Modded Voigt Anyone?

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Been scouring the internet looking for a relatively inexpensive but nice FR speaker project. I've built a set of the Audax HT speakers but want a high efficiency set strictly for listening pleasure. The plan is to use them with a Thorens TT, and Bottlehead tube components.

The consensus seems to be that Fostex drivers are a good economical entry point. I've been specifically looking at the 206's or 207's. I was intruiged with some of the project built around the 103's since cabinet size and style will be important for the WAIF factor. Doesn't look like you can get the 103's anymore (unless it's on eBay).

Right now I'm leaning towards the Singular probably with the FE 206's and the correction circuit. However, I do love the shape of those Voigt Pipes. Anyone have any feedback concerning these as opposed to the Singular? Would the Voigt be suitable for the 206's or 07's? And finally, what kind of negative impact would reshaping the design have (assuming the internal dimensions remained)? I was thinking that it would be nice to construct the Voigts but instead of making them so linear, add a gentle curve to the front baffle and possibly the back. Just a gentle, gradual curve backward. Also the internal dimensions would be the same, would this have an effect on the internal sound waves and their behavior? What would be the best method to research this aside from actually building them?

Thanks.
 
Have a look at this: http://www.diyaudio.com/forums/showthread.php?s=&threadid=71330&highlight=

They really aren't big enough to do the job properly, but the ported version will offer better performance. Not quite as efficient, but you'll get a better response. I'll have a quick check & get back to you.

As for the curves, I'm not sure. I'm not sold on the use of them, as LF don't appear to care much one way or the other, but I doubt it'd hurt.

Cheers
Scott
 
I built these for a friend, using FE206's and I really liked them. They required around 4 ohms of series resistance when paired with a SS amp...a SE tube amp will need less. The same design would work with the FE207 and no series R.

I now have the same drivers in Ron's Dallas II horn, which I like better, but is harder to build and weigh 140lb per side.
 

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Thank you for the reply. I was beginning to think that my idea had gone over like a lead balloon. My thought was to give the Voigt a more organic shape which could end up being fairly nice if done correctly.

Since I'm on the subject what are general feelings about the Voigt pipes? I don't see too much mention of them. Would I be better off with the Buschhorns? I'm also considering those since that seems to be a popular box design. My only question with the Buschhorns is that all seemed to be built for Fostex drivers no longer in production.

I'll take a look at the link and thanks again.
 
It depends what you call a Voigt Pipe.

The generic shape / cabinet style, where the sealed end is narrow and the open end (or end with an opening in) is wide is simply a Tapered Quarter Wave Tube (TQWT). See Jeremy's picture, or Martin King's Project 2 ML TQWT which remains my all time favourite budget ported enclosure, TL or otherwise.

The specific cabinet I believe you're refering to, the Lowther Club of Norway 'Voigt Pipe' is a loathsome contrivance in unmodified form. Not because it comes to a point at the top, which is the most common objection, but because a) it really doesn't have enough cabinet volume for the drivers it's allegedly designed for, and b) it's vent size is far too large. You can make it work by reducing the vent size as I suggested in the thread linked above. It'll reduce efficiency by a few db, but flatten the response out, and also give you an extra 20Hz LF extension. Not ideal, but it's much better than standard.

Would you be better off with a Buschorn? Depends on your priorities. The smallest version of the MK2 works with the FE83E, the larger with the FE103E, FE108ESigma, and also apparantly the FE126E with minor modifications. They have a great reputation for the midrange and top end, though they obviously have limitations in the low-frequency range.

Me, I'd take the middle approach, go for the 6 1/2in FE167E and use in Martin's Project 2 ML TQWT cabinet, particularly given that you like the appearence of the TQWT. (The 167 is a drop-in replacement for the the FE164 originally used, and if anything works a bit better). I've built 3 pairs, 2 of which were, er, borrowed by musician friends who refused to give them back. Solid performance from 40Hz-20KHz.

Best
Scott
 
Yes. As I say, I've built 3 pairs, the last of which (Mine! All mine!) is playing June Tabour as I type. First 2 had the FE167E, which simulate better in this enclosure than the original 164 did. The currect pair have the FF165K, a driver I happen to love. Only change needed to the cabinet is a reduction in port diameter to 2in from the original 3in. Gives a bit more bass, and a smoother, deeper mid. I like non-whizzer full / wide-rangers. There are other drivers that work too with minor vent modifications. As I say, the most versatile enclosure I have ever run across.

Best
Scott
 
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