Well, I finally got my laptop working and used the fantastic designs offered by Brian Steele and others to create what is probably a slightly insane idea of my own. It sacrifices a little bit of efficiency to offer a little more infrasound extension from the other designs, but should be fun to build! I humbly offer it to be dissected by the brilliant minds in this group. For what it's worth, I am already aware that the in-room response will not exactly follow the sim response and, yes, I am aware that the woofers magnet will require some sort of cutout to the wall behind it. The woofer in question is the same Dayton (Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm) I discussed before. Also, I apologize for the rough pencil drawing... I ain't got one of them, thar, fancy CAD thingys right now...🙁 Anyhow, enjoy!
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Hi bigdaddyrox4574,
Have a look at the T/S Parameters for the Dayton Audio RSS390HO-4 Driver.
Tapped Horn
b🙂
Have a look at the T/S Parameters for the Dayton Audio RSS390HO-4 Driver.
Tapped Horn
b🙂
Hmmmm... I copied them directly from the spec sheet, but I gather I must have missed something if you're bringing it up. I will take a look!
Never 'Buy' the Advertised Parameters(In prior befor use: Cross-Calculate all Parameter Numbers) from any Driver Manufacturer Company as they are almost always suffer from Rounding off Errors* and if a ZR Graph is attached it should be conforming with the given T/S Parameters too as the Semi-Parameters are important if Le is Large.
*Advantage for Sales and Number Eye-Candy for any Layman that will inscribe the T/S without hesitate.
b🙂
Not to worry; I will be hooking it up to my Woofer Tester and re-running the sim before I begin the build. 🙂
Based on gut feeling I think there are large losses due to the large amount of folds. Would it be possible to fold it in a different way, with less folds?
The pipe sections will be 15.5x4.25 inches. As far as the number of folds, I pretty much have to do it this way for the sake of SAF, but losses are a concern. If I use sections of paper tubing in the corners, might it help??
P.S., what I have is heavy, 4 inch diameter tubing that I can cut into 4ths to go into the corners.
Not really, it's the aspect ratio's friction in the corners, which in general is limited to 3:1 in heat/AC ducts. A huge flare at the terminus will help though.
GM
GM
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Gotcha. Hmmm. I guess I will try to play around a little more and see if I can maintain that same, tall, slender look the wife is requesting without having so many bends. If not, hopefully I can regain some of the losses with a bit of EQ. We shall see!
I came up with a refolding of my original idea. If I count right, it will reduce the bends by about half, simplify the build overall and maintain the same basic size and shape. The only odd thing is that I will be venting the terminus out of the sides of the box. Oh yeah... and I will have a little more fun figuring out how to deal with the magnet... 
I attached a rough sketch of the new idea that I drew in Paint as well as the original pencil drawing for the sake of comparison.
I attached a rough sketch of the new idea that I drew in Paint as well as the original pencil drawing for the sake of comparison.Attachments
Nah. I'll make it work. It just takes a little creative woodworking and I am more than up the task. I'm actually looking forward to the challenge! I was only banging my head on the wall as I tried to figure it out at that moment...
OK, but it doesn't take a significant percentage of obstruction to ruin a pipe's harmonic response.
GM
GM
Which is why I was banging my head 😉 I need to extract the woofer from it's current home and make some measurements to determine exactly how I will handle that little issue, but I know it can be done. I might even do something like the attached image, if need be. If done right, it will add a little interest to the front of this monolithic object!
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Another thing, I am sortof in a position where I MUST use a driver I already own if I am even to attempt a thing like this... it is what it is...
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