From: Richard d Pierce <DPierce@world.std.com>
Newsgroups: rec.audio.high-end
Subject: re: Antique Audio Equipment
Date: Fri, 13 Nov 1992 23:50:36 -0500 (EST)
Organization: University of Wisconsin - Milwaukee
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Dieter Koller writes:

>I think the design of stereo equipment is driven by two philosophies:
>
>1. Design loudspeaker systems, in which disturbing frequencies
>   (peaks and maxima in the the frequency spectrum) are *reduced* 
>   at a cost of low efficiency (80-90dB). The result is that you
>   have to use large amplifier to drive them. As well known, large
>   and powerful amplifier are difficult to design.
>   The sound of those (mid-price ca. $5000) loudspeaker - amplifier
>   combinations is squeezed and not naturally.
>2. The second philosophy is not to *reduce* disturbing frequencies
>   in the spectrum of a loudspeaker but to use a more sophisticated
>   design in the loudspeakers chassis etc., in order to "physically"
>   amplify the "weak" frequencies. The result can be a loudspeaker
>   with a efficiency of about 100dB and more. Some of those loudspeakers
>   are well designed horn systems. In this way you can
>   use moderate and small amplifier (even less than 3 Watt) in order
>   to get a very natural and airy sound. The reason is that you can
>   design low power amplifier with a very few number of parts.
>

I am not sure what you are talking about when you refer to using the
loudspeaker chassis to "physically" amplify the "weak" frequencies. As a
professional working in the field, I can say that this is complete bunk.
If you got a problem, then cure it, don't try to bury it under some other
problem.

Further there were very few, if any, well designed horn systems then (and
damn few now, certainly).

>At the beginning in the design stereo amplification, people are forced
>to use their skill in a very sophisticated design of loudspeakers with
>a very high efficiency, because the available tube amplifiers didn't 
>provide the necessary power to drive a low efficiency loudspeaker.
>Nowerdays, since powerful amplifiers are avaliable, the knowledge about
>the design of loudspeaker seems to be lost and most of the available
>loudspeaker are of low efficiency.

This is complete bunk. In the era you are refering to (late 50's and
before, nobody had much of a clue about how speakers worked. The analysis
tools, the measurement tools and the design tools were, for all practical
purposes, crude at best to non-existant. People punched holes in the front
of loudspeaker cabinets, saw that something changed in the bass, called it
bass reflex, and marched on, ignorant of what they were doing. These
system had little real bass, and very often had severe response aberations
that become pretty annoying quickly.

It took the work first of A. Neville Thiele followed by Richard Small to
provide a sound theoretical basis in the mid and late 60's before
engineers had a clear and unambiguous idea of how loudspeakers worked at
low frequencies and how to use that knowledge to design systems. No,
people did not abandon the older design philosophies because of the
reasons you cite. No, they abandoned the old ways because the old ways
were misleading, unpredictable, clumsy, unreliable, inaccurate, unweildy
and just plain bad. The connection you make between efficiency and
frequency reponse, to a great extent, is simply bunk, and unsupported both
by well-established theory and decades of actual experience.

Further, the level of "sophistication" in these older designs is, at best,
laughable. Some of the tricks people applied to systems to cure problems
they invented (trap doors to relieve internal pressure, slicing cones to
eliminate cone breakup, bizarre baffles, cello-shaped enclosures, strange
formulations of magic paper, etc...) were little more than voodoo
engineering with about the same positive effect. People designed
crossovers based on theories that they knew were inadequate to the task
because they could do no better. They knew the results were pretty bad,
but they had no choice. Simply scan the technical literature of the era,
and you will see the best engineers simply walking around in the dark, not
having any real clue as to what was going on.

The vast majority of those systems, on an objective basis (that is, their
ability to reproduce the sound of musical instruments in an accurate,
uncolored fashion) were simply lousy. That is not to say that they were
not pleasant. But as reproducers as opposed to sonic editorializers they
were not!

>Some people pursue the old philosophy and listen preferable
>to such antique audio equipment. I listened to some components
>and I'am convienced that you have to spend quite a lot of money in order
>to buy a comparable (modern) system.

Well, clearly this is your opinion. On the same token, it would probably
cost a minor fortune to build a copy of a Wright Flyer or a V-2, but I
doubt that anyone would argue that they are adequate replacements for
modern aircraft or space transportation (in spite of the fun even I would
have in a Wright Flyer).

On the other hand, if I would like to do something other than plod along
at 20 knots 100 feet off the ground, just about any modern aircraft of any
description (including about any modern ultra-light) will outfly,
outdistance, outrun, (and under-run), out-manouver, out-last a Wright
FLyer. You may like it, but the facts are what they are.

 |                Dick Pierce                |
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