"Jim Lesurf" wrote in message

In article , Bob
Latham wrote:
In article , Eiron
wrote:
Dave xxxx wrote:
On another forum a chap says, he has been told, its ok
to use a Quad power amp (140 watts) with a Quad 405
(100 watts) with the same pre amplifier.


The idea being the 606 powers the bass and the 405 the
tweeters.

Speakers being used Spendor s5e

Will this work ?

Quite pointless, as Serge said.

You are both correct from a simple electrical point of
view it is quite pointless. However, I might point out
that rightly or wrongly, probably a substantial majority
of people with an interest in Hi-Fi would say that
Bi-amped systems sound better

If bi-amped means active crossover, multiple amplifiers, multiple drivers,
then yes. That's a working technology that is widely used. It is widely used
in pro audio. It's even used in boom-boxes.

Where have you seen any figures to support the assertion
that the "majority" would say this? And would it mean
more than, "The magazines keep saying it does"? :-)

I'd like to see a reference to an article in an audio ragazine with
meaninful circultation about an actual high end product that bi-amps without
an active product. For example, has Stereophile or HFN ever reviewed a
biamped speaker with no active crossover?

and indeed to be "pointless" the amplifiers would have
to suffer zero load issues.

I know, you think the majority are fools - fair enough.

Not so much fools as poorly informed.

I can't speak for either Dave or Eiron. However I don't
think those who have the above belief are "fools".

Ironically, there's an argument that says that putting a normal woofer in
parallel with a highly reactive tweeter through a passive crossover makes
the reactive tweeter an easier load to drive. The signal through the woofer
drives the power amp output stage up its load line where the out-of-phase
current for the tweeters is coming from output transistors that are already
partially saturated from driving the woofer. The voltage across the output
transistors and the power dissipation in the output stage is therefore
reduced.

Firstly, there are circumstances where bi-amping can
change the results for simple engineering reasons. This
thread threw up an example. The amps have different
gains, thus - unless corrected - altering the frequency
response of the system. The result being an expensive and
inflexible 'tone control'.

Agreed. Anyboydy who assigns the 405 to the woofer and the 606 to the
tweeter gets to enjoy brighter treble and a little uptick in the midrange.
"Brighter is better", anyone? ;-)

It's just an expensive, non-adjustable equalizer.

Secondly, people can easily believe all kinds of things
if they base their ideas on what magazines tell them,
and/or 'listening tests' that aren't carried out in a way
that might lead to a reliable result.

In this case, an audible difference is likely. And, if the listener doesn't
agree with Spendor's speaker voicing, then they will perceive an
improvement.

Trivially easy to
mislead youself. No need to be a "fool". Just someone who
accepts what magazines ("experts") say and don't have any
idea how many ways there are for a listening test to give
a misleading or worthless result.

Interesting how many people pooh-pooh equalizers, but rush to accept an
badly-designed "Bi-amp" equalizer implmented by what might be the most
expensive and non-adjustable means possible.

In article , Arny
Krueger
wrote:
"Jim Lesurf" wrote in message

In article , Bob Latham
wrote:

[snip]

Where have you seen any figures to support the assertion that the
"majority" would say this? And would it mean more than, "The magazines
keep saying it does"? :-)

I'd like to see a reference to an article in an audio ragazine with
meaninful circultation about an actual high end product that bi-amps
without an active product. For example, has Stereophile or HFN ever
reviewed a biamped speaker with no active crossover?

I have a vague feeling that HFN may have once reviewed the 'systems' that
some people put together. In general, of course, that won't be anything
that was intended by either the speaker manufacturer or the amp
manufacturer.

However IIRC back in the 1980's there was a UK fad for using multiple Naim
power amps to 'bi amp' the Linn Isobarik. Not sure if Naim or Linn pushed
the idea, but some dealers and 'subjective reviewers' did at the time.

Personally, I disliked both the Isobarik, and the Naim amps. So for me the
main benefit was that it piled the items I didn't want somewhere away from
where I had to encounter them. :-)

FWIW The Isobarik had an impedance that went south at LF, and the Naim
amps of the period had an output 0.22 Ohm series resistor and limited
current capability. So the Naim/Isobarik system did have a different
response to using an amp with low output impedance and decent current
capability. However I tended to make the choice here that wasn't the one
touted in magazines at the time. :-)

At the time Linn dealers used to insist that 'stereo image' was a myth.
Perhaps because you couldn't get one when using Isobariks. ;-

The most dramatic change I ever heard was in a shop when the removed the
Isobariks and tried Quad 63's. From awful to excellent. They shop droids
hated the Quads. But then they were unable to hear that one of the tweeters
in one of the Isobariks was busted... :-)

[snip]

Ironically, there's an argument that says that putting a normal woofer
in parallel with a highly reactive tweeter through a passive crossover
makes the reactive tweeter an easier load to drive. The signal through
the woofer drives the power amp output stage up its load line where the
out-of-phase current for the tweeters is coming from output transistors
that are already partially saturated from driving the woofer. The
voltage across the output transistors and the power dissipation in the
output stage is therefore reduced.

A few months ago there was someone putting a flawed argument forwards on
the 'audioholics' website in a thread about bi-wiring.

The wording of the claims 'evolved' as it was challenged. However it tended
to be based on saying there was a form of 'intermodulation' occurring in
conventional wiring that biwiring removed.

Mysterious consequences were described such as components in the spectrum
that an FFT could not show. Doubters were treated as being unable to grasp
the reality as they lacked the scientific insight of the idea's presenter.
;-

The argument used was incorrect, or at least inappropriate, and thus lead
to an wrong conclusion. I did an analysis and it was another example of how
a simple misconception can mislead, but a detailed analysis takes ages to
show what a good engineer would have thought in the first place. i.e. No
such problem, so no need for biwiring as a 'solution'. No real problem
with the FFT, either. Nor indeed with mudane ideas like linear
superposition, etc. :-)

Shame if anyone though they were hearing what was claimed since the claimed
theory didn't stand up to either measurement or careful analysis based on
the physics involved according to the claimant's own descriptions.

None of which stopped the claimant from continuing to push his idea.

I wonder if any of that appeared in any USA printed mags?... Didn't appear
here in print so far as I know.

[snip]

Interesting how many people pooh-pooh equalizers, but rush to accept an
badly-designed "Bi-amp" equalizer implmented by what might be the most
expensive and non-adjustable means possible.

IIRC the use of biamping, biwiring, etc, all tended to only come into vogue
*after* the gurus decided that 'tone controls are baaaad' and makers saved
cash by stopped including them. No problem for them if the result was that
people bought more amplifiers. :-)

Personally I still like tone controls and balance controls to be avilable.
Although I appreciate them being designed to work well, and to be bypassed
if preferred. Much cheaper and more flexible than biamping IMHO.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.audiomisc.co.uk/index.html
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html

The most dramatic change I ever heard was in a shop when the removed the
Isobariks and tried Quad 63's. From awful to excellent. They shop droids
hated the Quads. But then they were unable to hear that one of the tweeters
in one of the Isobariks was busted... :-)


"Never in the field of domestic audio was so much bull**** dispensed by
so few and believed by so many"

With apologies to Winnie...
--
Tony Sayer

In article ,
tony sayer wrote:
The most dramatic change I ever heard was in a shop when the removed the
Isobariks and tried Quad 63's. From awful to excellent. They shop droids
hated the Quads. But then they were unable to hear that one of the tweeters
in one of the Isobariks was busted... :-)


"Never in the field of domestic audio was so much bull**** dispensed by
so few and believed by so many"

The problem, alas, was that it was a 'key' few people in just the right
places to influence readers of the magazines, and those who innocently
walked into the shops in question. IMHO the results blighted UK domestic
audio for over a decade.

I don't blame those who went into the shops, and bought the gear. Often
they were given no real chance to hear alternatives or make a judgement for
themselves without being led by the magazines and salesdroids. In the case
I had in mind we had to nag the driods until after I'd shown the Isobariks
were damaged to force them to even bring any other speakers (the 63's) into
the room. They did so with bad grace, mumbling comments about how poor the
63's were.

I wonder if they sold the Isobariks to someone without replacing the broken
tweeter...

Remember this was also the days when part of the 'wisdom' was that any
other speakers in the room might 'upset the sound'. Maybe by allowing the
listener to discover how they were being led to buy actually compared with
alternatives. :-)

Curiously, the items in question had carefully controlled 'franchises' with
higher mark up rates. Triumph of marketing over content. Given the
treatment in the magazines, the items 'sold themselves'. The punter walked
into the shop asking to hear that specific setup, heard it, and bought it.
No real comparisons or experimentation.

No doubt this all still goes on in some cases. One of the reasons I got fed
up with the audio biz as a living. I also know of other engineers who left
the field for similar reasons.

Maybe these days I am a gamekeeper turned poacher... :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.audiomisc.co.uk/index.html
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html

"Jim Lesurf" wrote in message
...
In article ,
tony sayer wrote:
The most dramatic change I ever heard was in a shop when the removed the
Isobariks and tried Quad 63's. From awful to excellent. They shop droids
hated the Quads. But then they were unable to hear that one of the
tweeters
in one of the Isobariks was busted... :-)


"Never in the field of domestic audio was so much bull**** dispensed by
so few and believed by so many"

The problem, alas, was that it was a 'key' few people in just the right
places to influence readers of the magazines, and those who innocently
walked into the shops in question. IMHO the results blighted UK domestic
audio for over a decade.

I don't blame those who went into the shops, and bought the gear. Often
they were given no real chance to hear alternatives or make a judgement
for
themselves without being led by the magazines and salesdroids. In the case
I had in mind we had to nag the driods until after I'd shown the Isobariks
were damaged to force them to even bring any other speakers (the 63's)
into
the room. They did so with bad grace, mumbling comments about how poor the
63's were.

I wonder if they sold the Isobariks to someone without replacing the
broken
tweeter...

Remember this was also the days when part of the 'wisdom' was that any
other speakers in the room might 'upset the sound'. Maybe by allowing the
listener to discover how they were being led to buy actually compared with
alternatives. :-)

Curiously, the items in question had carefully controlled 'franchises'
with
higher mark up rates. Triumph of marketing over content. Given the
treatment in the magazines, the items 'sold themselves'. The punter walked
into the shop asking to hear that specific setup, heard it, and bought it.
No real comparisons or experimentation.

No doubt this all still goes on in some cases. One of the reasons I got
fed
up with the audio biz as a living. I also know of other engineers who left
the field for similar reasons.

Maybe these days I am a gamekeeper turned poacher... :-)

Slainte,

Jim

--
Electronics
http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.audiomisc.co.uk/index.html
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html

When I was involved with consumer audio in the mid '80s, (some may remember
Beechwood Audio in Braintree and Bury St Edmunds) I ran an ad in the April
edition of Hi-Fi News offering single ear demonstrations. This required two
customers, one would listen with their right ear blocked, and the other with
the left. At the end of the piece of music, each listener would tell the
other what they had just heard, thus restoring the stereo experience.

It attests to the spirit of the time that only a few older customers
actually understood the ad for what it was......

Not surprisingly, I returned to the relative sanity of broadcasting shortly
afterwards.

S.

--
http://audiopages.googlepages.com