Bass amplifier project made with car sound module, will it work?

[Pedroga]

I'm looking to build a bass amplifier using a car sound module... the problem is that when I plug my bass into the car stereo to test the sound, the sound comes out totally distorted, now I don't know whether to give up or start the project.. .

I was thinking of putting a bank of capacitors to see if that solves the problem.

 

[KlausST]

Hi,

form your two lines description we can´t see what you connected how, what input signals you used ... and so on.

Give us complete informations and we can help you.
Draw sketches.

Klaus

 

[Pedroga]

Hi,

form your two lines description we can´t see what you connected how, what input signals you used ... and so on.

Give us complete informations and we can help you.
Draw sketches.

Klaus

I just turned the bass on the car radio. Distorted sound happens even when I use a car speaker on the bass amplifier

--- Updated Sep 18, 2022 ---

Hi,

form your two lines description we can´t see what you connected how, what input signals you used ... and so on.

Give us complete informations and we can help you.
Draw sketches.

Klaus

Here is a 125w automotive woofer connected to an 80w amplifier from a bass hub I have at home, it gets distorted and when I press something very low it goes up and down even making the strings stop vibrating

 

[BradtheRad]

1.
It's hard to be sure what frequency is coming from the speaker. There's a knocking sound about 3 times per second. It may be caused by the cone 'bottoming', that is reaching the limit of it's excursion.
Or else it may be coming from the amplifier.

2.
In addition to the amplifier's Watt rating, it is intended to drive a certain impedance. Can you find out what load it is rated for. Is it 2 ohms? 4 ohms? 8 ohms?
Does your speaker ohm value match? (Often it's printed somewhere, you may have to search for it.)

If the speaker is fewer ohms than the amplifier, then it tries to draw overmuch current. Distortion is likely especially at high volume.

3.
The amplifier's output stage might have an internal capacitor which blocks DC. The purpose is to send true AC to the speaker. This internal capacitor must be a high Farad value in order to pass low (bass) frequencies. A small capacitor causes distorted waveforms especially at high volume.

Or the amplifier might contain two bridged amplifiers. In that case a DC-blocking capacitor is unnecessary.

-----------------------

Have you tested setups where the amplifier is driving a different speaker, or the speaker is hooked up to a different amplifier? Is there any arrangement that yiedls proper sound from one or the other?

 

[InsAndOuts]

There is nothing wrong with your basic idea, it should work. I've used a cheap class D module, a battery and a speaker before to make a usable mobile bass amp.

You mention 'distortion' as the problem, but the video shows a large low frequency oscillation. Are the two problems happening at the same time?

The slow speaker movement in your video points at something not-audio related. It can be an active overcurrent protection in your supply or in the amp. Maybe the speaker is accidentally connected between out and GND while it should be connected to out+ and out- ?

It might help if you post a picture of the connections of the amp to the speaker and also to the power supply.

As far as distortion is concerned you should first make sure that at low volume you hear no distortion (play with both bass volume knob and any amp volume controls). If there still is distortion at low volumes, then adding capacitors will not help, but simply attenuating the input signal will.