TH-18 Flat to 35hz! (Xoc1's design) - Page 58 - diyAudio
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Old 16th May 2012, 02:37 AM   #571
NEO Dan is offline NEO Dan  United States
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I see what you have now, that makes better sense.

Well if there is going to be a flat centered over the driver as proposed here:
Click the image to open in full size.
If the V cut out for "cone control" seems unappealing and or you feel the need to deviate a bit to separate the DIY from the commercial design - why not make use of the scrap from the driver cutout and make a loading disc centered on the driver? I think it could potentially be the method to produce the most even load on the cone.?
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Old 16th May 2012, 03:37 AM   #572
Djim is offline Djim  Netherlands
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You are suggesting this ?

Quote:
Originally Posted by Djim View Post
An example of a simple cone correction made out disks cut from sheets:

Click the image to open in full size.


To make it fit for the 6-Fold you need to cut out a piece:

Click the image to open in full size.

You can cut out rings instead of full disks to save weight...
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Old 16th May 2012, 03:42 AM   #573
NEO Dan is offline NEO Dan  United States
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Quote:
Originally Posted by Djim View Post
You are suggesting this ?
Probably a single flat disc as the cone correction is now incorporated into the horns path and the more layers you add the more path length you have to give up.

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.
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Last edited by NEO Dan; 16th May 2012 at 03:53 AM.
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Old 16th May 2012, 04:05 AM   #574
Djim is offline Djim  Netherlands
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Or make a nice pyramid with difficult angles to prevent loosing the volume by the ring overlaps, lol... plenty of options
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Old 16th May 2012, 12:44 PM   #575
Xoc1 is offline Xoc1  United Kingdom
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Quote:
Originally Posted by weltersys View Post
The sketch is closer to "almost exactly" than "something like" the DSL TH-115.
Loose some of those volume robbing corner ramps you are so fond of and it would be even closer .

Art
Art
When I started this design process I had no idea of Tom Danleys designs apart from the information that Mr Danley had made freely available.
The size envelope was used as as given the performance of the DSL TH115 / 118 enclosures this is obviously big enough to work well.
The folding was purely based on JBells SS15 and DIYaudio based work on horn geometry.
As the user builds have shown although the design works well enough up to a limit of say 1.6KW the speaker is lacking in ultimate control at elevated power levels that the best drivers are capable of.
Though the course of development and discussion of the tapped horns on DIYaudio we eventally stumbled across a horn throat, which as you described it contains Mr Danley's 'Secret Sauce'.
Well the cats out the bag and theres no way of putting it back!
The layout of the Danley TH115 /118 is I guess exactly as you have described.
Question is what am i supposed to do?
I could just post an updated clone layout without any technical explanation.
I could just drop the whole project.
Or I could try to take onboard the advances on TH design that we have discovered, and try to present them in a valid and techinical manner so that we can try to learn something from them.
I am very hesitant about this, but I think that if we can make sense of the process of improving the horn throat then that technique can be used in other TH variants.
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Old 16th May 2012, 01:15 PM   #576
jbell is offline jbell  United States
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Quote:
Originally Posted by Xoc1 View Post
Art
When I started this design process I had no idea of Tom Danleys designs apart from the information that Mr Danley had made freely available.
The size envelope was used as as given the performance of the DSL TH115 / 118 enclosures this is obviously big enough to work well.
The folding was purely based on JBells SS15 and DIYaudio based work on horn geometry.
As the user builds have shown although the design works well enough up to a limit of say 1.6KW the speaker is lacking in ultimate control at elevated power levels that the best drivers are capable of.
Though the course of development and discussion of the tapped horns on DIYaudio we eventally stumbled across a horn throat, which as you described it contains Mr Danley's 'Secret Sauce'.
Well the cats out the bag and theres no way of putting it back!
The layout of the Danley TH115 /118 is I guess exactly as you have described.
Question is what am i supposed to do?
I could just post an updated clone layout without any technical explanation.
I could just drop the whole project.
Or I could try to take onboard the advances on TH design that we have discovered, and try to present them in a valid and techinical manner so that we can try to learn something from them.
I am very hesitant about this, but I think that if we can make sense of the process of improving the horn throat then that technique can be used in other TH variants.
Regards
Xoc1 (Martin)
My 2c on this.

I have never seen nor heard a danley sub. Art's got a leg up on me there. I am very respectful of IP and don't want to in any way infringe on Tom's work. To that end, I don't think I'd like an exact copy of anyone else's work... I would like it to always be my own. I like what NeoDan has shown a couple posts up. I think I can accomplish that within the single sheet design limitation that I placed on myself for the SS15. However, true 'cone correction' that DJIM and others are working on -- if that is truly the final bit of secret sauce... I think I'd prefer to leave it secret. If I can get a bit more low by having a slightly longer path, and a little bit better cone control by having a slightly better throat -- that sounds good to me...

I applaud the efforts and learning on this, but I don't have to have, or want... "exact."
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Old 16th May 2012, 03:19 PM   #577
Djim is offline Djim  Netherlands
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Cone Volume Correction can restore part of the low end in some situations where the low end in an actual build seems to be less compared to its theoretical HornResp model. It is nothing new and is used since the beginning of horn design. Therefore it is not Danley exclusive. 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.

That the Xoc1-TH18 becomes more and more a look-Danley-alike is not strange at all. Physics and building limitation force you to use it in the panel facing the driver. That means not many options are left, besides making it more complex than necessary. Using it as part of the folding is therefore nothing more than logic.

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.

(* = everybody should answer that question for himself since I am not here to judge anyone, but Danley didn't seem to have a problem with sharing all information and has been correcting people in the DIY community with additional info)

Last edited by Djim; 16th May 2012 at 03:44 PM.
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Old 16th May 2012, 03:42 PM   #578
Mark Kravchenko --- www.kravchenko-audio.com
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Design done independently is still your design. There is no patent on the fold geometry. Your independent work is documented on this thread. What do you have to worry about?

Second point is that the tapped horn concept is not an invention of Tom Danley. It has been popularized by his work with them.
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Old 16th May 2012, 04:22 PM   #579
epa is offline epa  Netherlands
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agreed with mark above.
imo there are no secrets in th's.
there are just some clever option's.

everthing here is "invented"here ,build on the knowledge of the diy community.
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Old 16th May 2012, 05:13 PM   #580
jbell is offline jbell  United States
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Thanks for the confirmation guys... I appreciate it. I also work in the software industry where protection of IP is not just the thing.. it's almost the only thing. That makes me extremely sensitive to it.

Clean Room Engineering is always safe, blatant reverse engineering or copying is not. (having clues from Art on how close to "exact" is kinda a grey area though... and is currently my personal issue on what I do with that information....)

I don't personally feel like to this point I have crossed any IP boundaries with my designs.
I have always made sure to do my own work, my own testing, and at the end of the day, I know I have something that is truly mine. As a benefit to those that freely share with me, I share in return.

I've tried circular, triangular, and S shaped openings in front of the driver, with various effects. Are any of these new? no.. Is a particular application of them in a TH style cabinet infringing? no. Knowing a production detail from someone else's work, and trying to replicate it... hmmm.. This would be an easier conversation for me without Art's comment.

so, I don't see any issue with pursuing this line of thinking, building, and testing. I just think that those with personal knowledge of protected designs, should be very careful about providing too much detail... so that everyone can feel comfortable knowing they are doing their own work....
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