Audio Convert 5.1 to 2.1 via some hardware

6pack

ex-Mod
I usually hear the 5.1 sound from movies through my pc via headphones. here i use ffdshow or inbuilt ac3decoders to convert 5.1 to 2.1, and i can hear all channels in headphone clearly. problem is when i attach my pc speakers to my computer, then i cant hear some sounds clearly (like voice, or sound effects) as compared to when hearing through headphones.

I get the same problem if i use pc speakers attached to the tv tuner. i can hear stereo sound clearly. when watching hd movies/ tv serials through tatasky hd, the 5.1 coming from tuner does not get properly decoded in the pc speakers and some of the tracks are very faint.

my pc speakers are altec lansing vs4121. my headphone is some sony headphone. forgot the number.

is there any hardware 5.1 to 2.1 convertor available that can be put between audio source and speakers? will an av receiver do the job properly? or should i get 5.1 speakers? i dont want to clutter my house with speakers, so that option is last. probably if nothing is available i will settle for my headphones.
budget - the less the better, but preference to quality.
 
That is a limitation of the speakers, which are not putting out a solid center image.

Ideally one would add a center channel at the very least, that should be enough. For the last 20 months, I've been operating in 3.1 or 3.0 mode and have no perceived need of the surround channels.

Moving the speakers closer together should help (reduce distance between left and right), as should sitting close to the speakers. Hardware mixing and software mixing will have similar to identical results.

ffdshow allows to individually tweak channel levels in the mnixdown where you can manually increase the level of the center channel in the mix, and also something called 'boost dialog'. Try both options.

We'll talk about hardware solutions once you try these few bits and bobs out.
 
i tried boosting center, rear left and right speakers in ffdshow audio. it makes a difference in headphones, but not the speakers. for some reason, the speakers do not reproduce these channels effectively.
sometimes, when boosting the center all other channels go dull, meaning i can hear the center more loudly than other channels. so i stopped doing that.

while watching tv, i cant do anything like this cause there's no setting in the tvtuner nor tatasky. even though i take audio from the rear analog L&R audio only, i can still get 5.1 sound in it. its noticeable in headphones, but again not through speakers. example, while watching the recent ipl matches through headphones, i could hear the stadium ambiance, plus sounds like people talking or that sonu nigam song being played throughout the stadium in background (clearly) while the commentators are talking. the commentators voices are quite loud and clear and come in foreground.

same scenario, if i remove the headphones and attach the speakers, the commentators voice gets softer, plus i can hardly hear the song in background. I cant hear the hum of people talking in background no matter how loud i keep it. the irritating part in this is the commentators voice keeps coming and going from foreground to background whenever the camera zooms out to show the whole ground when a cricketer has hit a ball for four, etc. also, all the bass gets muted in the speakers, like the sound is coming from somewhere far off.
 
even though i take audio from the rear analog L&R audio only, i can still get 5.1 sound in it.

This is not really possible, what you hear is a mixdown. So all effect channels get muxed into the main analog L&R. It's stereo audio, but with the signals from the L&R. This is also why you have such weird phasing issues with moving and panning sound.

I also wasn't talking about the mixer, but the matrix.

What you're looking for is this page:

400px-Ffdshow_audio_mixer.gif
Mix more of the center into the L and R channels (numbers close to 1 are louder).

This is not going to work on the STB, though, where a center channel might make sense but the way you're describing it to me seems to be an issue with the audio output of the STB or a problem in your speakers.

Note that when a mixdown is happening in stereo phase information is used to create the surround effects (as most television is still recorded in stereo). Since it is being played back with those effects in place, speakers will be far more affected by phase differences because in headphones because the left ear does not hear what the right ear is hearing, which is simply not possible in speakers.

OTOH it could be a miswired output. No way to tell from here. If it gets real bad, get a multichannel system to sort your issues out.
 
Mix more of the center into the L and R channels (numbers close to 1 are louder).
how do i do this? i tried searching on google, but there are no turorials. i cant understand how to do this. i noticed that the mixer auto populates the matrix if 2/0/0 is used when hearing a 5.1 track. i updated to latest version ffdshow 4422 now.

volumesw.jpg
.......
51input.jpg
.......
20mixed.jpg
 
1. Check 'Custom Matrix'. All values should become editable. The row is the output and the column is the input. You can see the 'L' is mapped to 'L and the 'Back L' is also mapped to L. That is probably why you face so many issues.

2. Increase Center on both 'L' and 'R' to (1) from (.707).

3. Delete 'Back L' and 'Back R' to 0 or 0.3, you will get a bit of surround. You can also try reverse mixing, mapping 'Back L' to both the L and R outputs in slightly different proportions for best results with your ears, speakers and room.

4. LFE checked means bass management is enabled, but you are not connecting a subwoofer separately (to the center/subwoofer jack). Uncheck LFE so that the main L/R output will carry the bass signal as well.
 
I tried some settings in custom matrix. putting 1 in center channel in L and R tends to flatten the sound in headphones and speakers for some reason. If C is 0 in C', there is no depth in sound. It feels too flat.
No center in L and R gives no voice track in headphones, but some voice in speakers. I ended up with this config - works for both speakers and headphones with some depth in sound and i can feel panning in sound too from one speaker to another.



don't know if i did it right or wrong.
 
Looks fine. Fundamentally, I would mix less of surround and mroe of center into the front outputs (reverse of what you have done).

But as long as it's working, don't mess around.
 
^thanks. I dialed the BackL and BackR to 0.6 each. 0.8 was a bit too much. I also tried mixing back L&R into front L&R by 0.1-0.3. Sounded like i was in some auditorium. removed it since treble was too much.
 
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