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Old 16th May 2012, 05:56 PM   #581
PASC is offline PASC  Brazil
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Hi Xco1!
If a magazine like Voice Coil April 2010, pages 19 till 21, Mr John Croft puts his thoughts about born of tapped horn clearly, imagine we can judge it ourselves also, can we?
http://img6.uploadhouse.com/fileuplo...7d7bf885aa.png
http://img2.uploadhouse.com/fileuplo...bc73b7e818.png
see patent 2,765,864:
Patent Fetcher - Patent Fetcher PDF Processing
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Old 16th May 2012, 07:10 PM   #582
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Quote:
Originally Posted by Djim View Post
In my (many) attempts to improve the notorious Jbell SS15 I first mentioned it, more than a year ago, with a drawing concept that includes very similar folding style. Since than I have mentioned it in several posts and Art was the only one asking me specific questions about it, half a year ago.

IF* any ethical line is passed, it is not the inclusion of Cone Volume Correction or folding techniques that are both the result of physics and old horn techniques but it is designing tapped horns in the first place.
Djim,

The "V" load is not just about "Cone Volume Correction", the stub formed on the horn throat side is important, as is the strength of the "V" shape.

Although Tom Danley privately shared the TH-115 plan design using the "V" load with me, it was already quite visible to all in pictures of the DSL TH-812.

This is one of the areas that Hornresp probably underestimates significance of a seemingly minor volume change in location.

That said, I was unaware of the potential of the “V” load when I undertook the design of the Keystone sub, and came up with another idea that seems to work quite well, as evidenced by low distortion, good frequency response, and little power compression at levels well above the AES rating of the BC18SW115-4 used in the design.

Like Thomas Edison experienced, there were many failures in the Keystone prototype process before determining what works well, good design is 10% inspiration, and 90% perspiration.

I wish I’d read the many patents from the 1950s describing in detail what we now identify as “Tapped Horns” when I had started building speaker cabinets back in the 1970s.

When I think of all the 400 pound quad loaded bass cabinets we lugged around for decades that could be replaced by a 150 pound sub using a single driver, makes me appreciate the wealth of information now at our fingertips if we only bother to use it.

Art Welter
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Old 17th May 2012, 06:38 AM   #583
rpa is offline rpa  Germany
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Quote:
Originally Posted by weltersys View Post
I wish I’d read the many patents from the 1950s describing in detail what we now identify as “Tapped Horns” when I had started building speaker cabinets back in the 1970s.

When I think of all the 400 pound quad loaded bass cabinets we lugged around for decades that could be replaced by a 150 pound sub using a single driver, makes me appreciate the wealth of information now at our fingertips if we only bother to use it.

Art Welter
were 70s era drivers up to the task to be tap loaded? i keep reading that mxax/xmech advancements facilitated the possibilities.
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Old 17th May 2012, 04:38 PM   #584
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Quote:
Originally Posted by rpa View Post
were 70s era drivers up to the task to be tap loaded? i keep reading that mxax/xmech advancements facilitated the possibilities.
There are a number of drivers from the 70s and before that work fine in the right TH.
There are drivers that can put out far more level now due to increased Xmax.

Xmax determines SPL output in any type of enclosure.

A TH can allow about 6 dB more output from the same speaker at the same excursion over a BR, assuming the cone is stiff enough to take the additional stress of horn loading. Many drivers that sim well in a TH ultimately can't put out much more output in a TH compared to BR because of cone deformation at high throat pressure.

Obviously, a 3mm Xmax speaker will have far less output potential than an 18mm Xmax speaker, but a 6 dB gain is a big deal no matter what the available Xmax is.

That said, in the days of 3mm Xmax (or less) woofers, the available amp power was a small fraction of what is available cheaply today, the potential to push the speakers beyond their limits was far less.

Art
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Old 17th May 2012, 06:16 PM   #585
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Quote:
Originally Posted by NEO Dan View Post
Actually now that I think about it your suggestion of a ring would make the most sense as it will displace the least volume and allow for the longer path length. I would make it a optional add in for the test cabinet.
Sounds like you are thinking of implementing just one ring (with or without the V-shape?). Where are you thinking of putting the one ring?
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Old 17th May 2012, 06:51 PM   #586
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by weltersys View Post
The "V" load is not just about "Cone Volume Correction",
Hi Art,
Did I make such claim?
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Old 17th May 2012, 07:08 PM   #587
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Quote:
Originally Posted by Djim View Post
Cone correction cannot be used above an S-shaped throat and the V correction makes the difference between the sides even worse... Just a small reminder, other drivers in the Danley TH18 didn't seem to have a long life time

(Edit: we tested V-shape cone corrections only in the symmetric folding lay-outs that don't have a S2 issue...)
I think he might just be referring to these (and a couple other) mentions where "V-shape" and "cone correction" were in the same sentence..
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Old 17th May 2012, 07:22 PM   #588
PASC is offline PASC  Brazil
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Hi!
Correct author's name on post #581 should be James Croft.
Forgot to mention patent nr.3,047,090:
Patent Fetcher - Patent Fetcher PDF Processing

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Old 17th May 2012, 07:23 PM   #589
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by CRESCENDO View Post
I think he might just be referring to these (and a couple other) mentions where "V-shape" and "cone correction" were in the same sentence..
Thanks Justin, I guess I'll have to be more specific next time and use the words 'Danley's V-method' and 'V-shape cone volume correction'

Last edited by Djim; 17th May 2012 at 07:28 PM.
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Old 17th May 2012, 08:26 PM   #590
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Makin progress. Just bein held up by this small lip on the caster board. I'll either have to wait til I get to a table saw again to rip the board a little better or get a few squares of 80 grit for my palm sander Gonna go check if I can manage with my circular saw in a bit.
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