On Fri, 20 Apr 2007 16:55:16 -0400, John Day
johnday@wordsnimages.com wrote:

I feel yer pain buddy!  My real Klipsches didn't survive a fire.  Gawd
I miss those horns.  Those proved that excellent speakers make
everything else in the system relatively unimportant.

John, did you copy the folded horn design or just the looks.  I've
pondered trying to build another set but I think that degree of
woodworking skill is just beyond my capabilities.

John

John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
All great things are simple and many can be expressed in single words:
Freedom, Justice, Honor, Duty, Mercy, Hope.  -Churchill

Hi John:

Many years ago after installing a new component Hi-Fi system into my house you
could hear noise coming out of the speakers that was objectionable.  I took the
Scott power amp back to the high end audio store where I purchased it and
complained.  It was meeting specs.  The problem was the speakers.  Rather than
degrade the speakers the Scott was returned and replaced with McIntosh
equipment and that solved the problem.

The speakers were Voice of the Theater.  A 15' woofer set back so it's voice
coil is in the same vertical plane as the voice coil in the horn.  The gap
between the woofer and the front of the box was filled in with an exponential
horn.  This construction kept the phase of the sound at the crossover frequency
(500 Hz) in phase.

With 1 mw drive you could hear a 1 kHz tone from across the room and the noise
level on the Scott amp was some big number of dB down from max output.  After
calculating the noise level it turned out to be maybe 10 dB above 1 mw.

So I'd say that excellent speakers may or may not make everything else unimportant.

Have Fun,

Brooke Clarke
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com

Neon John wrote:

From: Brooke Clarke brooke@pacific.net
Subject: Re: [time-nuts] OT: Audiophoolery
Date: Fri, 20 Apr 2007 15:49:14 -0700
Message-ID: 4629436A.1090705@pacific.net

Horns have so much higher effiency that normal speakers looks like a waste of
energy in comparision. Horns are however also harder to handle in many ways.
The best horns I've heard and used are based on the orthonormal oblate
elliptical form (don't recall the exact term now). They assume that the source
is a flat oblate at the throat and then the horn-wall is orthogonal to the
wavefront as it expands, and thus acts as the acoustical transformer that we
want them to be. I made extensive measurements of these horns, especially in
pseudo-anecoic measurement setups. We peaked at 139 dB @ 1 m in the mid and
136 dB @ 1 m in the top. We never used less than 4 a side. We had amps so we
could burn the elements up before clipping (important!) and we had limiters
that ensured we never burnt any elements (we never did). We hunted noise and
hum until (kids, don't try this at home!!!) you had to lay your head against
the speaker front to hear a very very faint noise while the amps and everything
was at their full level that would play the house clean. You DO want good
dynamics.

PS. I still have perfectly good hearing! I was never hit by even a temporary
run of rings in the ears when doing PA. I've only had a tone popping up
breifly at other times. Just enought to make me notice them but then gone not
too much later. This can be due to stress.

Cheers,
Magnus

At 05:54 PM 4/20/2007, Neon John wrote:

Sad, isn't it. But in those days I had a house with a good size
listening room ( 16m long, about 6m wide) that could handle them.

And the efficiency! I got turned on to horns by a now sadly departed
friend who had some upright folded horns that could fill his place
with only three or four watts.

The whole nine yards, so to speak. I based the design on a couple of
articles, possibly even academic papers, it is a long time back now,
that described the horn and its mathematics.

Well, don't despair. I have seen places that will accurately cut
materials for hobby cabinet makers and the likes. I beleive some of
them will do speaker stuff as well, give them some good accurate
drawings and they will do it. As for me, well it would need to be a
design that takes up no more than a square foot of floor space each!

John

Or high blood pressure.

Take care!

Tom Frank