Maybe you missed the point of my remarks. The 604 design comes from
an era when no one new how to design a box suited to a driver, and
no one new how to design a driver to fit in a box. People couldn't
do reasonable driver/enclosure and thus system designs because no one
knew, back in the middle 1940's what any of this stuff meant.

Well, to a substantial extent, I did. I have a reasonable electronic
background, but I don't claim to be a speaker designer. That said, and
not as a dig, a lot of those who do apparently don't know very much
either.

A number of variations of the 604 exist, but typical T/S figures
on them run something like:

Fs 27 Hz
Vas 450 L
Qms 2.32
Qes 0.22
Qts 0.20
Xmax 3 mm

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.

In the more typical cabinet used for these drivers, which is an excessively
large cabinet tuned with large ports at a very high frequency, the response
of the system is, well, abyssmal. How about an 11 dB peak at 80 Hz, with
a response that plummets like a rock below that.

And the horn is such that crossover frequencies like 900 Hz are a
bare minimum. That's asking an awful lot of an untreated paper cone.

2. A "real" large driver with very poor linearity that has no better
linear volume displacement than your alledged "cheap" smaller
drivers, with a stiff and VERY non-linear suspension.

With an excursion of all of about 3 mm, despite its enormous magnet
and underhung voice coil, this 15" driver has no more output capability
than one of those "cheap" 10" drivers you go about.

3. A "real" expensive crossover that was designed without any
consideration of conjugate load matching

Doug Sax of Mastering Labs designed a much better x/o but although
it's still available to order I think even he would admit biamping is
better.

But the basic item is SO handicapped by its fundamental limitations. It
was an amazing driver in its time. But it's time was 1945. That's almost
SIXTY years ago, my friend. Event ignoring your rather biased and poorly
constructed remark about "cheap" drivers, pretty much EVERYTHING that's
understood about the interaction of cabinets and drivers, system
integration, crossover design, driver design, EVERYTHING occured
significantly AFTER the 604.

You take ALL of that knowledge, lump it into a single pile, call it
"the stuff they sell at Madisound" and "Speaker Builder mentality
projects" as if that represented the Parnassus of loudspeaker knowledge
and proceed to tilt against it like some evil windmill. Well, there's a
much larger world of knowledge about loudspeakers than that, I would
hesitate to suggest. And the Altec 604 is NOT part of it, because it
was born 25 years too early.

I rail against the attitude of many hobbyists and High End Swinging
Dicks (hobbyists with money and ego who go in the high-end audio
business, selling their hobby projects-which might be well and fine as
hobby projects-for huge sums through chichi dealers with arrogant snob
salespunks that can't solder and wouldn't be allowed to clean the
toilet at Sear Sound) that they can throw something together cheaply,
package it in a form factor straight out of a Fifties cheesy sci-fi
movie or "The Wild, Wild West", and trendies form a conga line to buy
it. Look at that goofy thing on the cover of this month's Stereopile.
Would Hewlett, Packard, or Vollum have built anything that goofy
looking? And it's conservative compared to a lot of this crap. That a
hobbyist can build an amp as good as a c-j, Audio Research, or VTL, or
a speaker as good as a Thiel or Vandersteen for a fraction even
counting his own time at market technician/assembler rates, is
ludicrous. (But very true.) The only other industry I know where
building in the basement is cheaper is in light aircraft, where you
have huge overheads with type certification and (allegedly) product
liability insurrance.

I don't mean to insult Madisound, who are probably a decent vendor,
or Speaker Builder-now AudioXPress-who can only publish what people
submit, and from the looks of the magazine in the last few years the
submissions are getting lean.



No, you have already run up against the unresolvabel fundamental
design limitations of the the beast. Theya re intrinsically what
they are, and NO amount of fiddling will get them beyond that point.

Appreciate them for what they a probably one of the best examples
of the black art of speaker from 6 decades ago, a period where more
witchcraft and alchemy and kitchen-sink fiddling then science and
understanding and real engineering ruled.

604's, like T. Rex, is a magnificent specimen of a time long past.
We can admire them, study them, marvel at their anachronistic
magnificence.

The 604 was in volume manufacture for over 45 years, until corporate
acquisition made it (and several other Altec products) a red-headed
stepchild. It cost money to build and "overlapping" products in the
line cost less, apparently much less, to build. I had a phone
conversation with "the new guys" wherein the marketing manager
explained, with glee, that they had Dumpstered the tooling, that they
had happily walked away from hundreds of thousands of dollars per year
from Japanese and other overseas orders , that they could have sold
even more and/or jacked the price higher if they'd been willing to
build earlier versions-particularly with Alnico magnets, which would
have added $100 to the build cost of each unit, and finally that Les
Paul had been after them for 20 years to do a LP signature 604 which
they had diligently ignored.

Profitable legacy products are often killed,laying off workers and
idling plants, in corporate acquisitions no matter the demand. The New
Management has to show they have a bigger-on paper, it's ROI, but it's
just the age-old instinct for measuring penis size. The new one costs
less to build. Not only that, it probably has firmware, which is the
sacred god Intellectual Property and, costing nothing to copy, is of
infinite value. Why do you think all the new subsonic airliners have
FBW, even though, in a rare episode of sanity, the FAA requires they
still be aerodynamically stable?


But, like T. Rex, they're STILL extinct. Their time has come, and
their time has gone. R. I. P.

And yet: they sound better than many, many later efforts (although
I'd never say all.) Is there such a thing as "a good sounding driver"?
Apparently so.

Can we do better today? You'd think so. But I think it would mean
spending money, and the audio industry seems allergic to this.