How to design a folded Voigt Pipe???

Depends on the drive units. Some are suitable, some are not. It's 'Voigt' BTW. ;)

Theory here, with alignment tables (assuming an Fb = Fs tuning) and Excel based calculator to go with it: Transmission Line Theory

Hornrsp is the most popular easily available modelling software at present for QW designs. By and large, a folded pipe is no different to an unfolded in design terms. It just happens to be folded. There can be some subtle differences but for your purposes unlikely to affect matters.
Not really, it's better than nothing, but not by much, whereas MJK's Classic TL design routine is the 'real deal'. IIRC it use to be online at your linked site, but for whatever reason it was left out of the all new site.


edit: That said, this will calculate a real Voigt pipe, i.e. a [tapered] TL with no separate vent, though of course one can be added to tune it lower if desired [ML-TQWT] whereas your link is a horn tapered ML-TQWT [aka ML-horn], so either make a Voigt pipe tuned to Fs or one tuned up around 1.4-1.56x Fs and vent to whatever works best overall in room.
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I read through a lot of that material on the Transmission Line Theory link but quickly got lost in the sauce. I also searched for MJKs calculator to no avail.

There there a difference as to the amount of bass boost a Voigt Pipe gives and a Transmission Line gives?


Joined 2003
The links are at the bottom of the web page Scott linked to.

There is no MJK calculator per se, it's a WORD? doc with tables to manually work through it a step at a time to get a design and later on a member created an Excel WS to fill in the
blanks. It's been so long since it came out I can't remember if you actually need the Tables to use it and don't have Office loaded to check.

Traditionally; a TL speaker [damped 1/4 WL pipe] is basically a ~ IB response in a smaller bulk whereas the ML-horn is usually a short parabolic flared BLH to 'pump up' [3-6 dB] the mid bass to somewhat offset baffle step loss and vented to 'stretch' it a bit to a rolled off to whatever tuning bends best overall in room.

How much dB boost will depend on the driver's specs, how big the cab, vent.

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OK Scott, I input all the required data but don't know what to do with it. I don't know how turn this into a cabinet. Any Help.


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Is there a similar simplified spreadsheet for designing a mass loaded Voigt? I understand that the method is to tune the tapered Voigt tube/pipe up to about 1.1-1.2 times Fs and then use the port (line restriction) for final tuning, but what tool can I use to tune the port? Will a simple bass reflex port tuning tool such as WinISD work?
OK Scott, I input all the required data but don't know what to do with it. I don't know how turn this into a cabinet. Any Help.

I've been playing with it, too. To get a true Voigt, you are going to need to change that taper to something much greater. I have used the spreadsheet to reverse engineer a known ML Voigt design and the taper factor is 6.75, for example.

Once you get your taper factor in there, it'll tell you the surface area of the closed and open ends of the pipe, and the length. The actual dimensions you choose will be up to you, but you need to get as close to the open area and closed area as possible.

Good luck folding it, though!!!
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Ok, after reading all I can find on the subject and realizing that I have sheets of MDF and a real good brad Nailer I'll build 1 folded voigt pipe from the link in the 3rd post, 1 transmission line, and 1 vented cabinet and start testing. More to follow.
I don't know what Mass Loaded means. I appreciate any help you can help with. I'm using full range field coil 10" drivers. The below chart shows how the T/S changes with different voltages.


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No, you don't need the tables; you just put in the driver details & desired taper ratio & it calculates the physical & acoustical lengths, throat & terminus areas using the formulas in Martin's alignment tables (assumes an Fp = Fs tuning & a uniform of 0.5lbs ft^3 stuffing density of dacron).

Thanks! Input the basics into HR and use its Wizard to add damping, pass band filters and modify to 'taste' if desired using its real time sliders.