Hello to all. Having built several rather sophisticated horn-loaded systems, I've recently heard the Voigt Pipe speakers. Yes, I saw that video, too. And now my hands are itching again. And this time, you guessed it right - I would like to build the Voigt Pipe. In order to overcome the inherent weakness of full-range speakers when it comes to very dynamic passages, I decided to add a tweeter instead of relying on the wizzer. Initially, I was going to use the Tang Band W8 1808. But then I thought to myself, If I'm not using the wizzer cone why not use a comparable driver without one? So, here's the questio: what 8" driver would come the closest to the venerable Tang Band W8 1808 but without the wizzer cone?
If it iss the video i am thinking of, and you heard them and like them, imagine how you would like the same drive rin a properly designed ML- Voigt (a Voigt really nned sthe mass -loading to help tame the ripple.
dave
Anything with a similar spec., as far as maintaining a roughly similar alignment goes. Scan's 22W-8534G00 comes to mind. As Dave says though -it's not an especially well optimised design. If you want a proper Voigt style [single] tapped horn, a well-designed BIB is usually a better bet. If you like the general triangular aesthetic of the classical LCON Voigt pipe (and why not -I quite like it too), which the one in question basically is, you'd be better off with one designed & optimised to your requirements. That video is -not great. Some valid stuff, don't get me wrong, and I try to keep Thumper's Mother's advice firmly in mind, but I've done partial breakdowns of it in the past, and there are issues with it too.
One of those cases where you have to know more than he does, tomtese out what he says that is valid and what is not.
dave
Yes, properly designed. As I said, I would like to use a separate tweeter and I would like to build a folded pipe.
For fairly generic folded ML-Voigt check out the damped duct variations.
We did a couple similar (FE108e∑, FF105wk, FF165wk) and indepentently) they basically look like this. This foldeing gets the driver at teh top of the box.
Beware adding a tweeter to a FR, it is hard to do right.
dave
We did a couple similar (FE108e∑, FF105wk, FF165wk) and indepentently) they basically look like this. This foldeing gets the driver at teh top of the box.
Beware adding a tweeter to a FR, it is hard to do right.
dave
B200 is a very nice driver (once its glaring issues are largely tamed with phase plugs http://www.planet10-hifi.com/downloads/B200-phase-plug.pdf), but it is not really suitable for a box of any sort except a huge aperioidc box.
dave
dave
the vent looks awfully small...with that small vent alone and without the proper mouth, wouldn't it make the speaker just another reflex? I like the idea of extending the pipe by adding one more fold at the bottom…
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This is the box for a 4” driver with an xMax of 0.28mm. The van tis sufficient for the application.
The image was to give you an idea of the shape, folding, and mass-loading.
A reflex assumes uniforn particle velocity — did i get that right GM ? — the length of the line generates a quarter wavelength resonance. The Voigt takes advantage of that to get more use ou tof the back-wave at LF. A reflex has one resonance (and perhaps some HF artifacts), a quarter wave resonator has a series of them and the only one we are interested in is the lowest frequency. The taper in a Voigt crowds these closer to the desired harmonic making them more difficualt to kill. The mass-loading/restricted terminus creates a LP filter that can significantly suppress the harmonics. Note that the driver offset in the pipe is set at a very specific percent of the pipe length to laregly suppress the most obnoxious one. These 2 LP filters in the geometry means one can get away with less fill or lining and maximize th ebas syou can get. Also makes them more easily tuneable.
I don’t want to watch th video again, but i am pretty sure hw used “classic” techniques to design the box. ie a little bit better than a guess.
dave
T/S max flat alignment:
Vented net volume (Vb) (L) = 20*102*0.823'^3.3 = 1072.63 L
(Ft^3 = (Vb)/~28.31685) = 37.88 ft^3 = large even by my 'generous' standards!
Vented box tuning (Fb) (Hz) = 0.42*40*0.823'^-0.96 = 20.26 Hz
F3 (Hz) = 40*0.28*0.823'^-1.4 = 14.71 Hz
(Qts'): (Qts) + any added series resistance (Rs) 0.5 ohm = 0.823 Qts'
Vented net volume (Vb) (L) = 20*102*0.823'^3.3 = 1072.63 L
(Ft^3 = (Vb)/~28.31685) = 37.88 ft^3 = large even by my 'generous' standards!
Vented box tuning (Fb) (Hz) = 0.42*40*0.823'^-0.96 = 20.26 Hz
F3 (Hz) = 40*0.28*0.823'^-1.4 = 14.71 Hz
(Qts'): (Qts) + any added series resistance (Rs) 0.5 ohm = 0.823 Qts'
Actually..........
Using the pioneer's Vb = Vas/1.44, Fb = Fs yields a modest 70.83 L/2.5 ft^3 w/4" dia. x 5.43" vent damped to QL = 1 sims a normally inaudible ~ +2 dB rise/2 pi Vs mid-band, though could be damped more if room modes accentuated it, though of course doesn't go low @ -6 dB/40 Hz.
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I'm not Greg, but partly. A reflex / Helmholtz vented assumes a uniform air particle density and no Eigenmodes / standing waves. A QW pipe of any kind stretches one dimension relative to the others to deliberately generate and use standing waves as an (or the) primary mode of resonance. So in answer to the OP's question -no it doesn't make it a reflex box, because it doesn't use Helmholtz (cavity) resonance as its primary box loading.
From building large (20 - 30 ft^3) cabs for high Qt, Vas tuned to Fs systems there is a gray area where the aspect ratio can be high, but net Vb apparently swamps it to the point where I couldn't tell any difference from calc'd vented, but these were very large reflex (baffle thickness) vents, so an exception to the rule?
Yeah, it's about the only one I know of anyway. The longitudinal will still be there, but with so much Vb it's going to be a crapshoot whether you'll get much damping around Fb from it, especially if Qt is on the high side. In their smaller way the pensils lean a bit this way too, but then, their Vb is usually based on pre-Novak / Altec BR calculations, with the vertical being set as a proportion / ratio of Fb & nominal damping adapted from Augspurger.
