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Old 4th April 2007, 06:15 AM   #141
49 - for the 18th time - again!
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Just a little progress update.
Second speaker has had what I call the Mamboni Magic applied and is awaiting BudP's EnABL pattern. BudP and I have been working on developing a process by which to apply his pattern with a stencil and we have the pattern sized pretty well for the Pioneer 10 inch speaker that Mamboni specks in earlier post. Now to get the silkscreen stencil produced and tested - should be in the next day or two - providing that it is successful we will be able to show those interested what all is involved.

I still trying to get my MDF carved up for the speaker end caps and center brace. I thought that I would be able to rent a plunge router but have not had any luck finding a rental unit - or any buddies that have one either. Might wind up bitting the bullet and making a purchase - that will blow the budget - sigh

Only took an hour to apply the Mamboni Magic to the second speaker! Much less time than the first - getting over the learning curve is great!

Considering a future in consulting, speaking engagements, and how to do it DVD's - - Ok maybe for a soda.

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Old 4th April 2007, 07:49 AM   #142
BudP is offline BudP  United States
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ultrakaz,

Well, I have the same goals as Lynn, Romy the Cat, Island Pink, the moderators of this forum, you and very many others involved in DIY audio. I want a performance in my living room that satisfies my musical needs. I am used to extreme detail, correct depth of field, jubilant dynamic color as added by the musicians, a natural micro dynamic coherence and it's resultant stage setting for the musical event.

At the moment I am working on developing an amp and preamp of pretty simple circuit design and outstanding usefulness in developing audio transformers. The speakers have not changed in five years, except that I remounted the Linnaeum tweeters down on the speaker box and a recent trial addition of a Pioneer half can super tweeter, that may stay and may not.

I have recently discovered a method that allows me to uncover the back half of the musical notes, with the sort of clarity that the front half exhibits. This has added a depth of note decay and a coherence to chord structures in orchestras and piano's that I have not quite gotten used to yet.

Mostly I am just working towards a time when I have no further complaints with the equipment and I can explore the music I have collected, without constantly being distracted by my correlator warnings going off about this or that uncategorized and potentially dangerous noise.

I have to warn you, the speakers are not impressive looking. They were originally designed and built as workhorses, to allow me to audition the R&D from my transformer explorations. Just as the user adjustable dynamic color, true Litz wire, cables were invented, so I could listen for faults without having to worry about spurious cable colorations or loss of information content.

My contributions to this forum are meant to be a stepping stone for other people to use, so they might feel confident enough to explore and enjoy what this odd EnABL pattern brings to the reproduction of music, which is all I really care about

Bud
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Old 5th April 2007, 04:05 AM   #143
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Hi Bud,

Thanks for sharing your thoughts. I agree that we all do share a similar final goal. How to get there is something I've been attempting for the last 23+ years. And needless to say, I would certainly welcome a time where I don't have to worry about the sound of my equiptment.

I'm going to try the Manboni Walsh speaker with a pair of 15" Altecs. My crude experiment suggests that it is worthwhile to pursue. And I will use the Enabl treatment on the cone; Manboni on the inside and Enable on the outside (facing outward).

Where might I learn more about your litz wires and your method of uncovering the "back half of musical notes"?
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Old 5th April 2007, 06:37 AM   #144
BudP is offline BudP  United States
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ultrkaz,

Email me about the wires. Email c2cthomas about the Mamboni / EnABL treatment details.

The back half of the notes comes from having a method of preserving micro dynamic detail, the E Field portion of that detail, which becomes B Field. I do it by providing low threshold, dielectric dipole attached, sheet oriented electrons, on the ground plane. You can do this with poured ground planes and guite a lot of PCB varnish, or some huge stranded wires, 8 gauge or more and a measured amount of dielectric material both surrounding the wires and melted into them. You might even be able to use low threshold voltage Teflon, audio bipolar capacitors shorted to ground on both ends. What ever method you use will entail providing ground plane storage for an abundance of electrons so they do not return to service ground or further.

The research I have done on dielectrics in transformers, audio cables and now ground planes has shown me that while we have a very excellent handle on signal side electron manipulation we really have ignored the manipulation of the ground side signal of our equipment. I do have a solution, it is easy to apply, but it is very much applied voodoo physics.... more or less like the EnABL process is.... makes perfect sense after you understand how it works and why you might need it.

So, email me and we can talk about your interests.

Bud
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Old 5th April 2007, 09:00 PM   #145
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Hi Guys,

This is a fascinating thread!

Im in the process of designing an omnidirectional speaker myself. It is sort of a meld between what Duevel has done with their concave cone diffusers and the BeoLab 5. Below is a pdf of the current plan. Im about 90 complete with building a prototype for design testing. There is a thread about it over at HT guide forum, here, if you want to read more. Mentor2 Omni Thread

Essentially it is a 3way comprised of all up or downfiring drivers, two 8 woofers (RS225 metal cones), which fire at each other, but are separated by a diffuser, an upfiring 2 metal dome (RS52) which uses a modified PE 8 waveguide and fires into a concave cone diffuser, like the Duevels use. Housed in this diffuser is an upfiring soft dome neo tweeter (Dayton ND20FB), in a modified 6.5 MCM waveguide, firing up into a 7-1/2 dia. concave cone diffuser. Also attached is a photo of the incomplete test system. I have done a quite a lot of measurements to try and determine the right drivers, right diffuser types, diffuser heights, etc. The attached graph is a preliminary plot of the 3 drivers outputs with the waveguides and diffusers intact.

Im not trying to hijack this thread. Im posting for a couple reasons. One, there is clearly some serious interest in omnidirectional speakers amongst you all. Second, Im thinking that the Mamboni felt-BudP Enable-or Olsen modified Mamboni felt treatment might be of use in my design. What do you all think?

I was thinking that it would most surely help the woofers to do one or several of these treatments, but possibly all the drivers. Also, it might be helpful to treat the front side of both waveguides. It might also be helpful to treat the bottom side of the concave diffusers. Any thoughts?

Finally, it occurs to me that perhaps my tweeter implementation, using the waveguide/concave cone diffuser might be of interest to you all in your omni efforts, since it might allow you to continue the omni sound through the entire FR of the speaker, rather than switching over to directional for the tweeter.

Id be happy to provide any measurements I can (I use SoundEasy, but Im relatively new to it) and do some experimenting with the various processes you are working on/providing before and after measurements, etc.

BTW, have you all thought about adhesive backed felt? They sell it at many hardware stores or you can buy better stuff at McMaster-Carr online? This would seem to be a quicker way to install the felt treatments at lest ofr testing and yet let them remain removable if the experiment needs to be altered.

Also, we used to use adhesive backed printed sheets at work. They are of a pretty thick mylar-like material and might work as templates for the enable process. Also there are clear acetate that you can print on that could be cut into a template. I also wonder if there would be a non-permanent enable product that might be used. For example, take a bunch of the enable rectangles, print them on the adhesive mylar, cut them out and stick them on individually or in pairs if that was ok. They would be easy for anyone to make and fully removable, though that adhesive is very aggressive.

Just some food for thought. Id like to hear any of your thoughts on how the ideas you guys are testing might work with my omni application, etc.

Thanks!

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Click the image to open in full size.
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Old 5th April 2007, 09:06 PM   #146
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Whoops, I forgot to post the responce graph I mentioned above.

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Old 5th April 2007, 10:53 PM   #147
BudP is offline BudP  United States
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dineubec,

Pretty neat stuff. I have had thoughts on this sort of speaker for years but knew better than to attempt so much precision wood work.

The EnABL process will work on all of the drivers and all of the surfaces but will be quite an undertaking to do. I would recommend that you finish first. Then begin to categorize what you do not find satisfactory in the actual audible performance. My method here is to start with the fundamentals first, up to 1 k or so and listen for inaccuracies in the left hand of piano's and all bowed and plucked strings larger than a violin. I will often deliberately reduce very low frequency performance at first just to help clarify what is actually going on.

What I listen for is a garble of tones, at any particular frequency. Once I am familiar with what I am hearing I add a higher frequency driver and listen to how it modifies what I am familiar with. This sort of listening teaches me what is incorrect in only one driver and what is a multi driver problem.

Were these my speakers I would use a Vifa 3" mid in place of the metal dome and phase screen. The EnABL process can not control "systemic" resonances, those caused by materials and physical obstructions used in driver construction. I think it likely that you will find a garble from that mid dome that is directly related to the material used and treating with EnABL will only make it more pronounced, because everything else will work better around that frequency band..

Does not mean that you should change your plans, you may have already worked around what ever difficulties this particular driver exhibits, and they all exhibit many problems.

The EnABL process will ease the transition off of the round to square baffle and likely can control those surfaces and force them into phase and time coherency. The tweeter would work well with the process but you will have to disassemble it and treat the backside of the dome also. Neither of the dome drivers can be treated with other than a pen and guide pattern process, at least from my experience.

I will post any other thoughts I have on your thread.

Bud
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Old 6th April 2007, 12:17 AM   #148
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Hi Bud,

Thanks for the feedback!

Do you have some specific recordings that you use for your piano and string listening session?

Are you talking about eh 3" Vifa Dome? I looked at it, but was concerned about what looked to be very quick off axis roll off. It looks like the new version might be better, but I could not find a performance graph on it. Since we are essentially listening 90 off axis with an up firing driver, there tends to be a very quick roll off with many drivers that severely reduces the range you can use it in. The concave cone diffuser helps, but it is good to start with a driver that has very good off axis performance to start with. I hear you on the phase screen, however. I wish it was removable. I can always go back and try the Vifa, if the RS52 is not satisfactory. However, it has gotten very good testing reviews, for example here:http://206.13.113.199/ncdiyaudio/mar..._test_data.htm
and here:http://www.zaphaudio.com/smalltest/


I'm not clear on your thoughts about the EnAble use with the wave guides? Do you think it would help? If so, how would it be applied? Also, what about on the concave cone diffusers? I know there will be diffraction issues that will result from those round wave guides and diffusers and thought maybe the EnAble pattern would be an option help attenuate them.
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Old 6th April 2007, 03:55 AM   #149
49 - for the 18th time - again!
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Construction update:

Well yesterday I bit the bullet and purchased a plunge router - and seeing how I thought it unwise to sit on my butt and spin in order to cut circles I also purchased a circle cutting jig. Other item purchased included a respirator rated for toxic dust and fumes, safety goggles that would fit over my glasses, a disposable dust suit, router bits, and some lumber and braces to make a work stand out of. About the only thing I had on hand were some general carpentry tools and ear plugs.

So I banged together a work stand and placed it on a tarp outside in the fresh air where the breeze would blow the light dust away from me and after reading the instruction manuals (yeah, I read those things), I got to it and routed up some MDF and plywood.

Good thing I measured the inside diameter of the SonoTube before I started because the 14 inch stuff that I'm using measures more like 14.75 inches ID. Guess I'm going to have a little more bass than I expected!

Cold day outside today - still 45f at noon so I got a late start. Will finish cutting things up tomorrow and then it's on to putting things together!
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Old 6th April 2007, 04:56 AM   #150
R. Jamm is offline R. Jamm  United States
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c2cthomas,

BudP posted to contact you for the Mamboni / EnABL treatment details. Do you have a workable process (that anyone can do) of putting EnAbl on the pioneer woofer?

What type of treatment (paint or veneer or) are you going to do with the sonotube?

R. Jamm
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