Hopefully I'll get chance to hear a pair at some point, but I do know the drivers & the general type of load, & I know the LS3/5a well. I'd put money on the Fonkens flattening them. LS3/5a = one of the most over-rated speakers in the world. They're good for what they are, but nor are they as good as mythology suggests.
Port Dims on these confuse me.
I'm blowing the dust of this one here. I've just scanned it from the begining and I don't belive I've found out what I was looking for.
Here's what I'm after. I am looking into making a folded Metronome (monilth) ,inspired by Dave's Milvena, for a bi-polar set of Pio A11s. After reading the Met. artical, It seemed that you take the 1/4 wavelength of the Fs for the line length. Then you Multiply the Sd by 4 (8 for bi-pole) for So(?) and since I'm doing a monilith, zero out the closed end. I think that's right. I've attached a pdf of what I think is right.
Now where I get confused is how you calc the port area and length. As of yet, I do not have access to Martin's spreadsheets so I do all this on my own. Other than some vague Bigger=less damping and smaller=more, I haven't heard anything on how these are figured out. Is there an equation? They don't seem to be tuned like traditional BR ports so what's going on?
If I'm missing something completely obvious. Feel free to smack me in the head with a slide rule.
P.S. I pulled the port in my drawing from the fe127 Met. doubled the area as it seemed the most likely candidate.
I'm blowing the dust of this one here. I've just scanned it from the begining and I don't belive I've found out what I was looking for.
Here's what I'm after. I am looking into making a folded Metronome (monilth) ,inspired by Dave's Milvena, for a bi-polar set of Pio A11s. After reading the Met. artical, It seemed that you take the 1/4 wavelength of the Fs for the line length. Then you Multiply the Sd by 4 (8 for bi-pole) for So(?) and since I'm doing a monilith, zero out the closed end. I think that's right. I've attached a pdf of what I think is right.
Now where I get confused is how you calc the port area and length. As of yet, I do not have access to Martin's spreadsheets so I do all this on my own. Other than some vague Bigger=less damping and smaller=more, I haven't heard anything on how these are figured out. Is there an equation? They don't seem to be tuned like traditional BR ports so what's going on?
If I'm missing something completely obvious. Feel free to smack me in the head with a slide rule.
P.S. I pulled the port in my drawing from the fe127 Met. doubled the area as it seemed the most likely candidate.
Re: Port Dims on these confuse me.
No. That is not how you do it. Somewhere i outlined the procedure for turning a Met into a Monolith... but (the short version) you start by modeling an appropriate ML-TQWT in MJK. Fold it so that the driver is at the top, then you ignore the "top" which opens up the space that leads to a point.
The length needs to be longer than 1/4 Fs because it is a TQWT and the Sd plays no role at all in the design (except for the somewhat general & coincidental relation of Sd to Vas)
dave
gurley123 said:
No. That is not how you do it. Somewhere i outlined the procedure for turning a Met into a Monolith... but (the short version) you start by modeling an appropriate ML-TQWT in MJK. Fold it so that the driver is at the top, then you ignore the "top" which opens up the space that leads to a point.
The length needs to be longer than 1/4 Fs because it is a TQWT and the Sd plays no role at all in the design (except for the somewhat general & coincidental relation of Sd to Vas)
dave
Ok, so delussions of grandure on my part then.
So without MathCad and the MJK sheets I'm stuck? I'm guessing the math for figuring the length, volume and taper are pretty involved and might just cause an aneurysm in the untrained like me.
The problem is that I don't have the jack to layout for Mathcad right now.(a quick search showed the cheapest versions going for $129.00) Plus it would be hard to justify that purchase to the wife.
Are there any simplified equations that could get me in the ballpark?
So without MathCad and the MJK sheets I'm stuck? I'm guessing the math for figuring the length, volume and taper are pretty involved and might just cause an aneurysm in the untrained like me.
The problem is that I don't have the jack to layout for Mathcad right now.(a quick search showed the cheapest versions going for $129.00) Plus it would be hard to justify that purchase to the wife.
Are there any simplified equations that could get me in the ballpark?
No.
But you don't have to buy a copy of MathCAD, unless you want to save files. Martin links to the free MathCAD explorer on this page his site: http://www.quarter-wave.com/Models/MathCad_Models.html
But you don't have to buy a copy of MathCAD, unless you want to save files. Martin links to the free MathCAD explorer on this page his site: http://www.quarter-wave.com/Models/MathCad_Models.html
I have no problems with giving Martin his dues. That's only right and proper.
I had forgotten about the MathCad explorer. Since I forget many things I thought the full version was the one for me
I'll get Martin his money and see if I can't figure this out before my BUFu's arrive.
Thanks guy's.
I had forgotten about the MathCad explorer. Since I forget many things I thought the full version was the one for me
I'll get Martin his money and see if I can't figure this out before my BUFu's arrive.
Thanks guy's.
Hi Gurley123, nice drawing. If you don't mind my asking, what's your thinking in tackling this?
Have you sort of have ruled out simpler cabinet designs for a 4" bipole? Are you on a quest for more bass, perhaps? Or do you find the allure of horns and folding an exciting and seductive intellectual pursuit? I love bipoles and horns (though personally, I'm going back to very simple builds right now), and I'm just asking out of curiosity.
Have you sort of have ruled out simpler cabinet designs for a 4" bipole? Are you on a quest for more bass, perhaps? Or do you find the allure of horns and folding an exciting and seductive intellectual pursuit? I love bipoles and horns (though personally, I'm going back to very simple builds right now), and I'm just asking out of curiosity.
Attachments
Thanks rjbond3rd
I have a simple BR bipole for these. I was just dorking around and looking to make a floorstander. Plus I really like folding those long lines.
I have two pairs of these drivers right now. The idea is to have a Bipole cab where I can modify the drivers on one side and leave the other side stock to evaluate the changes.
Slotted port huh? Can it come out the bottom? I want to keep the symmetry of it so I can just turn it around and have the output the same.
I have a simple BR bipole for these. I was just dorking around and looking to make a floorstander. Plus I really like folding those long lines.
I have two pairs of these drivers right now. The idea is to have a Bipole cab where I can modify the drivers on one side and leave the other side stock to evaluate the changes.
Slotted port huh? Can it come out the bottom? I want to keep the symmetry of it so I can just turn it around and have the output the same.
gurley123 said:
You can download MathCad Explorer from my site. If you follow the instructions under "How to License the Worksheets" on the Upgraded MathCad Computer Models page you can download and install the MathCad Explorer program and then run a sample worksheet to make sure it works on your PC and experiment with editing the worksheets.
Hi Guys
I've just received a pair of well broken in Fostex FE207E with phase plugs.
After having read last year about Bill's success at the Burning Amp Festival with the 64 inch high cabinets, housing his Hemp 8 inch drivers, I have been wanting to build a bigger pair.
I'll post a few pics as the build progresses.
Steve
I've just received a pair of well broken in Fostex FE207E with phase plugs.
After having read last year about Bill's success at the Burning Amp Festival with the 64 inch high cabinets, housing his Hemp 8 inch drivers, I have been wanting to build a bigger pair.
I'll post a few pics as the build progresses.
Steve