Full range loudspeaker Dayton Audio RS100-4

This is a full range speaker for the Dayton Audio RS100-4 chassis from their reference range, popular due to low distortion and linearity. Sound pressure level is in the lower range with 83dBA, but the Re of 4 Ohm makes it easier for the amp to compensate with more power. 

Works well as a small monitor going as low as F3 55Hz, but for HiFi better combined with a subwoofer, and for house party mode ideally with high pass filter so you are not murdering the little fellows with bass amplitudes they can't handle. 

The response is quite linear, considered there is no DSP or passive filtering components worth hundreds of dollars involved - see attached REW measurements without and with subwoofer. Resolution and sound stage is very good, due to the small size full range speaker. A bit more in your face due to the elevate high frequency response than than the Mark Audio Pluvia 7.2 HD design I recently uploaded, but looks easier on the eye. 

There are some gimmicks in the design - note the non-parallel internal walls to prevent standing waves (if you are a believer), and the magnetically held grills. The enclosure design and dimension is inspired by the Q Acoustics 3010i speakers, if anybody cares. They can be used with or without the grills, and sound response is the same as my measurements showed. 

Printing: Standard PLA. PEI plate. Nozzle 0.6mm, layer height 0.24mm. 3 walls, 25% infill, gyroid preferred. Support on bed only. Place flat areas on build plate, e.g. front of the speaker, and back of the rear plate. The enclosures take at least 24h to print, this is so relaxing to watch... Preferably TPU for the feet. 

Magnets: not needed, if you don't want the grill. The holes for the magnets are in the CAD files (see X-Ray view picture), but will be simply bridged and left hollow when no magnets are inserted. However, if you want the magnetic grills, you will have to slice the files, and insert a pause command in the G-Code just before the magnet holes are covered. When printing with 0.24mm layer height, this was layer 13 in each instance. Once the printer pauses, apply a drop of Super Glue at the bottom of the hole (prevents rattling), and insert the magnets all in the same polarity direction. Same for the grills, the magnets will need to be inserted after a pause command - just make sure you get the polarity right by marking the magnets with a Sharpie dot after you worked out how they attract rather than repel each other. See the picture provided for the grill print. 

Grill: the fabric for the grills can be any cheap loudspeaker grill fabric, or even an old polyester T-Shirt like a rashy (I guess only Australians know what I mean). After folding the fabric over the grill insert the fixing ring and apply tension to the fabric to stretch. Push the fixing ring down against resistance. Once it looks good, apply Super Glue over the fixing ring, let it cure and then cut off the excess fabric with a razor blade or hobby knife. 

Assembly: glue the back plate in the enclosure with epoxy or plastic glue like JB Weld PlasticBonder, don't use Super Glue - it will leak because this stuff is too viscous and does not gap fill so you end up with a hissing box. Apply a weight or G-clamp for a few hours. 

Damping: Add 25mm thick damping material to the walls and back, like recycled cotton or high density polyester insulation. If you are not afraid of lung cancer, use mineral wool or glass fibre - the port will spew particles out like protomolecules when you crank up the volume. 

Bill of materials (links provided are just examples, not affiliate links):

• 2x Dayton Audio RS100-4 

• PLA - circa 1.2 kg per speaker. I use the cheap stuff from Sunlu/Jayo on eBay or AliExpress, 5kg spools for $50. Could use Matte PLA or PLA-CF, looks a bit more swanky. 

• for the grills: 24 Neodymium magnets 10x2mm

• Speaker grill cloth

• 4 Binding posts 4mm

• Epoxy glue/resin or JB Weld PlasticBonder

• Damping material, e.g. cotton or polyester batts

• 8x M3 Inserts M3x5.7 

• 12x M4 Inserts M4x8.1 

• 8x M3x10mm bolts for the feet

• 12x M4x12mm bolts for the speaker mount

• 50cm of 14G speaker cable