Convert Stereo to Mono in a Car Stereo

[dubstar]

As mentioned in my project thread, I need to convert from stereo to mono, so I can run just one speaker in the factory location.

I found a simple wiring diagram (see below) that apparently can convert stereo into mono, however I have found that it distorts the sound and also really limits the volume.  Can any of the electronics experts here tell me another way to get around this?

If I read the schematic correctly, I put resistors on all 4 wires (R+, R-, L+, L-) and then 1 big one between them.  I have used std type resistors rated at 1W.

Schematic:


My wiring:

[Pristle]

This is digging into the memory banks. I needed something similar 30 years ago for my Beetle.

You're on the right track I think. Look at this option:




or the one shown here: http://jwsoundgroup.net/index.php?/topic/7015-passive-summing-stereo-to-mono/


I remember adding caps in the circuit I used way back when. Which helped with tone and volume loss. 

[Gordo]

Was going to mention volume - if the original speaker is being used, it's probably rated for around 6W, maybe more, and the head unit may be overdriving it if you're not careful.

[qta4]

Both of these circuit diagrams relate to input to the amplifier stage.
I thought you were taking about the output stage to feed the Speaker's.

What you have will not work at output.

[dubstar]

Yes. I am talking about output straight into the speaker.  That revised schematic looks odd to me, they are grounding the return wires?

Will need to keep hunting.  What would be good is a bridgeable 2 channel amp that is tiny, maybe the size of the ashtray