my headphones are stereo but I would like the sound from the left and right to be combined then sent to both headphones.

The reason is I'm watching a video where the people speaking are in the right ear as well as the music but they never speak in the left ear (it is not because they on the right side of the screen) If I take the right headphone off then I only hear the music in my left and there is no speaking.

  • 1
    possible duplicate of superuser.com/questions/117494/… – Mehper C. Palavuzlar Apr 6 '10 at 21:11
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    no that question is about muting one side of the headphone, I want to play both left and right though both ears. (so in the left ear you hear the left and right audio same for the right ear) – Jonathan. Apr 6 '10 at 21:13
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    That question also explains to force mono sound. Assuming you want to do this on Windows, have you checked Control Panel > Sounds and Audio Devices > Audio > Sound Playback > Advanced ? You can set the speakers & headphones to all possible "Mono" choices you might have. – Mehper C. Palavuzlar Apr 6 '10 at 21:20
  • I am on windows 7 and no such options exist – Jonathan. Apr 6 '10 at 21:25
  • Can you tell us more about what kind of video it is? The type of audio you describe (left channel has only music, right channel has music and voice) is sometimes used in karaoke. – Bavi_H Apr 7 '10 at 3:13

11 Answers 11


I've noticed on a few occasions that I seemed to get mono sound on both sides when I accidentally pulled the plug partway out of the headphone jack.

  • 1
    I had noticed that before but typically now matter how carefully and slowly I pull it out part way it will not go mono.I have put a tiny piece of tin foil over the end of the jack (not covering the grounding part)and that has made it mono, hopefully it will not break the headphones. – Jonathan. Apr 6 '10 at 21:29
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    this effect works because you're basically short-circuiting the jack; it's not a particularly good workaround. – quack quixote Apr 7 '10 at 20:28
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    I was going for simplicity. ;) It won't hurt anything; you can buy adapters that do the same thing. – rob Apr 9 '10 at 16:25
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    It also requires getting it just right. Too little and nothing changes; too much and you get one speaker connected to the opposite channel and the other speaker disconnected altogether. – Synetech Feb 9 '12 at 3:49
  • gosh... it works. in my case it happens when u have just started to plug it in – boo Mar 7 '14 at 0:54

This is another situation where a program like JACK, or possibly Virtual Audio Cable, can come in handy.

JACK works like a recording studio patch bay, allowing you to take audio input from one source or program and reroute it through other programs for processing before getting to audio hardware.

For your usage, you'd use JACK to route audio through some type of mixer plugin (VST or similar) that will downmix the stereo output to mono before sending it to the soundcard. Optionally, you might duplicate the mono signal to both left and right channels so the soundcard thinks it's a stereo signal.

I've never tried Virtual Audio Cable, but saw it recommended on another question and it sounds like it does basically the same thing as JACK.


Some video players have options to play only the left channel or only the right channel on both speakers. For example, in VLC Media Player, you can click on Audio, Audio Channels, Right.

(I think that would be better than looking for a Mono setting. A Mono setting will mix the left and right channels together and send the mono mix to both speakers. In your video, that might cause the music to be louder than the voice.)


Two options:

  1. Do it in software: The OS or soundcard driver may have an option to force sound output to mono; some media players also allow this. This will of course depend on your software.
  2. In hardware: There are stereo->mono adaptors. See e.g. http://www.conrad.de/ce/de/product/325121/SPEAKA-35MM-MONOSTEREO-ADAPTER/SHOP_AREA_17473 Should be available at any well-stocked electronics shop, or online.

This would require cables and adapters. The connection is complex as you have to get cables and adapters from a place like Radio Shack.

3.5mm stereo male jack to dual male RCA left and right (white/red).

  1. Connect the dual male RCA left and right to a dual female RCA that ends in a single male RCA.
  2. Connect the single male RCA (now stereo into mono) to a double female RCA.
  3. Now reverse the process.
  4. Connect to the other side of the double female RCA a single male RCA to dual female RCA (mono on left and right channels).
  5. Connect each of the two female RCA to dual male left and right RCA (white/red).
    • Left and right channels don't matter since the audio is the exact same for both at this point.
  6. Connect the 3.5mm male to a double female 3.5mm adapter.
  7. Finally plug in your headphones or speakers to the female 3.5mm connection.

Parts required:

  • 2 x 3.5mm male to dual RCA male (white/red)
  • 2 x single RCA male to dual RCA female
  • 1 x dual RCA female
  • 1 x 3.5mm dual female

Happy mono listening on two channels.

  • That’s what I would do if there were not a software solution. It’s not as complex as you claim though, it’s quite easy, and cheap too since you can get all kinds of connectors for under $1 (and free shipping) on eBay. – Synetech Feb 9 '12 at 3:49

With any video player that supports windows codecs, you can use FFDshow to remap the audio anyway you like it, in realtime, using the "Mixer" matrix. FFDshow is a very flexible tool for anything you may wish, such as:

  • Dropping the left channel and sending only the right channel content to both sides
  • Combine both the right and left content at lower volume, and send that to both sides
  • All the way up to increasing the volume of center or rear channels in surround content, inverting channels, etc.

Try "Virtual Audio Cable":

  1. Create virtual line(One will be created after installation)
  2. Set it as default sound device
  3. Run "Audio Repeater" from VAC folder in start menu.
  4. Set your virtual line as "Wave in" and your real audio device as "Wave out".
  5. Select Mono for "Chanel config" and click start, it's done!

Note: the mixed mono sound may be directed to LEFT channel only, I think it depends on device. Enjoy.

  • 1
    This solution "works", however, after a few minutes of listening, a voice cuts in every 10 seconds and says "Trial." So this is only a good solution for someone willing to spend $25.20 (minimum) – Chloraphil Apr 19 '13 at 13:42

What you need is that program.


enter image description here

Choose your output device at first arrow and set up mono at second.

  • This program is amazing! I have missed this feature since it was removed in Windows 7 and Voicemeeter allows me to force the audio output in mono in software and so much more. – Chaoix Dec 29 '16 at 19:05

One solution that should work on Windows 7, 8, 8.1 and 10 is Equalizer APO (very complete and powerful tool to tweak audio outputs).

After selecting your device, add a Copy filter and set your Left and Right channels to be copied on both channels as shown in my screenshot below.
You may also add a Preamp filter to compensate the Peak gain (shown in red).

Here is my config (Windows 8.1):

Equalizer APO config


I followed few tutorial and this one is complete : https_://nirklars.wordpress.com/2014/04/26/realtime-digital-audio-processing-using-vst-plugins-in-programs-without-vst-support/

To sum it up it uses VB-Cable Driver and a VST to convert stereo to mono wrapped into VSTHost.

It seems a little bit complicated but once installed all you have to do is :

  1. Set "CABLE Input" as default playback device
  2. Drop stereomon.dll VST into VSTHost and select On in the VST GUI
  3. Go to Devices > Wave in VSTHost and select :
    • "CABLE Output" as Input
    • (your real playback device) as Output

Go to the control panel, find the program SmartAudio, drag the slider below the headphone graphic left or right depending on which earphone you'd like the audio to come through.

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