Bluetooth bass-reflex speaker

thingiverse

This started as a remix from https://www.thingiverse.com/thing:4668173 Edit 2021/02/15: Check out version 2. It prints much easier and sounds just as good: https://www.thingiverse.com/thing:4768470 I added STEP files. There is also an STL for a redesigned front panel. This one can be used in case you want to screw the speaker to the outside of the cabinet. Edit 2021/02/01: This tiny speaker is quite amazing with an amp that can boost the bass! The bass-reflex design works very well. Here is my 6 liter subwoofer for an awesome 2.1 system: https://www.thingiverse.com/thing:4838080 I added some photos of the speaker. Please bear in mind that I use this one for engineering and testing, not for cool looks. With a little more effort you can make it considerably more pleasing to the eye :) Original description: The original back horn speaker design by guppyk is very good looking but the sound was quite a letdown. The horn amplifies the mids as well and the reflective surfaces sounded like a reverb effect to my ears. I preferred the sound while completely covering the horn with my hand. After a bit of research I think horns need a much larger volume. The designs for this speaker are mostly 70-90cm tall (!) like this one: http://forum.visaton.de/showthread.php?t=20480 So I redesigned the speaker with - a bass-reflex enclosure using BoxSim (fb=96Hz for 1.83l enclosure volume) - M3 thread inserts for the speaker and side panels - curved surfaces to get rid of reverb and standing wave effects The sound is a lot better, although you have to keep in mind this speaker will never have a lot of bass - at least in such small enclosures. The bass-reflex pipe does its job as expected without amplifying the mids. With a sine-wave-test-sound it works well down to 60-70Hz. Lower frequencies are present but attenuated. Looking at professional bluetooth speaker designs there are a lot of electronics inside to make small speakers sound bigger than they are. I attached the speaker and 8mm MDF wood side panels with M3 screws and self-adhesive EPDM foam strips to get a good seal all around. Tight seal is crucial. This way I can easily experiment with wool fillings. A handful of polyester wool inside the speaker improves the sound as well. The wood side panels only slightly vibrate in the bass range, while the PLA surfaces transmit higher frequencies, too. Perhaps more infill or greater wall thickness would be better. I'm not planning on testing this, it is a long print already.