, wind
my own air core coils, built hundreds of passive and active crossover networks . I've
never put a cap in parallel (across) a speaker load to achieve what you guys are arguing
about, ?!?! heheh. If a cap could be used as a bandpass device in audio, that would be
great, since then I would start to wonder why we use coils (which are expensive, power
robbing, expensive, oh and did I mention expensive?, high quality audio air core coils can
reach upwards of $400!!!! or more (Cnd), for only 100Watts power dissipation!!!

Anyhow, great discussion!! A lot can be learned here!

--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19

 

[Brian Oakley]

"Switch" <clubkidd_toronto@hotmail.com> wrote in message
news:mQYLb.2994$fM3.22211@news20.bellglobal.com...

I will accomodate your wish about top posting. And dont be telling
people
what to do.

Usenet rules.... read the FAQ and rules and regulations of usenet, it is
in black and
white.

Doesnt matter, its not your job to tell people what to do. You can explain

the rules, but assuming to be the boss doesnt make you someones boss kid.

 

[Brian Oakley]

"Myron Samila" <myronx19@no.spam.sympatico.ca> wrote in message
news:VvAMb.6299$881.792100@news20.bellglobal.com...

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10032s3id8uba93@corp.supernews.com...


You clearly haven't studied many schematics if you think
that simple "1-pole" R/C filtering "is not pracical and not
used" it is used in virtually every AC-coupled circuit ever
made. Perhaps you don't recognize it because it is so pervasive.


Hate to say it Richard,

This person is right........ You cannot create a bandpass audio filter
with just a cap
across a speaker load as was mentioned that you could in a previous post.
If you put a
cap in series with the speaker load, you create a filter. (filtering out
low frequencies).

I think you missed the initial point that I brought up in this thread a
while back.

And you don't need to study schematics to understand how a speaker
crossover or bandpass
filter works. Usually, there are no more than 4 components (in a
24db/octave slope
passive crossover), this is the only component between a speaker and an
amplifier.

I think I also talked about the ham radio application and such, but
whatever. Points get
missed, heheh.

All I do is live and breathe professional audio, have done so for the past
10 years, wind
my own air core coils, built hundreds of passive and active crossover
networks . I've
never put a cap in parallel (across) a speaker load to achieve what you
guys are arguing
about, ?!?! heheh. If a cap could be used as a bandpass device in audio,
that would be
great, since then I would start to wonder why we use coils (which are
expensive, power
robbing, expensive, oh and did I mention expensive?, high quality audio
air core coils can
reach upwards of $400!!!! or more (Cnd), for only 100Watts power
dissipation!!!

Anyhow, great discussion!! A lot can be learned here!

--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19

I think the question that Switch asked was how does a cap across a speaker

roll off frequenceis at the top end. He didnt say anything about bandpass. A
bandpass filter consists of several poles made up of caps and coils. But a
cap across an 8 ohm load can roll off frequencies at the top end. Like I
said it depends on the size and type of the cap. Xc =2pi*f*C. This is the
formula one would use to calculate the capactive reactance to frequencies
with a given capacitance. Plug in the frequency in question with the
reactance in question and it will give you a capacitance that you need. Find
a good electronics book and a physics book. it does work.

 

[Brian Oakley]

"Switch" <clubkidd_toronto@hotmail.com> wrote in message
news:s2kMb.26$XZ.1990@news20.bellglobal.com...

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10032s3id8uba93@corp.supernews.com...


You clearly haven't studied many schematics if you think
that simple "1-pole" R/C filtering "is not pracical and not
used" it is used in virtually every AC-coupled circuit ever
made. Perhaps you don't recognize it because it is so pervasive.

We are talking audio (AC), not any other type of AC coupled circuit. You
are clearly (not
to you though) missing the point.

No I think he understands the point as it was originally described in the
original post.

Someone suggested you can bandpass audio using only a cap, how?(bandpass
passively on the
output of an amp) Where does it filter the low end? Are you going to put
a 100,000 mF
capacitor at 200V to cut out frequencies at 8 ohms? Practical?
ummmmmm.......

The suggestion of bandpass came up regarding ham radios........ that is
why we are on the
topic of audio, nothing to do with the OP.

The original post about filtering in ham radios was my post. It doesnt
mention bandpass, nor 8 ohm load for that matter. The original post says
1000 ohm impedence. There are a lot of things you can do with audio at 1000
ohms that may not be practical at 8 ohms. We are not talking hi fi audio
here. We are more than likely talking about a lowpass filter using a cap
across the speaker leads of a 1Kohm speaker (or headphones).

ie: 8ohm speaker, bandpass 500hz-6000hz, use a 40mF
(non polarized) cap in series with a coil of .212 mH, this
will bandpass at an effective slope of 6db/octave on the
upper and lower end of the shelf.

What now?? Qualify yourself, otherwise your posts
aren't of any use.

Well, if you go back and read the original post, it wasn't
even detailed enough to mention anything about using it
in speaker crossovers (or any other identifiable application).

I was responding to someone who said you can use a capacitor across a
speaker to achieve
bandpass, not the OP.

Im not sure where you keep getting the idea about bandPASS. BandWIDTH was
what was mentioned, and a cap can effectively limit the bandwidth by rolling
off the high end frequenceis. We were talking about a rolloff filter, one
that rolls off the higher frequencies. Theres a big difference.

Did you even understand the concept of the Shakespear quote?

We're talking electronics here.....I'm not in the
alt.shakespear.chat.forum, his rants are
about as out of date as your theorems.


You're still incorrect unless you can prove otherwise. Show me an example
using ONE
capacitor how you would filter frequencies between 100hz and 5000hz with
an 8ohm speaker
load?? we are assuming the signal is audio, from an amp. That is what I
was arguing, it
is incorrect and cannot be done, period......

Again, 8 ohms was not mentioned in the original post. 1000 ohms was the
load. For all you kids out there that dont know it, there is a lot of older
equipment that use higher impedence output audio. It can range from 6k ohms
on down to 8 these days. If Im not mistaken, PA systems use higher impedence
loads to limit the current drawn from the system.

Lets stop the misinformation here. I wasn't referring to the OP at all,
all previous
posts have snips of the question I was answering.


Do you own a stereo? Do you understand what I'm talking about at
all??!?! That is my
only question. If there is any other way of doing what I'm suggesting,
why doensn't
anyone else do it?

Like I said above, youre thinking high end hifi, not high impedence
communication audio amplifiers.

Just like the thread about 50hz vs 60hz motors, oh my, don't even get me
started on that
one. So much WRONG information, I only wish I jumped in on that one.

Not gonna comment on that.
Brian