[None]

wrote in message
...
geoff wrote: "- show quoted text -
No. 4 or 8 are the common specs, but the spec is for the minimum
load
impedance, so ann amp specced at 8 ohms *may* have trouble with a 6
ohm
load on peaks, but a 4 ohm output won't have any problem at all..

And 16 doesn't matter - if your amp will do the lower ones, it'll be
just fine with a lesser load (= higher Z).

geoff "

So you're saying that I can safely hook up speakers with a 4ohm
sticker on the back to my 8-16ohm receiver, but not a 6ohm.

No he's not saying that at all. If you do that, you might overheat
your amplifier, or cause distortion. There's that reading
comprehension problem again: the story of your life.

Clear as mud to me, but I'll trust you on this.

You're ****ing retard.

[[email protected]]

geoff:
But that's what it sounded like you said 6 posts ago:

"..so ann amp specced at 8 ohms *may* have trouble with a 6 ohm
load on peaks, but a 4 ohm output won't have any problem at all.. "

Reads to me like my 8-16 receiver won't have problems driving 4ohms.

"And 16 doesn't matter - if your amp will do the lower ones, it'll be
just fine with a lesser load (= higher Z).

geoff "

And that's what's confused me for decades: HOW could a 16ohm speaker present a LESSER load to the amp driving it than a 8ohm speaker?? Ohms measure impedance, so a higher ohm figure instinctively means higher impedance(resistance).


And N0ne/Nil/Alrich STAY THE **** OUT of this conversation and let geoff clarify what he said!!

[geoff]

On 10/12/2014 12:56 p.m., wrote:
geoff:
But that's what it sounded like you said 6 posts ago:

"..so ann amp specced at 8 ohms *may* have trouble with a 6 ohm
load on peaks, but a 4 ohm output won't have any problem at all.. "

Reads to me like my 8-16 receiver won't have problems driving 4ohms.

"And 16 doesn't matter - if your amp will do the lower ones, it'll be
just fine with a lesser load (= higher Z).

geoff "

And that's what's confused me for decades: HOW could a 16ohm speaker present a LESSER load to the amp driving it than a 8ohm speaker?? Ohms measure impedance, so a higher ohm figure instinctively means higher impedance(resistance).


And N0ne/Nil/Alrich STAY THE **** OUT of this conversation and let geoff clarify what he said!!



A lower Z draws more current for a given voltage so puts a heavier load
on the amp. A higher Z draw less current and puts a lesser load on the amp.

The word 'load' relates to the current drawn (therefore=power) - not the
'number' of the impedance.

So a lower number Z is a harder load to drive.

geoff

[[email protected]]

geoff wrote: "- show quoted text -
A lower Z draws more current for a given voltage so puts a heavier load
on the amp. A higher Z draw less current and puts a lesser load on the amp.

The word 'load' relates to the current drawn (therefore=power) - not the
'number' of the impedance.

So a lower number Z is a harder load to drive.

geoff "

Thanks for clarifying. Guess I was seeing it the other way around: The amp 'pushes' signal to the speaker, and meets more resistance from one with higher ohms than from one with lower ohms.

[Dave Platt[_2_]]

And that's what's confused me for decades: HOW could a 16ohm speaker
present a LESSER load to the amp driving it than a 8ohm speaker?? Ohms
measure impedance, so a higher ohm figure instinctively means higher
impedance(resistance).

Higher impedance (resistance) means this: for whatever voltage the
amplifier is producing, the speaker will "resist" the flow of current
more than a lower-impedance load would do, and less current will flow.

Think of it like a water-hose. If you put a certain amount of water
pressure at one end, then a thin hose will resist the flow of water
more than a big fat hose would. Less water will flow through the thin
hose (less water current) than would flow through a fat hose, if they
both have the same pressure (voltage) being supplied.

An audio amplifier tries, very hard, to be a "voltage" source. It
takes the signal at its input, increases its voltage by a specific
ratio, and feeds this voltage to the load (speaker). At any given
signal level, it's trying to feed the same voltage (peak or RMS) into
whatever speaker is attached to it. This means that the amplifier
must be able to provide a higher current into a low-impedance speaker,
than for a high-impedance speaker.

Providing high currents is a tough job for the amplifier. When it's
feeding high currents to the speaker, it's pulling high currents
through its transformer (which heats up), through its rectifiers and
filter capacitors, and through its output transistors (which also heat
up).

So, in order to drive a really low-impedance load (say, 1 or 2 ohms)
to a substantial voltage, an amplifier has to have a really hefty
power supply... big transformer, heavy-duty rectifier, big filter
capacitors... and robust output transistors capable of handling lots
of current... and a big fat heat-sink to get rid of the excess heat
generated in the transistors. These all cost $$$.

Cheap amps don't have these. If you try to drive a low-impedance load
with such an amplifier, the high currents required by the load will
overstress the power supply or overheat the output stage, or both. If
you're lucky, the amp goes into self-protect mode and shuts down. If
you're not lucky, something burns up, all the Magic Blue Smoke leaks
out, and the amp won't work.

[None]

wrote in message
...
Reads to me like

.... but you're a ****ing retard with reading comprehension problems.
In fact, it's not just reading, you have comprehension problems.

And N0ne/Nil/Alrich STAY THE **** OUT of this conversation and let
geoff clarify what he said!!

You seem to think I'm some other people. Another case of your being
****ing retarded. Don't bother whacking yourself on the head with a
clue-by-four; it would just splinter against the granite.

[Mark Zacharias]

"geoff" wrote in message
...
On 10/12/2014 1:19 a.m., wrote:
geoff wrote: "- show quoted text -
No. 4 or 8 are the common specs, but the spec is for the minimum load
impedance, so ann amp specced at 8 ohms *may* have trouble with a 6 ohm
load on peaks, but a 4 ohm output won't have any problem at all..

And 16 doesn't matter - if your amp will do the lower ones, it'll be
just fine with a lesser load (= higher Z).

geoff "

So you're saying that I can safely hook up speakers with a 4ohm sticker
on the back to my 8-16ohm receiver, but not a 6ohm. Clear as mud to me,
but I'll trust you on this.


Clearly "clear as mud".

NO. You should not hook up a speaker with a lower Z than your amp is
specified to drive. Higher Zs are no problem.


geoff


In my experience the manufacturers are simply trying to reduce the number of
warranty repairs to some extent by specifying the higher resistance. In
truth, with a bit of common sense applied at the volume control side of the
equation, a four-ohm speaker will work just fine with any solid state amp or
surround receiver of even minimal quality, such as Pioneer, Sony, Marantz,
Denon, Kenwood, etc PROVIDED as I say, some common sense is used and the
user isn't trying to use the thing as a sort of mini-PA system.

Problem is, people connect all sorts of speakers, even for example car
stereo speakers wired in unusual, often incompetent ways, then expect to be
able to blast away for hours on end.

Yamaha, for example, knows full well that one of their power transformers
will not have a failed thermal fuse in the power transformer in the absence
of customer abuse - playing the thing at a very high level, probably with
low impedance speakers (or combinations of speakers) for an hour or two more
or less continuous.

Therefore, they will only cover ONE power transformer under warranty. The
warranty servicer is expected to educate the customer that a second
transformer won't be covered.

In fact, the newest Yamaha's will "rat out" the user by recording how high
the volume was for more than one minute and how many times. This info is
accessible in the service menu.


Mark Z.

[[email protected]]

Mark Zacharias wrote: "In fact, the newest Yamaha's will "rat out" the user by recording how high the volume was"

?!?!

A 'black box' for an audio component? Scary. Will it also keep track of what radio stations, CDs, and digital files(iPod, haed drive) the driver played while driving to work or to their kids' soccer?

[Peter Larsen[_3_]]

skrev i en meddelelse
...

Mark Zacharias wrote: "In fact, the newest Yamaha's will "rat out"
the user by recording how high the volume was"

?!?!

A 'black box' for an audio component? Scary. Will it also
keep track of what radio stations, CDs, and digital files(iPod,
haed drive) the driver played while driving to work or to their
kids' soccer?

No, it will upload the telemetry data to a server the NSA has a backdoor
into. Welcome to the Internet of Things. No smiley, because I'm not totally
sure that it is a joke, in theory it _is_ possible.

Kind regards

Peter Larsen

[[email protected]]

On Friday, November 28, 2014 8:35:11 AM UTC-5, wrote:
My receiver(as well as most built in the last 20 years) calls for 8-16ohm loads.


All I'm trying to find out is if there will still be minimum 8ohm speakers available when I do decide to replace mine. And this trend of speakers with ohms that are not a factor of 4 is disturbing.

[geoff]

On 11/12/2014 7:08 a.m., wrote:
On Friday, November 28, 2014 8:35:11 AM UTC-5, wrote:
My receiver(as well as most built in the last 20 years) calls for 8-16ohm loads.


All I'm trying to find out is if there will still be minimum 8ohm speakers available when I do decide to replace mine. And this trend of speakers with ohms that are not a factor of 4 is disturbing.



They are the most common stanadard and that's not likely to change.

geoff

[[email protected]]

On Wednesday, December 10, 2014 3:43:48 PM UTC-5, geoff wrote:
On 11/12/2014 7:08 a.m., com wrote:
On Friday, November 28, 2014 8:35:11 AM UTC-5, wrote:
My receiver(as well as most built in the last 20 years) calls for 8-16ohm loads.


All I'm trying to find out is if there will still be minimum 8ohm speakers available when I do decide to replace mine. And this trend of speakers with ohms that are not a factor of 4 is disturbing.



They are the most common stanadard and that's not likely to change.

geoff
____

Thanks geoff - and sorry for yellin atchya!

I'm a very plain-spoken individual and I guess that kind of leads me to expect the same from others I encounter.

LOL

[Trevor]

On 10/12/2014 11:21 PM, Mark Zacharias wrote:
In my experience the manufacturers are simply trying to reduce the
number of warranty repairs to some extent by specifying the higher
resistance. In truth, with a bit of common sense applied at the volume
control side of the equation, a four-ohm speaker will work just fine
with any solid state amp or surround receiver of even minimal quality,
such as Pioneer, Sony, Marantz, Denon, Kenwood, etc PROVIDED as I say,
some common sense is used and the user isn't trying to use the thing as
a sort of mini-PA system.

Problem is, people connect all sorts of speakers, even for example car
stereo speakers wired in unusual, often incompetent ways, then expect to
be able to blast away for hours on end.

Yamaha, for example, knows full well that one of their power
transformers will not have a failed thermal fuse in the power
transformer in the absence of customer abuse - playing the thing at a
very high level, probably with low impedance speakers (or combinations
of speakers) for an hour or two more or less continuous.

Therefore, they will only cover ONE power transformer under warranty.
The warranty servicer is expected to educate the customer that a second
transformer won't be covered.

In fact, the newest Yamaha's will "rat out" the user by recording how
high the volume was for more than one minute and how many times. This
info is accessible in the service menu.


Amazing isn't it that a manufacturer can incorporate watch dog
electronics in a receiver, but not simply a more sophisticated
protection circuit to prevent damage in the first place!
I'd be looking elsewhere if that's the case.

Trevor.

[Mark Zacharias]

"Trevor" wrote in message
...
On 10/12/2014 11:21 PM, Mark Zacharias wrote:
In my experience the manufacturers are simply trying to reduce the
number of warranty repairs to some extent by specifying the higher
resistance. In truth, with a bit of common sense applied at the volume
control side of the equation, a four-ohm speaker will work just fine
with any solid state amp or surround receiver of even minimal quality,
such as Pioneer, Sony, Marantz, Denon, Kenwood, etc PROVIDED as I say,
some common sense is used and the user isn't trying to use the thing as
a sort of mini-PA system.

Problem is, people connect all sorts of speakers, even for example car
stereo speakers wired in unusual, often incompetent ways, then expect to
be able to blast away for hours on end.

Yamaha, for example, knows full well that one of their power
transformers will not have a failed thermal fuse in the power
transformer in the absence of customer abuse - playing the thing at a
very high level, probably with low impedance speakers (or combinations
of speakers) for an hour or two more or less continuous.

Therefore, they will only cover ONE power transformer under warranty.
The warranty servicer is expected to educate the customer that a second
transformer won't be covered.

In fact, the newest Yamaha's will "rat out" the user by recording how
high the volume was for more than one minute and how many times. This
info is accessible in the service menu.


Amazing isn't it that a manufacturer can incorporate watch dog electronics
in a receiver, but not simply a more sophisticated protection circuit to
prevent damage in the first place!
I'd be looking elsewhere if that's the case.

Trevor.




Oh, they have protection circuitry all right. Lots of triggers all monitored
by the microprocessor. Problem is, since music can be extremely dynamic in
nature, and since transistors can be destroyed so quickly, any circuit that
would absolutely prevent damage to output transistors caused by abuse, would
also protect the amp from being able to produce music at any decent level.

Some manufacturers are now monitoring temperature of the power transformer
as well, but I've already seen one where the transformer was not saved from
the internal thermal fuse opening.

They're getting better, though - I'm seeing fewer and fewer blown channels
due to abuse these days.


Mark Z.

[Trevor]

On 11/12/2014 10:39 PM, Mark Zacharias wrote:
"Trevor" wrote in message
...
On 10/12/2014 11:21 PM, Mark Zacharias wrote:
In my experience the manufacturers are simply trying to reduce the
number of warranty repairs to some extent by specifying the higher
resistance. In truth, with a bit of common sense applied at the volume
control side of the equation, a four-ohm speaker will work just fine
with any solid state amp or surround receiver of even minimal quality,
such as Pioneer, Sony, Marantz, Denon, Kenwood, etc PROVIDED as I say,
some common sense is used and the user isn't trying to use the thing as
a sort of mini-PA system.

Problem is, people connect all sorts of speakers, even for example car
stereo speakers wired in unusual, often incompetent ways, then expect to
be able to blast away for hours on end.

Yamaha, for example, knows full well that one of their power
transformers will not have a failed thermal fuse in the power
transformer in the absence of customer abuse - playing the thing at a
very high level, probably with low impedance speakers (or combinations
of speakers) for an hour or two more or less continuous.

Therefore, they will only cover ONE power transformer under warranty.
The warranty servicer is expected to educate the customer that a second
transformer won't be covered.

In fact, the newest Yamaha's will "rat out" the user by recording how
high the volume was for more than one minute and how many times. This
info is accessible in the service menu.


Amazing isn't it that a manufacturer can incorporate watch dog
electronics in a receiver, but not simply a more sophisticated
protection circuit to prevent damage in the first place!
I'd be looking elsewhere if that's the case.




Oh, they have protection circuitry all right. Lots of triggers all
monitored by the microprocessor. Problem is, since music can be
extremely dynamic in nature, and since transistors can be destroyed so
quickly, any circuit that would absolutely prevent damage to output
transistors caused by abuse, would also protect the amp from being able
to produce music at any decent level.


Rubbish. Transistor protection of SOA has been standard in many amps for
decades, and power outputs are now so high that only the *really* cheap
stuff has any problems providing "decent levels" into any normal
speaker. In any case we were talking about the transformer.



Some manufacturers are now monitoring temperature of the power
transformer as well, but I've already seen one where the transformer was
not saved from the internal thermal fuse opening.

So the protection circuit was inadequate, hardly surprising for many
cheap designs.


They're getting better, though - I'm seeing fewer and fewer blown
channels due to abuse these days.

Right, it's just not that hard these days. Some manufacturers will
always choose to cut corners however. And some do it deliberately as
part of their planned obsolesence :-(


Trevor.

[[email protected]]

Trevor:

"SOA"?

[Peter Larsen[_3_]]

skrev i en meddelelse
...

Trevor:

"SOA"?

== Safe Operating/Operation Area == combinations of frequency, voltage and
current that will not blow the device (transistor) up.

Remember again the issue of phase angle between output voltage and output
current in a reactive load, something that leads to a demand for output
current at zero crossing output voltage in some frequency/cies.

Amplifiers as well as SOA protection has to handle that situation well, lest
you should get situations like the previously mentioned unnamed amplifier
that had 300 watt in 8 ohms capability on the spec sheet and 11 watts in a
real world load when tested by some magazine that put a scope across the
loudspeaker leads.

Kind regards

Peter Larsen

[Mark Zacharias]

"Trevor" wrote in message
...
On 11/12/2014 10:39 PM, Mark Zacharias wrote:
"Trevor" wrote in message
...
On 10/12/2014 11:21 PM, Mark Zacharias wrote:
In my experience the manufacturers are simply trying to reduce the
number of warranty repairs to some extent by specifying the higher
resistance. In truth, with a bit of common sense applied at the volume
control side of the equation, a four-ohm speaker will work just fine
with any solid state amp or surround receiver of even minimal quality,
such as Pioneer, Sony, Marantz, Denon, Kenwood, etc PROVIDED as I say,
some common sense is used and the user isn't trying to use the thing as
a sort of mini-PA system.

Problem is, people connect all sorts of speakers, even for example car
stereo speakers wired in unusual, often incompetent ways, then expect
to
be able to blast away for hours on end.

Yamaha, for example, knows full well that one of their power
transformers will not have a failed thermal fuse in the power
transformer in the absence of customer abuse - playing the thing at a
very high level, probably with low impedance speakers (or combinations
of speakers) for an hour or two more or less continuous.

Therefore, they will only cover ONE power transformer under warranty.
The warranty servicer is expected to educate the customer that a second
transformer won't be covered.

In fact, the newest Yamaha's will "rat out" the user by recording how
high the volume was for more than one minute and how many times. This
info is accessible in the service menu.


Amazing isn't it that a manufacturer can incorporate watch dog
electronics in a receiver, but not simply a more sophisticated
protection circuit to prevent damage in the first place!
I'd be looking elsewhere if that's the case.




Oh, they have protection circuitry all right. Lots of triggers all
monitored by the microprocessor. Problem is, since music can be
extremely dynamic in nature, and since transistors can be destroyed so
quickly, any circuit that would absolutely prevent damage to output
transistors caused by abuse, would also protect the amp from being able
to produce music at any decent level.


Rubbish. Transistor protection of SOA has been standard in many amps for
decades, and power outputs are now so high that only the *really* cheap
stuff has any problems providing "decent levels" into any normal speaker.
In any case we were talking about the transformer.



Some manufacturers are now monitoring temperature of the power
transformer as well, but I've already seen one where the transformer was
not saved from the internal thermal fuse opening.

So the protection circuit was inadequate, hardly surprising for many cheap
designs.


They're getting better, though - I'm seeing fewer and fewer blown
channels due to abuse these days.

Right, it's just not that hard these days. Some manufacturers will always
choose to cut corners however. And some do it deliberately as part of
their planned obsolesence :-(


Trevor.




So-called SOA protection has always been imperfect at the VERY least. When a
solid state (lets just say consumer grade) amp runs into a short circuit,
it's at best a toss-up whether it blows before the protection can kick in.
Add to this that a consumer will keep trying repeatedly even when the
protection does trigger, a major failure is very often the result.

mz

[Trevor]

On 14/12/2014 5:39 PM, Mark Zacharias wrote:
So-called SOA protection has always been imperfect at the VERY least.
When a solid state (lets just say consumer grade) amp runs into a short
circuit, it's at best a toss-up whether it blows before the protection
can kick in. Add to this that a consumer will keep trying repeatedly
even when the protection does trigger, a major failure is very often the
result.

As I said it's just not that hard to prevent this these days. But
everything does cost money of course. So whether a manufacturer chooses
to do it properly is another argument altogether.

Trevor.

[[email protected]]

On Thursday, December 4, 2014 8:40:49 AM UTC-7, chuck wrote:
On Thu, 4 Dec 2014 05:10:48 -0800 (PST), wrote:
So given that, the question should be, are mfgs listing the
avg, max, or min impedance on the cabinet spec sticker?


Since there is no standard,

Wrong, there has been in existence for several decades, a widely
accepted standard for measuring ans specifying impedance. IEC
60268-5:
16 Impedance and Derivative Characteristics
16.1 Rated impedance - characteristic to be specified
NOTE This is a rated condition in accordance with 3.2.1.
The lowest value of the modulus of the impedance in the
rated frequency range shall be not less than 50% of the
rated impedance. If the impedance at any frequency
outside this range (including d.c.) is less than this
value, this shall be stated in the specifications.
16.2 Impedance curve
16.2.1 Characteristics to be specified
The impedance curve shall be specified, with represen-
tation of the modulus of the impedance as a function of
frequency.
16.2.2 Method of measurement
16.2.2.1 The loudspeaker shall be brought under normal
measuring conditions in accordance with 3.2.2
conditions a), b), and d).
16.2.2.2 A constant voltage or current shall be supplied,
the former usually being preferred. The value of voltage
or current chosen for the measurement shall be sufficiently
small to ensure that the loudspeaker operates in a linear
region.
Note Measurement of impedance may be strongly influenced
by drive level. If the level is either too low or too
high, inaccurate results may be obtained. The data should
be examined for consistency at several drive levels in
order to establish the best conditions.
16.2.2.3 The modulus of impedance shall be measured at least
over the range of 20 Hz to 20 000 Hz.
16.2.2.4 The results shall be presented graphically as a
function of frequency. The value of the voltage or the
current shall be stated with the results.

the manufacturers can list whatever impedance they want;

Well, more accurately: the manufacturers can choose to ignore
common, well established and agreed upon standards and can
thus make up any damned number they want. Unfortunately,
not a few do just that.

within the range of impedances that the speaker
has in its frequency range. For example, some speakers rated at 4
ohms dip below 2 ohms at certain frequencies.

And, if they so choose to follow the standard, they must state so.

Dick Pierce

[[email protected][_2_]]

On Thursday, December 4, 2014 8:42:57 AM UTC-7, wrote:
chuck:

That's the problem: No standards.

Nope, IEC 60268-5 (and its predecessor IEC 268-5) has been in effect
for decades and is quite current. There are any number of nationalized
versions of the same standard as well.

I was told about some standard for audio(measurement) that
was abandoned in the '70s or thereabouts.

No, it was never "abandoned" by anyone. Any number of manufacturers
may fail to follow it, but it is hardly abandoned.

Forgot the name of it.

IEC 60268-5

Dick Pierce

[[email protected][_2_]]

On Thursday, December 4, 2014 7:10:40 PM UTC-7, Trevor wrote:
On 5/12/2014 2:42 AM, wrote:
chuck:

That's the problem: No standards.
I was told about some standard for audio(measurement) that was
abandoned in the '70s or thereabouts.
Forgot the name of it.


The great thing about standards is there are so many to choose from! :-)

Really?How many standards for the measurement of loudspeakers
(ignoring national adoptions of the widely accepted ones) are
there?

Dick Pierce

[Trevor]

On 17/12/2014 1:14 AM, wrote:

Welcome back Dick!


On Thursday, December 4, 2014 7:10:40 PM UTC-7, Trevor wrote:
On 5/12/2014 2:42 AM, wrote:
chuck:

That's the problem: No standards.
I was told about some standard for audio(measurement) that was
abandoned in the '70s or thereabouts.
Forgot the name of it.


The great thing about standards is there are so many to choose from! :-)

Really?How many standards for the measurement of loudspeakers
(ignoring national adoptions of the widely accepted ones) are
there?

Sorry Dick, it was just a joke, hence the smiley.
(although a well used joke that does apply in many cases)
You are quite correct of course about the accepted standards for speaker
measurement, and the fact they are often ignored by many manufacturers.

Trevor.

[Peter Larsen[_3_]]

"Trevor" skrev i en meddelelse
...

On 17/12/2014 1:14 AM, wrote:

Welcome back Dick!

+1

Trevor.

Kind regards

Peter Larsen

[geoff]

On 17/12/2014 8:21 p.m., Peter Larsen wrote:
"Trevor" skrev i en meddelelse
...

On 17/12/2014 1:14 AM, wrote:

Welcome back Dick!

" As the actress said to the bishop ...."

;-)

geoff