DIY Loud Bluetooth Speaker for your car

Building a bluetooth speaker nowadays won’t require so much technical knowledge. You just need to know how and where to connect wires. You can now buy a bluetooth receiver with a built in amplifier online and make your own audio system for your car for cheaper price.

WHY DIY(Do it Yourself)?

Some cheap car amplifiers on the market is not honest on their advertised power, these are very common to cheap and not so known brands. By doing it yourself, aside from getting cheaper, you can also be sure that your amplifier has the right power you need.

What you need:

  1. Bluetooth Audio amplifier board


Buy here: lazada website

This is the easiest option to make as it will only consist of one board. It has a total of 100W output power which is loud enough. But If you want more power then you need to purchase separate amplifier board and bluetooth receiver board. This will be more expensive. I suggest you try this first. If you have no idea how load is the 100W audio is then try those mini component system with 100W RMS output power. Take note RMS and not the PMPO rating. Those PMPO or also known as “Peak Music Power Output” rating is just a marketing strategy. It is usually more than 10x of the RMS power.


2. Speaker


X12 TX-6995 COAXIAL Car Speaker 6″x9″.5-way speaker IMPP Cone

To make the speaker system simple, you can use a 2way or 3 way speaker instead. This will make the setup easier instead of wiring 3 or 2 speakers per channel. It will also save some space which is a good thing for a very limited car space. I suggest to use at least 6.5 inch speaker or larger for better bass frequency response. But take note that you also need higher power for lower frequency response. You can also use higher power speaker but this will not give any advantage if you will not also use higher power amplifier.


3. Fuse


Fuse is very important to prevent fire in case of short circuit on the board. Any type will do as long as the current rating is within the required current. The minimum current rating of the fuse is computed dividing the maximum power by voltage. For this design, the minimum current will be 100W/12V = 8.33A. Use a current rating a little higher than the computed current. For this case you can use a 10A fuse rating.


Connecting it together

Connecting it together is not that hard and do not require advanced technical knowledge. You just have to take caution on the power supply polarity. If you have accidentally reversed the power supply, it will damage and burn the PCB. When that happens, your board will be useless and be treated as trash. Below is the connection diagram:



Higher Power System

In theory, an amplifier can’t output voltage higher than its power supply. In this case we are using a 12V car battery and a 4 ohm speaker, computing for the max power will be:

(12^2)/4 = 36W

A car amplifier can only output around 36W per channel when you use a 4 ohms speaker. For 2 channel that would be only around 72W. If you need to produce higher power, you will need to increase the input voltage. This is possible by using a boost converter circuit. Boost converter works by increasing the input voltage. Luckily you can buy a ready made boost converter circuit. By doubling our power supply to 24V, the available power would be:

(24^2)/4 = 144W

By doubling the input voltage, the available power is increased by 4x.×9-3way-car-speakers-210w-4412893.html


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