"Dick Pierce" wrote in message
om...

Hnoestly, I think you have gone from a nostalgic but unrealistic
technical standpoint to an equally nostalgic but unrealistic
economic one. The 604, by ANY objective technical measure, is a dog.
In addition, it become nearly impossible to manufacture because of
it's very age. And because of that, it was no cash cow, it was a dead
mule and was given the ignominious burial it so richly deserved.

Whilst I agree with your general point Dick, I can't help but think you are
being a trifle unfair. The fact that some are still going after 50 years
proves the quality of construction at least. They were "magnetically
shielded" long before it became a design feature. They were dynamically "CD
ready", long before CD was invented, and from your earlier post :

Yes, it's got phenomenal efficiency at about 98 dB 1W @ 1m, but
at a pretty significant cost: look at the Qts figure of 0.2.
Aiming for a maximally flat response requires the speaker to be mounted
in a TINY box, on the order of 80 liters, tuned to about 50 Hz. The result
is impressively flat, less than 1 dB response variation (ignoring driver
response anomolies), but is hardly impressive bass-wise for a 15" driver,
struggling, as it does, to reach down to 53 Hz.

A 50Hz cut off is considered quite normal these days for many speakers, but
how many of them can do 98dB/W/M? None that I know of.
So yes they were designed before the science had arrived, and yes it's easy
to produce a better design these days (but still many don't).
The biggest problem was the box design, which can and was fixed by many
people who liked the idea of high efficiency/high SPL at 50Hz up.

IMO the main reason they are obsolete is the cost of construction Vs the
existence of cheap megawatt amplifiers these days.
I totally agree a viable market no longer exists.

TonyP.