Hello,
I wonder if on a TQWT for a 8 inches fullrange as the Supravox 215 or Visaton B200, the box wide and depth are critical??
As at this Supravox project the inside dimensions are smaller(W=25,6cm, H=102,5sm, D=36,5cm, Litrage=95,4Litres) than the Golden Ratio sizes:
http://www.supravox.fr/kits/tqwt215.pdf
According the Golden Rule the inside sizes would be> W=26 H=110cm D=42cm, Litrage=120 Litres;
This new, Golden rule bigger box may ruin the sound quality??
Thanks for any input.
I wonder if on a TQWT for a 8 inches fullrange as the Supravox 215 or Visaton B200, the box wide and depth are critical??
As at this Supravox project the inside dimensions are smaller(W=25,6cm, H=102,5sm, D=36,5cm, Litrage=95,4Litres) than the Golden Ratio sizes:
http://www.supravox.fr/kits/tqwt215.pdf
According the Golden Rule the inside sizes would be> W=26 H=110cm D=42cm, Litrage=120 Litres;
This new, Golden rule bigger box may ruin the sound quality??
Thanks for any input.
A couple of points straight off.
Firstly, nobody said golden rule dimensions have to be adhered to.
Next, what is relevant in a folded horn of this kind (TQWT in inaccurate modern parlance) is the length, driver tap location, expansion (viz. total volume), damping quantity & location, and if mass loaded, the dimensions & location of the duct. Since there is an internal line / expansion, golden rule HxWxD for a rectillinear cabinet is irrelevant. Note however that the more extreme the WxD ratio, the further you will depart from conical expansion into parabolic. The baffle dimensions & shape are relevant for baffle-step frequency & edge diffraction of course.
Firstly, nobody said golden rule dimensions have to be adhered to.
Next, what is relevant in a folded horn of this kind (TQWT in inaccurate modern parlance) is the length, driver tap location, expansion (viz. total volume), damping quantity & location, and if mass loaded, the dimensions & location of the duct. Since there is an internal line / expansion, golden rule HxWxD for a rectillinear cabinet is irrelevant. Note however that the more extreme the WxD ratio, the further you will depart from conical expansion into parabolic. The baffle dimensions & shape are relevant for baffle-step frequency & edge diffraction of course.
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Thanks for reply, I appreciated it.
One doubt remain, in terms of music/sound quality, what means a barabolic expansion??
Thanks
You're welcome.
Parabolic doesn't mean anything in terms of music or sound quality since music is the recorded medium, and sound quality is a nebulous concept that varies depending on what it is you mean by it. A parabolic expansion provides the lowest efficiency of the various horn expansion profiles, a catenoid the highest, with the hyperbolic family (inc. exponential) falling in between depending on the T value. This is rather moot, since folded pipes of the type you link to are too small to get any significant horn loading within their useful BW in any case; the majority are just standing-wave generators with a taper that spreads the harmonics; whether that's a good or bad thing depends on the design in question & the desired objective.
Parabolic doesn't mean anything in terms of music or sound quality since music is the recorded medium, and sound quality is a nebulous concept that varies depending on what it is you mean by it. A parabolic expansion provides the lowest efficiency of the various horn expansion profiles, a catenoid the highest, with the hyperbolic family (inc. exponential) falling in between depending on the T value. This is rather moot, since folded pipes of the type you link to are too small to get any significant horn loading within their useful BW in any case; the majority are just standing-wave generators with a taper that spreads the harmonics; whether that's a good or bad thing depends on the design in question & the desired objective.
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OK, Great explanation, Thanks. Iam a dumb about horns.
This Supravox project is too short to my taste, Do you would suggest a taller TQWT, around 130cm or 150cm tall??
Thanks
as are many, including come purveyors of commercial products
oops, did I say that out loud?
Not a problem.
I'd suggest a better designed cabinet, period. Tuning frequency is a function of axial length & taper, and the amount of mass-loading (if any) applied to the horn / TQWT / call it what you will. Going by memory (it's a while since I looked at them) those Supravox boxes don't IMO have sufficient Vb for the intended drivers though, so I'd antipate poor gain on the bottom-end.
They're published specs are as accurate as a popular English and American brand's. 
Same ol' aces n' eights for me, but having lost a several decades long pair of friends younger than me over the holidazes to fast acting diseases, I can live with that. Anyway, looking forward to catching up.
GM
Same ol' aces n' eights for me, but having lost a several decades long pair of friends younger than me over the holidazes to fast acting diseases, I can live with that. Anyway, looking forward to catching up.
GM
I have no doubt, but for what source, room conditions, etc., so best overall to my way of thinking for the DIYer is to either build to at least design using measured specs or make it somewhat larger to allow more frequency shaping tuning options, hence my general attitude of 'when in doubt, BIB rules'.
GM
GM
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