HydrogenAudio

Digital Audio/Video => Movie/Multichannel audio => Topic started by: thunderoq on 2011-02-20 22:06:25

Title: manual merging of 6 mono .wav's to 2 ch. ?
Post by: thunderoq on 2011-02-20 22:06:25
Hi there.

So i was trying to convert .dts file to .wav (eac3to) and some codec(s) in my PC are probably fucked up -- because the peaks in final .wavfile are fucked up..
So after that, i got 6 separated channels in 1411.. SurCode CD Pro DTS conversion is stereo wav with -12dB of static noise  (like yeah, fuck it, i gonna make it "manually")..

Here's my question:
How to do a MANUAL downmix from 6 (multichannel) to 2 (stereo) channels? R & SR to right ch. , L and SL to left -- i think that's clear. but WHAT ABOUT THE VOLUME of center and LFE channels? they should be mixed in both (left and right) channels, for sure, but C & LFE are just other channels and mix them into stereo file means like PASTE IT TWICE--doesn't it?.. Or maybe i'm wrong and thre's no way to downmix 5.1 like this....
i tried to mix them (C & LFE) into with a half-volume but i don't think that's correct (I'm Using GoldWave v.5.56) -- any solutions?
Title: manual merging of 6 mono .wav's to 2 ch. ?
Post by: DVDdoug on 2011-02-22 21:17:05
I assume that DTS, like AC3 has metadata in the file for the downmixing ratios.  But, I don't know how to read this data...

If you send the center & LFE signal to both left & right channels at the original amplitude, that's twice the power or +3dB, so it should be mixed at -3dB.

Quote
but C & LFE are just other channels and mix them into stereo file means like PASTE IT TWICE--doesn't it?.. Or maybe i'm wrong and thre's no way to downmix 5.1 like this....
i tried to mix them (C & LFE) into with a half-volume but i don't think that's correct (I'm Using GoldWave v.5.56) -- any solutions?
If you are mixing a mono file into a stereo file with GoldWave, and you've got both channels active for editing, it will automatically mix-into both channels.  Just set the mix-in level to -3dB, and everything should be good.

After mixing (and before saving), Maximize Volume (normalize) to bring the peaks down (or up) to 0dB and avoid clipping when you save.

It's up to you, but the LFE channel isn't usually downmixed...  It's usually lost.    The other 5 channels are supposed to contain full-range audio (including the "regular" bass).  The LFE channel is supposed to contain "extra" boom & explosion effect sound.

Most home theater systems don't have full-range speakers all-around, so the regular bass from these channels is mixed with the LFE and sent to the sub (via the receivers' "bass management").
Title: manual merging of 6 mono .wav's to 2 ch. ?
Post by: thunderoq on 2011-02-24 08:11:58
ok, thank you for the answer! and what about the surround channels? is it correct to mix them fully to the left/right OR is there any ratio?
Title: manual merging of 6 mono .wav's to 2 ch. ?
Post by: DVDdoug on 2011-02-24 19:17:02
If you want the same level as you would hear (or the same sound you'd get if you recorded with a mono mic),  you'd mix it in at 100%. 

But assuming it's like AC3,  when a DVD player does it "properly", it gets the level from the metadata in the file, which is determined by whoever does the surround-sound mix.  (I'm not even sure that DVD players will read & downmix DTS...  If you want ot use the analog-stereo outputs on a DVD player, you might have to choose the AC3 or LPCM track.)

Or, you might want to use your own judgement/taste dependiing on the rear-channel content...

The metadata default for the Aften Encoder[/u] (http://aften.sourceforge.net/longhelp.html) is -3dB.    (The default center-channel is also -3dB.)
Title: manual merging of 6 mono .wav's to 2 ch. ?
Post by: thunderoq on 2011-03-05 00:20:13
thanks again, mix them (surrounds) into wit full volume was correct ;-)