Inexpensive, easy, high-quality wound cardboard speaker

The third prototype of "syrinx" is a rather suspicious-looking rolled cardboard speaker.

[Rolled cardboard speaker]

Roll up a piece of cardboard and place the speaker on top of it. That's all there is to it. A little trick is to make steps on the inside and outside so that the speaker can be placed properly. (Just divide the cardboard into inside and outside and shift them.)

The sound is clear and good, similar to that of a carpet speaker. It's hard to believe that it's just a cardboard box. It resonates well and the bass is also enhanced.

If you search on the Internet, you will find several examples, but it seems that many people are unsure about how it works.

However, I think the theory is the same as with carpet speakers, except that the sound-absorbing material of cylindrical speakers has been replaced with cardboard.
Although the sound absorption of paper is less than that of carpet, wrapping it in cardboard provides a sufficient surface area, and its sound absorbing effect can attenuate mid- to high-frequency sounds. You can think of it as a thin paper tube filled with cardboard as sound absorbing material.
Considering this, it is a very rational structure in that the enclosure and sound-absorbing material are integrated.