Hey DIYers
A while back, I ran across a pair of AD12202 on a local auction site for a very reasonable price, so I had to jump on them.
Full-range drivers always kinda impressed me, and back when I was 15, I built a pair of Cyburg Sticks with W4-655C, which sparked my interest in TQWT (back then I thought this was this "Transmission Line" thing they were all talking about) designs. On a side note, my dad is still listening to these speakers today.
Seeing this, I decided to take it upon myself to design a TQWT enclosure for the AD12202, as I couldn't find any suitable designs on here or in other forums. However, even after all these years, I still feel slightly inferior when it comes to my maths, so I would highly appreciate some feedback on my design from some of the more seasoned designers here on the board.
Here you can see a drawing of the side view, next to it the SPL graph from my simulations.
Here are the pipe parameters:
Tuning Frequency: 42 Hz
Taper Ratio: 3.333 (repeating)
Length: 2.2m
Volume: 375l
Driver Position: 75cm
Now, a few questions:
I understand the comb in the FR is inherent to the standing waves occurring inside the cabinet, and I've done my best to iron it out. How much improvement can I expect from heavily dampening the beginning/narrow end of the pipe?
Second, I couldn't really find many resources on simulating the mass loaded vent in conjunction with the pipe itself, so I essentially just ended up using a port tuned to 35Hz with the length of it fixed to the depth of the beginning of the pipe (15cm). Franky speaking, is this dumb?
In my understanding, this should on one hand further extend the pipe, but also bring its own set of implications. Is there a way to simulate the entire system, namely one that doesn't cause cluster headaches? I expect to add another few Hz on the FR, but I have no idea what other chances in phase response or especially group delay I could encounter.
I am also unsure if a port of just 5cm in height will create problems related to port noise, even though the whole cabinet is 50cm in width, creating what I would call sufficient surface area for the amount of air I expect the cone to move.
All in all, do you think this about checks out? If not, where would you start improving?
Lastly, do you even think I should go the TQWT route? I am looking for reasonable extension, but more importantly, tight upper bass, which I expect the stiff paper cone to excel at. I did, of course, think about building open baffles, but I really don't think the drivers would deliver on my bass needs, and I am spiritually against the idea of deploying a subwoofer 😀 I also thought about building a classic BR, but there I really don't want to compromise on tightness.
Anyway, thanks so far!
A while back, I ran across a pair of AD12202 on a local auction site for a very reasonable price, so I had to jump on them.
Full-range drivers always kinda impressed me, and back when I was 15, I built a pair of Cyburg Sticks with W4-655C, which sparked my interest in TQWT (back then I thought this was this "Transmission Line" thing they were all talking about) designs. On a side note, my dad is still listening to these speakers today.
Seeing this, I decided to take it upon myself to design a TQWT enclosure for the AD12202, as I couldn't find any suitable designs on here or in other forums. However, even after all these years, I still feel slightly inferior when it comes to my maths, so I would highly appreciate some feedback on my design from some of the more seasoned designers here on the board.
Here you can see a drawing of the side view, next to it the SPL graph from my simulations.
Here are the pipe parameters:
Tuning Frequency: 42 Hz
Taper Ratio: 3.333 (repeating)
Length: 2.2m
Volume: 375l
Driver Position: 75cm
Now, a few questions:
I understand the comb in the FR is inherent to the standing waves occurring inside the cabinet, and I've done my best to iron it out. How much improvement can I expect from heavily dampening the beginning/narrow end of the pipe?
Second, I couldn't really find many resources on simulating the mass loaded vent in conjunction with the pipe itself, so I essentially just ended up using a port tuned to 35Hz with the length of it fixed to the depth of the beginning of the pipe (15cm). Franky speaking, is this dumb?
In my understanding, this should on one hand further extend the pipe, but also bring its own set of implications. Is there a way to simulate the entire system, namely one that doesn't cause cluster headaches? I expect to add another few Hz on the FR, but I have no idea what other chances in phase response or especially group delay I could encounter.
I am also unsure if a port of just 5cm in height will create problems related to port noise, even though the whole cabinet is 50cm in width, creating what I would call sufficient surface area for the amount of air I expect the cone to move.
All in all, do you think this about checks out? If not, where would you start improving?
Lastly, do you even think I should go the TQWT route? I am looking for reasonable extension, but more importantly, tight upper bass, which I expect the stiff paper cone to excel at. I did, of course, think about building open baffles, but I really don't think the drivers would deliver on my bass needs, and I am spiritually against the idea of deploying a subwoofer 😀 I also thought about building a classic BR, but there I really don't want to compromise on tightness.
Anyway, thanks so far!
Good call, I landed there to offset the resonance at ~180Hz that would get way worse if I moved the driver up further. But I think landing on middle ground and hoping for dampening to do its job might be the way.
I can only chime in so far as that I built a pair of Voigt Pipes (essentially an "original, unfolded TQWT").
They sounded very nice, natural and resonant, as transmissionlines do. But it still lacked some "body" to the sound.
Then I built a pair of BIBs (with the same W8 2145 speakers) and the difference was night and day.
I'd go for BIBs: https://speakerprojects.wordpress.com/cabinet-types/bib-loudspeakers/bib-calculator/
BIBs take up a little more floor space than a TQWT, yes, but not by much. They're just much taller, but most of the time the space "up in the air" isn't used anyhow.
They sounded very nice, natural and resonant, as transmissionlines do. But it still lacked some "body" to the sound.
Then I built a pair of BIBs (with the same W8 2145 speakers) and the difference was night and day.
I'd go for BIBs: https://speakerprojects.wordpress.com/cabinet-types/bib-loudspeakers/bib-calculator/
BIBs take up a little more floor space than a TQWT, yes, but not by much. They're just much taller, but most of the time the space "up in the air" isn't used anyhow.
Thanks for the input!
Getting even more lost here, though; isn't the BiB just a specific TQWT design? Like a rather basic one-fold cab with a non-mass loaded vent exhausting and the top?
Getting even more lost here, though; isn't the BiB just a specific TQWT design? Like a rather basic one-fold cab with a non-mass loaded vent exhausting and the top?
exactly, yes. it's more or less a very tall and large TQWT with an open end instead of a specific port, so it's also a horn. simple to build and superb performance.
Not really, it's technically a folded two flare parabolic* horn tuned an octave below Fs, so 1/2 WL (THWT or THWH?).
*has at least one set of parallel sides, which at the time I thought meant conical.
interesting input, thanks GM! further into the rabbit hole, I guess lol
I think building a pair of BIBs in this scale could turn into quite an expensive project. Still, I'm certainly intrigued by the concept, even if just to investigate the line between an asymmetrical folded parabolic horn (does the narrow end of the pipe essentially translate to some kind of pressure chamber?) and the Voigt design. Maybe, with efficient folding, I could slash the wood cost to something I can afford, but maybe a more traditional back loaded horn design could fit the bill better then?
OR maybe I should just stick to a dead simple vented shoebox design and just remain slightly underwhelmed by the tightness of the bass /s
I think building a pair of BIBs in this scale could turn into quite an expensive project. Still, I'm certainly intrigued by the concept, even if just to investigate the line between an asymmetrical folded parabolic horn (does the narrow end of the pipe essentially translate to some kind of pressure chamber?) and the Voigt design. Maybe, with efficient folding, I could slash the wood cost to something I can afford, but maybe a more traditional back loaded horn design could fit the bill better then?
OR maybe I should just stick to a dead simple vented shoebox design and just remain slightly underwhelmed by the tightness of the bass /s