Well, I suppose the misleading part of all this is actually calling them
square waves in th first place, as has been noted these do not exist.
There are other forms that can be used of course, the one sided square, with
a leading slope but a fast drop, and the inverse of this.
Then there are triangular waves of course, which sound almost as bad as
square waves.

I think the listening tests do prove some things though. Firstly, nobody is
really sure what 'right' actually is, so an amp may sound bad, but it might
be actually more accurate than one you like.

It is interesting sometimes to put a scope on the psu when an amp is running
too, often some frequencies exist at quite high levels, despite all the
decoupling in the world being there, indeed, decoupling itself can make an
amp sound leaden.

In the complexity of the audio and all the bits in the chain to how the
brain perceives the whole is still not well understood, I feel.

However, I do not think that most speaker wire tests are actually testing
the wire...

Brian

--
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Blind user, so no pictures please!
"Don Pearce" wrote in message
...
On Sun, 10 Jan 2010 18:30:55 +1300, Mike Coatham
wrote:

Jim Lesurf wrote:
Hi,

I've just put up a new web page at

http://www.audiomisc.co.uk/HFN/Squar...quareDeal.html

that looks at the use of squarewaves for assessing amplifiers, etc.

During a tidy up I found a 6 page article on "Square Wave Testing of Audio
Amplifiers" in the NZ publication - Radio & Electrical Review - of August
1955. In it, it goes on to describe the testing of amplifiers using square
waves as a relatively new process.

And just to show that that the more things change the more they stay the
same, the article also says - and I quote "Now when we have a number of
amplifiers whose specifications, as outlined , indicate such excellent
performance, one might legitimately expect, when listening tests are
conducted, using identical programme material, and the same pick-up and
speaker system, that all the amplifiers sound the same. It was with
considerable surprise that we found exactly the opposite. "

They did tests on 7 un-named amplifiers and included oscillograms of the
amplifiers at 30hz, 400hz & 10,000hz.

The conclusion reached was that square wave testing "can help sort the
sheep from the goats. With all its advantages, this type of test will
still
not give an unambiguous answer to the 40 dollar question ...Will this
amplifier sound well on music?. It will give the experienced worker a
pretty good idea of where his designs could be improved, and it seems that
the very best amplifiers do give very similar square wave results. Where
faults are apparent, the test shows them up much more clearly than any
other method, and will also indicate fault conditions that cannot readily
be discovered at all in any other way."

So here we are, 55 years down the track and its deja vu all over again :0

Mike


No chance of scanning it and making it available, is there? That would
be interesting.

d