I'm making a miniature subwoofer. I contacted someone with a 3D printer, and the enclosure arrived today. I've put some glasses in the pic for comparison.
The length of the enclosure is 1.55 metres, which is exactly 1/4 of 6.2 metres.
I'm using a 3" Tang Band subwoofer, with resonant frequency 55 Hz. Sound waves with this frequency have a wavelength of 6.2 metres.
According to quarter wave theory, this enclosure should synchronise the sound waves at the woofer and the port of the enclosure, and effectively double the power of the subwoofer at 55 Hz.
There should also be some interesting 3rd harmonic boosts at 55 x 3 = 165 Hz and 55 ÷ 3 = 18.3 Hz. It will be a result if this tiny subwoofer can generate infrasonic vibrations 😊
The length of the enclosure is 1.55 metres, which is exactly 1/4 of 6.2 metres.
I'm using a 3" Tang Band subwoofer, with resonant frequency 55 Hz. Sound waves with this frequency have a wavelength of 6.2 metres.
According to quarter wave theory, this enclosure should synchronise the sound waves at the woofer and the port of the enclosure, and effectively double the power of the subwoofer at 55 Hz.
There should also be some interesting 3rd harmonic boosts at 55 x 3 = 165 Hz and 55 ÷ 3 = 18.3 Hz. It will be a result if this tiny subwoofer can generate infrasonic vibrations 😊
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hows anything resonating at 18.3 hz? Pipes not long enough
i like to play test tones at x3 and x5 and then listen to music with no crussover and try and hear when those get excited. (they’re annoying 🤓)
i like to play test tones at x3 and x5 and then listen to music with no crussover and try and hear when those get excited. (they’re annoying 🤓)
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From the looks of the result i would guess old school theory.
Modern TL/QW theory (and practise) has come a LONG way since then.
From just the looks, your line is probably too small (cross-section). A TL should to be modeled with a moidern tool to get a really good result..
dave
Lots of long pipes with no tapers or offset drivers, etc to address the lower freq harmonic junk, etc
Mr Dave:
https://youtube.com/@hexibase?si=ZxmxvHCcfAF3LNaa
Mr Dave:
https://youtube.com/@hexibase?si=ZxmxvHCcfAF3LNaa
The mcroTower tribute for instance. But it does use mass-loading. https://www.diyaudio.com/community/search/1632615/?q=microtower&c[title_only]=1&o=relevance
https://www.diyaudio.com/community/threads/microtower-bipolar-ml-tl-for-chr-70-or-el70.148901/
dave
A 3" subwoofer seems pointless to me. Pretty much good for nothing. 
Basically a desktop speaker without the bandwidth.
jeff
Basically a desktop speaker without the bandwidth.
jeff
Did watch some of Hexibase's videos? 3" subwoofers work in a car. They are too small for a room.
i tried. They seem more about the printing than the designs.
Some of what i did hear wasn’t very reassuring.
dave
That's what I've used them for. The low sensitivity and low power handling limit their use much beyond near-field.
If you want a very small enclosure (less than a liter) and decent bass extension, the W3-1876S is one of the few that'll do it without resorting to DSP/EQ. Of course another driver needs to pick up the range above a few hundred hertz.
"Miniature" and "1.55 meters" are mutually exclusive statements.
It's not a thing.
https://www.diyaudio.com/community/.../1219924-c9f4a076c8ce7b26fd8f8fb7b0e4dccf.jpg
Instead of this unnecessary complicated and expensive enclosure, build simple vented or closed box (with the same volume) with real 6" subwoofer.
Vented or closed boxes aren't very sexy, so there is no point doing much YouTube videos about them, because something more exotic and new is much more interesting and makes much more revenue. However, revenue does not equal audio quality, and usually is made with cost of audio quality (or anything). Perhaps there is good reason something is exotic and not common. This is something that takes some time to realize, a DIY person doesn't need any of it, any of the marketing and bling. But after one does realize it, it gets much easier to navigate forward with DIY projects. 99% of stuff we see online is just marketing, or myths, or stuff that is true in some context but not in another, and it takes some more time to learn to see the context where anything matters and that yours might be different than mine.
But, in the end all that matters is having fun with a hobby, so anything goes 🙂
ps. for bass volume displacement is about all that matters. Multiply Sd with p-p xmax to get rough idea of volume displacement capability of a transducer. Here it's about 27cm3. As comparison, average 15" would do about 850cm3, whopping 30x mo output at any low frequency. 15" seem to make fun bass, and I bet 12" are quite much fun as well ( ~550cm3 ), but getting smaller and smaller the fun fades away with exceptions of course. Some top shelf models can do quite a lot of volume displacement, 1000cm3 from 10" exists. My 5" fullrange speakers had nice bass with ~70cm3 volume displacement, it just didn't had enough output which eventually broke them. For 3" woofer with 27cm2 cone area to make 70cm3 it would need to have 1.3cm xmax one way. To make 550cm3 it would need to have 10cm xmax.
But, in the end all that matters is having fun with a hobby, so anything goes 🙂
ps. for bass volume displacement is about all that matters. Multiply Sd with p-p xmax to get rough idea of volume displacement capability of a transducer. Here it's about 27cm3. As comparison, average 15" would do about 850cm3, whopping 30x mo output at any low frequency. 15" seem to make fun bass, and I bet 12" are quite much fun as well ( ~550cm3 ), but getting smaller and smaller the fun fades away with exceptions of course. Some top shelf models can do quite a lot of volume displacement, 1000cm3 from 10" exists. My 5" fullrange speakers had nice bass with ~70cm3 volume displacement, it just didn't had enough output which eventually broke them. For 3" woofer with 27cm2 cone area to make 70cm3 it would need to have 1.3cm xmax one way. To make 550cm3 it would need to have 10cm xmax.
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