I am beginning construction on a pair of Voigt Pipes using the Herbert Jeschke dimensions at http://melhuish.org/audio/DIYTQ4.html with the driver mounted on the vertical front surface. I am trying to decide if it would benefit this design to mount the drivers on circular baffles as in the Cain & Cain Abby and other designs, or just mounted on the pipe itself. Also got to wondering if the baffle would be better if made from solid wood or good plywood. Thanks for any input.
If I understand the theory correctly, the circular false baffle you find on a lot of Voigt Pipes a back horns is supposed to help with the baffle step loss and general defraction signature. I'll have to admit that to date, I haven't done any testings, but I think:
1. The diameter of the circular false baffle isn't big enough to make much difference in the baffle step, particularly when compared with the vertical dimension of the baffle.
2. Full-range drivers tend to beam significantly at high frequencies, and at the frequencies important to edge defraction, not much energy reaches the edge of the cabinet anyway.
3. The circular false baffle does ad mass to the driver frame and stiffness to the baffle. These are good things.
Once spring gets here and I can do some decent testing, I expect to verify my suspicions.
Bob
Brines Acoustics
1. The diameter of the circular false baffle isn't big enough to make much difference in the baffle step, particularly when compared with the vertical dimension of the baffle.
2. Full-range drivers tend to beam significantly at high frequencies, and at the frequencies important to edge defraction, not much energy reaches the edge of the cabinet anyway.
3. The circular false baffle does ad mass to the driver frame and stiffness to the baffle. These are good things.
Once spring gets here and I can do some decent testing, I expect to verify my suspicions.
Bob
Brines Acoustics
Decware FE206 drivers
I have ordered a pair of the modified Fostex FE206 drivers from Decware. I already have 3/4" maple plywood cut for the front pieces and the sides. I was tempted to use them for awhile first without any circular baffle, and then add the baffles later and compare the sound. I was just thinking if it is conventional wisdom that the baffles would help, why not just put them on to begin with.
I have ordered a pair of the modified Fostex FE206 drivers from Decware. I already have 3/4" maple plywood cut for the front pieces and the sides. I was tempted to use them for awhile first without any circular baffle, and then add the baffles later and compare the sound. I was just thinking if it is conventional wisdom that the baffles would help, why not just put them on to begin with.
Nice website, Bob
You have a very interesting website Bob, especially relevant considering my project. I saw you mentioned you reduced the port height to 2" and increased the port width to 8.75", so this would have been the entire interior width of 8.75". Thats a lot smaller than the original design but looks closer to the port on the C&C Abby. For the throat width you found 1/4" to be optimum, by throat width you mean the distance between the vertical front piece and the angled back piece, which were separted by a small horizontal top piece? Thanks,
Jim B
You have a very interesting website Bob, especially relevant considering my project. I saw you mentioned you reduced the port height to 2" and increased the port width to 8.75", so this would have been the entire interior width of 8.75". Thats a lot smaller than the original design but looks closer to the port on the C&C Abby. For the throat width you found 1/4" to be optimum, by throat width you mean the distance between the vertical front piece and the angled back piece, which were separted by a small horizontal top piece? Thanks,
Jim B
Decware FE206 drivers
Bob, I ordered the modified Fostex FE206E drivers from the Decware site at http://www.decware.com/newsite/mainmenu.htm
They designate them as FE206E-M. They list the spexs as QTS 0.23
38 Hz to 20 kHz
Sensitivity 1W/1M 96 dB
QMS 3.03
QES 0.23
RE 6.69 ohms 8 ohm nominal
VAS 54 ltrs / 2.01 cubic feet
I have already built and am using one of the K-502 integrated tube amp kits from Antique Electronic Supply (Tubesandmore.com) I plan to use with them.
Bob, I ordered the modified Fostex FE206E drivers from the Decware site at http://www.decware.com/newsite/mainmenu.htm
They designate them as FE206E-M. They list the spexs as QTS 0.23
38 Hz to 20 kHz
Sensitivity 1W/1M 96 dB
QMS 3.03
QES 0.23
RE 6.69 ohms 8 ohm nominal
VAS 54 ltrs / 2.01 cubic feet
I have already built and am using one of the K-502 integrated tube amp kits from Antique Electronic Supply (Tubesandmore.com) I plan to use with them.
OK, brain fart. I see the answer above. Let me think about this (FE206E) a while. Apparantly the mods don't affect the T/S parameters.
Bob
Brines Acoustics
Bob
Brines Acoustics
Re: Decware FE206 drivers
Herb's pipes were not designed for the FE206... the likelyhood of it being anywhere close to optimum is quite small.
You have Bob thinking about it, which is a good thing
In the meantime go read Martin Kings 206 ML-TL project
http://www.quarter-wave.com
dave
james_b said:
Herb's pipes were not designed for the FE206... the likelyhood of it being anywhere close to optimum is quite small.
You have Bob thinking about it, which is a good thing
In the meantime go read Martin Kings 206 ML-TL project
http://www.quarter-wave.com
dave
OK, try this:
L=60in
So=8.75x1in
Sm=8.75x12in
driver=34" down
port=4"diax5"long 55.5" down
Stuff 0.25 lb/ft^3 from top to 6" below driver
This asumes an amp with output Z=3 ohm or a series resistor.
You will need to add some stuffing near the bottom to the pipe to damp the ringing at cut-off. Also, since the driver is so close to the floor, you will wint the driver on the sloped side.
Bob
L=60in
So=8.75x1in
Sm=8.75x12in
driver=34" down
port=4"diax5"long 55.5" down
Stuff 0.25 lb/ft^3 from top to 6" below driver
This asumes an amp with output Z=3 ohm or a series resistor.
You will need to add some stuffing near the bottom to the pipe to damp the ringing at cut-off. Also, since the driver is so close to the floor, you will wint the driver on the sloped side.
Bob
An externally hosted image should be here but it was not working when we last tested it.
Its a hobby
Unnnnn- bee lievabllle!!! You sound like that Ruby Rod character in that Bruce Willis sci-fi move The Fifth Element.
The same reason that people buy a CD player, DVD player, amplifier or speakers and then upgrade capacitors, resistors, op amps, wiring, power cords, transformers etc. The same reason people buy a new car and then replace perfectly good brand new parts with aftermarket hotrod parts. Some people spend more on hubcaps than these drivers cost (its all relative). Generally they all want improved performance above that of the stock parts.
The reason I chose the Decware modified driver is that according to them it reduces beaming and shout and relieves the need to add a supertweeter. Decware is an established well regarded company, home of the famous Zen tube amp, and I trust their ability to do the mod. In fact they use these same drivers in their HiDefinition tower speakers. Modifying a driver is not something I would want to attempt myself, I’d probably poke a hole in it, so am willing to pay for them to do it. In addition to the phase plug they also treat the cone, like many people do with Damar varnish or similar products. Who cares what it is made of as long as it works. I wanted to build a true single driver, full range set of speakers and did not want to have to add a supertweeter and turn it into a 2-way system, and am hoping their mods as advertised will not require one.
Besides this is a DIY site and mods are part of that, and as a hobby its pretty fun.
ps If you know someone that sells them for $70 each please fill us in because they retail for much more than that.
Unnnnn- bee lievabllle!!! You sound like that Ruby Rod character in that Bruce Willis sci-fi move The Fifth Element.
The same reason that people buy a CD player, DVD player, amplifier or speakers and then upgrade capacitors, resistors, op amps, wiring, power cords, transformers etc. The same reason people buy a new car and then replace perfectly good brand new parts with aftermarket hotrod parts. Some people spend more on hubcaps than these drivers cost (its all relative). Generally they all want improved performance above that of the stock parts.
The reason I chose the Decware modified driver is that according to them it reduces beaming and shout and relieves the need to add a supertweeter. Decware is an established well regarded company, home of the famous Zen tube amp, and I trust their ability to do the mod. In fact they use these same drivers in their HiDefinition tower speakers. Modifying a driver is not something I would want to attempt myself, I’d probably poke a hole in it, so am willing to pay for them to do it. In addition to the phase plug they also treat the cone, like many people do with Damar varnish or similar products. Who cares what it is made of as long as it works. I wanted to build a true single driver, full range set of speakers and did not want to have to add a supertweeter and turn it into a 2-way system, and am hoping their mods as advertised will not require one.
Besides this is a DIY site and mods are part of that, and as a hobby its pretty fun.
ps If you know someone that sells them for $70 each please fill us in because they retail for much more than that.
Re: Its a hobby
Also substantiated by a number of independent "reviewers" that have been able to compare both.
Steve is an inveret tweaker and has a pretty solid reputation of selling goods that represent very good value for the dollar.
$84.30 each at Madisound. So about $65/speaker. Given the time it takes to modify a driver that is quite reasonable -- people pay me to mod drivers so i know (i haven't got the rep to charge that much yet thou)
dave
james_b said:
Also substantiated by a number of independent "reviewers" that have been able to compare both.
Steve is an inveret tweaker and has a pretty solid reputation of selling goods that represent very good value for the dollar.
$84.30 each at Madisound. So about $65/speaker. Given the time it takes to modify a driver that is quite reasonable -- people pay me to mod drivers so i know (i haven't got the rep to charge that much yet thou)
dave
I was reading the explanation of the sonic miracle on the decware website.
The proposed test to check for the validity of the approach was to stick a finger in the socket hole it to hear the difference.
Right then and there I got what Mr. Decware is all about.
I wonder why you never read this kind of brilliant insights on NP site or Linkwitz or some of the many other really-real audio engineers.
70-83 bucks close enough.
The proposed test to check for the validity of the approach was to stick a finger in the socket hole it to hear the difference.
Right then and there I got what Mr. Decware is all about.
I wonder why you never read this kind of brilliant insights on NP site or Linkwitz or some of the many other really-real audio engineers.
70-83 bucks close enough.
grataku said:
I always read Steve with a grain of salt... but the proof is in the pudding, Steve delivers good product for a fair price.
And with the dustcapectomy done if James wants to try other phase plugs -- ie we have a wooden 206/207 plug going into production -- then it is easy for him to experiment. A dustcapectomy can be an intimidating thing to do if you have never weilded a scalpel on a pair of drivers before and the reduction in stress & anxiety in a case like that is probably well worth the price differential alone.
dave
I recently built this pipe for the 206e, and I came up with nearly the same dimensions Bob suggested, interestingly enough. Anyway. I can tell you that they perform extremely well, but do require series R with a SS amp. Here's my design. I concur with Bob's suggestion to put the driver on the slanted side, it would work better. I listen to mine tilted back slightly.
voigt / fostex
How did that set up work out ? I'm now building the same...what do you think of the Decware / Fostex drivers ?...I love my voigt pipes and I'm trying different drivers in them....I have , Stephen's Trusonics , P audio coaxials , Tannoy dual concentrics , and now I ordered the Fostex , I also want to try the Moth Audio also.
How did that set up work out ? I'm now building the same...what do you think of the Decware / Fostex drivers ?...I love my voigt pipes and I'm trying different drivers in them....I have , Stephen's Trusonics , P audio coaxials , Tannoy dual concentrics , and now I ordered the Fostex , I also want to try the Moth Audio also.
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