Your requirements are non-sensical to begin with. Google: Robinson-Dadson equal loudness contours to see why your requirement is a bit of a fools errand. There is also masking, where higher frequencies being reproduced mask the lower frequency content.
Also, you seem to want to be handed a 'plan'. This is not how DIY works. DIY stands for do it yourself. If you can't take advice from experts with literally decades in the industry, then so be it.
What if you had a powerful centrifugal fan, blowing ( and pressurising ) a large chamber, and had a butterfly valve controlling an exhaust from the chamber. The butterfly valve could be operated by a solenoid, or a lever connected to a sub. I thick I'd go for multiple small valves to reduce inertia. You'd still need a large volume to be effective, unless you got it up to a decent pressure.
no but I am not sure of the formulas I use and I would like some advice on the construction and not the whole project, I just want to know the dimensions of the pipe because I see that with organ pipes it works so I believe that I can do it too and then some tips for building
yes what you told me I can do, so now I'm concentrating on the tube by folding it. if you need to pressurize it I do it and even 18 hz is fine, if you can I could take an organ pipe and fold it but I don't know if it is feasible
I was more imagining a box than a tube, constantly pressurised by a fan, and the pressure ( hence low frequency sound ) released in a controlled way by a butterfly valve, perhaps a more sophisticated way would be to have anouther butterfly valve on the intake of the fan, both valves would be half open, when you wanted a positive pressure wave the valve exhausting the box would open more and the valve on the fan would partially close, when up wanted a negative pressure wave the exhaust valve would close, and the intake valve would open more. This would mean that a constant speed, powerful fan could control the pressure in a box, much like a huge displacement speaker driver, or a rotary sub without the variable pitch blades.
Calliope organs are (mostly) lost to history, but there are a few modern examples. They were basically the same as pipe organs in cathedrals, but mobile.
"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?"
My size guesstimate was based on 10cm diameter corrugated agricultural pipe: you could fold a 20m length of that pipe into a cube enclosure of about 1.2m (with space between sections of pipe for filler). Using smaller pipe would pack down into a smaller enclosure.
However, real pipe organs are big in diameter for a reason - to maintain timbre and volume. The change in timbre is because:
"narrow pipes are rich in harmonics"
https://en.wikipedia.org/wiki/Organ...lished this as a,circumference of such a pipe.
The narrower the pipe, the more harmonics (high frequency noise). These harmonics could easily seem louder than the fundamental, because your hearing is more sensitive in the band that the harmonics occupy.
You could try to suppress these harmonics, e.g.
- by having the pipe exit downward (so that the gap between box and floor acted as a plenum).
- by using a sliencer / foam / lagging
- by having flared / different diameter sections
...but I don't know the science behind this. I know that these techniques exist, and are used commercially (to reduce noise in air ducts), but I do not not how to design + build them.
"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,""
Yes, you could use plumbing pipe and elbow bends - but that would be expensive and fiddly. I'd go with:
- flexible pipe
- fold it like small intestine
- use wire / spacers to keep a small gap (keep sections of pipe from touching each other)
- filling in that gap (with gap-filling foam, or similar)
...would be a lot faster and cheaper. Basically copying this idea from construction / building foundations.
If this was not feasible, then trombones, saxophones etc. would not exist.
Maybe the use of a smaller diameter pipe wuth mote harmonics is not even detrimental due to the louder impression. Mybe it would even be better to use "synthesized bass" using artificial harmonics from the beginning.
Right, the pipe's diameter must be WL/pi for max proper harmonic structure ('speak'), so ~34400/pi/10 Hz = ~1095 cm/431.1"!, hence using multiple smaller diameter pipes to accomplish this and even then to get the desired performance requires a pretty powerful air pump based on the Church I frequent to get my organ 'fix'.😉
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I was wondering about this since our internal processor will reconstruct the full WL given sufficient harmonics, though of course not the impact, but what's the point in this case since the harmonics for infra bass is still quite large?
Sweet link. I really should go to a performance. I used to work with a man who plays Bach cantatas, but never pulled my finger out and attended one.
This one also looks delightful - but I haven't been there, either.
https://en.wikipedia.org/wiki/Sydney_Town_Hall_Grand_Organ
Would the 8hz pipe be the big one shown in the middle of the photo? It looks pretty chonky, but "only" about a metre in diameter, a bit shy of the "ideal" 🙂
Dunno, but considering it's even bigger than the 10 Hz + having an even larger harmonic structure since the lower the frequency, the wider its BW, I'm guessing it's the entire first row, which I assume will also be doing double duty for a goodly portion of the higher frequencies.
Yes, they are still large but none the less definitley smaller and making a compact solution deliver more output. I don't know what the physical impact of 10 Hz is outside when generated with rather small devices up to a few meters in size.
ok even if this solution is not the tube but, if it respects the dimensions requested by me then okay, maybe tell me some advice for the construction, in order to understand better
your build image is doable for me i can fill the spaces with rock wool or polyurethane foam, your creeds need to be as wide as possible and bend them with u-fittings. i can also use more resonant materials like iron, it wouldn't cost that much, the only problem is how to power it ie use a fan or compressor?
ah ok so using artificial harmonics to contrast is a great idea also because it is better if the diameter is small, from your calculations how much should the diameter be?