Oninions ?- Transmission Line over Reflex and Acoustic Suspension ?
Hi. I posted a previous inquiry in reference to building a pair of TL speakers in the design of a narrow, tall, column tower design.
I am somewhat inexperienced in TL's other than assisting my brother in duplicating an existing design in a publication by David Weems, " Great Stereo Sound Speaker Manual with Projects." We did this some time ago, around an inexpensive Pioneer 6-1/2" translucent woofer driver, a cheap Motorola piezo radiant tweeter, and a simple crossover.
The sound, from my recollection, was astounding, and unusual for such an inexpensive design and small woofer. The reason we did it was experimental, and they delivered on the promises Weems made about them. Anyway, my brother is still using them in his den.
I also had the opportunity to hear a pair of Vandersteens, when invited to a friend's boss' house for a party several years ago, and recall many people (myself included) marvel at the warm, depth, clarity and imaging of these amazing speakers.
I had a similiar experience listening to KEF s and Soliloquoys, among others on other occasions, and really felt they had a beautiful sound by comparison to other quality speakers I've heard over many years, and cannot describe the apparent difference. For this reason I have taken a serious interest in unusual designs such as Voigt pipes, tapered lines, labyrinths, folded horns, etc.
Would any or most of you agree that they are sonically superior by design ? Does anyone have different views regarding TL's ?
Most of the material I have been reading regarding TL theory suggests these designs are superior and capable of producing bass down to a woofer's given free-air frequency, and do not impose limitations on the woofer that inhibit clean, natural, uncolored bass, particularly in the upper and middle-bass frequencies. Advocates of lines all seem to unanimously agree that they beat all other designs on all counts. (Efficiency, lack of coloration, depth, etc.) Often they condemn acoustic suspension designs for pressure buildup in one side of the cone, and vented bass reflex systems for "ringing", and port noise, etc.
Just interested to see what some of you out there, think, in your honest and professional experience and opinions.
I'm wondering if it is worth all of the effort to build such a large enclosure, when many cite I could obtain the same reults in a smaller, less expensive, less time (and space) consuming box.
I truly appreciate any of your opinions, value your DIY experience, and your willingness to share your knowledge.
Thankyou. Warm Regards, Eric
Hi. I posted a previous inquiry in reference to building a pair of TL speakers in the design of a narrow, tall, column tower design.
I am somewhat inexperienced in TL's other than assisting my brother in duplicating an existing design in a publication by David Weems, " Great Stereo Sound Speaker Manual with Projects." We did this some time ago, around an inexpensive Pioneer 6-1/2" translucent woofer driver, a cheap Motorola piezo radiant tweeter, and a simple crossover.
The sound, from my recollection, was astounding, and unusual for such an inexpensive design and small woofer. The reason we did it was experimental, and they delivered on the promises Weems made about them. Anyway, my brother is still using them in his den.
I also had the opportunity to hear a pair of Vandersteens, when invited to a friend's boss' house for a party several years ago, and recall many people (myself included) marvel at the warm, depth, clarity and imaging of these amazing speakers.
I had a similiar experience listening to KEF s and Soliloquoys, among others on other occasions, and really felt they had a beautiful sound by comparison to other quality speakers I've heard over many years, and cannot describe the apparent difference. For this reason I have taken a serious interest in unusual designs such as Voigt pipes, tapered lines, labyrinths, folded horns, etc.
Would any or most of you agree that they are sonically superior by design ? Does anyone have different views regarding TL's ?
Most of the material I have been reading regarding TL theory suggests these designs are superior and capable of producing bass down to a woofer's given free-air frequency, and do not impose limitations on the woofer that inhibit clean, natural, uncolored bass, particularly in the upper and middle-bass frequencies. Advocates of lines all seem to unanimously agree that they beat all other designs on all counts. (Efficiency, lack of coloration, depth, etc.) Often they condemn acoustic suspension designs for pressure buildup in one side of the cone, and vented bass reflex systems for "ringing", and port noise, etc.
Just interested to see what some of you out there, think, in your honest and professional experience and opinions.
I'm wondering if it is worth all of the effort to build such a large enclosure, when many cite I could obtain the same reults in a smaller, less expensive, less time (and space) consuming box.
I truly appreciate any of your opinions, value your DIY experience, and your willingness to share your knowledge.
Thankyou. Warm Regards, Eric
I have built Mass Loaded Transmission Lines and Bass Reflex cabinets for the same driver. Bass does sound more controlled by the MLTL, but there are other considerations. See:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=96968&highlight=
Regards,
Andy
http://www.diyaudio.com/forums/showthread.php?s=&threadid=96968&highlight=
Regards,
Andy
"Eggs" and Transmission Lines
Those "Eggs" (speakers) you discussed in the thread seem very interesting.
Reminds me of a design I saw once, where the guy called his speakers the "centipede." It was made up of a group of series/parallel, full-range, Tang Band drivers, consisting of a several round, egg-shaped "spheres," mounted on an S-curve bend wrought iron rail. These were a left and right pair.- I believe twenty-some, total, in all.
Do you have an opinion regarding TL's over vented and/or sealed enclosures?
Do you feel they offer better sound?
Do you share the common belief, as many others have indicated that, "it is a waste of time to build such large cabinets, when you can obtain good results from a smaller, less complex, easier to build enclosure which occupies less space?"
Those "Eggs" (speakers) you discussed in the thread seem very interesting.
Reminds me of a design I saw once, where the guy called his speakers the "centipede." It was made up of a group of series/parallel, full-range, Tang Band drivers, consisting of a several round, egg-shaped "spheres," mounted on an S-curve bend wrought iron rail. These were a left and right pair.- I believe twenty-some, total, in all.
Do you have an opinion regarding TL's over vented and/or sealed enclosures?
Do you feel they offer better sound?
Do you share the common belief, as many others have indicated that, "it is a waste of time to build such large cabinets, when you can obtain good results from a smaller, less complex, easier to build enclosure which occupies less space?"
There is a large spread of designs that can be called TLs. Some drivers are suited, some aren't.
For a suitable driver a TL is a very nice box.
dave
For a suitable driver a TL is a very nice box.
dave
Re: "Eggs" and Transmission Lines
I certainly don't. I've built my own 1/4 wave Transmission Line speakers and they are VERY worth the effort. Deep DEEP bass is quite possible with a small-ish driver (mine uses a 8" woofer).
Do it! You won't regret it!
NepaEric said:
I certainly don't. I've built my own 1/4 wave Transmission Line speakers and they are VERY worth the effort. Deep DEEP bass is quite possible with a small-ish driver (mine uses a 8" woofer).
Do it! You won't regret it!
Dayton Drivers on thier way.
I am going to build them. I have an excellent design from a friend who modeled them with the MathCad program. They seem promising, based on the graphs, which show a very good, flat response curve. Thanks, Eric
I am going to build them. I have an excellent design from a friend who modeled them with the MathCad program. They seem promising, based on the graphs, which show a very good, flat response curve. Thanks, Eric
Eggs and onions? How about some cheese and hash browns?
Speakers for breakfast? Hope you brought some coffee.😀
If I were you I would read some recent stuff about TL's. Much of the hype that has been perpetuated for 40-odd years about these enclosures has been debunked. They are revealed to behave as damped 4th order systems of the nature of reflex boxes, but with a different (more complicated) resonant mechanism. They generally are much larger than an equivalent reflex. They ring or resonate at multiple frequencies just like Bass reflex. The whole concept of acoustic suspension being a "pressure box" (in a negative way) is flawed. All enclosures radiate sound in proportion to the amount they pressurize the air inside the box.
Good things about TL's, the cabinet construction lends itself to automatic bracing - less box talk. They also have the audiophilia nervosa mystique factor that will make your tweekaholic friends envious.
Ron E said:
That is untrue. Because we have a greater understanding on TL-space does not undo how good the best of the breed are/were capable of or make any less valid the positive attributes a TL can bring to the table. It does mean that the success rate of good TLs has gone from probably 10% up to 90%.
Further, an unstuffed TL is a 4th order system, but it can be taken down to a 2nd order system id you want with the addition of juditious stuffing.
If one is willing to live with the size, a TL can bring alot to the table. For one thing a TL is more tolerant (than a BR) of the shifting T/S parameters that happens with the weather or how loud we turn it up.
dave
Small Box design for Kef 139
Planet10
I interested in building a TL using Kef139. Any recommendations or plan's you can refer me to re making the speaker as compact as possible ?
Thanks
Jozua
Planet10
I interested in building a TL using Kef139. Any recommendations or plan's you can refer me to re making the speaker as compact as possible ?
Thanks
Jozua
I have a sub I've built as a TL design (by people off of this forum). Using just 2 6" drivers it achieves very deep bass. Measurements haven't been too successful but in room it seems to be merely a db or two down at 20Hz. A big box in relation to the drivers but very effective.
planet10 said:
A damped 4th order can also be achieved with BR. A BR with "port damping in excess" acts as a sealed box. I have seen BR boxes with a 1st order initial rolloff...
When a flat impedance is desired, shorted coil DVC alignments and drivers with damping stapled tightly over the basket are admirably flat...
I am not trying to discourage anyone from building a TL, just giving my alternative point of view. It seems that anyone who listens to anything vaguely resembling or touted as a TL, whether it actually is or isn't (many are simply a variant/hybrid of BR) praises its bass.
The myths that they go down to resonance, that they have a first order roll off, that they are transient perfect, etc..... live on despite evidence to the contrary.
Much of DIY audio seems to be about fashion, or even just "being different" and expressing oneself. Build what you want, but one doesn't always have to delude oneself with decades old audio mythology to appreciate the music.
caveat emptor
Ron E said:
Conversly, with the fasion for tall, skinny floorstanders there are a lot of boxes that are called BRs that are actually ML-TLs.
dave
Right. Quite a few (commercial in particular) designers, when this layout became fashionable a few years ago, found themselves having to go back & re-tune their boxes because they found they were getting more LF extension & gain than they expected due to the QW action.
An MLTL (probably more accurately described as an ML QWR -not a happy choice of name IMO) is not a reflex box. Sorry. A BR assumes no standing waves; an ML QWR deliberately generates and uses standing waves. Generally you can take the transition from one to the other as being the point at which you have to adjust the box tuning to account for the standing wave action.
As for 'decades old mythology' -read MJK and Augsperger on transmission lines lately? Not much mythology in there, unless you've been reading versions of their papers I have yet to run across. The main problem in TL design IMO is that people use the term to mean different things & sometimes complete opposites. I sometimes wish Bailey had never coined the term.
An MLTL (probably more accurately described as an ML QWR -not a happy choice of name IMO) is not a reflex box. Sorry. A BR assumes no standing waves; an ML QWR deliberately generates and uses standing waves. Generally you can take the transition from one to the other as being the point at which you have to adjust the box tuning to account for the standing wave action.
As for 'decades old mythology' -read MJK and Augsperger on transmission lines lately? Not much mythology in there, unless you've been reading versions of their papers I have yet to run across. The main problem in TL design IMO is that people use the term to mean different things & sometimes complete opposites. I sometimes wish Bailey had never coined the term.
Scottmoose said:
The name is GL (George) Augspurger.
Enclosure design and simulation is one of my main interests. I wrote a program like Unibox 10 years ago. I once had dreams of marketing it, but people are too interested in freeware nowadays. To me, MJK and GLA's efforts are most interesting in what they disprove, namely much of the 40 year old mythology (and design methods) behind TL's.
Anyway, I am familiar with their research, and that was the "recent stuff" I was suggesting the OP read in my first post.
Yes, I know. Apologies for the typo. 
Yes, they've done stirling service in ejecting a lot of the nonsense. That said, in fairness to both Olney (Acoustic Labyrinth) and Bailey (God help us... the 'transmission line', despite the fact that the example he presented wasn't really a TL), both their papers are actually very good, within their remit. In reality a lot of the problems appeared post-Bailey, and I get the distinct impression that many people simply hadn't read his article properly, resulting in problems, none of them helped when Bradbury took a bit of a wrong turn (nice idea, but...). George & Martin, finally (thank God), went back to basic physical principles, disproving a lot of the waffle, and also showing that some of the pioneers were in fact pretty good, until their work was diluted or lost.
Yes, they've done stirling service in ejecting a lot of the nonsense. That said, in fairness to both Olney (Acoustic Labyrinth) and Bailey (God help us... the 'transmission line', despite the fact that the example he presented wasn't really a TL), both their papers are actually very good, within their remit. In reality a lot of the problems appeared post-Bailey, and I get the distinct impression that many people simply hadn't read his article properly, resulting in problems, none of them helped when Bradbury took a bit of a wrong turn (nice idea, but...). George & Martin, finally (thank God), went back to basic physical principles, disproving a lot of the waffle, and also showing that some of the pioneers were in fact pretty good, until their work was diluted or lost.
There are only three cons to transmission line
1. Time delay(but I like it)
2. Some cancellation creeping in mids(tried different stuffing it gets fixed)
3. And the hard work to get it right
And it's worth while for every pro it provides
1. Time delay(but I like it)
2. Some cancellation creeping in mids(tried different stuffing it gets fixed)
3. And the hard work to get it right
And it's worth while for every pro it provides
1/ given the distance involved and the frequencies involved the waveforms are in phase but the terminus is behind in time, if you are using the line to extend the bass.
2/ Not if the line is done right… all the mids get sucked into the line and absorbed so one can get less time-smeared midrange coming back thru the cone.
3/ if you know your way around a TL and use a good modeler one can often nail a design on the first try. It does take more knowledge than doinga. sealed box and one has to be concerned with the same kind of alignment issues one has wit a BR. The largest issue, as is often the case, is choosing a suitable set of compromises.
dave
2/ Not if the line is done right… all the mids get sucked into the line and absorbed so one can get less time-smeared midrange coming back thru the cone.
3/ if you know your way around a TL and use a good modeler one can often nail a design on the first try. It does take more knowledge than doinga. sealed box and one has to be concerned with the same kind of alignment issues one has wit a BR. The largest issue, as is often the case, is choosing a suitable set of compromises.
dave
