Learn about DIY hi-fi, acoustics, circular economy, and more in our blog.
Circular Sound Loudspeakers
This article describes the Circular Sound loudspeaker models in detail. We will dive into the technical specifications and also go into detail on how you can build your own
Good feelings by recycling loudspeakers
“The transition to a circular economy needs to produce good feelings in addition to measurable positive outcomes”, writes Joonas Sirviö

RD Physics BB project
BB1 and BB2 are two versions of our boombox design. No internal batteries means this DIY build is good for the planet and your wallet. Power is supplied via a USB-C interface.
RD Physics CX2
A coaxial loudspeaker with 3D printed enclosure means coherent radiation, minimal edge diffraction and stiff panels in a convenient one-piece print.
RD Physics CX1
A coaxial loudspeaker 3D printed from wood using the Desktop Metal Forust method.
Artificial intelligence in loudspeaker design
AI is gaining popularity and some have used it to create images of loudspeakers. We show the best results so far and explain how AI can help loudspeaker designers.

DSP vs. Acoustic panels
Is it enought to do room correction with DSP or do you still need acoustic treatment? Check out our measurements!
DSP for headphones
Every headphone can benefit from equalization using digital signal processing. See how you can improve the sound of your cans without spending a dime.
Headphones vs. Loudspeakers
We explain the pros and cons of using headphones instead of loudspeakers. It is found that headphones can be a superior choice when the listening environment is challenging.
RD Physics SW2
3D-printed passive subwoofer with a 5″ driver and 6.5″ passive resonator. The inner walls can be lined with sound deadening mat to increase mass and damping. TangBand W5-1138 drivers from:
RD Physics SW1
3D-printed active subwoofer with a passive resonator and plate amplifier. The walls can be filled with epoxy to increase mass and stiffness significantly. The enclosure is printed in two parts and bonded together. Dayton Audio DSA175 drivers from:
RD Physics FR project
Learn why spherical enclosures are so good and choose a favourite project to make yourself using the files provided.