dizzy wrote:
On 20 Jun 2005 04:07:36 -0700, wrote:
By your description, these are probably from the late-50's or
early- to mid-60's vintage systems. This was from a time when
few people in the industry had a comprehensive understanding
of the notion of designing speakers using a systems approach
as described by Thiele and then later Small.
But the overwhelming factor is that these speakers were INTENDED
as junk, DESIGNED as junk, MANUFACTURED as junk, all to save lots
of money, and then intended to be SOLD to people who didn't know
or didn't care much about the quality of the sound.
I think you're being too hard on them. Did they know as much back
then as we do today? Of course not.
Didn't I just say something to that effect:
"This was from a time when few people in the industry
had a comprehensive understanding of the notion of
designing speakers using a systems approach as described
by Thiele and then later Small."
As to Thiele and Small, AFAIK that's for bass-reflex designs,
Wrong. Consider the series of articles written by Small in the JAES:
Direct Radiator Loudspeaker System Analysis (1972 June)
Closed-Box Loudspeaker Systems, (1972 Dec, 1973 Jan-Feb)
Vented-Box Loudspeaker Systems. (1973 Jun, July/Aug, Sep, Oct)
Passive-Radiator Loudspeaker System Design, (1974 Oct, Nov)
which that old stuff was generally not.
Also not correct. Most of the stuff made by Magnavox and the like
were nowhere near sealed box. Typical configurations where very
light, flexible cones in stiff suspensions with small voice coils
and magnets. The result was a moderate efficiency, high resonant
frequency (60 Hz for a 15" cone would be quite typical) and VERY
underdamped (free-air total Q factor in the range of 2-4). These
drivers were then often placed in cabinet volumes that were dictated
NOT at all by the acoustical and mechanical requirements of the
driver but by the requirements of the furniture designer. Usually,
the rear of these systems was little more than a perforated masonite
board, sometimes it was plywood, and a gratutious port is punched
through the front baffle.
I have no doubt that (at least the more thoughtful) designers back
then made reasonable attempts to design systems with decent
performance,
Yes, and NONE of them have worked represented by the likes of
Magnovox.
within the limitations of the technology and design
practices of the time.
Then explain the ENORMOUS disparity in the design and implementation
in the early 1960's by, oh, Acoustic Research and, say, Magnavox.
The same PHYSICAL limitations were imposed on both. Why did the
Magnovox have such a tiny magnet and the AR no if they were both
contrained by limitations of the technology of the time?
Oh, it's those pesky "design practices" that must be it. You know,
the ones where the cabinet designers ruled and basically handed
the "speaker designer" a given cabinet, and they bascially stuck
any ol piece-o'-**** collection of utterly unsuitable drivers in
it, threw a couple of caps in and then they're done.
Large magnets as what are common today simply
were not appropriate back then.
Not "appropriate?" Do you mean to say that physics has changed,
and what is "appropriate" now wasn't then?
Or maybe that, given the fact that the portion of the design and
manufacturing budget alloted to speakers was SO paltry, that junk
HAD to be the rule.
Most stuff sold back then was not nearly as "junk" as most stuff sold
today...
There's more functionality and acousticalt performance in a $400
boom box today than there was in a 1960's Magnavox stereo console.
Hell, there's even more magnet on them.