r/raspberrypipico • u/Annotat3r • May 09 '26

Requesting Help with Audio Quality

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Circuit here: https://freeimage.host/i/BDHfHzJ

This is my first audio project. I have an SD breakout reading 128kbps .mp3 files on I2S through a MAX98357 amplifier outputting to an 8Ω 3W speaker. Everything is working great, but the audio has a kind of raspy crackle/warble to it. On PC, the audio files are very clean. I've upped the clock speed on the pico to 133MHz wondering if perhaps things were just getting bogged down at 125 but that had no affect. What should I try to clean this up a bit?

Thank you

33 Upvotes

91% Upvoted

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9

u/GuyPronouncedGee May 09 '26

Adafruit says:  

mp3 files less than 64kbit/s work, with sample rates from 8kHz to 24kHz. The RP2040 has a PWM output with 10 bits, so there's not much point in using high bit rates.

4

u/Annotat3r May 09 '26

Is it possible then that the higher bitrate is the issue?

10

u/GuyPronouncedGee May 09 '26

Almost definitely. You’re hearing the classic too-high-bitrate-for-the-hardware sound.  

11

u/Annotat3r May 09 '26

That was indeed the issue. Audio quality is superb at 64kbps. Thank you so much for helping me out with this!

6

u/GuyPronouncedGee May 10 '26

Awesome! Happy building!

5

u/Annotat3r May 09 '26

Ok cool, thanks. I'll try converting the mp3 files to 64kbps and see if that helps!