My friend - it seems that you may be a little new to this forum.
The gentlemen like planet10 and GM are folks that I’ve seen around here for about the 9+ years that I’ve been lurking around here in general - I’ve learned much from them, and have gained immense value from their posts…
As such - I just hope you don’t get too hot headed with your posts the next few times…these people are generally quite friendly, and would love to be able to answer your questions as best they can
They’re just wanting to help answer your question - you likely have more value to gain from everyone’s posts, than you have to push them away…
Nonetheless -
You mentioned earlier something about guitar bodies, if I can recall correctly - guitar construction isn’t really all that relevant to the sound it can produce, as the cabinet rigidity/baffle isn’t all that meaningful compared to the baffle itself.
As the holes in the baffle aren’t meant for to produce sound, but rather the strings vibrating and reflecting off of the baffle (like a horn or waveguide) is what it’s meant to do…the cutout is simply to relive pressure buildups within the cabinet itself
The gentlemen like planet10 and GM are folks that I’ve seen around here for about the 9+ years that I’ve been lurking around here in general - I’ve learned much from them, and have gained immense value from their posts…
As such - I just hope you don’t get too hot headed with your posts the next few times…these people are generally quite friendly, and would love to be able to answer your questions as best they can
They’re just wanting to help answer your question - you likely have more value to gain from everyone’s posts, than you have to push them away…
Nonetheless -
You mentioned earlier something about guitar bodies, if I can recall correctly - guitar construction isn’t really all that relevant to the sound it can produce, as the cabinet rigidity/baffle isn’t all that meaningful compared to the baffle itself.
As the holes in the baffle aren’t meant for to produce sound, but rather the strings vibrating and reflecting off of the baffle (like a horn or waveguide) is what it’s meant to do…the cutout is simply to relive pressure buildups within the cabinet itself
wot, yes you can fold the TL. Basically all TL builds you see are folded once or more. Length is important for the resonance and cross sectional area is important to provide the internal volume, you can adjust the two or use what GM provided.
Path length might change a bit due to fold, I believe you can plot the box on a sheet of paper, draw a line to the middle and measure the length. There might be some spreadsheets available to give all the dimensions. See The Subwoofer DIY Page - Horn Folding for inspiration, might even provide a suitable fold for you
I have never built any though, so I don't know the details of TLs.
ps. few weeks worth of evening googling and thinking provides lot of knowledge on TLs, or rocket science, or anything Of course nicest way to get into the core of something is by consulting the experienced, but searching for the info by yourself and connecting the dots is not too cumbersome these days. The oracle in the pocket (smartphone) will answer any question you ask.
Path length might change a bit due to fold, I believe you can plot the box on a sheet of paper, draw a line to the middle and measure the length. There might be some spreadsheets available to give all the dimensions. See The Subwoofer DIY Page - Horn Folding for inspiration, might even provide a suitable fold for you
I have never built any though, so I don't know the details of TLs.ps. few weeks worth of evening googling and thinking provides lot of knowledge on TLs, or rocket science, or anything
Of course nicest way to get into the core of something is by consulting the experienced, but searching for the info by yourself and connecting the dots is not too cumbersome these days. The oracle in the pocket (smartphone) will answer any question you ask.
Last edited:
Wot, not everyone is online all of the time, and not everyone subscribes to every thread (so may not see a response/question). For instance I've been awol for a couple of months, due to life getting in the way...
I have no experience with TL's hopefully checking out the link GM provided, plus the two posts above gives you enough to continue your adventure.
Tony.
I have no experience with TL's hopefully checking out the link GM provided, plus the two posts above gives you enough to continue your adventure.
Tony.
Thanks for your answers. Just not sure which way to go right now.
Since I have a pair of KEF B139 replicas by Falcon Acoustics I really want a box that will use them to the max.
The one I'm thinking of uses one active and one passive , with the passive basically in place of a port.
The one that was described is supposed to be highly efficient even down as low as 15watts so my Aleph running at 25 watts should do it justice. I just need some working drawings for that.
Sorry for losing patience before, I was checking every day but there were no answers for ages and now I just happened to find these.
GM gave me some kind of a formula so I tried applying it and I just wanted to know if I had understood it or not. I find much of this theoretical stuff very hard to follow so for me a design is everything. I don't want to spend a huge amount of time building and rebuilding without any idea if I'm doing any of it right.
Now ReDress, I really wonder what all this means? Are you talking about a guitar or a speaker box here?
If you understand what makes a guitar work then this is not an explanation that resonates for me.
The way I understand guitar is it has a box/enclosure which is similar to a speaker box and the soundboard is equivalent to a driver.
For that driver to work efficiently the box must be structurally as rigid as possible and areas that might vibrate in that box need to be braced to take their resonating frequencies above midrange so there are less cancellations in that area.
The driver being made of wood and activated by the strings needs to accommodate the string tension and at the same time move as freely as possible in as many nodes as possible to achieve a wide range of efficiency across the spectrum of frequencies.
While there are formulas written by physicists on this it is not possible to just take a formula and design a good sounding guitar, though there have been some serious attempts.
My method has involved a lifetime of research and development, by gradually changing things in small increments and carefully evaluating whether that was the better way or whether another direction was needed for better results.
I just don't have a lifetime to devote to discovering a great speaker box the long way .
So I am seeking to shortcircuit that search and find something that has been shown to work and build it to the best of my ability.
My maths and calculation are fairly basic compared to most of you guys but my skills lie more in production and application.
So the question is whether this is a good place to be or whether I just need to start begging certain people for a drawing that I can follow?
Since I have a pair of KEF B139 replicas by Falcon Acoustics I really want a box that will use them to the max.
The one I'm thinking of uses one active and one passive , with the passive basically in place of a port.
The one that was described is supposed to be highly efficient even down as low as 15watts so my Aleph running at 25 watts should do it justice. I just need some working drawings for that.
Sorry for losing patience before, I was checking every day but there were no answers for ages and now I just happened to find these.
GM gave me some kind of a formula so I tried applying it and I just wanted to know if I had understood it or not. I find much of this theoretical stuff very hard to follow so for me a design is everything. I don't want to spend a huge amount of time building and rebuilding without any idea if I'm doing any of it right.
Now ReDress, I really wonder what all this means? Are you talking about a guitar or a speaker box here?
If you understand what makes a guitar work then this is not an explanation that resonates for me.
The way I understand guitar is it has a box/enclosure which is similar to a speaker box and the soundboard is equivalent to a driver.
For that driver to work efficiently the box must be structurally as rigid as possible and areas that might vibrate in that box need to be braced to take their resonating frequencies above midrange so there are less cancellations in that area.
The driver being made of wood and activated by the strings needs to accommodate the string tension and at the same time move as freely as possible in as many nodes as possible to achieve a wide range of efficiency across the spectrum of frequencies.
While there are formulas written by physicists on this it is not possible to just take a formula and design a good sounding guitar, though there have been some serious attempts.
My method has involved a lifetime of research and development, by gradually changing things in small increments and carefully evaluating whether that was the better way or whether another direction was needed for better results.
I just don't have a lifetime to devote to discovering a great speaker box the long way .
So I am seeking to shortcircuit that search and find something that has been shown to work and build it to the best of my ability.
My maths and calculation are fairly basic compared to most of you guys but my skills lie more in production and application.
So the question is whether this is a good place to be or whether I just need to start begging certain people for a drawing that I can follow?
4 would be nice given the (relative to moderan drivers) older design. I love the B139.
f you want to extract the most from these i would suggest one of the TLs Scott and i have done.
A number of versions have been built and people are happy. The boxes on the top row,
Transmission Line Speakers
I like this one best
dave
Thankyou Dave.
I'll probably try the first on that line to start.
I am confused by the plan showing the pair of speakers from above where one is on the edge of the box but the other is set in. Can you clarify that detail? The side view doesn't support it as it shows each speaker on the edge which is logical. I assume the placement of speakers there is just a suggestion to show them back to back.
The notes mention minimal bracing shown so I assume there is much more required. Is that arbitrary or are there ideal distances and dimensions for those? I assume they are like the ones I put into guitars to prevent midrange cancellations in which case no area is left unbraced for more than 6inches?
I see there is a specific horizontal centre line for speaker placement but not a dimension given for the vertical centre. Instead it shows a relationship to the vertical baffle which I assume is a judgement rather than a definite dimension. Maybe it's not quite critical or maybe the drawings are to scale that can be transferred to full size for accurate placements?
I notice that the top of the box has internal 'shoulders' which are fully enclosed so maybe these could be cutoffs instead of having the box square there? Just to add a variation on the appearance?
Finally I have polyester wadding for the stuffing. Would that be suitable?
Anyway if you don't answer I will go ahead using my assumptions and thanks again for something I can get my teeth into.
Cheers,
Dan
I'll probably try the first on that line to start.
I am confused by the plan showing the pair of speakers from above where one is on the edge of the box but the other is set in. Can you clarify that detail? The side view doesn't support it as it shows each speaker on the edge which is logical. I assume the placement of speakers there is just a suggestion to show them back to back.
The notes mention minimal bracing shown so I assume there is much more required. Is that arbitrary or are there ideal distances and dimensions for those? I assume they are like the ones I put into guitars to prevent midrange cancellations in which case no area is left unbraced for more than 6inches?
I see there is a specific horizontal centre line for speaker placement but not a dimension given for the vertical centre. Instead it shows a relationship to the vertical baffle which I assume is a judgement rather than a definite dimension. Maybe it's not quite critical or maybe the drawings are to scale that can be transferred to full size for accurate placements?
I notice that the top of the box has internal 'shoulders' which are fully enclosed so maybe these could be cutoffs instead of having the box square there? Just to add a variation on the appearance?
Finally I have polyester wadding for the stuffing. Would that be suitable?
Anyway if you don't answer I will go ahead using my assumptions and thanks again for something I can get my teeth into.
Cheers,
Dan
Last edited:
My on-going problem is I don't always get a thread update [including spam, trash folders I check daily], especially old ones brought back from the archives, though with this one only gotten one yesterday, but didn't recognize it as one I'd posted on [I follow probably as many or more than I post on], so just now getting around to 'catching up'.
You're welcome, I think.........
That's what my calculator computes.......
Correct.
This is a stuffed TL, so not necessary, but if you need to do it to make it fit a particular box shape, just a good plan to have one dimension = > 1.5x the driver's depth unless you can mount the driver motor side out.
Assuming this is net, then technically ~ 6 L short, though I intentionally designed it with some wiggle room, so even if gross should be fine. The main thing is to make sure its axial length is close since this is what dictates how low it will go.
Last edited:
Thanks GM, Sorry for my impertinent impatience [and I was a bit rude too, sorry]. I really appreciate this reply . I am new to this speaker forum [though I have hung out in the Pass section for awhile] and had not realized I was practically communicating with royalty. Salutations.
The room it's going in allows all of that to go under a pantry bench and then the drivers will project through the wall into the main room.
There probably also needs to be a port somewhere into the listening room so the pantry isn't the main source of great bass.
I would like to build Dave's design as a freestanding pair for my studio so with that and your formula I _should_ be able to make a fixed one that works too.
Again I'll make careful notes and report back .
Regards,
Dan
The room it's going in allows all of that to go under a pantry bench and then the drivers will project through the wall into the main room.
There probably also needs to be a port somewhere into the listening room so the pantry isn't the main source of great bass.
I would like to build Dave's design as a freestanding pair for my studio so with that and your formula I _should_ be able to make a fixed one that works too.
Again I'll make careful notes and report back .
Regards,
Dan
You're welcome!
Understood; newbies stand out like the proverbial 'sore thumb'.
Cool!
Duh!
That general rule [ROT] formula is for constant expansion [pipe] TLs, so recommend doing a 10:1 compression ratio [CR] and as a ROT, make the terminus [open end] = driver [Sd], so of course the closed end = 10x larger.
This allows a much shorter ~34400/8/Fs or whatever you want to tune it to.
'Sounds' like a plan.
