Raspberry pi pico noise issue while mp3 is playing through speaker
March 6, 2023, 20:46
I hooked up a low pass filter to my raspberry pi pico, I thought it removed the noise but it turns out it was just the audio file playing, Its not an issue with the file its all the right sample rate, I did the math and made sure the frequency was okay as well, I'm not sure why its still making noise and it only happens while audio plays and discontinues once the power to the amplifier as stopped.
what noise
what LPF
oh no...
use full circuit
Full circuit?
Oh wait the same one we talked about last time?
take inspiration from pi4 schematics
yes
Should I build that entire schematic?
ommit U5, ommit C88, ommit D4 and use only one branch.
this is for stereo
Oh right I’m using mono anyway
so basically just this
Ohhhh I don’t use the op amp right?
2nd question do I need to calculate the total resistance and capacitance to find the cutoff frequency?
this is original circuit used on raspberry.
it should work for you as well.
so copy the values as shown
?
yes
okay, thank you
You have lpf, but you do not limit dc at all.
Also what noise
Provide recording
That sounds like regular hiss
Is there a way to stop it?
or am I just stuck with it
Did you build that filter?
I did
No change?
It reduced it
Yay
thank you
Not weigh then i guess
weigh?
Enough
Autocorrect
Do I just keep filtering it?
Wdym
Can i use multiple low pass filters
Keep that filter between pi and amp
That won't help
what would help? and would there be any way to reduce the noise completely
I would need to see that noise on spectrum analyzer to see what it is
I doubt you have oscilloscope
Got one in college but doubt they are about to let me whip out my circuit lmao
You could ask
I might tbh
No harms there
Btw... what are you trying again?
Ah right, custom playback
What are parameters of your mp3 <@341973065057566720> ?
Bitrate and samplerate
64kbps, 24000 sample
Mhm...
And you are sure you used spi pin
on the amp or on the input for audio
On pico
I used the SPI0 RX pin
GP0
Try opposing corner...
Gp16
You got it upside down
<@341973065057566720>
its the same
when i flip it
Show your code
import board
import audiomp3
import audiopwmio
audio = audiopwmio.PWMAudioOut(board.GP16)
decoder = audiomp3.MP3Decoder(open("GO.mp3", "rb"))
audio.play(decoder)
Looks fine
I'll try to figure it out, I think its a grounding issue
Could be
Or power
Try different power supply
I’ll try
no changes
not sure whats causing it
<@456538086453805068> I apologise for the ping, Do you think it would be better for me to use a raspberry pi 3 to act as an audio interface rather than a pico?
I have a raspberry pi 3B I have access to and could use, as its currently lying around
Gibe it a try
I’ll set it up later and see what happens