Rhythmic noise on speakers plugged on audio jack (video)

Products & Technology ReSpeaker
#1

Hi all, I installed raspberry pi OS in my pi zero 2w to run it as a home assistant satellitte using wyoming protocol. For that, I just bought a respeaker 2-mic.
It works great and the quality, specially of the microphones, surprised me greatly, but I am having an awful, repetitive noise coming through my speakers after it boots (as you can see here: https://youtu.be/MQIluxfddTM). Admitidelly, most of the time is not as bad as the video, but it is always there
About my setup: the respeaker itself is not powered, only the pi, since as far as I understood from the documentation it would only be necessary to power it if I needed to use the amplification from the board.
The speakers are plugged with a 3.5mm jack to RCA cable, and my speakers have its own amplification.
What I have tried:

  • Plugged with a different cable, but it yeld the same result.
  • Plugged another computer instead of the respeaker, it makes the noise go away.
  • Powering the respeaker at the same time as the pi, I do think it made it less loud, but the noise did not go away.
    Please let me know if it would be helpful to share any file or log as part of solving this, as well as pictures of the product and the setup.
#2

Hi there,
You got one of two things happening there,
(sounds like 60minutes theme TICKING music) :grin:
Grounding problem ,

Power supply Noise problem,
is it a switching power supply it’s plugged into (RPi), swap it out.
is everything , ie. your powered speakers and RPi and computer plugged into the same wall outlet or power strip?
post a picture of it setup , we can LQQK

HTH
GL :slight_smile: PJ

I would use a long test lead grounded and touch the Minuses(-) or grounds of the devices, better or worse.? YMMV

2 Likes
#3

switch mode power supply is my vote!

1 Like
#4

you here it sounds like a bomb :grin: :bomb:
LOL

Who puts a bomb in a speaker??? :smile: :shushing_face:

1 Like
#5

Thank you so much y’all. The power strip where I keep my TV and speakers had usb charging outlets and that is what I was using. I plugged it in the wall directly and with a power supply made for raspberry pis and the noise stopped.
Now, a couple of questions probably more important than my original post: how did you figure it out so quickly? Why exactly did this happen when I plugged in the power strip?

1 Like
#6

Hi there, Great! :+1:
Grey hair, LOL only partially though, comes with experience, you did a good preliminary run down so connecting the dots was easy.
GL :slight_smile: PJ
:v:

Those outlets are Isolated, so the grounds have a filter on them the ticking was the RC time constant of the circuit It “resonates” at a frequency that is factor of the high impedance and a ground path.
to check unplug it from the system , test the grounds for continuity between. either very LOW or open completely. :+1: is what you’ll find.

1 Like
#7

i learned by sitting on the ground in 100 F summer swetting my A$$ off and reached up and grabed 110V i thought was turned off… and i heard the vibrating sound… A big fat wet butt is one hell of a grounding rod…

1 Like
#8