Basic speaker Q

[Phil Allison]

"Steve" <niftydog@hotmail.com> wrote in message
news:e28c5b43.0311031453.2db1236e@posting.google.com...

Read it to yourself, moron - it screams of some 15 year old,
pimply faced, jerk off.

How you have surmised that from a simple email address is beyond me...

** Intelligent though is way beyond a fool like you.

but it couldn't be further from the truth.

** Jeez, this wanker cannot mentally separate his email addy from
himself.

... and STILL no one can tell me what is so bad about using my hotmail
address.

** Explain why you sniped and IGNORED my reason ????

Get a real addy - and then use your full name.

Your cred will go up by an order of magnitude.


So if I make up a "real" name and have an email address that doesn't
contain the word "hotmail" then people will respect me?!?!

** Nothing of the sort was posted - you imbecile.

READ what WAS posted or go fuck your "nifty dog".




............... Phil

 

[Phil Allison]

"Anthony Fremont"

First off, I wish to offer my apologies to the rest of the group for my
childish outburst. I don't normally conduct myself like that without
allot more prompting, especially when making my first posts to a group.

As for you Phil, your sig line should carry a warning serving to inform
others that you are incapable of conducting a civil discussion.

** I do not have to politely discuss anything with lying Yank mental
midgets.




............ Phil

 

[Phil Allison]

"Rod Speed"


** The Rusty Robot has revealed yet again what a mental ( metal ?) cripple
he is.

Can't even get a single thing right.




........... Phil

 

[Mark Hathaway]

"
Well, to a first approximation, you're correct, but in the first
approximation, the details of X are QUITE important. one issue
before proceeding further:

There can be a large difference between the relationship between
the DC resistance and the impedance of a single driver and that
of a multi-way system, so we need to be careful in specifying
which we are discussing.

Let's explore the contributors to the impedance of a single
driver, let's say (and this is derived from a quick reading
of the context of the discussion, as I just looked it up)
we are loking at a woofer.

The following are the major contributors to the impedance of
such a driver:

1. The electrical impedance of the vooice coil itself

2. The mechanical impedance of the driver, as reflected through
the transduction trasnformation of the voice coil/magnet. The
transformation ratio here is B^2 l^2, where B is the flux
density in the gap in Tesla, and l is the length of wire immersed
in the flux.

3. The acoustical impedance of the driver, as reflected through
to the mechanical domain by the driver radiating area, then
reflected through to the electrical domain by the voice coil
and magnet. The acoustical-to-mechanical transformation goes
as Sd^2, where Sd is the emissive area of the cone.

Now, assume, for the moment, we are talking a typical direct-radiator
driver of the kind found in most domestic music system loudspeakers.
The total contribution of the acoustical impedance is actually quite
small, usually less than 1% of the total reflected electrical impedance,
and, no suprise, corresponds to the reference efficiency of the
driver. Since in order to produce sound, the speaker must do work into
an impedance, and the efficiency is small, then the contribution of'that
impedance into which the work is being done is similarily small. We'll
see that come up again and again, though it's not often discussed in
texts.

By the time one sees then acoustical impedance reflected back into the
electrical domain, it is a VERY small portion of the total that has
the property of going, roughly as frequency squared up to a limit
that's determined by the emissive area of the diaphragm. The problem is
no simple electrical analog has a f^2 impedance analog, but we're safe
becase the effect is, as we said, a very minor part of the total.

Then there is the mechanical contribution to the impedance. By far
the single largest contributor is the bulk motional impedance of
the speaker due to the fundamental mechanical resonance of the driver
at some low frequency. You have a mechanically resonant circuit
which consists of the reactive components of the mass of the diaphragm
and the compliance of the mechanical suspension, and a loss element
due to friction in the suspension (some have mentioned the air-load mass
and the air compliance, but these are small compared to the simple
mechanical mass and compliance of the system). As reflected back
through the voice coil, these look all the world like an ordinary,
everyday parallel RLC resonant tank circuit. To the amplifier or
crossover, it could just as well be and RLC tank circuit.

Now, add a box and a port and other things, and this makes this
circuit a little more complex, but we can get a pretty damned
good approximation to within a couple of % of reality with less
than 10 equivalent passive components, i.e., inductors, capacitors
and resistors.

And last we have the electrical portion. To a reasonable first-order
approximation, this looks like a simple RL series combination, where
R is the DC resistance of the voice coil, and L is the inductance.

So, a first stab at the electrical properties of the impedance nets
a circuit that looks like this SPICE net list (values taken from
an actual set of measurements for a SPICE model was developed):

Re 1 2 6.25 * DC voice coil resistance
Le 2 3 0.67MH * voice coil inductance
Lces 3 0 57.8MH * inductive equivalent of compliance
Cmes 3 0 320.9UF * capacitive equivalent of mass
Rces 3 0 26.8 * resistive equivalent of suspension losses

This is for a 6 1/2" driver that has the following T/S and
electromechanical parameters:

Fs 36 Hz
Vas 32 L
Qms 2.06
Qes 0.48
Qts 0.39
Re 6.25 Ohms
Mms 20.1 g
Cms 0.97 mm/N
Rms 2.21 kg/s
Bl 7.70 N/A
Sd 1.54 x 10^-2 m^2

But, upon comparing this to the measured impedance, while we find
the fit is very good in the low frequency region (up to 200 Hz),
we find a widening gap between model and physical reality above 500
Hz. The model's impedance, no surprisingly asymotically reaches a
slope of 2 (the impedance doubles every octave), while the reality
only reaches a slope of approximately sqrt(2).

The reason is one someone else in the thread alluded to in reference
the Lipschitz/Vanderkooy article. There is a very important mechanism
at work at higher frequencies: the metal part of the magnet assembly
surrounding the voice coil are electrically conductive. The time-varying
field generated by the voice coil induces eddy currents in these
metal parts in a manner that is, to a first approximation, freuqency
dependent.

The net result is a rather surprising (at first, until you think
about it) effect: the effective resistive part of the voice coil's
contribution to the impedance INCREASES iwith increasing frequency,
while the effective inductive part of of the voice coils impedance
DECREASES with increasing frequency. More and more of the magnetic
field generated by the voice oicl goes into the production of these
eddy currents as you go higher and higher in frequency. The real
electrical resistance seen by these eddy current causes real work
to be done: it heats up the pole piece and front plate of the magnet!
These metal parts look like the seondary turns of a transformer whose
coupling increases with increasing frequency.

Above 500 Hz, we see THIS phenonenon as THE dominating factor of the
electrical impedance of woofers.

Now, to answer the original bait, uh, I mean, question: the impedance
seen at around 200 Hz, which is higher than the DC resistance of the
voice coil, is the result of several contributors:

1. The DC resistance of the voice coil
2. A small portion of the the mechanical impedance of the
driver's fundamental resonance
3. The voice coil inductance
4. Eddy current losses in the conductive metal parts of the
magnet assembly
5. Lots of other small particpants, the sum of which has a
very minor effect on the total impedance magnitude, such
as the radiation impedance of the driver, mechanical
resonances in the cone, as so forth.

And the notion that it is 20% greater that the DC resistance is
simply one possible figure out of a fairly wide range of typical
values. I have seen it as low as a couple of percent, seldom higher
than 20%.

Now, the question of what is the "nominal" impedance is, in fact,
a matter of convention and, in some cases, standardization. TO the
latter point, one finds such documents as IEC 60268 which has specific
recommendations of how one determines the "nominal" impedance of
a driver or speaker. There are various reasonable justifications for
the recommendations given, and I would direct anyone interested in
learning these rationalizations to the relevant documents.



+---------------------------------------+
| Dick Pierce |
| Professional Audio Development |
| Acoustics and Digital Audio |
| (1) 781/826-4953 Voice and FAX |
| dpierce@cartchunk.org |
+---------------------------------------+

"



"Mark Hathaway" <markhathawayREMOVEME@bigblue.net.au> wrote in message
news:bo06vf$1mpl$1@news.ausix.net...

1. Vance Dickason, "how to plot and understand Complex Impedance" Speaker
Builder, 1988, page 15.

2. Vance Dickason, Speaker Design Cook Book, fourth Edition

3. R. Small, "Direct Radiating Loudspeaker System Analysis" JAES june
1972

4. Author's Reply to "comments on "an Empirical Model for loudspeaker
Motor
Impedance" JAES, Volume 40, no 1. p 43, 1992

5. Author's Reply to "Comments on 'A Model of Loudspeaker Driver Impedance
Incorporating Eddy Currents in the Pole Structure'" Vol. 38, Number 3
pp. 147 (1990) Author: John Vanderkooy

6. A Model of Loudspeaker Driver Impedance Incorporating Eddy Currents in
the Pole Structure Vol. 37, Number 3 pp. 119 (1989) Author: John
Vanderkooy

7. http://www.ctc.puc-rio.br/icee-98/Icee/papers/207.pdf

8. http://www.icspat.com/papers/177mfi.pdf



Z = (R^2 + X^2) ^(1/2)

the X term contains all the electrical, mechanical and acoustic impedance
variables


Mark Hathaway








"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3fa36db6$0$28120$afc38c87@news.optusnet.com.au...

"Mark Hathaway"

I'd love to see your source, or is this your own theory?
I checked my answer against a few publishments, I'd love to see you
contradict them.


** Go ahead - post them.

Make my day......



......... Phil

 

[Phil Allison]

"Mark Hathaway"


** Shame the pommy wind bag he did not give as clear an answer as I did.






........... Phil

 

[Phil Allison]

"Alan Peake" <

The extra power is mostly converted into heat by the rapid flexing the
suspension material while some is converted to sound. Since most speakers
are not even 1% efficient at converting electricity into sound energy
nearly
all the extra power is dissipated in flexing the suspension – i.e. the
spider, surround and cone.

The conversion (electrical/acoustical power) efficiency is greatly
influenced
by the acoustic load on the speaker cone.

** I posed the question about a bass driver without any special
loading.

Horn-loaded speakers have been quoted at up to 80% (Klipschorns)

** Utter rot.





............... Phil

 

[Rod Speed]

Phil Allison <philallison@optusnet.com.au> wrote in message
news:3fa71e57$0$2390$afc38c87@news.optusnet.com.au...

Mark Hathaway

Shame the pommy wind bag he did not give as clear an answer as I did.

Pity yours was just a steaming pig ignorant turd which couldnt even
explain the considerable peaks and troughs in the impedance chart
with a single speaker without any added electronics at all.

 

[Mike Harding]

On Mon, 03 Nov 2003 17:30:36 GMT, "Anthony Fremont"
<NOspam-me@houston.rr.com> wrote:

First off, I wish to offer my apologies to the rest of the group for my
childish outburst. I don't normally conduct myself like that without
allot more prompting, especially when making my first posts to a group.

Don't worry about it, Phil even managed to make Winfield
Hill loose his temper (although he did have to work at
it for a long time). Mind you, it cost him his internet account,
you'll notice he no longer posts to sci.electronics.design.

Phil is a social misfit of the worse kind, he and his ilk are
the price we have to pay for usenet. It is important we
continue to stand up against such bullying lest he
dominates the group to such a degree people are afraid
to post.

Mike Harding

 

[Phil Allison]

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bo8vt7$1bffvi$1@ID-69072.news.uni-berlin.de...

Phil Allison <philallison@optusnet.com.au> wrote in message
news:3fa71e57$0$2390$afc38c87@news.optusnet.com.au...
Mark Hathaway

Shame the pommy wind bag he did not give as clear an answer as I did.

Pity yours was just a steaming pig ignorant turd which couldnt even
explain the considerable peaks and troughs in the impedance chart
with a single speaker without any added electronics at all.

** A cone speaker has just one impedance peak - at the bass
resonance.

There is one broad trough - in the mid band as I specified over
and over.

BTW

Go fuck yourself Rod.



............. Phil

 

[Phil Allison]

"Mike Harding" <mike_harding1@nixspamhotmail.com> wrote in message
newsk1gqvcc4mm5igotm9iv6o13tf8hb60e9e@4ax.com...



Mike Harding is a social misfit of the worse kind, he and his ilk are
the price we have to pay for usenet.

This lying, criminal pig should be ignored at all times.






.......... Phil

 

[Mike Harding]

On Wed, 5 Nov 2003 13:11:58 +1100, "Phil Allison"
<philallison@optusnet.com.au> wrote:

Mike Harding is a social misfit of the worse kind, he and his ilk are
the price we have to pay for usenet.

This lying, criminal pig should be ignored at all times.

Now Phil, I know you're paranoid and, occasionally,
delusional (and probably lots of other " 'oids' too)
but where do you get the "criminal" accusation from?

Mike Harding

 

[Phil Allison]

"Mike Harding"


Mike Harding is a social misfit of the worse kind, he and his ilk are
the price we have to pay for usenet.

This lying, criminal pig should be ignored at all times.




............ Phil

 

[Anthony Fremont]

Mike Harding wrote:

On Mon, 03 Nov 2003 17:30:36 GMT, "Anthony Fremont"
NOspam-me@houston.rr.com> wrote:

First off, I wish to offer my apologies to the rest of the group for
my childish outburst. I don't normally conduct myself like that
without allot more prompting, especially when making my first posts
to a group.

Don't worry about it, Phil even managed to make Winfield
Hill loose his temper (although he did have to work at
it for a long time). Mind you, it cost him his internet account,
you'll notice he no longer posts to sci.electronics.design.

Lost his account huh, K-man hasn't even managed that yet. That must
have been quite an interesting thread that led to that. A quick look at
the archives show some kind of firefight going on last Jan-Feb.

Phil is a social misfit of the worse kind, he and his ilk are
the price we have to pay for usenet. It is important we

I guess if it weren't for maggots, we'd be knee deep in dead animals. I
suppose Phil and his counterparts serve some usefull purpose along those
lines. ;-)

continue to stand up against such bullying lest he
dominates the group to such a degree people are afraid
to post.

Looking at the archives, it appears that poor Phil has been on the
receiving end of some abuse. Of course he's been on the pitching end a
whole hell-of-a-lot more.

 

[Phil Allison]

"Anthony Fremont" <NOspam-me@houston.rr.com> wrote in message
news:gN_pb.2213

Lost his account huh, K-man hasn't even managed that yet.

** Mike H is making wild and malicious assertions on matters he has no
knowledge of.

My change of ISP some time back had NOTHING to do with Win Hill.

Looking at the archives, it appears that poor Phil has been on the
receiving end of some abuse.

** You are NOT kidding - did you see the death threat on rec.audio tubes
?

Of course he's been on the pitching end a whole hell-of-a-lot more.

** The incoming and outgoing ones are very nearly the same number - since
I respond to nearly all abusive posts.

I rarely initiate abuse - unless someone is posting dangerous
misinformation.






............ Phil

 

[Rod Speed]

Phil Allison <philallison@optusnet.com.au> wrote in message
news:3fa85b91$0$3791$afc38c87@news.optusnet.com.au...

Rod Speed <rod_speed@yahoo.com> wrote
Phil Allison <philallison@optusnet.com.au> wrote
Mark Hathaway

Shame the pommy wind bag he did
not give as clear an answer as I did.

Pity yours was just a steaming pig ignorant turd which couldnt even
explain the considerable peaks and troughs in the impedance chart
with a single speaker without any added electronics at all.

A cone speaker has just one impedance
peak - at the bass resonance.

Wrong. As always.

And even if it did, that isnt 'explained' by your pig ignorant steaming turd anyway.

There is one broad trough - in the mid band

Wrong. As always.

And even if there was, that isnt 'explained' by your pig ignorant steaming turd anyway.

as I specified over and over.

Yep, you never did manage to get even the simplest stuff right.

Or comprehend the real explanations either.

 

[Phil Allison]

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bo9v68$1b7vgs$1@ID-69072.news.uni-berlin.de...

Phil Allison <philallison@optusnet.com.au> wrote in message
news:3fa85b91$0$3791$afc38c87@news.optusnet.com.au...
Rod Speed <rod_speed@yahoo.com> wrote
Phil Allison <philallison@optusnet.com.au> wrote
Mark Hathaway

Shame the pommy wind bag he did
not give as clear an answer as I did.

Pity yours was just a steaming pig ignorant turd which couldnt even
explain the considerable peaks and troughs in the impedance chart
with a single speaker without any added electronics at all.

A cone speaker has just one impedance
peak - at the bass resonance.

Wrong. As always

** Fraid that is right - you stinking Robot liar.

There is one broad trough - in the mid band

Wrong. As always.

** Fraid that is right - you stinking Robot liar.



The Stinking Robot never did manage to get even the simplest stuff right.

Or comprehend the real explanation I posted either.





.......... Phil

 

[Mike Harding]

On Wed, 5 Nov 2003 13:45:41 +1100, "Phil Allison"
<philallison@optusnet.com.au> wrote:

Mike Harding is a social misfit of the worse kind, he and his ilk are
the price we have to pay for usenet.

Can't justify the use of the word "criminal" then Phil - tut tut,
still it's not the first time you've told lies, is it?

This lying, criminal pig should be ignored at all times.

Why don't you kill file me? Then I could make a badge:
"Phil Allison killfiled _me_!"

Mike Harding

 

[Mike Harding]

On Wed, 05 Nov 2003 04:13:00 GMT, "Anthony Fremont"
<NOspam-me@houston.rr.com> wrote:

Mike Harding wrote:
Don't worry about it, Phil even managed to make Winfield
Hill loose his temper (although he did have to work at
it for a long time). Mind you, it cost him his internet account,
you'll notice he no longer posts to sci.electronics.design.

Lost his account huh, K-man hasn't even managed that yet. That must
have been quite an interesting thread that led to that. A quick look at
the archives show some kind of firefight going on last Jan-Feb.

That would be about the time I think.

Phil is a social misfit of the worse kind, he and his ilk are
the price we have to pay for usenet. It is important we

I guess if it weren't for maggots, we'd be knee deep in dead animals.

Love it!

continue to stand up against such bullying lest he
dominates the group to such a degree people are afraid
to post.

Looking at the archives, it appears that poor Phil has been on the
receiving end of some abuse. Of course he's been on the pitching end a
whole hell-of-a-lot more.

Trouble is he has antagonized so many people with his
foul mouthed abusive behaviour that people will tend to
be a little aggressive with him from the outset - although
he enjoys that because it gives him an opportunity to feel
hard done by. I have no sympathy at all with him, he has
brought it all on himself and continues to do so. Surely
he can't behave in this fashion in real life? He'd have no
teeth left by now.

It's unfortunate he is such a damaged personality because
he actually does have a good knowledge of electronics
in some areas and could be (indeed, sometimes is) an
asset to the group.

Mike Harding

 

[Mike Harding]

On Wed, 5 Nov 2003 15:28:28 +1100, "Phil Allison"
<philallison@optusnet.com.au> wrote:

** You are NOT kidding - did you see the death threat on rec.audio tubes

No. But I'd like to

Mike Harding

 

[Phil Allison]

"Mike Harding" <mike_harding1@nixspamhotmail.com> wrote in message
news:l15hqv47o4hd8dl28qtivrlkh6fms1978o@4ax.com...

On Wed, 5 Nov 2003 15:28:28 +1100, "Phil Allison"
philallison@optusnet.com.au> wrote:

** You are NOT kidding - did you see the death threat on rec.audio
tubes

No. But I'd like to

** See what I mean about Mike being a criminal.



........... Phil