Inexpensive, easy, high-quality wound cardboard speaker

"syrinx" Prototype No. 3 is a very suspicious winding cardboard speaker.

[Wound cardboard speaker]

Roll up a piece of cardboard and put the speaker on it. That's it. I devised a little so that the speaker can be mounted well, so that the inner and outer stages are set. (Simply divide the cardboard into inner and outer parts and shift them.)

The sound is clear and good, similar to carpet speakers. I don't think it's just a cardboard box. It sounds reasonably well. Bass is also enhanced.

If you look it up on the Internet, you'll find some examples, but many people seem to be puzzled about the operating principle.

However, I think the theory is the same as carpet speakers. It's just that the sound-absorbing material of the cylindrical speaker has become cardboard.
The sound absorption of paper is less than that of a carpet, but corrugated cardboard can secure a sufficient surface area, and its sound absorption effect can attenuate mid-to-high frequencies. You can think of it as a thin paper cylinder filled with cardboard as a sound absorbing material.
If you think about it, it is a very rational system in that the enclosure and the sound absorbing material are integrated.