Circular Baffle for Voigt Pipes? - diyAudio
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Old 6th February 2005, 05:24 AM   #1
james_b is offline james_b  United States
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Default Circular Baffle for Voigt Pipes?

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.
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Old 6th February 2005, 09:41 AM   #2
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Default Re: Circular Baffle for Voigt Pipes?

What drivers are you going to use?

dave
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Old 6th February 2005, 01:04 PM   #3
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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


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Old 6th February 2005, 01:36 PM   #4
james_b is offline james_b  United States
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Default 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.
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Old 6th February 2005, 02:08 PM   #5
james_b is offline james_b  United States
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Default 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
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Old 6th February 2005, 03:33 PM   #6
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What driver are you going to use?

Brines Acoustics
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Old 6th February 2005, 03:45 PM   #7
james_b is offline james_b  United States
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Default 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.
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Old 6th February 2005, 04:57 PM   #8
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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

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Old 6th February 2005, 06:56 PM   #9
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Default Re: Decware FE206 drivers

Quote:
Originally posted by james_b
I have ordered a pair of the modified Fostex FE206 drivers from Decware
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
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Old 6th February 2005, 08:51 PM   #10
james_b is offline james_b  United States
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Default cabinets

Thanks for the replies, at least if the Voigt Pipe does not prove to be the best combination, being a DIY effort I can think about another style cabinet for my next project.
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