Long pipe to sequester rear wave

Ben,

In your original post, you wrote "A disadvantage, at least for my sub, is that it's about 13 cu feet.. For some reason people believe the silly "Iron Law"."

Assuming we are referring to Hofmann's Iron Law (low bass extension, high efficiency, small size- pick two) your 13 cubic foot cabinet in no way breaks it.

Do you still believe Hofmann's "Iron Law" is "silly"?

Art
 
Do you still believe Hofmann's "Iron Law" is "silly"?
Let me unpack the silly "iron" law. In essence, it just reminds us that low freq waves are long. So if you have a two-sided opposing-phase point-source, you need to keep the two sides from interacting destructively. The "law" possibly speaks to sealed boxes, if it applies to anything else at all.

The size of the "thing" that keeps the two sides from interacting destructively depends on your cleverness as well as the laws of physics. Is an infinite baffle using an attic space big? Is my labyrinth that takes only 17 x 17 inches of floor space in the corner of the room (for 12 Hz reach) big? Dipoles big? Can you live with a wonky freq response or poor transient behaviour? OK to increase distortion?

The part about "efficiency" makes no sense since - with cleverness, time, or money - you can always secure a more efficient driver with fancy or precision bits or use a more efficient (Class D) amp.

I usually talk about the "iron law" of motorcycle mufflers to illustrate designs with competing trade-offs (engine breathing, size, weight, durability, complexity to manufacture or repack, sound control, cost, appearance......*). Substituting an electric motor solves the problem, eh.

Like with the Iron Law, you need to add "if you are short on imagination" to make it true.

B.
* Have I left out other considerations? Visibility for the manufacturer's brand label?
 
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The "law" possibly speaks to sealed boxes, if it applies to anything else at all.
Hofmann's Iron Law (low bass extension, high efficiency, small size- pick two) applies to all boxes and transducers.
Is an infinite baffle using an attic space big?
Yes, most would consider an attic space "big".
Is my labyrinth that takes only 17 x 17 inches of floor space in the corner of the room (for 12 Hz reach) big?
In terms of a foot-stool size cabinet, yes, your 17x17x72 inch tall 13 cubic foot cabinet is big.
Can you live with a wonky freq response or poor transient behaviour? OK to increase distortion?
Poor frequency and transient response or distortion have no direct relationship to bass extension, efficiency, or size.
The part about "efficiency" makes no sense since - with cleverness, time, or money - you can always secure a more efficient driver with fancy or precision bits or use a more efficient (Class D) amp.
Class D amplification can exceed 90%, about double the efficiency of the tube amplification used for the first loudspeakers, while a moving coil driver in a 2 cubic foot sealed box with an F3 of 30Hz still won't exceed about 0.18% efficiency (<86 dB one watt one meter) regardless of how much cleverness, time, or money you put into it.
Drop an octave in response in the same size box to 15Hz, and efficiency drops about 9dB.
Conversely, increase the volume of the sealed box by 8 times (16 cubic feet, a "small" attic space..) and the 9dB loss is eliminated.

A 13 cubic foot cabinet constructively utilizing both sides of a moving coil driver can certainly be more efficient than that driver in smaller box, though since the relative efficiency is still so low, most won't care about Hofmann's Iron Law, and will choose to use more power in a smaller box to achieve the similar results.
...with the Iron Law, you need to add "if you are short on imagination" to make it true.
I guess most of us are "short on imagination" of the laws of physics governing loudspeakers changing any time soon, but one can dream...

Art
 
Hey you can give the old dump truck sub a rebuild for 2022😃 not much there to see just a little bit different approach and some other real estate to stuff maybe? Maybe it’s both outputs in the same location you’ll notice something different

Or you can swap the first three cross-sectional areas out for 1296 cm2 go under the 20,000 leagues mark.
 

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The only issue I can think of with going so low (assuming it’s pushing the issue in a way that’s not typical) for base extension is the group delay will start racking up points quick Why do you hit that threshold. And you’re already using a reduction in cross-section to do so.

However that may or may not bother someone if they’re not sensitive to it or don’t perceive it. Kinda hard to say and some people seem to like portions of the lowest notes at that point you can barely hear anyhow as long as they’re still around and present maybe they’re still a good contribution to your listening experience or Not that much lower and it’s a ‘feeling’ experience more than audible?

I’m Still waiting for a driver to get back in stock at parts Express so I can have two of them and try my best at making a 12-16 Hz infrasonic experiment And see what it’s all about
 
??? Historically, the point was to fill in missing (sub) harmonic fundamentals (Fs) to (re) create a more life-like audio/visual experience be it a low B pipe organ symphony recording or action movie LFE since the lower the (Fs) the wider its (perceived) BW, a big plus for those of us that typically only had an otherwise ~ 20/50 - 12 kHz system.
 
??? Historically, the point was to fill in missing (sub) harmonic fundamentals (Fs) to (re) create a more life-like audio/visual experience be it a low B pipe organ symphony recording or action movie LFE since the lower the (Fs) the wider its (perceived) BW, a big plus for those of us that typically only had an otherwise ~ 20/50 - 12 kHz system.
This is what I was hoping to do and sneaking underneath everything with a super subwoofer(infra) because of how much you have to give up of that low end as a result of attacking the upper subbase region with the dual parallel types of approach which themselves have a signature and very pronounced punch to that area of base that once you hear it it really has a potential to be the perfect Kickdrum as if you were literally sitting in front of the percussion set up at any concert. It could be excessive and even uncomfortable to the inner ear so it has to be dealt with to be reasonable but at the same time one cannot deny especially if you like that sort of bass in that area that there’s something special in these cabinets that is allowing us to experience more than others tend to give up.

I think that may extend all the way into the Keystone the Paraflex the roar and probably a couple others. There’s some thing to the offset driver entry version as well I don’t know if it’s quite so sharp but the whole point in some of these is once you can get the distances in your folding perfect in a repetitive sequence that doesn’t do anything but support the fundamental and smaller and smaller parts of it something is definitely changing in there as opposed to a base reflects cabinet or whatever things people just lump sum and toss together without regards to standing waves or potential usefulness of that distance as contribution to a low pass filter effect by using the position of the actual node for the harmonic. And this point of fold abd /or driver entry in the cabinet. And from both ends in many designs this can create oh unification of all of those things too which is only expressed in the details of simulation you can see far up out of the past band something special happens. Probably for another discussion as it’s unique to only a few designs seems

What once was 00349206349 (Thats 20/360* , is now in a compound cabinet 05238 or 30/360 with with 300 separating the drivers.

6.2857142 (360 cm) is the total and 5.238 is 300 cm Between the drivers and .5238 is the distance from each closed end , from a zero and 360 essentially . So its 1/12 and 11/12 of a circle if using that as the basis for the cabinet design. Which once you do everything works out beautifully. Can you can see that Further using circumference equals two pi R and using pieces of radius to define those arcs as a radian to divide up these numbers as angles or what they are in degrees as centimeter?? it works both ways. You can see it in different designs were both numbers can affect the other. But since we’re not familiar with radians we don’t use that for much of anything anymore it’s long gone with navigation to GPS nobody’s familiar with that and the numbers to seem odd to all of us as a result..

Originally 03492 in a 300 cm cabinet was 104.76 cm. ((It’s 20° and 300° and 60° in a variety of explanations numerically describe them ) Either way it’s still The absolutely perfect position to put the driver entry in in the ODTL mode. And it’s giving it the correct cross-section for the drivers TS parameters appropriately that all worked out excellent every time.

And the same idea then becomes the alignment to which you want things overlapping in the compound cabinet and the same approach has then much greater advantage in that acoustical output and low pass filter effect it will once you’re incorporating it.

And what you get out of these things like the Paraflex that normally were very sloppy and nasty and places that require more recently as they find huge amount of stuffing and Band-Aids to fix things is that those are all gone and they don’t even need to be there it requires a little shuffle in the layout that might not be PA friendly but the numbers and the results are like a small oasis in the desert of issues that previously were big issues as soon as you put a paraflex in a boundary condition a lot of nastyStuff started showing up that never did I was notice before and of course not many people try to use those in anything but the PA application and the more and more people would the more we would run into the idea that these things are horrible and burn them in the dumpster fire.

But as it turns out with a little bit more investigation they don’t. They just need to deviate entirely from the original version created for PA. Because that is a scrambled egg if you look at its results and how it simmed and folded and design it’s chopping up a disaster that shows up more and more at certain frequencies that have to somehow run into each other in the cabinet and simply do not agree they are colliding inappropriately from their endpoints came from and That can get out of hand quick room that produces more of the same or extends the problem so to speak.. small room obviously being the absolute disaster but also the place to learn the very most about this.

it’s always in the same area it could be an 86.4, it could be 93.75 and 108 or so. It really depends on the details but
Those frequencies that oddly given the right arrangement get nasty inherently all the time.

until you fix it and then it seems to have all disappeared. And then it just seems like the honest to goodness approach to a plain Jane transmission line that happens to have one piggybacking it that just gives more output because it’s an acoustical advantage nothing more nothing sloppy nothing weird nothing strange encountered. And nobody has the damp things out to the point where they’re compromising with their already trying to get initially.

The only thing left to do Is the normal stuffing that one would want to do Because their preference or their ability to hear boxy sounds or whatever I don’t know I can’t speak for other people’s hearing but there are things that don’t matter what I end up throwing some some of that party for him places just dial in things and the smallest level not huge catastrophic disasters that need that typically because they shouldn’t unless you’re coming up short on the other end or you’re forced to compromise things in order to fit the design into certain size shape etc. which no one can avoid and that’s always going to be a problem for all of us if we have to do that.

There’s absolutely positively something that has been missed . That is that number 05238 it’s the same number as the volume of the sphere is when radius is .5 versus .1

that number goes on to be the swing of the panel and 30° in one second

That number is the basis for everything in the tire universe and not even only acoustical advantages but the mathematical location of planet earth is relying on that exact number to describe its orbit and it’s hexagon or dodecahedron points of interest laid upon that mathematically are exactly over and over again the mathematical orbital mean of our own planet.


it’s the same approach as a 03492 which has been a number that both yourself and Martin King were using in everything when you wanted to drive or entry point to fill in that harmonic.

But that’s a number and the ones he incorporates entire orders becomes a number to find the exact location in our own existence in the space and time if you look.

And whatever it does is our speaker designs is undeniable as well. And more than I can type here is about three or four pages of simple basic math that all of us with digest no problem but that spells out the connection between all of us and our own existence in our own solar system and the galaxy next to it and even more.

It’s the same numbers and even more so the numbers within all that that you can find a simulation further it to the most amazing detail it’s almost hard to not choke up , and wonder why this was hidden all this time. Not discovered along the way except for the fact that no one was able to look there simply wasn’t for a reason up at all recently.

It’s not for a combination of things in peoples ideas from different areas all coming together with a man providing us the ability to looking all in anyway I possibly could together they created a narrowing down of things further and further into The island the little tiny speck where it all came together at.

literally half of that number is the location in degrees of planet earth and 3/4 of it is Mars. It’s an absolute is the definition of the speed of light as it’s on wave form if it had a sine wave hypothetically speaking with a zero at an X axis and a pressure velocity Max minimum either end in between.
 
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There’s something going on that’s played out very well in some of the higher order cabinets. You can see it in the simulation as you pull weight parts and put them back in horn response thankfully.

individual links being stripped from or put back into the system or exact locations of activity in all the bandwidth as compared to in the bandwidth.

But there’s something odd at860 And also every single frequency that adds up to beyond that as in 1720 2580 3440 …. When you were lined to wear those are completely canceled out like nothing else ever can be. It’s doubled from both sides of the enclosure inputs so to speak.

you will see -990 DB innocent like there’s a vacuum it out location in pressure. Two things about that are incredibly unique. Number one you obviously had to fold that as you described as the cabinet or understand what you what that means and where but number two it’s describing circle and it’s rotation intervals and the drop of the number for over and over from the get-go.

that’s 864-4 1728-8 and 2592 -12 and Those are the numbers of time to us both in the microcosm of one day or 24 hours but also in the 72×360 which is the season or beeThose are the numbers of time to us both in the microcosm of one day or 24 hours but also in the 72×360 which is the year any much grander grasp of the concept that the entire earth is tilted from one side of the access to the other all seasons and weather patterns have also shifted in that. And that can be divided into four at 6480. And some of this starts to make sense because Harmonics at a higher level and bodes law is what found in describe every single planet in our solar system in the same exact manner using the same exact numbers which those represent in centimeters if derived from parts of a centimeter which describe things in depth which is the one over25Harmonics at a higher level and bodes law is what found in describe every single planet in our solar system in the same exact manner using the same exact numbers which those represent in centimeters if derived from parts of a centimeter which describe things in depth which is the Conversion factor between an inch in centimeters where this information has always existed in for eternity will continue to accept it we’re expanding and everything is expanding further and further apart from everything including 3.8 cm a year ourselves end of the moon


if you look at the conversion from centimeters to an inch as 001/254 and also in another column list 003÷254 numbersWhich are the decimal points of all of those and taken all the way out 36 intervals to see what they say and what those numbers are in radians. But also these carry an extra signature of another sequel to numbers and another pattern within. Conversion between again angles but also description of them is radians. It’s truly amazing what that is saying and how it has everything to do with acoustics as well as everything in astrophysics or astronomy to be plain and simple and blunt and obvious.

Exact same triangles you could draw in place of sine wave shapes which art arch can be broken down to become hexagons and dodecahedrons made up of those triangles which is merely the 3060 9120 relationship all the way up to 436Exact same triangles you could draw in place of sine wave shapes which art arch can be broken down to become hexagons and dodecahedrons made up of those triangles which is merely the 3060 120/240/360 overlaid on circumference.

If you just start with a centimeter numbers and you have a computer calculator or scientific calculator that would take those and show you a lot of decimal points if not you can double down on the number and it will push it over so you can see the next sequence I just keep adding that as if it was still the initial .001 or the .003 so you can see more and fill it in until you see it start to repeat itself.

Take those numbers and extrapolate them into what they might mean or stand for or what information you could get from them as a result of what they are.


Quickly he becomes obvious there’s something there initially it’s kind of difficult because the 00.3937 -00-7874 015748… don’t say much . until you get to the 31496 and the 62992 that you realize working backwards you can come up with 192 and 96 and 48 and 24 and 12 . And those exact frequencies are the ones that break down the perfectly aligned version of a compound or series whatever I order cabinet, to the 860, 1720 Absolute cancel sequence that they both straddle mathematically to the same thing just like they do and the time sequence in the distance from the sun to every single thing that Einstein or Stephen Hawking or any of these people would refer to if they only had looked like maybe Nikola Tesla was attempting to at what we can see now crystal clear thanks to software and the Internet that provides it. And all the information to connect all these things together

it’s truly amazing how is all the same. But nobody looked at what it took to reproduce sound and the connection between that and the harmonics and that’s a whole Nother chapter it seems because we all understand music in harmony and the science and physics of that nobody tripped over and fell into the rabbit hole of the deep connections to speaker design precisely I don’t think…,

And maybe we are now as we look at what I’m talking about because it spreads into quite a few areas and other designs as well. How this information has always been inside Egyptian pyramid precisely car got a granite in a room. That’s the only place where I found the same exact numbers or proportionally in different units of measure of which were very difficult to figure out and confusing endlessly until it all clicked.