I've planning to commence my first speaker building project for some time now, I was going to follow Fred's Voigt pipe design for the foxtex FE166e. http://fredt300b.smugmug.com/gallery/147575
I've got the drivers already.
But due to Wife Acceptablity factors I've got to have a less intrusive profile for it to remain in the house after I've built it. So how to I go about modifying the design so it is a folded Voigt pipe instead?
I've got the drivers already.
But due to Wife Acceptablity factors I've got to have a less intrusive profile for it to remain in the house after I've built it. So how to I go about modifying the design so it is a folded Voigt pipe instead?
Well, you can fold it. I wouldn't bother though: don't even think about using the FE166E in a TL is my advice. And avoid the 'traditional' Voigt pipe (created by the Lowther Club of Norway in what I can only assume was a moment of madness) like the plague. This is not a good driver / cabinet combination for a number of reasons. Have a look here for more information on this cabinet:
http://www.geocities.com/rbrines1/Pages/Voigt_Pipe.html
The cabinet coming to a point is not a good thing generally -you get a horrible and severe ripple effect. And the FE166E, with its low Q and naturally rising response thanks to the Lowther-like power of its magnet is going to need a high level of correction to bring it into line. Only Terry Cain has managed to combine a TQWT with the FE166E well to my knowledge, and the exact internal dimensions of his Abby are understandably kept quite close to his chest, it being a commercial product.
My suggestion: you obviously want a TL type enclosure, which is fair enough, but of a size and shape closer to a traditional floor-standing speaker, yes? OK, that's easy. Firstly, forget the FE166E, and go for its sister driver, the FE167E, which is much more suitable to resonant enclosures, and will need far less correction. You could build the folded version of Martin King's superb Project 2 ML TQWT from the plans Bob has put on his site here: http://www.geocities.com/rbrines1/Pages/Proposals.html I have built 3 pairs so far of the original, unfolded type, and they are superb. The folded version Bob has drawn should perform pretty much as well as Martin's originals.
Alternatively, splash out and spend $25 on a set of the plans Bob sells for his FT1600MK2, which is even better, and well worth the little money he asks for: Bob is the master of refining designs. You'll get a series of superbly detialed diagrams, cutting plans, and all the help you could ever need. http://www.geocities.com/rbrines1/Pages/FT-1600_MkII/Main.html
Either way, you'll get a much better speaker at the end of it, and one which will outperform most anything at twice or 3 times the price. In some ways such as transparency, they're pretty much as good as anything available, regardless of cost. Good luck
Regards
Scott
http://www.geocities.com/rbrines1/Pages/Voigt_Pipe.html
The cabinet coming to a point is not a good thing generally -you get a horrible and severe ripple effect. And the FE166E, with its low Q and naturally rising response thanks to the Lowther-like power of its magnet is going to need a high level of correction to bring it into line. Only Terry Cain has managed to combine a TQWT with the FE166E well to my knowledge, and the exact internal dimensions of his Abby are understandably kept quite close to his chest, it being a commercial product.
My suggestion: you obviously want a TL type enclosure, which is fair enough, but of a size and shape closer to a traditional floor-standing speaker, yes? OK, that's easy. Firstly, forget the FE166E, and go for its sister driver, the FE167E, which is much more suitable to resonant enclosures, and will need far less correction. You could build the folded version of Martin King's superb Project 2 ML TQWT from the plans Bob has put on his site here: http://www.geocities.com/rbrines1/Pages/Proposals.html I have built 3 pairs so far of the original, unfolded type, and they are superb. The folded version Bob has drawn should perform pretty much as well as Martin's originals.
Alternatively, splash out and spend $25 on a set of the plans Bob sells for his FT1600MK2, which is even better, and well worth the little money he asks for: Bob is the master of refining designs. You'll get a series of superbly detialed diagrams, cutting plans, and all the help you could ever need. http://www.geocities.com/rbrines1/Pages/FT-1600_MkII/Main.html
Either way, you'll get a much better speaker at the end of it, and one which will outperform most anything at twice or 3 times the price. In some ways such as transparency, they're pretty much as good as anything available, regardless of cost. Good luck
Regards
Scott
Another Terry Cain 166e pipe. I think the FE166 needs a big enclosure to work in a pipe. You might be able to get it to work in places more suited to an FE167 with some series resistance to raise its q.
Folding it you keep the relative position of the driver from the pipe end and total pipe length and taper similar, probably turning it upside down to do so. You end up with a smaller bafffle and driver near its top instead of in its middle, Im not sure how much effect this has.
Folding it you keep the relative position of the driver from the pipe end and total pipe length and taper similar, probably turning it upside down to do so. You end up with a smaller bafffle and driver near its top instead of in its middle, Im not sure how much effect this has.
None, frequency response will be unaffected by a single fold, so long as the basic parameters are not changed. Like Bob, I personally wouldn't use any of the FE**6E series drivers in a resonant enclosure: they're for horns really. The FE**7E series need less correction to bring them into line, and the less correction needed the better in my view. They also generally produce better bass in these enclosures.
I know Terry's Bigger Is Better box well; it measures better than it simulates, but while we're on the subject, I'd make a few changes to make the most of the geometry. My version on the theme: Fostex FF165K (Okay, okay, a low Q driver, but we all have an exception to our rules, yes?!?). So=0.25Sd (one of the few occasions I'd use an area of less than Sd -it doesn't affect the predicted response), Sm=5Sd. 128" pipe length. Driver mounted at 28% of line length. 0.4 lbs to cubic foot of stuffing above the driver and a layer on the base. Mass load it rather than leaving the top completely open. A 2"x2" circular port will do the job. I leave the width and depth of the cabinet open to taste. They give an interesting response: flat from 25Hz to 100Hz, a sudden 6db lift at 100Hz, then pretty much flat again until the drivers roll off. Adding some series resistance (about 4ohms) will probably help there, along with a basic BSC circuit. With that, they should thunder.
I know Terry's Bigger Is Better box well; it measures better than it simulates, but while we're on the subject, I'd make a few changes to make the most of the geometry. My version on the theme: Fostex FF165K (Okay, okay, a low Q driver, but we all have an exception to our rules, yes?!?). So=0.25Sd (one of the few occasions I'd use an area of less than Sd -it doesn't affect the predicted response), Sm=5Sd. 128" pipe length. Driver mounted at 28% of line length. 0.4 lbs to cubic foot of stuffing above the driver and a layer on the base. Mass load it rather than leaving the top completely open. A 2"x2" circular port will do the job. I leave the width and depth of the cabinet open to taste. They give an interesting response: flat from 25Hz to 100Hz, a sudden 6db lift at 100Hz, then pretty much flat again until the drivers roll off. Adding some series resistance (about 4ohms) will probably help there, along with a basic BSC circuit. With that, they should thunder.
Thanks for the replies guys.
So am I out of luck with these FE166e I've already purchased? I would attempt the fostex design given with the speakers, but I think my woodworking skills would let me down. Or is it not as hard as it looks to get it all square? Or are there any more simple horn designs around that I could attempt? The problem with the profile is only it's height so going wider or deeper wouldn't be so much of a problem.
So am I out of luck with these FE166e I've already purchased? I would attempt the fostex design given with the speakers, but I think my woodworking skills would let me down. Or is it not as hard as it looks to get it all square? Or are there any more simple horn designs around that I could attempt? The problem with the profile is only it's height so going wider or deeper wouldn't be so much of a problem.
zBuff said:
No, just consider it a learning experience. OK, that doesn't help; so I'll do my best now!
A wad of series resistance to artificially raise the Qes will help; and you'll just need to use some hefty BSC to bring them into line. On the up side, the big magnet will give fractionally more detail, but you'll have a higher F3 than if you used a higher Q driver. I would advise giving the Fostex horn a whirl: it suits these drivers well, and it's not overly large / tall. You could also try to downscale the Jerico horn for the 166 -it might work, I don't know, but could be worth a shot.
Jericho horn, I wonder if they derived that name from the biblical namesake, looks like it would be harder to make than the fostex design, well at least getting the angle right. Well it looks at this stage I might just have to give the Fostex horn a go, I was just hoping there was an easier to construct alternative.
Height I guess anything under 1.4 metres would be fine.
GM it's funny everytime I read your "Greets" as "Greeks", makes me feel like eating a souvlaki
Height I guess anything under 1.4 metres would be fine.
GM it's funny everytime I read your "Greets" as "Greeks", makes me feel like eating a souvlaki
zBuff said:Height I guess anything under 1.4 metres would be fine.
GM it's funny everytime I read your "Greets" as "Greeks", makes me feel like eating a souvlaki
Greeks!
A simple straight ML-TL with series R = DCR (Vs the FE167E's ~3 ohms in the same cab) yields an aneochoically T/S max flat ~35 Hz F3 using published specs and has the benefit of being a 'faster'/better damped driver in the critical mids/HF than the FE167E. Of course LF output will be modest unless there's some room gain, but that's true of the FE167E also.
L = 53"
CSA = 103.68"^2 (recommend ~8.00" d. x 12.96" w.)
zdriver = 18"
zport = 40"
rport = 2"
Lport = 2"
density = ~0.4 lbs/ft^3 down to just below the driver
GM
Seems I've just got the go ahead from the wife to build a larger speaker on the condition that it does not exist in the bedroom or main living areas, so I decided to pounce on this ASAP and build a pair of BiBs quickly before she changes her mind
Scott you've made the BiBs using the FE166e before, the dimensions you used of 16 1/2" in depth and a height of 64", would you recommend them? How thick should the panels be? And is there a port? I can't seem to see one in any of the pictures or diagrams around on the net.
Scott you've made the BiBs using the FE166e before, the dimensions you used of 16 1/2" in depth and a height of 64", would you recommend them? How thick should the panels be? And is there a port? I can't seem to see one in any of the pictures or diagrams around on the net.
Welcome to the club.
As it happens, if I was going to rebuild these pipes for the FE166E, I'd actually go back to the original cabinet dimensions, but using 3/4" material rather than 1" -that'll give the driver a little more breathing room, but not too much -those I built worked fine, but were probably better suited to different drivers -I've learned a lot over the past few weeks, and from the new pair I've built.
So, you'll end up with a box, built from 3/4" material, with external dimensions of 7"x14"x70" (WxDxH). Driver mounted 39" from the base. Start the sloping internal baffle 1/2" an inch down from the top of the internal wall of the front baffle. It ends 5 7/8" from the base and 5 7/8" from the internal front and rear walls. The top is completely open. Stuff to taste -start with lightly stuffing the point above the driver, and a 1" layer on the base, and work from there to suit your room, drivers and listening preferences. These cabinets need to be pushed right up against a rear wall to work; slammed into corners is even better.
A few thoughts / comments. Make sure the drivers cross about 1 - 3 feet in front of your head. Don't even think about adding a circular baffle like Terry's, unless you're as good as Terry with a lathe, and can make two with identical, constantly radiused profiles. Use at least 18AWG magnet wire as internal and speaker cable, 24AWG even better. And give the drivers a good hammering before making any changes -100 hours minimum. A thin layer of 2mm cork on the front face of the sloping internal baffle I found helped too, but mine were constructed from MDF, which wasn't ideal. These cabinets are very room dependant, and at present, difficult to simulate. I haven't heard of anyone who's been disapointed yet though.
However, don't dismiss the cabinet GM suggested -as you expect considering the source, that's a good one! A very good one actually. If you don't like the BIB boxes, or find they don't work well in your room, that's definately the one to try.
Hope some of this helps
Scott
As it happens, if I was going to rebuild these pipes for the FE166E, I'd actually go back to the original cabinet dimensions, but using 3/4" material rather than 1" -that'll give the driver a little more breathing room, but not too much -those I built worked fine, but were probably better suited to different drivers -I've learned a lot over the past few weeks, and from the new pair I've built.
So, you'll end up with a box, built from 3/4" material, with external dimensions of 7"x14"x70" (WxDxH). Driver mounted 39" from the base. Start the sloping internal baffle 1/2" an inch down from the top of the internal wall of the front baffle. It ends 5 7/8" from the base and 5 7/8" from the internal front and rear walls. The top is completely open. Stuff to taste -start with lightly stuffing the point above the driver, and a 1" layer on the base, and work from there to suit your room, drivers and listening preferences. These cabinets need to be pushed right up against a rear wall to work; slammed into corners is even better.
A few thoughts / comments. Make sure the drivers cross about 1 - 3 feet in front of your head. Don't even think about adding a circular baffle like Terry's, unless you're as good as Terry with a lathe, and can make two with identical, constantly radiused profiles. Use at least 18AWG magnet wire as internal and speaker cable, 24AWG even better. And give the drivers a good hammering before making any changes -100 hours minimum. A thin layer of 2mm cork on the front face of the sloping internal baffle I found helped too, but mine were constructed from MDF, which wasn't ideal. These cabinets are very room dependant, and at present, difficult to simulate. I haven't heard of anyone who's been disapointed yet though.
However, don't dismiss the cabinet GM suggested -as you expect considering the source, that's a good one! A very good one actually. If you don't like the BIB boxes, or find they don't work well in your room, that's definately the one to try.
Hope some of this helps
Scott
GM said:
Greeks!
A simple straight ML-TL with series R = DCR (Vs the FE167E's ~3 ohms in the same cab) yields an aneochoically T/S max flat ~35 Hz F3 using published specs and has the benefit of being a 'faster'/better damped driver in the critical mids/HF than the FE167E. Of course LF output will be modest unless there's some room gain, but that's true of the FE167E also.
L = 53"
CSA = 103.68"^2 (recommend ~8.00" d. x 12.96" w.)
zdriver = 18"
zport = 40"
rport = 2"
Lport = 2"
density = ~0.4 lbs/ft^3 down to just below the driver
GM
Sorry for my ignorance.
Is this box for 166, or for 167?
FE167E is drop-in replacement for FE164 in Martin King's Project 2. The whitepaper has a couple alternate cabinet shapes, including a folded version. If I were building it I'd probably build the version in fig 5, purely visual aesthetic. For one, I prefer the wooden vent rather than plastic circular.a_men said:Thank you very much
What box should I do for 167?
I'll be thankful for dimensions.
I think about ML TL of course
http://www.quarter-wave.com/
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