MiniBox loudspeaker enclosure by Joe9001

Last crawled date: 3 years ago

Hello everybody,
here comes a little more information necessary for the build of the MiniBox.
The Peerless 30N18AL03 full-range speakers are available e.g. at Digikey, the Tymphany W1640 woofers at Blue Planet Acoustic - the latter only in the 6-pack, so there are 2 pieces left over when building a pair.
In the back wall are openings for 2 rectangular passive radiators, which are covered with additional mass, so that a tuning frequency of about 44 Hz is achieved. The passive radiators are available at Ebay or Amazon from Chinese sellers. Since exactly the types that I had bought apparently are no longer sold, it may be necessary to adapt the housing to the passive radiators used.
The added mass for my radiators was 40g, but different radiator will require a different amount to achieve the desired tuning frequency.
Tuning of the passive radiators can be checked by impedance measurement.
For impedance measurement you can use e.g. a standard sound card and the program "Limp" from the "Arta" software bundle (or any other audio measurement software).
To make the crossover still somehow fit into the housing, all capacitors are designed as bipolar electrolytic capacitors. If, contrary to expectation, there is still room on the crossover board, it might be worthwhile to replace the rough foil electrolytic capacitor in series with the full-range with a smooth-foil electrolytic capacitor. Upgrading does not make much sense with all the other capacitors.
I have 3D printed the housing in two parts and glued them together, but it can also certainly be made of sheet wood, if you increase the material thickness to at least 8 mm.
The part5 stl is the small internal housing for the full-range speaker and is to be glued behind the small opening in the baffle. Forgot a hole for the cable, so that has to be drilled and sealed afterwards with epoxy or hot melt.
In order to keep the printing time reasonable, it is recommended to use a 0.8 mm Nozzle.
For damping: The bass volume remains completely undamped, i have filled the volume of the full-range with a small cube of Basotect - other damping materials should work just as well. When using wool, stuff it if necessary.
The crossover board sits on one of the sides of the housing.
The sound:
A well-balanced and pleasant medium and high-range combined with an astonishing bass.
The speakers, despite their small size of just 2 liters, come down to 40 Hz - if the room acoustics "helps" even deeper.
This is not apparent from the acoustic measurement, because I try to filter out the room modes, but unfortunately that means that the measurement for the range below 100 Hz does not quite reflect the reality.
Note: the big black boxes under the Loudspeaker are old PC enclosures and not part of this thing. ;-)
Would be happy to see some makes :-)
Edit: forgot to mention that the two W1640 woofers are to be wired in parallel.