665g new loudspeaker technologies for DIY

I started the self-construction of a low-cost acoustic speaker to be used with T-AMP + DAC-USB + PC, I ended up patenting a new type of ultralight loudspeaker “665g”. Robin srl has filed the patents of a new technology for audio speakers. The first prototype “665g” in a desk configuration is visible on the website robinsrl.it. Replication for personal use is allowed for DIY.

The main technical characteristics of the 665g loudspeakers are:

  • emission of coherent and delayed secondary sound waves without the use of electronic circuits and / or multiple loudspeakers,
  • single driver with Faital Pro 3FE25 wide band speaker,
  • omnidirectional in the horizontal plane,
  • no internal sound reflection.

The project is still evolving. The part that generates the sound is well defined, for over a year the waveguide (the tube) is not modified. The space location is still changing, the current form of the desk-fixing bracket was first tested in November. Anyone who wants to hear the sound reproduced by the 665g speakers must do so with the spirit of the experimenter. A DIY can assemble the couple with a total cost of some tens of euro. Who is willing to finance Robin srl can order a prototype for 200 euros. Who is in the area of Sassari can get in touch for a demo.

A couple of photos.

Web site: http://www.robinsrl.it
Italian free ebook until January 6th reader.ilmiolibro.kataweb.it/v/1 … 5g_1186345

I would be very curious of hearing how it sounds!
Nice concept!

I can communicate the selling prices of the speakers that will be available starting from January 2018.
Pair of desk supports + pair of 665g 190 euro VAT included.
Pair of speaker cables, low capacity, length 2 meters 60 euros VAT included.
For more information send an email to robinsrl@tiscali.it.

Waiting I try to describe how the 665g sound.

The emission of coherent and delayed secondary sound waves without using electronic circuits and / or multiple loudspeakers is the object of patents and is what differentiates the 665g speakers from all the others. In the conventional loudspeakers at the listening point the primary emission of the loudspeaker arrives first and then with delays of the order of 5 - 10 milliseconds arrive the non-coherent reflections generated by the walls and by the objects present in the room. With 665g after the primary emission at the listening point, coherent secondary waves controlled by the geometry of the speakers arrive with a delay between 1 and 3 milliseconds. Only later do the inconsistent reflections of the walls and furniture arrive. At the psychoacoustic level the recognition of sounds is facilitated and the realism of reproduction increases.

As for other single driver the maximum sound pressure is limited, it can not make the floor shake. On the other hand up to 90dB is extremely detailed and clean and with a sufficient extension on low frequencies.

The omnidirectional emission of the high frequencies is suitable for reflective environments even if not acoustically treated. The energy of the high frequencies is redistributed to 360 degrees, preventing the quality of reproduction from worsening. The perception of sounds was acceptable even in completely empty rooms. The omni-directional single driver speakers have the problem that the speakers on the market are designed to provide a uniform sound pressure in a more or less large frontal lobe, widening the lobe and in the absence of reflections the sound pressure of the high frequencies can be reduced too much. In environments with a lot of acoustically absorbing material: curtains, rugs, open shelves, etc., there have been detected levels of reproduction on the reduced highs. Also in this case, listening can be still pleasant due to the presence of secondary waves.

It is possible to order both 665g diffusers and 662g cables.

A pair of 665g speakers in desk configuration cost € 199.99, VAT and transport included.

A pair of 662g speaker cables cost € 61.00, VAT and transport included if ordered with the speakers.

Deliveries are currently activated only for Italy.

At the link: robinsrl.it/condizioni_13.html
the conditions of supply are indicated.


The 669g project upgrade the 665g project, the acoustic screen is rigid and the acoustic transformer use paper. More bass, less distortion.
The 669g loudspeaker is a single-driver with multiple section acoustic load.

At link robinsrl.it more information and more projects 621g 665g 666g 667g.

Hi everyone

in the new site: claudiogandolfi.it I published the projects of the new prototypes: 439h, 419h and 227h derived from the old models 665g, 621g, 666g, 667g and 669g.

These are acoustic speakers that use the Huygens principle to spread all spectrum frequencies at 360 degrees.
With a series of waveguides of different lengths, secondary and consistent sound waves are emitted at different points in the space.
I called this technique MDD Multi Delays Difraction.

Soon the old robinsrl.it site will be decommissioned, the contents of the main pages will remain available for download in pdf files at the end of the contact page: claudiogandolfi.it/contatti.html.