I have an FM receiver with 3W stereo output. https://www.amazon.com/gp/product/B01N4AHISZ/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
I am putting it into an enclosure with a single 3W speaker. https://www.banggood.com/1pc-40mm-4...=105229698&sc_uid=65ujid9eVc&cur_warehouse=CN

What can I use to combine the left and right channels into the single speaker?
I was thinking about adding a resistor in series to the L&R outputs then tying the two resistors together at the speaker. If that would work, I have no idea what the resistor values should be. Any thoughts will be appreciated.

 

I'd be inclined to mix the channels at the input level and then just use one channel for the speaker.

 

I'd be inclined to mix the channels at the input level and then just use one channel for the speaker.

I guess that would be possible if I cut into the PCB at the audio amps, but the question remains, is using 2 resistors the way I described the way to go and what should the values be?

 

In general don't add resistance at the speaker power output as it reduces the damping factor of the speaker cone EMF into the output stage impedance causing 'muddy' sound. For a low power application like this with small speakers the effect might not be too noticeable but many audio amps are designed to have the speaker circuit loop floating in respect to other circuit potentials. Wiring two power channels together with resistors might have unexpected results like letting out the 'Magic Smoke'.

 

"many audio amps are designed to have the speaker circuit loop floating in respect to other circuit potentials."

If I understand this correctly, you are suggesting that I leave one channel open and just connect the other channel. If that is what you are suggesting, I would lose all the info in the floating channel.

 

"many audio amps are designed to have the speaker circuit loop floating in respect to other circuit potentials."

If I understand this correctly, you are suggesting that I leave one channel open and just connect the other channel. If that is what you are suggesting, I would lose all the info in the floating channel.

'Floating' in this context means the speaker leads (left or right SP+ SP-) are not connected to anything else other than the speaker.

Blend the LR signal before sending it to the amplifier input.
http://www.icstation.com/digital-st...s-microphone-module-with-display-p-10545.html

Check the Stereo/Mono Setting

 

Thanks to spooky for the image. Based on that ...

The "Stereo'Mono" jumper location is a single control line to the receiver chip and a GND point. The user manual is not perfectly clear, but my guess is that no jumper = stereo; and installing the jumper produces a mixed mono signal to both speakers. You can test this by installing a 2-pin header. Then install and remove a shunt while listening to a stereo source.

ak

 

Outstanding! A jumper across the mono/stereo location it is.