Folded TQWT for Pioneer A11EC80-02F

mxv146 · 21st November 2004, 07:16 AM

Hello folks,

I have a couple of 4-1/2 inch Pioneer A11EC80-02F drivers. I would like to build folded TQWT (voight pipe) enclosures for the above.

All the folded TQWT designs I found on the web seem to be for larger diameter drivers. I was wondering if anyone could please help me design a suitable enclosure for these drivers.

The relevant equations I found on the web are:

D = 1/(2 + sqrt(Area_small/Area_big))
Fs = Vs/(4*L)

where D is the distance from tapered end to the center of the driver, and L the total length of the tube. Vs is the speed of sound, and Fs the resonance frequency of the TQWT.

In the above equations, there is no mention of the width of the TQWT enclosure, or the size of the exit port at the larger end of the tube. How do I decide on the dimensions of the above?

I would appreciate any help on this.

The driver parameters are:

Power handling: 20 watts RMS/30 watts max
* Voice coil diameter: 1"
* Impedance: 8 ohms
* Frequency response: 70-15,000 Hz
* Magnet weight: 9.3 oz.
* Fs: 70 Hz
* SPL: 90 dB 1W/1m
* Vas: .31 cu. ft.
* Xmax: 1.1mm
* Qms: 1.40
* Qes: .47
* Qts: .35
* Net weight: 2 lbs.
* Manufacturer model number: A11EC80-02F
* Dimensions: Overall Diameter: 4-1/2", Cutout Diameter: 4-1/8",
Mounting Depth: 2-3/8", Magnet Diameter: 3-1/8", Magnet Height: 1".

Best Regards

Mahesh

planet10 · 21st November 2004, 07:31 AM

Sounds like you have found the plans for a classic TQWT. Unfortunately these mostly do not work. The actual size of the box has nothing to do with the driver size (except in that there is a very loose association relating driver size to Vas).

If you do a search here or on the full range forum you will likely find a design for an ML-TL or ML-TQWT (probably from GM) already worked out.

BillFitzmaurice · 21st November 2004, 12:37 PM

The overall volume of the pipe is determined by the Vas and Qts; in your case the ratio of Vas/Vp is 3.2. The area at either end depends on your taper ratio, with 3:1 to 4:1 being considered the usual range for best results. Determine the overall volume, in this case about 1 cu ft, decide on pipe length and taper ratio and use that to find the areas of the closed and open ends of the pipe.

21st November 2004, 07:16 AM	#1
mxv146 diyAudio Member Join Date: Oct 2004	Folded TQWT for Pioneer A11EC80-02F Hello folks, I have a couple of 4-1/2 inch Pioneer A11EC80-02F drivers. I would like to build folded TQWT (voight pipe) enclosures for the above. All the folded TQWT designs I found on the web seem to be for larger diameter drivers. I was wondering if anyone could please help me design a suitable enclosure for these drivers. The relevant equations I found on the web are: D = 1/(2 + sqrt(Area_small/Area_big)) Fs = Vs/(4L) where D is the distance from tapered end to the center of the driver, and L the total length of the tube. Vs is the speed of sound, and Fs the resonance frequency of the TQWT. In the above equations, there is no mention of the width of the TQWT enclosure, or the size of the exit port at the larger end of the tube. How do I decide on the dimensions of the above? I would appreciate any help on this. The driver parameters are: Power handling: 20 watts RMS/30 watts max Voice coil diameter: 1" * Impedance: 8 ohms * Frequency response: 70-15,000 Hz * Magnet weight: 9.3 oz. * Fs: 70 Hz * SPL: 90 dB 1W/1m * Vas: .31 cu. ft. * Xmax: 1.1mm * Qms: 1.40 * Qes: .47 * Qts: .35 * Net weight: 2 lbs. * Manufacturer model number: A11EC80-02F * Dimensions: Overall Diameter: 4-1/2", Cutout Diameter: 4-1/8", Mounting Depth: 2-3/8", Magnet Diameter: 3-1/8", Magnet Height: 1". Best Regards Mahesh

21st November 2004, 07:31 AM	#2
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Re: Folded TQWT for Pioneer A11EC80-02F Sounds like you have found the plans for a classic TQWT. Unfortunately these mostly do not work. The actual size of the box has nothing to do with the driver size (except in that there is a very loose association relating driver size to Vas). If you do a search here or on the full range forum you will likely find a design for an ML-TL or ML-TQWT (probably from GM) already worked out. __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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21st November 2004, 12:37 PM	#3
BillFitzmaurice Banned Join Date: May 2004 Location: New Hampshire	The overall volume of the pipe is determined by the Vas and Qts; in your case the ratio of Vas/Vp is 3.2. The area at either end depends on your taper ratio, with 3:1 to 4:1 being considered the usual range for best results. Determine the overall volume, in this case about 1 cu ft, decide on pipe length and taper ratio and use that to find the areas of the closed and open ends of the pipe.

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