you're speaking about GM's ?
TL is by dimensions and driver & port position
read this , for amusement : 6moons audio reviews: Stephæn's Altec 604 Dream Speaker
TL is by dimensions and driver & port position
read this , for amusement : 6moons audio reviews: Stephæn's Altec 604 Dream Speaker
No, a TQWT has an expanding squaresection, a shrinking pipe is a transmissionline and those two work in entirely different ways, except the quarterway resonant behavior.
The tl principle has as primarily goal to achieve maximum linearity through damping while sacrificing efficiency.
A TWQT instead uses the qw resonances to raise efficiency in the low end by the impedance transformation that is there on account of the expanding pipe, naot att all to the same extent as a real horn but still enough to make som dB gain, this is then carefully contolled with sparse damping in the pipe to milden the inherent unlinearity all qw systems suffer from.
Well executed they, `TQWT´s`can be very well extended, dynamic and,IMO, very nice speakers for music.
No Buzz, we regard the taper from closed to open end.
A tqwt is growing larger as we approach open end, a tl is shrinking as we go there.
A 42" tall box without inner walls to make a `pipe´, with a port, anywhere, is a bassreflex, shure it has a quarterwave resonance, as has all boxes with parallell walls , size determines frequency.
A proper tqwt or tl is either very tall or folded, the entire pipelength determines lf qw frequency.
A tqwt with the driver properly positioned in the pipe lengthwise gains from the same kind of impedancetransformation as a proper horn but to a much lesser degree, but also in a somewhat more linear manner, corectly done You gain efficiency in the low end of the combined system, box+driver, with decent linearity and without damping to much of the dynamics.
A tqwt is growing larger as we approach open end, a tl is shrinking as we go there.
A 42" tall box without inner walls to make a `pipe´, with a port, anywhere, is a bassreflex, shure it has a quarterwave resonance, as has all boxes with parallell walls , size determines frequency.
A proper tqwt or tl is either very tall or folded, the entire pipelength determines lf qw frequency.
A tqwt with the driver properly positioned in the pipe lengthwise gains from the same kind of impedancetransformation as a proper horn but to a much lesser degree, but also in a somewhat more linear manner, corectly done You gain efficiency in the low end of the combined system, box+driver, with decent linearity and without damping to much of the dynamics.
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My bad, Thats what i thought. I was incorrect in my understanding of a TQWT. A Tl can also be constant with no taper or expansion, correct. I could have sworn GM said that horn is expanding and tqwt is tapered, but just read "inverse" tapered. Duh! THanks Ingvar.
I case of BR or MLTL, I thought line/pipe length is what determined frrequency, assuming astated Vas. Guess I did not consider that both parameters are involved. What happens to tuning with two different boxes, both same length/heighth, but one with less Vb. Are we just talking rate of rollof, or complete change of response.
Geez. I gotta go read MJK stuff again. UGH!.
I case of BR or MLTL, I thought line/pipe length is what determined frrequency, assuming astated Vas. Guess I did not consider that both parameters are involved. What happens to tuning with two different boxes, both same length/heighth, but one with less Vb. Are we just talking rate of rollof, or complete change of response.
Geez. I gotta go read MJK stuff again. UGH!.
A pipe, wichever type, should have, at least, about the same vb as a br cab for the same lf tuning, wich will almost always automatically be the case, the pipe will be larger, but once in a while senile old men do silly misstakes.
Here the pipes, TQWT, are 420cm long but the vb is just too small so they still
died down at around 100Hz, the rectified version, slightly more than twice as wide, produce just what they were supposed to do.
Here the pipes, TQWT, are 420cm long but the vb is just too small so they still
died down at around 100Hz, the rectified version, slightly more than twice as wide, produce just what they were supposed to do.
My pleasure!
Indeed he did, I was one of them. He mailed and later emailed me various info I was interested in and we would occasionally 'bench race' W.E./Altec design.
Did you know Bill personally?
I only knew him through the local Altec distributor and of course later on the early audio BBs, then some web forums before he 'disappeared', resurfacing every once in awhile on the Altec User's Forum to post pics of speaker projects he'd done.
GM
It raises the system Q for one, lowering damping and if it’s transformer coupled it creates a ‘smiley face’ [with a tooth or two if there's an XO] EQ as it tracks the system impedance with all the good and bad performance potential this implies.
GM
Which one? Westend’s? It’s just a high aspect ratio vented cab [MLTL] with some bracing.
The Pensil is called a RAC because its net Vb is many times larger than the driver’s Vas, so is basically a vented I.B. which in turn must be well damped to make it ~aperiodic to get good performance.
A TL is either a 1/4 or ½ WL resonant pipe, so no vent [1/2 WL resonator] to mass load it, ergo like the RAC in that it requires considerable damping to be smooth.
Correct, venting [mass loading] a TL reduces its path-length somewhat for a given Fp[Fb].
GM
An approach i like!
Why dont go horn/horn
The RLK is designed for 2 8" or one 12" but is easily adaptable for one 15"
This will go low, vell below 30 with the 416, and will play music with the dynamics, joy and of course, defects, inherent in large horns, still usable domestically, slightly below 10 cu ft.
I don´t know why the drawings get distorted but clicking them shows to scale.
hey buzz. In view of the posts that should be arriving........
check out the 902 from GPA Altec Lansing GPA 802 804 806 902 909 902-8A 909-8A NEW | eBay REALLY good value for money AFAIC for NEW drivers that will go past 15khz
check out the 902 from GPA Altec Lansing GPA 802 804 806 902 909 902-8A 909-8A NEW | eBay REALLY good value for money AFAIC for NEW drivers that will go past 15khz
Hi guys
Can someone post the pics for the actual design for GM's 416b MLTL? The link in the 'Altec 416b MLTL, design by GM' thread does not work anymore. It goes to what seems like a discussion of Iowa/Minnessota st. college football (I'm from South-Africa, so that's a very uneducated guess). The build thread on Audio Karma also does not show the design itself. And how adaptable is that design to other drivers? Or even modern GPA equivalents?
Thanks,
Deon
Can someone post the pics for the actual design for GM's 416b MLTL? The link in the 'Altec 416b MLTL, design by GM' thread does not work anymore. It goes to what seems like a discussion of Iowa/Minnessota st. college football (I'm from South-Africa, so that's a very uneducated guess). The build thread on Audio Karma also does not show the design itself. And how adaptable is that design to other drivers? Or even modern GPA equivalents?
Thanks,
Deon
Just punching 'Altec 416b MLTL, design by GM' into google bring these up 
Altec MLTL with Model 19 drivers - AudioKarma.org Home Audio Stereo Discussion Forums
GM's MLTL with 416-8B
Altec MLTL with Model 19 drivers - AudioKarma.org Home Audio Stereo Discussion Forums
GM's MLTL with 416-8B
Had the same thought as i designed it, worried about strange or bad imaging,
still wanted to try as these 8" units sound realy good.
It works beautifully with very precise imaging and ambience if there is any in the recording, probably mostly due to that edges on transients and sibilance comes mostly from the HF unit and the brain hears direction firstly by this information.
And it has gained unconditional acceptance from even the most discerning ears.
Just a guess, but I'd go for BIG & fugly (he says watching on with interest from shadows
)
GM,
Is the muliway you posted pictures of in the Pub of similar size to your MLTL for the 416? Its funny how chamfering the front corners cand reduce the appearance of size. It seems to me that the 4552 was an unnecessary expense in that build, considering the presence of the 288. I guess it could be argued that he didnt need the 288 with the 4552. Also, i can see how the 414 would perform nicely as a midbass, but doesnt this kind of waste the abilities of the 515 and 416. Was the idea to bump the XO for the horn above the majority of the vocal range.
Is the muliway you posted pictures of in the Pub of similar size to your MLTL for the 416? Its funny how chamfering the front corners cand reduce the appearance of size. It seems to me that the 4552 was an unnecessary expense in that build, considering the presence of the 288. I guess it could be argued that he didnt need the 288 with the 4552. Also, i can see how the 414 would perform nicely as a midbass, but doesnt this kind of waste the abilities of the 515 and 416. Was the idea to bump the XO for the horn above the majority of the vocal range.