4" transmission line speaker box

thingiverse

This design is intended to make a Bluetooth enable transmission line speaker with a transmission line on approx. 60cm for a 4" driver. the TL can be filled with light weight glass wool or similar to get the wave response frequency down to approx. 60hz-> depending on the filling. It is designed to hold 8 18650 Lithium batteries, but to enable a regulator and protection circuit it is best used between 3-6 batteries. The holes in the bottom part will fit a ZK-502L Bluetooth board. This has been chosen for the volume button, to enable mixing the stereo to mono, by removing the dial and mixing the the the 2 channels into 1, with resistors. The not used input Chanel of the amplifier, is grounded. Standard on/ switch and charger port is used, and all can be purchased on Ebay. Some electronic experience is required, especially regarding the use of Lithium batteries! Preferred design: • 3s2p 18650 • voltage current regulator board set to 1A 12.4V • 3S BMS • amplifier board with Bluetooth ZK-502L • 2Pin ON/OFF Position Snap-in Black 21*15mm • Jack Socket Adapter Connector 5.5*2.5mm or 2.1 • 4” driver not deeper than 55mm • 2A schottky diode (between voltage regulator and BMS to avoid back flow of current into the regulator, draining the batteries) • misc. of wires • silicone of acyl sealant • fuse 4A