Subject:Mono to stereo processing

Posted by: Djipy

Date:2/18/2004 2:06:47 AM

I've got self-made loops (acoustic guitar, mono wave) and I would like to process the sound to get a wide stereo effect without artifacts. What is the best way to do that ? Phase ? Chorus ? How do they work in pro studios ?

Thanks !

Subject:RE: Mono to stereo processing

Reply by: Rednroll

Date:2/18/2004 7:57:44 AM

"What is the best way to do that?"

Mix them in stereo in the first place. Really though, this has got to be one of the dumbest things I've heard......and I've heard a lot of dumb things on these forums. If you created the loops, and are looking for a wide stereo sound then why would you mix them in mono? That's like saying, I added a bunch of noise to my music and mixed it, does anyone know a good noise reduction plugin so I can remove the noise?

Subject:RE: Mono to stereo processing

Reply by: vanblah

Date:2/18/2004 9:41:32 AM

Although you can never achieve true stereo unless its recorded in stereo (and even then it may not be true stereo) you can copy your mono file to another track and then add delay to one side (or slide one track forward or backward a little bit). You'll have to listen for phase problems. Then add a touch of reverb to the both tracks.

Doug

Subject:RE: Mono to stereo processing

Reply by: Chienworks

Date:2/18/2004 10:31:04 AM

I still like the simple little technique my brother tought me ages ago. Convert the mono file to a stereo file (the two channels will still be identical). Select the left channel and bring up graphic EQ with the 20 band view. Raise bands 1, 3, 5, 7, 9 ... etc about 6dB and lower bands 2, 4, 6, 8, 10 ... e tc about 6dB. Do exactly the same thing on the right channel, but swap the odds & evens. This results in very little overall change in the sound, but there will be a distinct separation between the two channels. You can control the amount of separation by the amount of boost/cut you use. Don't go too far though or each channel may sound odd when heard independantly of the other.

Subject:RE: Mono to stereo processing

Reply by: stebsly

Date:2/18/2004 3:12:02 PM

"That's like saying, I added a bunch of noise to my music and mixed it, does anyone know a good noise reduction plugin so I can remove the noise?"


... not the same at all .. there are many reasons someone would record loops as mono .. the main reason, imo, would be if mixing in a "traditional" fashion (like on an old 24 track analog recorder) where each track is a seperate MONO track .. or in my case very recently I had a bunch of sounds that were SUPPOSED to be 3D sounds mixed by a "game engine" - 3D sounds MUST be mono to be correctly placed in a 3D audio environment .. it turned out we wanted all of these sounds to now be 2D, so I had to convert them all to (fake) stereo.

Rednroll, based on past posts you've done, you obviously know this and are experienced in working in mono ("How do you Record a Mono Track? When Recording Multitracks of Vocals or Voice overs I would like to be able to record Mono tracks so I can save on the resources of my computer by playing back Mono Tracks instead of Stereo. It seems like Vegas only records in Stereo and then I have to do a convert in Sound Forge.") ..

so perhaps you're just busy lately / under stress and felt like flaming someone with a very simple question ...So in my opinion, the only dumb thing being said in this thread is your curt response, Rednroll.


So, to answer to the original question, I always use the preset in the channel converter called "Mono to Stereo - Invert phase pseudo-stereo" and have had no problems with it ...

Steb

Subject:RE: Mono to stereo processing

Reply by: Rednroll

Date:2/18/2004 3:27:02 PM

"traditional" fashion (like on an old 24 track analog recorder) where each track is a seperate MONO track"

Oh really, and no STEREO tracks where recorded on a 24 track analog recorder? Yes, each track is mono, but that's why you had to use 2 tracks to record Stereo signals. So there's nothing "traditional" about your example. Now you're really showing the meaning of "dumb" and what little knowledge you have in the subject. Even if this was a valid point, it's pretty easy to convert a Stereo track to mono, but it doesn't work the other way around. It's simple physics, you still can't break those laws.

"3D sounds MUST be mono to be correctly placed in a 3D audio
environment .. "

Then if they must be mono, then easy enough....again convert them to mono. I believe the original post was they created their own loops and mixed them down to mono, but what they really want is a wide stereo image. By definition, MONO is NOT a wide stereo image. Do you need some definitions on understanding the difference between mono and stereo? The above listed techniques are good advice, but in no way are any of them going to give you a wider "stereo" image. They are all pseudo stereo techniques, but in no way will give you a true stereo image. Try taking something that pans from left to right, convert it to mono, then use any of the pseudo stereo techniques, and tell me the image again pans from left to right. My analogy is right on!!!! If you want a wide stereo image then mix it that way from the start if that's what you really wanted.

Subject:RE: Mono to stereo processing

Reply by: stebsly

Date:2/18/2004 4:00:35 PM

ahem .. my POINT is that there are many reasons someone would have recorded a source as mono ..

nowhere in his original post does it say he mixed his loops to mono .. in fact, it is logical to deduce that his source recording was done entirely in mono to begin with (it is acoustic guitar loops - if he was using a pickup, it would stand to reason that he had one mono source to record, if he's a typical home studio user - he has just one mic to record his acoustic with - end result AGAIN is a MONO file or a stereo file that just has the same data in the l/r channels..)

on the "dumb" point .. really, does it matter? Who's to say who has more knowledge, you or I?? We don't know each other or how long we've each been "in the biz" - again my point is that there ARE many reasons to use mono .. and many ways to fake a wide image out of a mono source. My way of working is probably very different than yours - and flaming someone based on a different method of working is just being an arsehole.

I have to do this all the time in my line of work. And if a client needs their files to be mono, I'm sure as sin not going to double the amount of hard drive space needed for the source files by recording them in stereo.

if you wish to discuss this off list .. stebsly#hotmail.com (replace the # with @).

Steb

Subject:RE: Mono to stereo processing

Reply by: captn_spalding

Date:2/18/2004 9:18:49 PM

The question of pseudo-stereo sometimes comes up in restoration work. I try to disuade clients explainig you can't put back audio information that is not there. When pushed to the wall what Chienworks suggests is what I use. I guess I have to ask dpjiy what is your ultimate objective of your project? If it's to have the sound of an accouestic guitar in a large, realistic sound-space, then red is right - re-record it in stereo in such a space or re-record in stereo and use accoustic mirror. If the object is some non-realistic sound-space (like one's head thrust into the sound hole of Martin D15 - and I'm not NECESSARILY disparaging such a thing!) process away!!

..spalding

Subject:RE: Mono to stereo processing

Reply by: EdMLL

Date:2/19/2004 2:39:58 AM

For Mono acoustic guitar loops reproduce it inside 2 or 3 tracks using extreme pan for them in a multrack system like Acid, with 3 tracks put the 3 in the center and use diferent ambiences for 1 and 2 to simulate stereo ambience.

Subject:RE: Mono to stereo processing

Reply by: ImdurC

Date:7/9/2004 1:14:51 PM

There's nothing wrong with mono > stereo mixing. No need to be so negative guys. It's a very useful thing to know. I'm currently mixing two videos of a theater performance together = one stereo and one mono. Both shot from different dates. And I'm also faced with the challenge of turning it into surround!

http://www.soundonsound.com/sos/mar03/articles/qa0303.asp?session=521dabbb9d9b110d0a01aab4cb63fb36#Anchor-41087

I've also been testing my own ideas about how to achieve this and have been able to create a very realistic sounding stage in 4.1!

Peace,
Adam.

Subject:RE: Mono to stereo processing

Reply by: Rednroll

Date:7/11/2004 9:31:19 PM

Now that I have reread the original question, I realize that I may have misinterpreted the question. He said, "(acoustic guitar, mono wave)". My appologies. To me, that now means he's only recording a single source, "acoustic guitar" and creating loops or these acoustic guitar recordings.

There's a few things that could be done to give the acoustic guitar a wider stereo image.

1. Try multiple micing the guitar instead of a single mic, and run each mic to a seperate track. You might want to try a couple stereo mic setups, with 1 mic pointed at where the body meets the neck, and another pointed towards the rear of the hole. You could also place another mic back 4-6 feet and get some ambience, or an x-y configuration to give more of a stereo ambience track. Then when you mix them, you can pan each track to different locations and mix to stereo.

2. Another thing is that you can take your mono loops, and add some reverb. A Large room, would probably be good. Reverbs are stereo processors, so although your original recording is mono, the Reverb will be in Stereo and give you a wider image. You could try some chorus too, but that might muck up the clarity. Chorus will thicken the sound of the guitar, so if it needs some fullness, you could add some chorus, just be conservative.

Further details would be appreciative, of what your intention of the loops are for. If they are meant to be played by themselves with no other acompaning instruments, than knock your socks off by adding some effects to them. If the plan is to later add accompaning instruments, then it is probably better to leave off the effects. This way, you can add the reverb and other FX's and control the levels within the mix, to make it fit the other instruments better.

"I've also been testing my own ideas about how to achieve this and have been able to create a very realistic sounding stage in 4.1!"

4.1? Why stop there? You can get 5.1 and 7.1 surround with a stereo file using a Dolby Prologic II or Logic 7 decoder.