Hello,
only double the horns does´t make sense,
only if you cut the 2 low, but understandable
to use a second horn because the FE166 and
the A166 has not much Xmax,
0,6 mm makes only 1/2 W in the bass,
so a doubling is needed,
the POSAUNE would be a alternative,
smaller, the Xmax is enough, down to 30 Hz
only double the horns does´t make sense,
only if you cut the 2 low, but understandable
to use a second horn because the FE166 and
the A166 has not much Xmax,
0,6 mm makes only 1/2 W in the bass,
so a doubling is needed,
the POSAUNE would be a alternative,
smaller, the Xmax is enough, down to 30 Hz
Attachments
hm said:
It's not actually double the number of horns. It's one horn, bifurcated. The front has to be curved if you want the twin termini to behave as a single vent -with a flat baffle, the wavefront is collimated & not equally balanced / distributed, as Ron says & found when plotting the wavefronts in his software. That said, as Terry Cain and others have found, that doesn't mean the uncurved varieties don't sound good. Image depth for example is rather good, at the expense of some point-source imaging.
An alternative is to deliberately design two horns, the lower tuned 1/2 octave higher than the upper so they come in at a single point, if that's what's desired. In all cases, you're getting a larger mouth size for a given footprint (important for a forward-firing design), a narrower cabinet for improved L-R imaging, etc. So they do in fact, make sense.
ronc said:
That's two of us (though I'm not in your league re design either). An unhappy choice of phrase on my part Ron. My apologies. What I was trying to (delicately) suggest is that while TC was the materials and construction Master, he was more of an intuitive than a scientific designer.
Of course. Which part don't you follow Horst, so I can direct you more effectively? It's all fact / physics, neither Ron, nor myself have any time for pseudo-science in audio (or anything else), I promise.
If it's splitting a horn, that's nothing new -Harry Olson was doing it 60 years ago. All you do is design & simulate a horn (any horn you like), then divide it at some point in the flare (doesn't have to be at the throat) into two separate halves.
If it's about the output from each mouth, & summing it or otherwise, Ron is better at this than I am, but I'll do my best to explain the basic principle. OK, this is a layout thing. You can't simulate it, because there's only one piece of software that can, and it's Ron's. Again though, it's just physics and the principle is easy to follow. The real trick is refining and optimising it.
Picture a double horn with a flat front. The wavefront emerges from each mouth like a pair of large, expanding bubbles. The output from the lower mouth will not be the same as that from the upper either, because it will 'see' the floor reflection boundary condition, while the upper will not (to the same extent). However, by curving the front of the enclosure into a concave shape, you form a single mouth (note that the two sides extend slightly forward, in front of the driver). The output will be in the form a single, larger, expanding bubble. The curve also helps the wavefront return to it's natural curved state better than a flat panels does.
At present, the only curved-front double-mouth design in the world AFAIK is Chang, which I designed with Ron for the FE207E (I did the cabinet, Ron designed the curved front). It's a BVR type enclosure rather than a long-path horn, but it will at least give an example of how the curved front is applied. See the design here: http://homepage.mac.com/tlinespeakers/FH/download/Chang-NBVR-map-140807.pdf Page 1 shows the flat-front cabinet, Page 2 the curved-front version.
Hope that's of some help
Scott
If it's splitting a horn, that's nothing new -Harry Olson was doing it 60 years ago. All you do is design & simulate a horn (any horn you like), then divide it at some point in the flare (doesn't have to be at the throat) into two separate halves.
If it's about the output from each mouth, & summing it or otherwise, Ron is better at this than I am, but I'll do my best to explain the basic principle. OK, this is a layout thing. You can't simulate it, because there's only one piece of software that can, and it's Ron's. Again though, it's just physics and the principle is easy to follow. The real trick is refining and optimising it.
Picture a double horn with a flat front. The wavefront emerges from each mouth like a pair of large, expanding bubbles. The output from the lower mouth will not be the same as that from the upper either, because it will 'see' the floor reflection boundary condition, while the upper will not (to the same extent). However, by curving the front of the enclosure into a concave shape, you form a single mouth (note that the two sides extend slightly forward, in front of the driver). The output will be in the form a single, larger, expanding bubble. The curve also helps the wavefront return to it's natural curved state better than a flat panels does.
At present, the only curved-front double-mouth design in the world AFAIK is Chang, which I designed with Ron for the FE207E (I did the cabinet, Ron designed the curved front). It's a BVR type enclosure rather than a long-path horn, but it will at least give an example of how the curved front is applied. See the design here: http://homepage.mac.com/tlinespeakers/FH/download/Chang-NBVR-map-140807.pdf Page 1 shows the flat-front cabinet, Page 2 the curved-front version.
Hope that's of some help
Scott
Bubble, bubble, toil and Jello…
TC was always active with regard to speaker design. He made many different boxes in an effort to discover what sounded best. If he wasn’t an engineer in the formal sense he had instincts and probably did a lot of the engineering in his mind as he thought things thru. For the sake of hearing the sonic difference he put two back horns together and recognized the sonic advantages. While measurements may not have been formal, they were audible. If the sound was worse he would have said so. Were the double horns optimized from a mathematical sense, not likely. But the sonic advantage was clearly audible without nit picking measurements. Fine tuning came later during listening tests. When he took a pipe and basically doubled it the BIB as we now know it was reborn. Measurements were poor – sound was excellent. If it was not for TCs desire to experiment, build and listen many of us would not have such good sounding speakers. The software designers, engineers and mathematicians took over from there and began maximizing the advantages TC heard with so many different full and wide range drivers that we now have a slew of amazing designs that do not nit pick the measurements even if the measurements are slightly off. Exotic, difficult to build back horns have been de-mystified over the past few years which – spawned – a collection of incredible designs that don’t just look great but have all the physics behind them legitimatizing what music lovers knew all along. TC played a major role in this and, in my opinion, was the catalyst.
Once Jello was enjoyed only by Kings and Queens during the Victorian period. Now everyone, rich or poor can enjoy it. Speaker designs TC experimented with, built, listened to, discussed, shared and ultimately sold to us were speakers built for Kings. His efforts contributed to an exchange of knowledge that brought costs down and performance up. Now, so many of us can build for ourselves amazing speakers much less expensively than only a few years ago and enjoy them almost as easily as a bowl of Jello taken from the fridge. There are a lot of contributors now but without TC we may not have come this far.
Mmmm, Jello.
Godzilla
TC was always active with regard to speaker design. He made many different boxes in an effort to discover what sounded best. If he wasn’t an engineer in the formal sense he had instincts and probably did a lot of the engineering in his mind as he thought things thru. For the sake of hearing the sonic difference he put two back horns together and recognized the sonic advantages. While measurements may not have been formal, they were audible. If the sound was worse he would have said so. Were the double horns optimized from a mathematical sense, not likely. But the sonic advantage was clearly audible without nit picking measurements. Fine tuning came later during listening tests. When he took a pipe and basically doubled it the BIB as we now know it was reborn. Measurements were poor – sound was excellent. If it was not for TCs desire to experiment, build and listen many of us would not have such good sounding speakers. The software designers, engineers and mathematicians took over from there and began maximizing the advantages TC heard with so many different full and wide range drivers that we now have a slew of amazing designs that do not nit pick the measurements even if the measurements are slightly off. Exotic, difficult to build back horns have been de-mystified over the past few years which – spawned – a collection of incredible designs that don’t just look great but have all the physics behind them legitimatizing what music lovers knew all along. TC played a major role in this and, in my opinion, was the catalyst.
Once Jello was enjoyed only by Kings and Queens during the Victorian period. Now everyone, rich or poor can enjoy it. Speaker designs TC experimented with, built, listened to, discussed, shared and ultimately sold to us were speakers built for Kings. His efforts contributed to an exchange of knowledge that brought costs down and performance up. Now, so many of us can build for ourselves amazing speakers much less expensively than only a few years ago and enjoy them almost as easily as a bowl of Jello taken from the fridge. There are a lot of contributors now but without TC we may not have come this far.
Mmmm, Jello.
Godzilla
Terry Cain was one of the most creative men I've ever known, and I greatly miss his forum contributions (I believe his last was in fact in the BIB thread), and our occasional emails. As noted in the Spawn pages, the doubled designs were inspired by his own speakers. I remember seeing a shot of his first, in the room-treatment page of the SDS, staring at it in amazement and thinking that I, too, wanted to build a pair. Not perfect, and certainly nothing like as refined as an Austin, but they offer something a bit different for people who want it. Ultimately, it comes back to the compromises you're willing to accept. Adding a curved front will remove several of these too.
hm said:
Yes, I know. I mentioned that it's a BVR (Big Vent Reflex) type of horn. As I said, I posted that link simply as an example of how a curved front is applied to an over-under mouth layout (it makes no difference whether it's a long-path or end-corrected reflex -it still sums the mouth outputs). The floor does make a considerable difference in BVR enclosures by the way -far more so than a small-vent reflex design. For example, see what Robert, who's just completed a box of this type I designed for the Feastrex 5in driver, comments about what happens to the bass when he lifts it up off the floor. There is still horn action in these boxes.
Yes, as I said, there are several ways of designing these, and that's certainly one effective approach -you can use one horn tuned to a higher frequency, & use that for the lower path to balance the overall response. Or, you can design a single horn, and split it in half. The second is the one that needs the curve, to sum the mouth outputs (although the first would also benefit in a sense in that the curve will help shape the wavefront back to its natural state & reduce distortion.)
Hope that helps
Scott
The output will be in the form a single, larger, expanding bubble. The curve also helps the wavefront return to it's natural curved state better than a flat panels does.
Good example. Here is a bit more.
As the frequency goes up the bubble becomes a smaller dia So the focus has to occur over a range of frequencies all the way to the baffle action(note the baffle is slightly recessed). With the driver in the center of the "bubble" as the frequency increases the centerline of the energy remains the same so there is a more stable image position(at any given frequency) that is only limited by the driver and amp. What you are doing ,with the dbl mouth/curve, is concentrating the energy throught the frequency spectrum at a given point.
Another point. Any sound wave in nature is or is trying to return to a spherical form. By allowing greater expansion rates to be achieved along the major length of an out of 1:1 aspectic ratio mouth you return the energy to a spherical form. The two actions (of this paragraph and the above) combine to achieve a superior performance.
ron
Good example. Here is a bit more.
As the frequency goes up the bubble becomes a smaller dia So the focus has to occur over a range of frequencies all the way to the baffle action(note the baffle is slightly recessed). With the driver in the center of the "bubble" as the frequency increases the centerline of the energy remains the same so there is a more stable image position(at any given frequency) that is only limited by the driver and amp. What you are doing ,with the dbl mouth/curve, is concentrating the energy throught the frequency spectrum at a given point.
Another point. Any sound wave in nature is or is trying to return to a spherical form. By allowing greater expansion rates to be achieved along the major length of an out of 1:1 aspectic ratio mouth you return the energy to a spherical form. The two actions (of this paragraph and the above) combine to achieve a superior performance.
ron
Chang With Double B20s
Hello, and thanks in advance for your help, and suggestions.
I enjoy my music very loud! I’m interested in building a variation of the “Chang” double BVR that includes two of the B20’s and a tweeter in each enclosure. I suspect that its not as simple as just doubling the widht, etcetera?
I would also like to do a version using the 12” woofer at the link here. I really love the sound at the movies, but want my speakers to be musical not just loud.
I would also like to get more information on these unique designs. Any suggestions, links?
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=275-070
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-045
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-391
Hello, and thanks in advance for your help, and suggestions.
I enjoy my music very loud! I’m interested in building a variation of the “Chang” double BVR that includes two of the B20’s and a tweeter in each enclosure. I suspect that its not as simple as just doubling the widht, etcetera?
I would also like to do a version using the 12” woofer at the link here. I really love the sound at the movies, but want my speakers to be musical not just loud.
I would also like to get more information on these unique designs. Any suggestions, links?
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=275-070
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-045
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-391
Greets!
Hmm, let's see...... bolting two separate speakers together or one wide one with the same driver complement, but without the two vertical divider panels to save some $$...... seems a bit of a 'stretch' to me
, yet hard to fault the reasoning. That said, in theory it will be tuned a little higher due to the increased vent friction, but I seriously doubt you'd be able to hear the difference, at least in-room.
Yeah, I like loud too if it's 'clean'.
As for design theory, you'll have to either have a good grasp of horn theory and/or trial n' error experience AFAIK, though I'm pretty sure these are more a product of playing with a suitable simming program such as MJK's rather than from just doing them with formulas and measuring/tweaking proof-of-concepts as the pioneers of audio that invented them did. Or there may be some published data from MJK or others that I've missed/not read yet: http://www.quarter-wave.com/
BTW, since you're local to me, have we met? I don't recognize your moniker.
GM
Hmm, let's see...... bolting two separate speakers together or one wide one with the same driver complement, but without the two vertical divider panels to save some $$...... seems a bit of a 'stretch' to me
, yet hard to fault the reasoning. That said, in theory it will be tuned a little higher due to the increased vent friction, but I seriously doubt you'd be able to hear the difference, at least in-room.Yeah, I like loud too if it's 'clean'.
As for design theory, you'll have to either have a good grasp of horn theory and/or trial n' error experience AFAIK, though I'm pretty sure these are more a product of playing with a suitable simming program such as MJK's rather than from just doing them with formulas and measuring/tweaking proof-of-concepts as the pioneers of audio that invented them did. Or there may be some published data from MJK or others that I've missed/not read yet: http://www.quarter-wave.com/
BTW, since you're local to me, have we met? I don't recognize your moniker.
GM
AFAIK Martin hasn't published anything. I'm no great shakes at math (and that's putting it mildly) so I haven't as yet been able to work out any formulas worth mentioning, beyond the most rudimentary, for sizing the vents. It's about time I did; problem is, I have a couple of evil thoughts brewing in what passes for my mind for the next take on this sort of cabinet, which I'd like to get your opinion on Greg. Best do that via PM though as I don't want to clag up the thread.
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