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I made a pair of Voigt pipes and

I was using them with a pair of Fostex Sigma 208s. The sound was fast, but a tad lean. I later found out that the Voigt cabinets themselves, because of their narrow fronts, tend to eliminate some lower frequency extension of any fullrange driver used. This was something I found out while writing back and forth with TWL, another member who has a Voigt pipe with Lowther EX-3 or 4 drivers. He found a way of remediating this.

Before you go to his thread, I think I understand why the speaker and its narrow front baffle eliminated some lower frequency. If you think of the fullrange driver as the beginning of a ripple, in order for it to expand exponentially, you will need a large area. Think the image of a pond. Nevertheless, because the Voigt pipes are narrow, as the sound waves propagate, their ripples tend to become cut off, expecially towards the sides of the cabinet, I think this is what causes the loss of lower frequencies.

Tom Lyons, AKA:TWL, came out with an ingenious solution. He added "wings" to the sides of his cabinets, if the front was 12", he added 12" wings to each side, that are hinged with some piano hinges. They can be in a plane with the front baffle or angled backwards, depending of the effect that was needed. For what it seems to be, his system must sound glorious.

I myself, cannibalized the Voigt pipes and have placed the Fostex in a folded horn cabinet, a Zhorn that Tom Zuworsky made for me...because I wanted some lows. On top of that, I added a powered subwoofer for even a more pronounced lower end.

I am happy with the sound I get now.

The Voigt pipes, with the winged mods should not be hard to make. It took me about a day to get the pieces cut. You need some room to manouver the sides and the front...if you have the space and one helper, I think you can make them for about $450, with ply and drivers included. They do sound dynamic, better than a 3.5 K commercial pair of speakers that I still have around.

PS: With the winged mods, I am sure that the Voigts will sound explosive by themselves.
bemopti123
bemopti123 OP
303 posts
 
Sean, was that your website or someone else's? It was very nicely done. What I would like to see are some specific diagrams for easy making of the main speaker enclosure. I have been also attracted to the Jordan drivers, mainly because of the cost, but their sensitivity is mediocre and might need more than some SET amp can provide, beyond horn territory. Nevertheless, I am interested to see what the enclosure construction entails.

PAUL
sean
6,231 posts
 
Shirasagi: I do what i can and am glad that this helped your understanding a bit. As i've mentioned before, if you really want to learn, you've got to do it yourself. I'd be glad to recommend some books if you're really interested. Personal experimentation with stuff like this also helps : )

Bemopti: I had nothing to do with that website. I know just enough about computers to annoy the hell out of you folks, let alone try to figure out how to put up a website like that. I simply reposted the same link that Viggen had provided, but did so in "clickable" form. I agree that it was a nice site / good "find" on Viggen's part and wanted to encourage others to visit it to see what we were talking about here. Viggen's "legwork" provided some great visualization aids to this thread.

With that in mind, this specific set looks beautiful. Don't know how well they work, but they look nice : )

Why not try emailing the guy that has the website? With all of the work that he's put into this project, i'm sure that he'd like to hear from someone that finds it interesting.

One thing that i would add is that you can use lightweight materials to form the wings ( easier to bend / conform to shape ) and then damp / brace them as needed. Starting off with something thin and easy to work with and then applying layers of other materials once you've achieved the shapes that you want would probably provide the easiest and least resonant path possible.

Believe it or not, "paneling" can be great for something like this. It is both cheap and easily bent. On top of that, if you can get the type with staggered width vertical lines cut into it, this can help break up standing waves along the surface of the baffle / wing. This can smooth the response even further. Sean
>

PS... The longer that you make the "wings", the more effective they are at lower frequencies. Shorter "wings" work best at higher frequencies and would be best suited for upper midrange and tweeter arrays.
bemopti123 OP
303 posts
 
Sean, regardless, the website is very well done. Just wish that it had some specific plans and measurements for the main cabinet. The wings, I am able to get the concept upright now.

PAUL
cdc
1,773 posts
 
Sean, I think you're ready for the big time. I vote to kick out Sam Tellig and have "Sean's Space" instead.
I would think adding wings would make a speaker sound more boxy. Maybe I'm wrong and have a lot of conflicting listening experiences but the Revel F30, with a wide front baffle, sounded very boxy. B&W Nautilus doesn't but maybe that's due to the curved cabinet as much as the narrow front baffle.
But then again Audio Physic Virgo's are so hung up on a narrow front baffle they are willing to put the woofers on the side which seems like a very BAD idea to me. Maybe it's for looks more than sound?
DynAudio Contour (?) 2-way monitors sounded incredibly boxy IMO. OTOH I had Ascend Acoustics CBM-170 which has a wide front baffle and I just could not hear any (or any significant) difference between them and my "tweeter on top" Nautilus 804. But then again, the Nautilus is nice because the tweeter on top makes a smaller cabinet which looks nicer and resonates less.
The most interesting demonstration of reducing boxiness was at the Paradigm dealer. He went up the line from Atoms to Titus (?) etc and each notch up the sound became more open and spacious. Despite the Atoms being the smallest speaker of the bunch.
Then again B&W claims the "drivers hung in space" design is the ultimate design. What Hi-Fi? said the floorstanding B&W CDM-7 came closest to the sound of their CDM-1 standmount than any other mfg'r floorstander vs. standmount. They said they added range way more than compensated for the slight resonance from the larger cabinet and that it was very rare for a floorstanding speaker to be able to do this. Something to do with cabinet design they said.
A local dealer actually had a speaker guy from CA stop by with his 3 way consisting of drivers mounted in those white plastic tubes you can get from Home Depot. The tubes were located but some type of wire framework. I guess they sounded really good. But $5,000 for 3 drivers and some plastic tubing? Whoa, I don't think so.
So if you want to approach a confusing issue, at least to me, what makes a speaker sound boxy? I don't think the baffle width or cabinet size has the effect that some mfg'rs like Audio Physic would lead us to believe.
gregm
3,405 posts
 
Cdc sez:
what makes a speaker sound boxy
Usually a resonant peak @ 250-300Hz. The wood resonates giving a "honky" hue to the sound.

Virgo- I respectfully disagree that putting the woof on the side is that bad an idea. What Joacheim is doing is keeping the front baffle narrow (to help imaging) and, for low frequencies that CANNOT be easily located by our ears (i.e. there's no imaging), he uses the side baffle that is WIDER, placing the woof close to the floor (i.e. reducing baffle-step loss AND hoping for some floor boost).

Whether we like the result, is another matter:), but it makes sense!
Cheers
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