The initial question was whether it was possible to develop a shelf box that offered a voluminous sound and could reproduce the lowest frequencies even without a subwoofer.

The result was the PACTO, a shelf box, constructed as a so-called FAST system (Fullrange and Subwoofer technology) in an inconspicuous bass reflex housing. The W 130 x- 2x 4 Ohm enables an extremely low cutoff frequency of 42 Hz and is supported in the mid-high frequency by the FR 58- 8 Ohm. The two drivers are separated at 250 Hz by a simple series crossover with just three components. This means that only one loudspeaker is responsible for the very important vocal range, which makes the sound appear extremely precise.

The double-layer baffle can be contrasted in color with the rest of the housing, allowing more design freedom when building the housing.

Thanks to the bass reflex opening on the front, the relatively small box can be stored discreetly on a shelf and still fills your living room with a rich and full-bodied sound. This makes the PACTO our first compact shelf box, which we can warmly recommend to everyone without a subwoofer recommendation.

Technical data :

 Construction

First, all panels are cut according to the list. With the exception of the two stiffeners where the width does not depend on the millimeter, this can easily be done at the hardware store. Since the boards are glued together, assembly is not particularly difficult and is also suitable for beginners.

The first step is a short dry assembly to check the fit of the cuts. The openings for the drivers in the front and in the front panel, as well as for the terminal in the back, can then be sawn or cut. be milled. Particular care must be taken with the 2.4 mm deep recess on the back of the front panel.

Now the radii are milled into the front panel. ground. Floor and BR boards also need to be rounded to minimize flow noise. The bevels on the side walls can now be attached (e.g. using a table saw or a suitable milling cutter). Since these taper to an acute 30° angle, they are very sensitive.

Once all the boards have been finished, the base, the lid, the front and the back wall are glued appropriately (butting together) onto a side wall, which is then placed on the work surface in front of you. It is important to ensure that the boards are flush (the nail trick helps here). The second side is now placed on top of the housing and weighed down (but not glued yet) while the glue dries. You can also check whether the upper side wall is flush with the vertical boards. During the drying process, the two plates for the internal housing of the FR 58 - 8 Ohm are glued together.

Once the glue is dry, the BR boards, the small internal housing and the stiffeners can be glued into the housing. Now the crossover can be screwed into the housing (see crossover position). The side wall is then glued to the housing.

After a further drying phase, the swelled glue is removed and the housing is sanded smooth. Now follow the pre-drilling of the mounting points of the chassis and the terminal, as well as the cable passage in the tweeter housing. Now the final wiring can begin (see connection plan). Finally, all chassis and the connection terminal are screwed together and connected to the crossover. The cable outlet in the tweeter housing should be sealed airtight with hot glue.

The front panel is attached last. This makes it possible to paint them in a different color than the rest of the case. For revision reasons, it is recommended to attach this to the housing using four hot-glue dots, double-sided adhesive tape or Velcro, for example.

The kit contains all the components listed in this assembly list, but no housing.

Woofer W 130 X- 2 X 4OHM 1 pc.

Broadband FR 58-8 Ohm 1 piece.

Crossover crossover PACTO 1 ST.

Connection terminal ST 77 1 piece.

Screws 4 x 25 mm (cylinder head) 4 pieces.                  

Screws 3.5 x 25mm (countersunk head) 8pcs.

Cable 2 x 1.5 mm² 1 meter