909-8A: 400Hz tractrix horn?

[adam_ecofan]

Presumably the flare begins at the phase plug, but this is not really something you have much control over.

...

Beyond the question of frequency response and dispersion there is the fuzzier but critical notion of sonic "presentation," which includes but is not limited to these measurable quantities. I guess I'm trying to get at something like "musicality" which there are no meters for.

...

The Klangfilm horn is easy and unstressed sounding, colorful, detailed...just a real joy to hear.

hi geekstar,

was wondering about flare from phase plug because the
transition to throat (could be) the most sensitive area for
discontinuity (if significant).

think you have it with the nebulous musicality - your plug
for the klangfilm flare is quite persuasive. i don't need in
your face precision but i do like a lively presentation -
'unstressed' is a pleasing thought. mmmm.... alnico....

do like the scale and presence from horn systems - even
from the rather compromised sounding A700's.

have a friend in east germany with an ecofan '45' - must
encourage him to seek klangfilm fans in his neck of the
woods, (closer to poland than berlin....)

....

what effect does total interior volume of the horn have?
is it less important than the growth in area of the section?

not well formed question - just something tugging at the
corners of my mind.

cheers,

a

[Geekstar]

was wondering about flare from phase plug because the
transition to throat (could be) the most sensitive area for
discontinuity (if significant).

Certainly true...but what were you planning to do about it? You are stuck with what the factories made.

I think this is one of the reasons that I'm liking the Renkus Heinz setups....very thin driver with a short fast flare rate integral throat in the driver body connected to a throatless fast flare horn. Whole/holistic system design. Smooth expansion all the way.

Within most of the included angle of the RH horn, the diaphragm is line-of-sight. Or, it would be except for the bug screens and phase plug in the way!

Why not play around with Hornresp and simulate a few designs, play with the variables. That will give you an idea of trends.

Hornresp

The subjectivist in me, or let's say the experientialist, says the math won't predict what will sound good, but it can tell you what a given design can achieve in gross metric terms.

I'm not a horn designer...more of a junk collector and listener.

[voice of the theater]

clarry also has model 19's in his front room now...

Lucky guy!

hi all,

rig in new location - will load pictures to my picasa page
and post link; my thread at audio heritage has pictures
of rapid prototyper output from the machine at tech -
pretty good resolution objects.

also, my source for the A700's had a rummage and has
turned up 299-8A's as an alternative to the 909's....

any thoughts?

warm regards,

a

Adam, I found this pic at L.H. Are these the 299's you have access to?

[adam_ecofan]

...

Adam, I found this pic at L.H. Are these the 299's you have access to?

...

Lucky guy!

hi v.o.t. ,

those are indeed the drivers i have access to...
don't own them but they can be made available
for conversion into 2 or 3 way systems.

chap in question has means to match the drivers
according to frequency response etc. same fellow
has solid folder of official altec box plans - hope
to have a good read at some point.

fellow with the model 19's is local number one
for valve guitar amp repair - also sees all sorts of
hifi esoterica - mean to post some pictures at
my picasa photostream; lovely guy too.....

thanks for checking in, all thoughts welcome,

cheers,

a

[adam_ecofan]

Certainly true...but what were you planning to do about it? You are stuck with what the factories made.

I'm not a horn designer...more of a junk collector and listener.

hi geekstar* ,

knowing curve from phase plug to throat suggests matching rate of
expansion to that flare rather than starting a second curve from the
exit of the compression driver. probably limits family of curves to
choose from, (maybe helpfully), or points towards compound or
hybrid flares..... (like dave fastlane's 'contrac' for klipschistes)

relate to the junk collecting and listenerhood - am barred from technical
depths by getting the music genes instead of the maths ones....

friend who is learning hornresp too busy to help at the moment - really
won't be free til january but could find another bod sooner, will hunt
around. simulate - build - measure - listen - simulate ... exploratory
philosophy with this one, experience limited so far, will proceed gently,

cheers,

a



* rhymes with 'jeepster'?

[adam_ecofan]

... is there a plain english explanation for the operation
of phase plugs - jbl radial, altec tangerine, tannoy pepperpot?

same job - different geometry - how does it work?

hi all,

pretty good explanation here - can't judge veracity
but at least wrapping my eyes round the idea helps
clear the picture for me,

cheers,

a


Phase Plugs

[adam_ecofan]

hi all,

with the possibilities multiplying
time to focus.

driver 909 crossed over at
24db per octave, 1200Hz

horn 1: 600Hz round tractrix
horn 2: " square 'trix
horn 3: " radial

friend has figured out how to
get solidworks to drive a router
from the algebra - will buy a
sheet of the truck decking -
shoot for density.

still to consider: round to sq
& machining first section of
throat for ease of comparison.

let me know if i'm more or less
on track...

happy trails,

a

[adam_ecofan]

hi all,

with the possibilities multiplying
time to focus.

driver 909 crossed over at
24db per octave, 1200Hz

horn 1: 600Hz round tractrix
horn 2: " square 'trix
horn 3: " radial

friend has figured out how to
get solidworks to drive a router
from the algebra - will buy a
sheet of the truck decking -
shoot for density.

still to consider: round to sq
& machining first section of
throat for ease of comparison.

let me know if i'm more or less
on track...

happy trails,

a

[adam_ecofan]

hi all,

went and had a good look/listen to the
'lion rockers' soundsystem - very impressive
piece of work. all vinyl, no digital playback...

didn't get to chat about it - serious sound
pressure at work - good thing i like dub & roots.

not high fidelity though - difficult room to
play in too - hope to hear the rig in an outdoor
setting soon. (system lives out at one of
auckland's black sand beaches.)

still room for a super clean valve top end
i reckon....

regards,

adam

[adam_ecofan]

hi all,

finally got to play some records over the altecs.
had been playing through laptop til now - hooray!

can see why full eq useful for a show - rig in
double garage - very clear sound for some
distance around the building.

good records jump out, have to throttle back the
rougher ones. scale, dynamics all there - craving
triodes on the tops though....

looking into laminating solid timber for horns -
more experienced woodworking friend quite keen,

anyhow, pictures to come over on the
audio heritage thread,

cheers,

a