# Using potentiometer to adjust volume on usb speaker

#### Djzlazy

Joined Mar 20, 2021
22
So I am currently trying to build a multi-platform portable. I'm using a raspberry pi zero w. I have a USB speaker with its own audio card inside. I am attempting to use a potentiometer to allow volume adjustment. With the soldering points on this speaker board, I am unsure what to attach to the potentiometer aside from the ground.
Using a B10K 10K Ohm 13 mm Shaft PCB Mounted Linear Dual Potentiometer

I'm honestly fairly new at this stuff and can't find anything online unfortunately. If anybody has any type of help for this I would be truly grateful. Thanks

#### Audioguru again

Joined Oct 21, 2019
4,958
Volume controls are never linear and marked "B". Instead they are logarithmic and are marked "A".
Each of your linear volume controls will have most of its volume range crammed close together near where it is turned down (left) and have little affect on volume level when turned up (right).

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#### Djzlazy

Joined Mar 20, 2021
22
Volume controls are never linear and marked "B". Instead they are logarithmic and are marked "A".
Each of your linear volume controls will have most of its volume range crammed close together near where it is turned down (left) and have little affect on volume level when turned up (right).
Thanks for the reply! So pretty much don't use the B10K and use A10K?
And let's just say I have an A10k potentiometer. How would I wire that to this usb speaker board? I'm unsure due to it being L/R with their own output, but no input besides the 5v, DP, DM, and GND?

#### sghioto

Joined Dec 31, 2017
3,357
How would I wire that to this usb speaker board?
What is the impedance of the speakers?
Do you need the volume to go from full on to zero?
To control volume directly from the speaker output requires a L-Pad type attenuator.

Last edited:

#### Djzlazy

Joined Mar 20, 2021
22
What is the impedance of the speakers?
Do you need the volume to go from full on to zero?
To control volume directly from the speaker output requires a L-Pad type attenuator.
View attachment 233261
The speakers are very small. Uses 3.1v I think? That's what it has on the board. I can only find L-Pad attenuator for 15W-100W. Not gonna lie, very noobish with technicals. So I apologise about that.

#### sghioto

Joined Dec 31, 2017
3,357
The speakers are very small. Uses 3.1v I think?
Speakers are measures in ohms anything from 3 to 32 ohms.
Is there a number on the back side of the speaker?
The L-Pad should match the speaker impedance.

#### Djzlazy

Joined Mar 20, 2021
22
36-5
40 3W
Is what I see on the back

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#### sghioto

Joined Dec 31, 2017
3,357
Looks like a 4 ohm 3 watt speaker.

#### ErnieM

Joined Apr 24, 2011
8,328
Speakers are measures in ohms anything from 3 to 32 ohms.
Is there a number on the back side of the speaker?
The L-Pad should match the speaker impedance.
All true, but keep in mind you cannot use an ohmmeter to measure that resistance.

It is an AC reactance, really.

#### sghioto

Joined Dec 31, 2017
3,357
The board for the speakers on has 5V, DP, DM, and GND.
The USB speaker sound card has a digital input. That module you posted is for analog input.
A 4 ohm low wattage stereo L-Pad is what you need.

#### Djzlazy

Joined Mar 20, 2021
22
The USB speaker sound card has a digital input. That module you posted is for analog input.
A 4 ohm low wattage stereo L-Pad is what you need.
Unfortunately I cannot find 4ohm low wattage L-Pad anywhere. I've only seen 8 ohm and up

#### sghioto

Joined Dec 31, 2017
3,357
Well the 8 ohm is not ideal but I think it will work OK.
What is the model # of that USB speaker?

#### Djzlazy

Joined Mar 20, 2021
22

#### Djzlazy

Joined Mar 20, 2021
22
Also I'm trying to stick with stereo sound rather than mono

#### sghioto

Joined Dec 31, 2017
3,357
May be difficult getting a L-Pad in that small enclosure.

#### Djzlazy

Joined Mar 20, 2021
22
I plan on 3D printing my own housing for the portable and placing everything inside the unit

#### Djzlazy

Joined Mar 20, 2021
22
Appreciate you chattin it up with me bro. This has been a real headache. Especially since my knowledge is limited lol

#### Audioguru again

Joined Oct 21, 2019
4,958
AliExpress sells your very tiny stereo speaker for only $8.95US. They say its output power is very low. The speakers in it are so small that they will produce only squeak sounds. Haven't you tried it? It does not have an audio input like all other pc speakers I have seen, instead its input is USB, then a normal audio volume control cannot be used. My pc speakers are 4 times larger and cost 6 times more. They have a volume control and a real audio input and sound very good. Thread Starter #### Djzlazy Joined Mar 20, 2021 22 AliExpress sells your very tiny stereo speaker for only$8.95US. They say its output power is very low.
The speakers in it are so small that they will produce only squeak sounds. Haven't you tried it?

It does not have an audio input like all other pc speakers I have seen, instead its input is USB, then a normal audio volume control cannot be used.

My pc speakers are 4 times larger and cost 6 times more. They have a volume control and a real audio input and sound very good.
I have tried them and got the audio to come out of the usb speaker on my raspberry pi zero. They sound great for price and size.
There's gotta be some way to Jerry rig this