Pretty commercial TQWT (-w- Jordans)

[pjanda1]

I've been pondering whether the folding scheme on the TQWT's (is that lingo going to catch on, or will everyone keep using TL?) I'm building will reduce the reflections that get back to the driver. These guys claim to have it figured out, and they've made some darn pretty bends. I do get the "human form" look. It also sounds as if they are using BSC, which isn't always the case with commercial single driver offerings. Do you suppose those are layered? Seems like it would be tough to make those tight radius bends.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers
edit: forgot the link on the first go!

[vinylkid58]

Originally Posted by pjanda1

Seems like it would be tough to make those tight radius bends.

Not on a CNC it's not. And yes, they do appear to be layered.

Jeff

[pjanda1]

I meant if one were trying to bend a flat sheet around that radius. I certainly understand that you could layer such a shape.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

[vinylkid58]

I think it would depend on the material thickness and the initial bend radius. You'd have to start with thin material to get the desired shape, and then build up several layers. I'm sure I've seen this approach somewhere.

Jeff

[d to the g]

Originally Posted by vinylkid58

I'm sure I've seen this approach somewhere.

Jeff

poinz does the kerfing

[picowallspeaker]

Do they want to avoid " interchannel crosstalk" between sections of the pipe?
Seen that way , every section seems free to resonate (or do not!) ,letting acoustic energy "migrate" freely to the mouth.
As I see , those are multiple layer CNCed, not curved sheets.

[Andrewbee]

Kerfing would allow those bends easily.
There is also a type of plywood which I know as "Bendy" plywood which is extremely flexible although I would probably just cut the kerfs.

CNC machines (routers really) can cut just about any shape and size, wastes a lot of material though and like a lot of "progress" nowadays, the art, technique and craftsmanship is lost .

[planet10]

Originally Posted by pjanda1

I've been pondering whether the folding scheme on the TQWT's (is that lingo going to catch on, or will everyone keep using TL?)

Used in its broadest sense (an atypical use), a TQWT could be any of the genre we typically call TLs, Voigt Pipes, Horns, and Metronomes... i use the term TL in its broadest sense to mean the same thing.

I think we will continue to see TL used for boxes with openEnd xSection =< closedEnd with the strictest definition being that it is damped to almost aperiodic, TQWT for boxes with openEnd xSection > closedEnd with a linear taper (ie TQWT=TQWP=Voigt). In its broadest sense this is also a horn but a horn is usually openEnd xSection > closedEnd with an expansion which cannot be defined with a straight line.

The commercial thing you pointed to is a TL. I would never call that a TQWT.

On top of that you can mass load them, and or add an air-cavity. The traditional Bailey/Radford/IMF TL has both, is end loaded, and is not stuffed enuff to fit the strictest definition of a TL.

dave

[pjanda1]

I have been following the logic that a recall GM proposing: that there is no electrical analogy to a tapered line, and since TL is a borrowed word, it makes sense to use TQWT for any line that is tapered (in either direction). I could be mistaken, or misrepresenting his idea, but it makes sense to me. I do suspect the term Transmission Line is here to stay. Seems I recently saw some manufacturer referring to it as a "reverse horn." That was a new one on me.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

[planet10]

That is what i meant in the broadest sense.

GM started using the term reverse taper TQWT... i' personally going to stick with the traditional use of the terms -- i have avoided the use of TQWT for sometime, prefering Voigt Pipe.

dave