Yes, they can get to 16Hz which is infrasonic. But only in a large room like a church. There are many subwoofers that in the right enclosure and enough power can get below 20Hz. You’ll just have to look at your system as a whole, including the size of your room.
Better to use no void plywood such as Baltic Birch, Apple-ply or marine grade to make a square pipe for ease of folding, construction.
Again, the basic axial (down the middle) length is ~344/4/10 Hz = 8.6 m assuming an end loaded pipe with sufficient CSA, which will depend on what drives it and how much SPL is required; I mean every time we go down an octave it requires +6 dB more power handling, so if one 20 Hz Fs subwoofer = X dB, then tuned to 10 Hz must be at least X + 6 dB = 2 subwoofers and if we factor in human hearing perception we're looking at needing as much as + 24 dB below 20 Hz, so up to 2*2^3 = 16 high power 20 Hz subwoofers would be required if you want to audibly perceive 10 Hz rather just 'feel' it.
Anyway, based on my understanding of your postings, you can't get what you want for outdoors and will have to rely very much on your room's construction to go this low at any meaningful SPL same as I did for a 14 Hz tuning of (4) 20 Hz Fs 15" in a total of vented 40 ft^3, which BTW it turned out that my house apparently has a ~14 Hz Fs since it caused a portion of my ceiling and all its stored 'stuff' to come 'raining' down on us during a depth charge scene in the movie U-571 on bluray; plus being a 'floating' floor construction, it cracked one of the concrete block cement joints on a nearby sub floor support pillar, so consider yourself forewarned when going this low at any SPL higher than a background pressure wave.
I used to read " model engineer magazine " in my youth, basically people making live steam locomotives in 2 1/2 to 7 1/4 inch gauge, one of the problems was getting a scale whistle to sound low or even a hidden larger folded whistle to have the same tone as the one used on the full sized locomotive; one person came up with an interesting solution, instead of a long, folded length, he used a chamber like a Helmholtz resonator.
yes then the helmoltz resonance used together with thermoacoustics to create infrasound exists and is a technology of professor V.W. Slaton I sent him a letter for assembly instructions but got no reply, however it is a valid technology
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I repeat using a subwoofer with the speaker is inconvenient for me and I leave it as a last choice, for now I prefer to concentrate on the tube and its construction, and then I want to use it also outdoors and not only indoors
no anyway for the outside I can use the bass shaker or I leave it alone. instead for the inside the SPL that I want to reach is greater than 100 Db. provided that I will be 1 meter away from the generator considering therefore it will take less power. however 4 subwoofers are a lot considering their size. but a normal metal tube, folded on itself of length x and width 20 cm with a fan or a subwoofer at the base, could be fine? I repeat I would like to make the tube with the base to move the air I will put a fan or a subwoofer, like Gavreau's experiments.
No problem. I was just answering the question you had asked me about the 4 four subwoofers reaching 16Hz. By the way, this video really helped me understand some of the physics of sound.
good morning GM then what can be the dimensions of the tube, for a frequency of 10 hz even if I can increase up to 15 hz it all depends on the final size of the tube, and with an SPL greater than 80 Db, always considering that the tube will stay at 1 meter away from me
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hello also send you the same question then what can be the dimensions of the tube, for a frequency of 10 hz even if I can increase up to 15 hz it all depends on the final size of the tube, and with an SPL greater than 80 Db, always considering that the tube will be 1 meter away from me
Since you want output adequate for outdoor use, I'd suggest using the Danley DTS-10 design.
The DTS-10 "tapped horn" (folded 1/4 wave pipe using both sides of the drivers) can do about 97dB at one meter at 10Hz.
https://data-bass.com/#/systems/5b11c00551412e00047d6695?_k=te9ofe
That said, a relatively small bass reflex using a single 13" high Xmax driver can do around 103dB at one meter 16Hz:
https://data-bass.com/#/systems/5b11c1e3a201f10004e39d67?_k=5jw6vf
Pipes, tubes, TH are far more efficient relative to BR, but come with a severe size penalty.
Hofmann's Iron Law: low, efficient, small, pick two.
Art
Greets!
As 'Dan' and I have already pointed out it will be really quite large with a typical open pipe for a 10 m^2 room and even bigger for outdoor usage at the same SPL, so much better overall to compromise with one (or multiples) of Art's suggestions.
Portability might be a problem. This instrument looks like it would need two people or a trolley to move. Lowest note 15Hz.
https://en.wikipedia.org/wiki/Subcontrabass_tuba
Maybe something like an air-driven calliope pipe organ would work for you?
"A calliope is typically very loud. Even some small calliopes are audible for miles."
a) obtain an air horn (for a truck or train) as the sound generator.
b) obtain about 25m of flexible (corrugated) agricultural pipe
Connect a + b to get a crude one note organ. I assume this would work. Flutes, tubas etc play lower the longer the instrument is.
For a permanent install, you could bury the pipe in a trench (or wall cavity or whatever).
For a mobile build, you could coil the pipe up in a large box (a cube of about 120cm). Use a spacer to seperate the coils, and fill the voids between them with something (concrete if you have a forklift; expanding foam or similar if you are using a trolley + muscles).
Since competition car subs are almost one note, I wonder how a organ pipe would fare in a " bass off ".
A long tube as a Helmholz resonator will give one note. Wideband at low frquency and reasonable SPL is more difficult.
What would happen if you used a loud speaker driver as a "reed" in an organ pipe ? would it be like a very narrowly tuned band pass ?
JL Audio 13W7-D1.5 end loaded ~23.5 Hz (driver Fs) 1/4 WL pipe 1:1 CR (blue)/335 cm axial length Vs 2:1 CR (red)/335 cm/0.707 = 473.8 cm comparison, so a bit more than 'one note' 😉, and if a 0.5:1 CR, then it fills in the rolled off response to (Fs).
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wow the data are perfect, I already knew the bass reflex but I was afraid of the large size, I am interested in that it is as big as a 40-45 liter travel suitcase. if the dimensions coincide or poosomally get to those of a suitcase then I choose the bass reflex
I did not know this Calliope tube, however it seems excellent to me so together with the bass reflex it is an excellent condidate, but the problem is always the dimensions, which I want them to be as small as possible obviously without exaggerating, so for me 120 cm per side is a lot also because would not fit the car at most 80 - 90cm would be fine? maybe bending the pipe in an orderly manner with elbow bends and using resonant materials like, for example, plumbing? What do you think about it,