Steven Sullivan wrote:

Nousaine wrote:
"Pete Rogers" wrote:

...snip to content......

One thing that I think may put off some home users is the fact that their
speakers are mostly active with built in electronic crossovers and power
amplification. Passive versions are available but I would venture that
using these brings a downside in both technical performance and cost even
if
they allow use of your favourite amps.

Powered speakers have been around since the 70s. They have never been
popular
in the consumer market, at least partly because customers usually already
own
"power" and they also limit the number of boxes retailers can push ou tthe
door. Paradigm discontinued their Active line (among the best speakers I've
ever tested) because nobody would buy them

Active speakers have basic performance advantages. They replace passive
components with electronic EQ, XO, level matching which have far greater
control capabilities. Plus they can employ control and protection functions
and
properly sized power for each driver indivually. In the latter regard it
makes
it possible for one to hand any person the remote control and leave the
room
without having to worry about returning to the smell of melting voice coil
glue.

In this modern age I find they have one other very useful function...they
free
up rack space for more signal sources. For example I need space for a cd
player, a controller, satellite receiver, tuner, D-VHS machine, DAT,
cassette,
laser disc and projector. I no longer have space for a rack of power
amplifiers.

S&V's Feb/March issue has a one-page article on Bang & Olafsun's
powered-speaker amplifiers, which they've apparently managed to shrink down
to the size of a few postage stamps.

Class D to the rescue.


My concerns about powered speakers all center around the power source.
If a cord to an electrical outlet, that means *more* wires running on or
under
the floor and walls, and possibly more constraints on placement.

You still have to string wires for passive speakers. Modern housing have AC
outlets that can accomodate most placements. Indeed in my places finding AC was
easier than stringing speaker wire. Of course, I still had to string an RCA.


If a battery, it had better be long-lasting, and
cheap, 'cos I sure don't want to be changing them every month or two.

What I want is wireless speakers. Then you only need AC. I'm wondering why
wireless speakers aren't now generally available. The technology seems to be
extant. Someone I asked in the industry surmised it's because no standards
exist.


At the CES I had demos of dsp-controlled loudspeakers that combined the
combine
the advantages of active speakers with digital control and with a mic input
also add room-correction as well.

Were these the large B&Os that look a little like Daleks? ;

--

-S.


Nope; Phase Technolgy and NHT.

Nousaine wrote:
Steven Sullivan wrote:

Nousaine wrote:
"Pete Rogers" wrote:

...snip to content......

One thing that I think may put off some home users is the fact that their
speakers are mostly active with built in electronic crossovers and power
amplification. Passive versions are available but I would venture that
using these brings a downside in both technical performance and cost even
if
they allow use of your favourite amps.

Powered speakers have been around since the 70s. They have never been
popular
in the consumer market, at least partly because customers usually already
own
"power" and they also limit the number of boxes retailers can push ou tthe
door. Paradigm discontinued their Active line (among the best speakers I've
ever tested) because nobody would buy them

Active speakers have basic performance advantages. They replace passive
components with electronic EQ, XO, level matching which have far greater
control capabilities. Plus they can employ control and protection functions
and
properly sized power for each driver indivually. In the latter regard it
makes
it possible for one to hand any person the remote control and leave the
room
without having to worry about returning to the smell of melting voice coil
glue.

In this modern age I find they have one other very useful function...they
free
up rack space for more signal sources. For example I need space for a cd
player, a controller, satellite receiver, tuner, D-VHS machine, DAT,
cassette,
laser disc and projector. I no longer have space for a rack of power
amplifiers.

S&V's Feb/March issue has a one-page article on Bang & Olafsun's
powered-speaker amplifiers, which they've apparently managed to shrink down
to the size of a few postage stamps.

Class D to the rescue.


My concerns about powered speakers all center around the power source.
If a cord to an electrical outlet, that means *more* wires running on or
under
the floor and walls, and possibly more constraints on placement.

You still have to string wires for passive speakers.

Of course, but the prospect of adding *another* line from the speaker is not
appealing...and in the future, the usual speaker wire will be replaced by
wireless transmission.

Modern housing have AC
outlets that can accomodate most placements. Indeed in my places finding AC was
easier than stringing speaker wire. Of course, I still had to string an RCA.

In my case, the outlet closes to the front speakers is already full...so
that'd mean another six-outlet strip.

If a battery, it had better be long-lasting, and
cheap, 'cos I sure don't want to be changing them every month or two.

What I want is wireless speakers. Then you only need AC.

Yup. Me too. And I want room correction, either speaker based or
head unit-based.

--

-S.

"They've got God on their side. All we've got is science and reason."
-- Dawn Hulsey, Talent Director

--
Pete Rogers
"Stewart Pinkerton" wrote in message
news:xOePb.107434$8H.202810@attbi_s03...
On Mon, 19 Jan 2004 19:21:55 GMT, "Pete Rogers"
wrote:

A typical ATC
monitor will come equipped with 3 amps working mostly in class A ( 200
watts
for the bass, 100 watts for midrange and 50 watts for the tweeter).
Although
it is impossible to make direct comparisons I would estimate that the
amplifier quality is at least par for the course for true high-end.

While not in any way denigrating the excellent ATC active monitors,
it's worth pointing out that the amplifiers are absolutely *not* class
A, but are conventional class AB designs.

Yes Stewart; that's why I used the word "mostly". Actually I have never got
my pair out of the region in which their bias keeps them in in class A* (
beyond it's way too loud) .

How are they in the home? IMHO excellent ( I have used them for nearly 10
years without lusting after alternatives). The only caveat that I would
make
is that, being "accurate" (a disputatious term I'm afraid) , you can't
get
away with an inferior front end.

Agreed - excellent but unforgiving. Prepare to hear just how badly
recorded are many of your favourite albums!

I have around 3000 albums. Maybe a dozen sound bad (or maybe I have no
taste). Most recording engineers actually know what they are doing after
all. The "unforgiving" possibility is partly why I refer to the need for
good front ends. Generally , across a range of sources, I find them no pain,
no strain. However I must agree that poorly set up ATCs- especially early
samples- can provoke that "ouch" feeling.

* Confirmed by their electronics designer Tim Isaac.

Pete

On Thu, 22 Jan 2004 02:37:14 GMT, "Pete Rogers"
wrote:

--
Pete Rogers
"Stewart Pinkerton" wrote in message
news:xOePb.107434$8H.202810@attbi_s03...
On Mon, 19 Jan 2004 19:21:55 GMT, "Pete Rogers"
wrote:

A typical ATC
monitor will come equipped with 3 amps working mostly in class A ( 200 watts
for the bass, 100 watts for midrange and 50 watts for the tweeter).
it is impossible to make direct comparisons I would estimate that the
amplifier quality is at least par for the course for true high-end.

While not in any way denigrating the excellent ATC active monitors,
it's worth pointing out that the amplifiers are absolutely *not* class
A, but are conventional class AB designs.

Yes Stewart; that's why I used the word "mostly". Actually I have never got
my pair out of the region in which their bias keeps them in in class A* (
beyond it's way too loud) .

That would be below a couple of watts, which no normal person would
refer to as 'mostly' class A for a 200 watt amplifier! OTOH, most
people do play music at an *average* power level of less than 5 watts.

It's easy to test - If you can keep your hand on the heatsink when
there's no music playing, they are definitely *not* class A above 20
watts per amp!

* Confirmed by their electronics designer Tim Isaac.

What *exactly* did he say about class of operation?
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Steven Sullivan wrote in message news:MxCPb.116591
My concerns about powered speakers all center around the power source.
If a cord to an electrical outlet, that means *more* wires running on or under
the floor and walls, and possibly more constraints on placement.


Yea, I originally had these concerns as well. But after playing with
powered speakers, these concerns fell away. Because .... I
think just about all will agree, best placement of power amps is close
to speakers. (Some might want to debate this, but honestly, if folks
don't already know this, they need to go back to gear setup square one
or two.) So AC power is usually not far from speakers, and is cetainly
present wherever the speaker cables would normally begin, ie at the
amp. So picture simply running an extended interconnect and AC line
from the amp location to each of the speakers; in lieu of an amp and
speaker cable. I've found it to be a clean alternative --- even for
the simplest of cases, full range speakers and a single stereo amp.

And for more advanced configurations the benefits just get greater.
One additional performance aspect of powered speakers that Tom alluded
to, is the xover. Often, in better powered designs, an active xover
feeds true multi amp power. Biamping is very common, and I know of at
least one true quad amped speaker. Imagine all the equipment
clutter/wiring mess for the same setup conventionally driven. Later,
Mark

"Mark Wilkinson" wrote in message
...
Steven Sullivan wrote in message
news:MxCPb.116591
My concerns about powered speakers all center around the power
source.
If a cord to an electrical outlet, that means *more* wires running
on or under
the floor and walls, and possibly more constraints on placement.


Yea, I originally had these concerns as well. But after playing
with
powered speakers, these concerns fell away. Because .... I
think just about all will agree, best placement of power amps is
close
to speakers. (Some might want to debate this, but honestly, if folks
don't already know this, they need to go back to gear setup square
one
or two.) So AC power is usually not far from speakers, and is
cetainly
present wherever the speaker cables would normally begin, ie at the
amp. So picture simply running an extended interconnect and AC line
from the amp location to each of the speakers; in lieu of an amp and
speaker cable. I've found it to be a clean alternative --- even for
the simplest of cases, full range speakers and a single stereo amp.

And for more advanced configurations the benefits just get greater.
One additional performance aspect of powered speakers that Tom
alluded
to, is the xover. Often, in better powered designs, an active xover
feeds true multi amp power. Biamping is very common, and I know of
at
least one true quad amped speaker. Imagine all the equipment
clutter/wiring mess for the same setup conventionally driven.
Later,

When considering the advantages and disadvantages of powered speakers,
they have to be separated into two categories: The advantages of
having the amp located in the speaker cabinet, and the advantages of
designed the amp and speaker to work together. This latter does not
require the amps to be physically located in the speaker cabinet, but
can be obtained by any system where both amps and speakers are
designed as a single unit. Thus, all the amps to drive the speakers
can be located in one box--perhaps the subwoofer--and most of the
advantages of powered speakers will still be available.

I've thought about this, and come to the conclusion that some company
will eventually bring out a surround sound system where the amplifiers
will be connected to the speakers with a 4-wire cable; 2 wires will
carry the current and the other 2 will carry the negative feedback
signal to the amp--a so-called 4-wire connection. Although heavy
speaker wire will still be necessary to reduce the power loss in the
wire, at least there will be no quality loss due to the length of the
wire.

The first models will probably operate from the 6 analog outputs of a
CDDA/SACD/DVD-V/DVD-A player. Eventually the entire signal will be
digitized and sent down a single coax. Power to feed this player
could even be simplexed back up the coax.

Norm Strong

"normanstrong" wrote:



"Mark Wilkinson" wrote in message
...
Steven Sullivan wrote in message
news:MxCPb.116591
My concerns about powered speakers all center around the power
source.
If a cord to an electrical outlet, that means *more* wires running
on or under
the floor and walls, and possibly more constraints on placement.


Yea, I originally had these concerns as well. But after playing
with
powered speakers, these concerns fell away. Because .... I
think just about all will agree, best placement of power amps is
close
to speakers. (Some might want to debate this, but honestly, if folks
don't already know this, they need to go back to gear setup square
one
or two.) So AC power is usually not far from speakers, and is
cetainly
present wherever the speaker cables would normally begin, ie at the
amp. So picture simply running an extended interconnect and AC line
from the amp location to each of the speakers; in lieu of an amp and
speaker cable. I've found it to be a clean alternative --- even for
the simplest of cases, full range speakers and a single stereo amp.

And for more advanced configurations the benefits just get greater.
One additional performance aspect of powered speakers that Tom
alluded
to, is the xover. Often, in better powered designs, an active xover
feeds true multi amp power. Biamping is very common, and I know of
at
least one true quad amped speaker. Imagine all the equipment
clutter/wiring mess for the same setup conventionally driven.
Later,

When considering the advantages and disadvantages of powered speakers,
they have to be separated into two categories: The advantages of
having the amp located in the speaker cabinet, and the advantages of
designed the amp and speaker to work together. This latter does not
require the amps to be physically located in the speaker cabinet, but
can be obtained by any system where both amps and speakers are
designed as a single unit. Thus, all the amps to drive the speakers
can be located in one box--perhaps the subwoofer--and most of the
advantages of powered speakers will still be available.

I've thought about this, and come to the conclusion that some company
will eventually bring out a surround sound system where the amplifiers
will be connected to the speakers with a 4-wire cable; 2 wires will
carry the current and the other 2 will carry the negative feedback
signal to the amp--a so-called 4-wire connection. Although heavy
speaker wire will still be necessary to reduce the power loss in the
wire, at least there will be no quality loss due to the length of the
wire.

The first models will probably operate from the 6 analog outputs of a
CDDA/SACD/DVD-V/DVD-A player. Eventually the entire signal will be
digitized and sent down a single coax. Power to feed this player
could even be simplexed back up the coax.

Norm Strong

At the CES I was given demonstrations by NHT and Phase Technology of dsp
controlled loudspeaker systems. While the Phase Tech system was still in
breadboard the NHT seemed to clearly be based on a separate control box that
would house the dsp and power amplification outboard of the speaker enclosures.

"normanstrong" wrote in message news:%6WQb.115030$Rc4.890080@attbi_s54...

When considering the advantages and disadvantages of powered speakers,
they have to be separated into two categories: The advantages of
having the amp located in the speaker cabinet, and the advantages of
designed the amp and speaker to work together.

Hi Norm, Yea, these two catagories make sense. Another way of
describing them is sonic, and logistic. The amp/speaker design being
sonic, and the amp location being logistic.

This latter does not
require the amps to be physically located in the speaker cabinet, but
can be obtained by any system where both amps and speakers are
designed as a single unit.

Sure, witness the proliferation of prosound DSP loudspeaker managers
that have settings for many of the widely used speakers.

Thus, all the amps to drive the speakers
can be located in one box--perhaps the subwoofer--and most of the
advantages of powered speakers will still be available.

Yea, you get the sonic benefits, but you lose considerable logistic
benefits.
A centralized amp stack requires the following: speaker runs of
sufficient guage to carry PEAK current loads -- at pretty long
distances given any decent sized room, and possibly pretty high
current if the system rocks. Also, one of the major inherent sonic
benefits of active speakers is the ability to truly multiamp post an
active xover. A centralized setup would need multiple runs for each
speaker.

I've thought about this, and come to the conclusion that some company
will eventually bring out a surround sound system where the amplifiers
will be connected to the speakers with a 4-wire cable; 2 wires will
carry the current and the other 2 will carry the negative feedback
signal to the amp--a so-called 4-wire connection.

What do you mean by negative feedback? Amp output sensing could be
done at the amp rack. Driver sensing, however, would require a return
data line -- this would be one more reason to put the amps at the
speaker

Although heavy
speaker wire will still be necessary to reduce the power loss in the
wire, at least there will be no quality loss due to the length of the
wire.

Power loss, if it truncates peaks, is quality loss. Otherwise it is
just wasted amplifier -- which often ain't cheap!


The first models will probably operate from the 6 analog outputs of a
CDDA/SACD/DVD-V/DVD-A player. Eventually the entire signal will be
digitized and sent down a single coax. Power to feed this player
could even be simplexed back up the coax.

I'll try my visionary hat. First, transmit data (signal), not power.
Digitized signal will soon travel via a bus (either looped or starred)
to our speakers. First by wire, someday wireless. (We'll be able to
sit in our listening chair with a wireless console. Today this is
easily possible with a single wire from a laptop controlling a remote
DSP processor -- although the DSP outputs to speakers are still
analog) Processors in the speakers will catch their respective data,
convert to analog, and feed their integral amps. Note you cannot
transmit power to the speakers wirelessly! and it's inefficient to do
it via wire! all we have to do it get AC to our speakers and the best
of all world's opens up. Later, Mark

(Mark Wilkinson) wrote in message ...
"normanstrong" wrote in message news:%6WQb.115030$Rc4.890080@attbi_s54...
A centralized amp stack requires the following: speaker runs of
sufficient guage to carry PEAK current loads -- at pretty long
distances given any decent sized room, and possibly pretty high
current if the system rocks. Also, one of the major inherent sonic
benefits of active speakers is the ability to truly multiamp post an
active xover. A centralized setup would need multiple runs for each
speaker.

I've thought about this, and come to the conclusion that some company
will eventually bring out a surround sound system where the amplifiers
will be connected to the speakers with a 4-wire cable; 2 wires will
carry the current and the other 2 will carry the negative feedback
signal to the amp--a so-called 4-wire connection.

What do you mean by negative feedback? Amp output sensing could be
done at the amp rack. Driver sensing, however, would require a return
data line -- this would be one more reason to put the amps at the
speaker

This form of remote sensing is old news in the power supply industry,
it was common in the 1960's and was described and well understood 2
decades prior to that (another example of how utterly out of date the
high-end audio industry is. The rationale is simple: by sensing the
voltage as close to the load as possible, you compensate for all losses
up to that point.

Although heavy
speaker wire will still be necessary to reduce the power loss in the
wire, at least there will be no quality loss due to the length of the
wire.

Power loss, if it truncates peaks, is quality loss.

Goodness gracious, please show us an example, short of a fuse, of
wire causing truncation of peaks. Can you suggest ANY possible
mechanism for such extraordinary behavior? (hint: no, because it
doesn't happen).

Otherwise it is
just wasted amplifier -- which often ain't cheap!

Uh, no. Let's look at an extreme example: compare running 20 feet
of 12 guage vs 20 feet of 22 gauge speaker wire. Just how much power
do you think the latter is wasting?

Well, 20 feet of 22 gauge wire has about 0.65 ohms of total loop
resistance. Looking at a nominal 8 ohm load, that means that about
8% of the total power will be dissipated in the wire. That's about
1/3 dB. Compare that to the 12 gauge, loosing about 0.03 dB.

Now, considering we picked a rather extreme example, that 0.34 dB
hardly constitutes an enormous waste of power, indeed, is essentially
inaudible. More realistically, even consider 18 gauge wire, with it's
"expensive" loss of about 1/8 dB.

The first models will probably operate from the 6 analog outputs of a
CDDA/SACD/DVD-V/DVD-A player. Eventually the entire signal will be
digitized and sent down a single coax. Power to feed this player
could even be simplexed back up the coax.

I'll try my visionary hat. First, transmit data (signal), not power.
Digitized signal will soon travel via a bus (either looped or starred)
to our speakers. First by wire, someday wireless. (We'll be able to
sit in our listening chair with a wireless console. Today this is
easily possible with a single wire from a laptop controlling a remote
DSP processor -- although the DSP outputs to speakers are still
analog) Processors in the speakers will catch their respective data,
convert to analog, and feed their integral amps.

All of this is ancient history everywhere but in the high-end
audio realm. Ho-hum, another breakthrough.

Note you cannot
transmit power to the speakers wirelessly! and it's inefficient to do
it via wire!

Really? That's a rather bizarre claim when compared to fact.

"Mark Wilkinson" wrote in message
...
"normanstrong" wrote in message
news:%6WQb.115030$Rc4

snip, only slightly relevant to below

I'll try my visionary hat. First, transmit data (signal), not power.
Digitized signal will soon travel via a bus (either looped or starred)
to our speakers. First by wire, someday wireless. (We'll be able to
sit in our listening chair with a wireless console. Today this is
easily possible with a single wire from a laptop controlling a remote
DSP processor -- although the DSP outputs to speakers are still
analog) Processors in the speakers will catch their respective data,
convert to analog, and feed their integral amps. Note you cannot
transmit power to the speakers wirelessly! and it's inefficient to do
it via wire! all we have to do it get AC to our speakers and the best
of all world's opens up. Later, Mark


Sony at CES already has spec'd and is promoting a CAT6/Ethernet standard
that will transmit six channels of high-res DSD or PCM with two (or
three?...memory bad) feedback channels. The stated purpose of this standard
is to allow complete distributed wiring of studios for modern production.
Thus not only studio - control room but, say, control room - mix room,
control room -final mixdown soundcheck room, etc. I think your vision is
just around the corner.

On Tue, 27 Jan 2004 02:30:54 GMT, "Harry Lavo"
wrote:

Sony at CES already has spec'd and is promoting a CAT6/Ethernet standard
that will transmit six channels of high-res DSD or PCM with two (or
three?...memory bad) feedback channels. The stated purpose of this standard
is to allow complete distributed wiring of studios for modern production.
Thus not only studio - control room but, say, control room - mix room,
control room -final mixdown soundcheck room, etc. I think your vision is
just around the corner.

Hi Harry:
Must be two feed back channels as CAT6e has 8 shielded wires, so
six channels plus two feed back channels equal eight.

-=Bill Eckle=-

Vanity Web pages at:
http://www.wmeckle.com

(Dick Pierce) wrote in message ...
(Mark Wilkinson) wrote in message ...

What do you mean by negative feedback? Amp output sensing could be
done at the amp rack. Driver sensing, however, would require a return
data line -- this would be one more reason to put the amps at the
speaker

This form of remote sensing is old news in the power supply industry,
it was common in the 1960's and was described and well understood 2
decades prior to that (another example of how utterly out of date the
high-end audio industry is. The rationale is simple: by sensing the
voltage as close to the load as possible, you compensate for all losses
up to that point.

Excuse me, the discussion was about where to locate power amps, not
when sensing technology came to be or what it is. Besides, what
sensing technology were we (not) discussing, the voltage at load you
mention? or driver excursion? or driver temp? or power at load? Sure
these have all been around for ages --used by some-- not by many --
what does that have to do with home audio being out of date, and why
are you raising this point?


Power loss, if it truncates peaks, is quality loss.

Goodness gracious, please show us an example, short of a fuse, of
wire causing truncation of peaks. Can you suggest ANY possible
mechanism for such extraordinary behavior? (hint: no, because it
doesn't happen).

Sure. (hint: voltage loss in wire is a function of current) Peak
current varies; peak voltage with it. I'll lay an example of a good
100w amp with 6db headroom on your wiring examples below:

Otherwise it is
just wasted amplifier -- which often ain't cheap!

Uh, no. Let's look at an extreme example: compare running 20 feet
of 12 guage vs 20 feet of 22 gauge speaker wire. Just how much power
do you think the latter is wasting?

Well, 20 feet of 22 gauge wire has about 0.65 ohms of total loop
resistance. Looking at a nominal 8 ohm load, that means that about
8% of the total power will be dissipated in the wire. That's about
1/3 dB. Compare that to the 12 gauge, loosing about 0.03 dB.

Using your 20ft of 22 gauge wire at .65ohms into 8 ohms, and my
100watt with 6db headroom amp, gives a peak voltage loss of 4.0v, or
..64db. 12 gauge peak loss =.6v or next to nothing.

But we were talking about wire lenghts that reflect distances from
centralized equip racks to speakers, so let's call a 15x20 room
typical, and place the equipment rack midway on a side wall. At least
one real world speaker run will be more like 35 ft minimum. Also, I
specifically mentioned wiring for peaks, so let's forget nominal
impedance, and look at worst case. Let's call 8ohm nominal, 4 ohn
minimum.

So plugging in new wire length and load, we get 22 gauge has a 9.9v
loss, or 2.5db, and 12 gauge has a 1v loss, or an insignifigant .2db.
But even the 18 gauge you mention has a 3.9v loss or .9db.

And let's readjust your calculations for my length and load: 22 gauge
becomes 2.2db loss, 12 gauge .24db, (and 18gauge .9db)

Now I'm not enough of an electrician to know if the losses from
current through the line and the losses from voltage apportionment
between line and load are strictly additive. But I'll assume they are
since the loss from current is calculated independent of load.
(Perhaps you'll be kind enough to help out here.) If simple addition
is correct, I get total peak losses of 4.7db for 22 gauge, .44db for
12 gauge, and 1.8db for 18 gauge.

Now, considering we picked a rather extreme example, that 0.34 dB
hardly constitutes an enormous waste of power, indeed, is essentially
inaudible. More realistically, even consider 18 gauge wire, with it's
"expensive" loss of about 1/8 dB.

Well, as said, I feel your length and load need adjusting and peak
currents matter. So IMO, more loss is on the table. Personally, I
don't want to leave more than 1db on the table just from wire. (And
I'm a "wire is wire" dude if ever there was one.) So I'd use 12
gauge. Which was my point in the previous post. With active speakers
using multi amps, you could get allot of not exactly inconspicuous
wire running aroung. My selpowered system has quad amped mains,
biamped surrounds, and subs ... that's allot of stinkin wire.


I'll try my visionary hat. First, transmit data (signal), not power.
Digitized signal will soon travel via a bus (either looped or starred)
to our speakers. First by wire, someday wireless. (We'll be able to
sit in our listening chair with a wireless console. Today this is
easily possible with a single wire from a laptop controlling a remote
DSP processor -- although the DSP outputs to speakers are still
analog) Processors in the speakers will catch their respective data,
convert to analog, and feed their integral amps.

All of this is ancient history everywhere but in the high-end
audio realm. Ho-hum, another breakthrough.

Please show me an example of an example of a console/player, that
wireless transmits digitized audio to speakers that then decode and
amplify the signal. Show me a commercially available, economically
viable, sonically acceptable unit. Hey, we weren't talking about the
timeline of discovered technology, we were talking about product
availability. What's "ho-hum, another breakthrough" about? Listen, I
think the "high-end" is by and large full of bull, too. But I try not
to display that attitude with every comment.....

Note you cannot
transmit power to the speakers wirelessly! and it's inefficient to do
it via wire!

Really? That's a rather bizarre claim when compared to fact.

Really? Inefficient in what context? Is it efficient to transmit a
power signal via wire if you can transmit line level signal wirelessly
and then convert to power at destination? Is it efficient to run run
multiple speaker lines to one multiamped speaker, or pick up a digital
data line (wirelessly) at the speaker? Why put up with lines or line
loss at all?

"Penury" wrote in message
news:vtnRb.123141$Rc4.972024@attbi_s54...
On Tue, 27 Jan 2004 02:30:54 GMT, "Harry Lavo"
wrote:

Sony at CES already has spec'd and is promoting a CAT6/Ethernet standard
that will transmit six channels of high-res DSD or PCM with two (or
three?...memory bad) feedback channels. The stated purpose of this
standard
is to allow complete distributed wiring of studios for modern production.
Thus not only studio - control room but, say, control room - mix room,
control room -final mixdown soundcheck room, etc. I think your vision
is
just around the corner.

Hi Harry:
Must be two feed back channels as CAT6e has 8 shielded wires, so
six channels plus two feed back channels equal eight.


That was my thought as well, but I could swear that the literature that I
read (but didn't take) said three. Perhaps it is configurable as three if
you want to restrict the other to five. In any case, it took me a bit by
surprise because I hadn't heard anything about it.

BTW, they were also promoting their DSD-W processing modules for eq, volume
control, and switching, and actually had a prototype consumer preamp to
promote the modules which would constitute a straight passthrough,
presumably to a DSD-capable switching amp at the speakers themselves. The
prototype was a consumer preamp, but the pitch was to pro equipment
manufactures for studio use.

(Mark Wilkinson) wrote in message ...
Now I'm not enough of an electrician to know if the losses from
current through the line and the losses from voltage apportionment
between line and load are strictly additive. But I'll assume they are
since the loss from current is calculated independent of load.
(Perhaps you'll be kind enough to help out here.) If simple addition
is correct, I get total peak losses of 4.7db for 22 gauge, .44db for
12 gauge, and 1.8db for 18 gauge.

Sorry to post to a post, but last night I sorted things out in my
head.
My "peak" math is a merely a special case duplication of the math that
apportions power between between line and load. Dick is right -- wire
can't attenuate peaks. Hey, he's forgot more math than I know ... but
I'm trying. So the bottom line seems to be all that matters is the
resistance of the line relative to the resistance of the load, all the
resultant attenuation -- which is usually minimal.

Anyway, I do think you need to consider worst case impedance in
choosing wire size, because given a certain wire resistance the losses
calculate higher for lower impedance loads. It would seem that wire
does have a freq response effect if it is undersized relative to the
impedance dips??? And what little I know about speaker design is that
impedance dips are associated with output dips -- is this correct? So
overall speaker freq response dips would be increased by undersized
wire?

I realize the practical effect is probably minimal for most
applications. (And that 12 gauge wire suffices for most all home use).
But I play with multiple subs that can present 1.5 ohms in certain
configurations, and would like to clean up my understanding. Thx.
Mark

On 28 Jan 2004 16:04:38 GMT, (Mark Wilkinson)
wrote:

Anyway, I do think you need to consider worst case impedance in
choosing wire size, because given a certain wire resistance the losses
calculate higher for lower impedance loads.

Yes, this is correct.

It would seem that wire
does have a freq response effect if it is undersized relative to the
impedance dips???

Yes, you should calculate your preferred wire resistance based on the
lowest point of the impedance curve.

And what little I know about speaker design is that
impedance dips are associated with output dips -- is this correct? So
overall speaker freq response dips would be increased by undersized
wire?

No, there's no fixed relationship between impedance and output
response curves for a complete multiway speaker. If the loop
resistance of the cable is more than say 10% of the minimum impedance
of the speaker, then you may certainly see FR variations. This is a
perennial problem with the much-vaunted Single-Ended Triode amps,
which can have an output impedance of more than an ohm.

I realize the practical effect is probably minimal for most
applications. (And that 12 gauge wire suffices for most all home use).

Indeed it will.

But I play with multiple subs that can present 1.5 ohms in certain
configurations, and would like to clean up my understanding.

Keep the loop resistance of your cable to less than 0.075 ohms in this
case, and you should have no problems.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

(Mark Wilkinson) wrote in message ...
(Mark Wilkinson) wrote in message ...
Now I'm not enough of an electrician to know if the losses from
current through the line and the losses from voltage apportionment
between line and load are strictly additive. But I'll assume they are
since the loss from current is calculated independent of load.
(Perhaps you'll be kind enough to help out here.) If simple addition
is correct, I get total peak losses of 4.7db for 22 gauge, .44db for
12 gauge, and 1.8db for 18 gauge.

Sorry to post to a post, but last night I sorted things out in my
head.
My "peak" math is a merely a special case duplication of the math that
apportions power between between line and load. Dick is right -- wire
can't attenuate peaks. Hey, he's forgot more math than I know ... but
I'm trying. So the bottom line seems to be all that matters is the
resistance of the line relative to the resistance of the load, all the
resultant attenuation -- which is usually minimal.

Anyway, I do think you need to consider worst case impedance in
choosing wire size, because given a certain wire resistance the losses
calculate higher for lower impedance loads. It would seem that wire
does have a freq response effect if it is undersized relative to the
impedance dips??? And what little I know about speaker design is that
impedance dips are associated with output dips -- is this correct?

Generally, no. There is no general correlation between the impedance
response and the frequency response, assuming you're driving the
speaker from true voltage source. Some examples to illustrate
how the exceptions completely overwhelm your "rule:"

1. A two-way system using 2nd order crossovers can have a bump
at the crossover point. Hook the woofer and tweeter in phase,
and you can have a sharp null at the crossover, flip the
phase of the tweeter, and the null goes away. But the
impedance at the crossover point remains exactly the same.

2. Reflex-tuned systems always have two impedance peaks in the
bass (actually, they have one large peak with a smaller hole
in the middle). However, they do NOT (and, indeed, CANNOT)
have two corresponding peaks with a hole in between.

So
overall speaker freq response dips would be increased by undersized
wire?

Well, you're partly correct: the frequency response CAN be affected
by driving a frequency-dependent speaker impedance from a non-ideal
source, specifically one which has a source impedance whose magnitude
is sufficient relative to that load to cause frequency-dependent
attenuation.

In article NMURb.45681$U%5.239723@attbi_s03,
Stewart Pinkerton wrote:

No, there's no fixed relationship between impedance and output
response curves for a complete multiway speaker. If the loop
resistance of the cable is more than say 10% of the minimum impedance
of the speaker, then you may certainly see FR variations. This is a
perennial problem with the much-vaunted Single-Ended Triode amps,
which can have an output impedance of more than an ohm.

Or a Futterman OTL amp driving a full-range ESL?

Mike Squires
--

Mike Squires (mikes at cs.indiana.edu) 317 233 9456 (w) 812 333 6564 (h)
mikes at siralan.org 546 N Park Ridge Rd., Bloomington, IN 47408

(Dick Pierce) wrote in message ...
(Mark Wilkinson) wrote in message ...
And what little I know about speaker design is that
impedance dips are associated with output dips -- is this correct?

Generally, no. There is no general correlation between the impedance
response and the frequency response, assuming you're driving the
speaker from true voltage source. Some examples to illustrate
how the exceptions completely overwhelm your "rule:"

1. A two-way system using 2nd order crossovers can have a bump
at the crossover point. Hook the woofer and tweeter in phase,
and you can have a sharp null at the crossover, flip the
phase of the tweeter, and the null goes away. But the
impedance at the crossover point remains exactly the same.

2. Reflex-tuned systems always have two impedance peaks in the
bass (actually, they have one large peak with a smaller hole
in the middle). However, they do NOT (and, indeed, CANNOT)
have two corresponding peaks with a hole in between.


Thank you, Dick, and Stewart:

I could see how there is no correlation between speaker freq response
and impedance when xovers and acoustic coupling are in play, but the
bass reflex example kinda surprised me. So even for a single driver
operating only in its intended passband, there's no correlation? Is
this true regardless of enclosure type? eg sealed, reflex, IB, horn?

So
overall speaker freq response dips would be increased by undersized
wire?

Well, you're partly correct: the frequency response CAN be affected
by driving a frequency-dependent speaker impedance from a non-ideal
source, specifically one which has a source impedance whose magnitude
is sufficient relative to that load to cause frequency-dependent
attenuation.

I see, as in Stewart's SET example. Does an amp's source impedance
vary with load and output level? For instance, when an amps current
output is insufficient to drive a low impedance load to rated power,
is it proper to think of the amp's source impedance as varying? I'm
sorry if these questions are muddled or show a lack of understanding.
Maybe I should just be asking for an explanation of source impedance.
Thx again, Mark

(Mark Wilkinson) wrote in message ...
(Dick Pierce) wrote in message ...
(Mark Wilkinson) wrote in message ...
And what little I know about speaker design is that
impedance dips are associated with output dips -- is this correct?

Generally, no. There is no general correlation between the impedance
response and the frequency response, assuming you're driving the
speaker from true voltage source. Some examples to illustrate
how the exceptions completely overwhelm your "rule:"

1. A two-way system using 2nd order crossovers can have a bump
at the crossover point. Hook the woofer and tweeter in phase,
and you can have a sharp null at the crossover, flip the
phase of the tweeter, and the null goes away. But the
impedance at the crossover point remains exactly the same.

2. Reflex-tuned systems always have two impedance peaks in the
bass (actually, they have one large peak with a smaller hole
in the middle). However, they do NOT (and, indeed, CANNOT)
have two corresponding peaks with a hole in between.


Thank you, Dick, and Stewart:

I could see how there is no correlation between speaker freq response
and impedance when xovers and acoustic coupling are in play, but the
bass reflex example kinda surprised me.

Why?

So even for a single driver
operating only in its intended passband, there's no correlation? Is
this true regardless of enclosure type? eg sealed, reflex, IB, horn?

Essentially correct. Let me give another example. Take ANY speaker
with a horrible frequency response. In parallel with that speaker
place a complex conjugate network, so that the electrical impedance
is now flat, essentially resistive. Poof! A speakers whose electrical
impedance is flat and whose frequency response has peaks and dips
all over the place.

So
overall speaker freq response dips would be increased by undersized
wire?

Well, you're partly correct: the frequency response CAN be affected
by driving a frequency-dependent speaker impedance from a non-ideal
source, specifically one which has a source impedance whose magnitude
is sufficient relative to that load to cause frequency-dependent
attenuation.

I see, as in Stewart's SET example. Does an amp's source impedance
vary with load and output level? For instance, when an amps current
output is insufficient to drive a low impedance load to rated power,
is it proper to think of the amp's source impedance as varying?

Su the amp, at that point, is clipping (pretty much by definition),
and all bets are off as to its performance at that point.

I'm
sorry if these questions are muddled or show a lack of understanding.
Maybe I should just be asking for an explanation of source impedance.

What it IS or how does it arise? Two different questions, the latter
having MANY different possible answers.

In a Thevenin equivalent description, a typical audio amplifier
will consist of a "perfect" voltage source, i.e., one which has
zero series impedance. In series with that is one or more circuit
elements that model the output imepdance. In the simplest case,
this might be a simple resistor, but in the real world, it's more
complex than that. For example, in a reasonably well designed tube
amplifier having a reasonably well designed output transformed, that
circuit actually consists of both series inductance and capacitance,
because the source impedance goes up at low and high frequencies.
The circuit elements could also be level dependent.

Where this behavior comes from is much more complex, and is beyond
the scope of a simple discussion.