Kharis 100 nearfield monitor building description
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THIS IS PRELIMINARY DESIGN INFORMATION!
The Kharis 100 loudspeaker has not been built yet. The plans are based on manufacturer data, and simulation with measurement data of similar drivers, therefore the crossover may need fine tuning. The first builder of this loudspeaker may get free help from the designer. Further information: help for DIY speaker builders.
It's expediential to have the enclosure prepared by a joiner owning a CNC machine. It's rather difficult to make the countersinks for the speaker baskets at home. Of course it can be made using a router, provided you have the proper router bits, and a circle cutting jig. The internal edge of the midwoofer cutouts must be chamfered, at approx. 7 mm depth, as exemplified in the next image.
PVA wood glue, D3 type is recommended for gluing.
The internal cross brace is an 18x70 mm cross sectional MDF element.
The back of the enclosure should be lined with 3 cm thick egg-crate foam, the sides with 2 cm thick normal foam. Only open cell (acoustic) foam will do. The foam blocks should be cut about 5 mm bigger than the distance they are to fill, so they will be snug in their place. Place 3 dkg pillow stuffing material such as polyester pillow fill or long-fibre wool loosely in the bottom of the cabinet.
The crossover can be mounted on the cross brace behind the mid-woofer or in the bottom of the cabinet. Components with 5% tolerance are recommended. The best solution for fastening components seems to be cable ties. Tie them to a thin (e.g. 5 mm thick) HDF plate and screw that plate to the inside of the cabinet. I haven't made a component layout or PCB plan, just solder components together across their leads or with suitable cables, wherever the leads are not long enough.
All inductors are air core. Don't fasten coils with ferromagnetic metal screws (e.g. steel), because they may cause some distortion. To prevent crosstalk, place coils at least 10 cm away from each other or - if they are closer - direct their axes perpendicular and skewed:
The hard-to-come-by capacitor values can be attained by connecting more common values in parallel. By parallel connection, the capacitances are summed. In the circuit diagram of the crossover, the shown voltage of capacitors is the minimum suitable rating, you can also use capacitors with higher withstanding voltage. I recommend the 400V DC rated Jantzen Cross Caps for this design. I generally don't recommend nonpolar (bipolar) electrolytic capacitors, except if they are types designated for use in crossovers. Even so, foil capacitors have better characteristics. Never use polarized (unipolar) elcos in crossovers.
Copper or CCAW speaker cable of at least 0,35 mm2 cross-section is recommended.