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Old 4th November 2013, 08:21 PM   #561
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Quote:
Originally Posted by noSmoking View Post
Thanks for the comments ,I have some reading to do don't I!
Has anyone built anything like these,Like a diy layout? Pictures?Drawings.
Thanks,
NS
So far, no one (to my knowledge) has made a column similar to the SBH-10 using coax drivers and various height Paralines.

There are plenty of drawings of how to lay out Paralines, making a cabinet similar to the SBH-10 would not be any more difficult than making the Paraline PA I built.
That said, it would be a hell of a lot more work and expense than I'd want to put in to a relatively low output 160 x 10 degree column speaker .
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Old 4th November 2013, 08:34 PM   #562
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Quote:
Originally Posted by noSmoking View Post
Thanks for the comments ,I have some reading to do don't I!
Has anyone built anything like these,Like a diy layout? Pictures?Drawings.
Thanks,
NS
This is close, but doesn't use coaxes:

Click the image to open in full size.
Square Pegs
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Old 4th November 2013, 09:24 PM   #563
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Does SBH10 want for a variant with virtual center at the top?
Since we note that power spreads with length of the slot.
More for the back of the room, less for up close.
Assuming these things are above ear level...
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Old 4th November 2013, 09:37 PM   #564
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Hi Patrick,

thank for for your response. Unfortunately, it did not answer my question. The referenced Synergy patent recites in relevant part, p. 9, line 30 - p. 10, line 5 (emphasis supplied):

Quote:
As used herein, the term "local expansion rate" refers to the distance it takes for a small but readily measurable increase in area of the acoustic passageway (e.g. doubling of the acoustic passageway crosss sectional area), starting at a point where the driver is tapped into the hom. Thus, the term "local expansion" bears reference to a small portion of the acoustic passageway as opposed to a reference to the expansion throughout the overall length of the horn.
O.K. so the definition of local expansion rate is a distance over which the area increases by a constant, e.g., 2. Despite this rather peculiar definition, I can construct a plot of distance as a function of, e.g., constant increase of an area. This will happen every time that the difference between the distances is square root of the constant for a square-sided conical horn. So what?

However, given this definition of expansion rate, that you appear to have accepted by sending me to re-read the patent, I am still unsure, how to translate it to your presentation as frequency as a function of distance?

You tried to explain it in the following:
Quote:
The reason you can calculate the flare rate at any point along the throat is that a Unity or Synergy horn is basically a horn feeding a horn feeding a horn. Picture each segment as an independent horn that's stacked together.

So that's how you calculate the local flare rate. (Hornresp helps a lot - and JLH has documented how to do that in this thread.)
Could you please re-phrase your explanation, because I am not sure how I am supposed to calculate the flare rate, which according to you is the Synergy definition of "distance it takes for a small but readily measurable increase in area of the acoustic passageway (e.g. doubling of the acoustic passageway cross sectional area)" at every point (i.e., distance) as you wrote.

And no, I am not prepared to use Hornresponse, without understanding what I, and the Hornresponse, are doing.

Kindest regards,

M

Last edited by mefistofelez; 4th November 2013 at 09:41 PM.
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Old 4th November 2013, 09:56 PM   #565
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Now the devil is into the details
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Old 4th November 2013, 10:11 PM   #566
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front closure of the paraline is definately not expanding...
You could vary depth to maintain expansion, but you do
not want a wide exit slot, so you have to put up with it
being flawed...

A virtual curved front does help blend out the abrupt
change of flare (from none to whatever angle the face
is shaped to cover). The line array presents reflected
acoustic power back through the paraline to drivers,
all at same distance. The synergy array presents that
reflection at a multitude of distances, so better hidden
I would think?

The parabolic reflector is at a multitude of distances
even in the line array case, so no great problem there.
The reflection and transition from radial wave expansion
to plane wave non-expanding on journey to the merger.

I don't know if the cone sees radial expansion as the
compression driver would. since the cone surface
is uniformly distributed within the expansion, is that
section really expanding from the cone's perspective?
or not?

Last edited by kenpeter; 4th November 2013 at 10:21 PM.
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Old 4th November 2013, 11:05 PM   #567
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Quote:
Originally Posted by kenpeter View Post
I don't know if the cone sees radial expansion as the compression driver would. since the cone surface is uniformly distributed within the expansion, is that
section really expanding from the cone's perspective?
or not?
Assuming a 20mm wide Paraline exit in the SBH10, and an average of around 190mm height for each driver, each exit averages 3800 square millimeters, the cone area (Sd) is 7500 square millimeters.
The HF driver sees an expansion in area, the cone almost a 2/1 reduction in area at the Paraline exit.

The Paraline works for the HF end of the spectrum, the lower end is working pretty much like any 5 foot cone driver line array does.
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Old 4th November 2013, 11:39 PM   #568
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Here's a dopey idea... for continuous expansion...

Suppose you make the return to center in two layers instead of one.
Each layer cut like a comb of flat trumpets. But the layers would be
staggered such that: Paraline reflectors would be continuously open
to the throats of at least one layer of flat trumpets or the other...

Keep it simple, it could be flat triangular trumpets... The mouth still
limits how much expansion is possible, but it could at least be made
to continuously expand. I don't know if that makes much difference.

Last edited by kenpeter; 4th November 2013 at 11:45 PM.
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Old 5th November 2013, 11:20 AM   #569
JLH is online now JLH  United States
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To calculate the local area of expansion (the local flare rate) you look at the distance over which it takes to double the cross section area of the horn. Let’s say our mids tap into the horn where the area of the horn is 30cm^2. We then look to see how far down the horn it takes for the horn to expand to 60cm^2. For our example let’s use 6cm. Use Horn Response and enter 30 for S1. Enter 60 for S2, and 6 for L12. Hit “E” on your keyboard while you have the L12 field highlighted. This will make the horn contour Exponential. The flare rate will be displayed in the F12 field. In our example this should equal 316Hz.
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Old 5th November 2013, 06:00 PM   #570
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Hi JLH,

thank you for the response. My English must be really poor, since it appears that I could not get my question across.

I do understand how you and Patrick Bateman are using Hornresponse to calculate the "local area of expansion (the local flare rate)" as you describe it.

However, I was trying to understand the concept of local flare rate a the application thereof to the driver loading. I have derived a relationship based on my assumption of what the Synergy patent is trying to disclose, but the resulting curves when overlaid on Patrick Bateman's curves, purportedly derived by your method from Hornresponse, did not agree. Hence my question regarding the underlying concept, to enable me to check my work.

However, yesterday I discovered Tom Danley's "A White Paper on Danley Sound Labs Tapped Horn and Synergy Horn Technologies", wherein Fig. 4 illustrates "Approximate driver loading of SH-50 based on where along the horn the driver is located". When I entered the parameters of SH-50, a square conical horn with 50 deg included angle, to my formula, and overlaid the resulting curve on Fig. 4, I have a match.

Based on the foregoing, I will now proceed under the false assumption that my understanding is correct. ;-)

Kindest regards,

M

Last edited by mefistofelez; 5th November 2013 at 06:09 PM.
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