Bluetooth Audio Module - Distortion and Quality Issues at High Volume

[LeonSKenn]

Hi everyone,

I’m working on a speaker project using the BT-201 Bluetooth audio module. I’m powering the module with a 3.7V 18650 battery and directly connecting the output to the speaker. However, I’m experiencing significant distortion and loss of audio quality at high volume levels.

Here’s what I’ve tried so far:

• I used an MT3608 DC-DC step-up module to increase the voltage to 5V. The distortion slightly reduced, but the amplifier shuts down when the volume goes above 85%.
• I can somewhat control the distortion by keeping the volume below 85%, but the audio output is not loud enough.
• I connected a PAM8403 amplifier to the output of the BT-201. Initially, I only got static noise, but after checking the connections, I managed to get sound. However, there was no significant improvement in audio quality.

In summary, the audio output from the BT-201 module becomes heavily distorted, especially after 85% volume level. The sound from the speaker is noisy and lacks clarity. I need to use this module due to its AT commands, but the current audio quality is a major issue.

Does anyone have suggestions on how to solve this problem?

Thanks.

Bluetooth Audio Module - Distortion and Quality Issues at High Volume​

 

[Harald Kapp]

What speaker are you using?
This module is good for 3 W on a 4 Ω speaker. As usual this is a euphemistic value. 50 % aka 1.5 W is more realistic. For higher power use an additional power amplifier.
Your PAM8403 is also only 3 W with more realistically usable 1.5 W

 

[LeonSKenn]

speaker is 3W 4Ω. Connected directly to the BT-201's speaker output.

 

[bertus]

Hello,

The BT201 module already has a 3W amplifier on board.
A PAM8403 is also 3W so it will bring no extra power.
For more power have a look at a PAM 8610 module wich is 10 W.

Bertus

 

[Alec_t]

Perhaps the distortion is mainly due to the speaker itself, particularly if the '3W' is the so-called 'music power' rating?

 

[bertus]

Hello,

Is the speaker in a proper enclosure?
Do you really need more power?

How Much Power?

Power requirements for hi-fi listening.

sound-au.com

Bertus

 

[LeonSKenn]

Hello,

Is the speaker in a proper enclosure?
Do you really need more power?

How Much Power?

Power requirements for hi-fi listening.

sound-au.com

Bertus

i don't want more power actually because the highest volume of speaker really good and enough but after level of %80 treble is good but bass getting worse. I'm just searching for fix it , if there is a way.
Thank you

 

[davenn]

i don't want more power actually because the highest volume of speaker really good and enough but after level of %80 treble is good but bass getting worse. I'm just searching for fix it , if there is a way.
Thank you

You have been told the solution by both people that responded to you

driving the 3W amp and speaker an am to its fullest is why you are getting distortion, particularly on the bass
as you get close to full volume

Having a better amplifier, say the suggested 10W unit, means you wont have to drive it so hard to get a decent
volume out of it and this will instantly get rid of the distortion, as the amplifier and or speaker wont be working so hard

Dave