VASK Forum (VW Audi SportKlub of NZ)

GENERAL => Technical Stuff => Topic started by: dubstar on January 15, 2013, 11:17:30 AM

Title: Convert Stereo to Mono in a Car Stereo
Post by: dubstar on January 15, 2013, 11:17:30 AM
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:
(https://www.vask.org.nz/proxy.php?request=http%3A%2F%2Fi2.photobucket.com%2Falbums%2Fy39%2Fkiwidubstar%2Fstereo20to20mono20circuit_zpse702f57f.png&hash=d9b755ceeb69169b7a003724293f28e5829a7f17)

My wiring:
(https://www.vask.org.nz/proxy.php?request=http%3A%2F%2Fi2.photobucket.com%2Falbums%2Fy39%2Fkiwidubstar%2Fad08e115771b677cace31b680cc7baac.jpg&hash=9899b451f7e2d87988ac44a1be595f28a3cecfea)

(https://www.vask.org.nz/proxy.php?request=http%3A%2F%2Fi2.photobucket.com%2Falbums%2Fy39%2Fkiwidubstar%2F97766bc7c72fc53b3a47ff2fcdc8af1a.jpg&hash=e7bb292a10cbe7b2777f3db40efd0d42d3868862)
Title: Re: Convert Stereo to Mono in a Car Stereo
Post by: Pristle on January 15, 2013, 05:20:23 PM
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:

(https://www.vask.org.nz/proxy.php?request=http%3A%2F%2Fbit.ly%2FRVc8Ay&hash=1666a49db31ad6a87d3245ff2ffa561105aea52a)


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. 

Title: Re: Convert Stereo to Mono in a Car Stereo
Post by: Gordo on January 15, 2013, 06:22:31 PM
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.
Title: Re: Convert Stereo to Mono in a Car Stereo
Post by: qta4 on January 15, 2013, 07:51:22 PM
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.
Title: Convert Stereo to Mono in a Car Stereo
Post by: dubstar on January 15, 2013, 10:06:37 PM
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