What is stereo?

B

bwest

Well-known member
Can someone explain something; I’m beginning to realize I don’t understand!
Stereo…what is it? I know one needs two ears, two mics [condensers], and two channels, but I realize now this is the same for dual mono, and most likely what I’ve been making! I’ve read plenty enough now on mic placement and different styles of mic configs. [ms, ortf, xy etc.] and about freqs and patterns [ hypers, cardioids, omnis, bi’s and shotguns ] but I think I’m still missing something, something that goes on in post? I’m not currently working on anything stereo for any project, I’m just curious about what I’m misunderstanding? Hope this makes sense!
 
Dual Mono would be taking the exact same soundtrack and putting it on both channels.

Stereo soundtracks (at least in the context of a live recording) would have two mics placed at different places in the room, recording the event. Having two separate mics at different places will yield some separation to the soundtrack, and can make it more approximate what it would sound like had you actually been there and listened to it with your own ears.

The very nature of a stereo soundtrack is such that the channels will be different; some sounds will be louder (or perhaps only heard) on one channel, and not on the other; this allows our brains and ears to feel that the soundtrack is three-dimensional rather than what one would get with "dual mono"; in "dual mono" both channels are identical so there's no differentiation between the channels, and hence no spatial recreation in the listener's head.
 
Barry_Green said:
Dual Mono would be taking the exact same soundtrack and putting it on both channels.

Stereo soundtracks (at least in the context of a live recording) would have two mics placed at different places in the room, recording the event. Having two separate mics at different places will yield some separation to the soundtrack, and can make it more approximate what it would sound like had you actually been there and listened to it with your own ears.

The very nature of a stereo soundtrack is such that the channels will be different; some sounds will be louder (or perhaps only heard) on one channel, and not on the other; this allows our brains and ears to feel that the soundtrack is three-dimensional rather than what one would get with "dual mono"; in "dual mono" both channels are identical so there's no differentiation between the channels, and hence no spatial recreation in the listener's head.
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This is incorrect. Dual mono is only referring to whether or not the stereo file is interleaved or not. They are both a stereo signal, just one (stereo) is treated as one file and the other (Dual mono) is treated as two seperate sound files. Either way, a NLE will know how to treat these files and interperate them for you, so don't worry about it.:thumbsup:
 
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Yes, three dimensional sound, thats what i'm looking for...better choice of words! I use to listen for endless hours to Jimmy Hendrix as a teen. One would think I knew what stereo was. Maybe its this 'interleaving' I'm missing! I currently own two matched Oktava's and the old Sound Device's mp-2 [the preamp, not mixpre]. My post is done on Vegas-7. I havent tried stereo yet due to not being confident in understanding it. I just finished a good thread on stereo here in this forum, which just exacerbates my dilemma. http://www.dvxuser.com/V6/showthread.php?t=81537
 
What are you recording? Dialogue is recorded in mono. Background sound is in stereo etc... Maybe I can help more if you tell me what you're recording
 
Just to throw in a bit of confusion - almost all movies are recorded "mono" - that being each microphone is recorded to a single track (whether recorded multi-track and isolated or mixed together, still to one track). The creation of a "stereo" mix occurs in post-production, when all of the various audio components (dialogue, music, ambient, SFX, foley, etc.) are all mixed together and then panned and faded appropriately to create the necessary separation.

That doesn't mean that having to matched Octavas is a waste. There are always situations where having two mics can be beneficial, but usually (in my experience) in shots where there is so much separation between characters that you cannot cover them with one mic (also in multi-camera setups, with one mic covering each camera).

There are also other specialized situations where multi-mic is used, such as the specialized mics that can be used to record surround.

Phil

Phil
 
what I'm recording...i wish to be irrelevant! I want what Barry describes "approximate what it would sound like had you actually been there and listened to it with your own ears." So, not necessarily just music but dialogue as well. I've been recording everthing from tree frogs, birds, dialogue, and some day music.
 
Well that's tough dude. You're speaking in very ambiguous terms and it's hard to give you any direction if I don't know what you recording. I'ts not like I can sum up in a few sentences exactly how to get "three dimentional sound" or whatever. I have 7 years Pro audio experience and it can't be summed up in a few words on a forum on the internet. Ask some specific questions and I can answer them.
 
I guess what I'm most after is the fundamentals of stereo recording, so I can create my own sound library, and worry about specific recording technics later, when I'm in the field. Sorry, I know I'm speaking in an ambiguous fashion...but mostly because stereo recording has me a bit confused. I've learned my hypers on my oktavas were worthless for tree frogs! I do like the sound of my camera mic from time to time [dvx]. I'd like to recreate or improve on that when I video from a distance. When the mic is too far away for a descent recording! Maybe panning and fading in post is all I need to learn?
 
conrad_johnson said:
This is incorrect. Dual mono is only referring to whether or not the stereo file is interleaved or not. They are both a stereo signal, just one (stereo) is treated as one file and the other (Dual mono) is treated as two seperate sound files. Either way, a NLE will know how to treat these files and interperate them for you, so don't worry about it.:thumbsup:
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For someone that professes to do sound design I think you have a very poor understanding of the meaning of mono and stereo. Barry's explanation is a lot closer to the truth than yours.
It has nothing to do with whether or not 2 sound files are interleaved. In fact it has nothing to do with files at all. For instance, take an analog tape recording that was made with 1 microphone patched to 2 seperate tracks on the machine. Here you have 2 identical tracks or a DUAL MONO recording. Now Plug 2 mics into the same tape machine, one to each channel, and set them up in an opposing direction and you will have 2 tracks with similar recordings but not identical. Here you will have a STEREO recording.:thumbsup:
 
bwest said:
I guess what I'm most after is the fundamentals of stereo recording, so I can create my own sound library, and worry about specific recording technics later, when I'm in the field. Sorry, I know I'm speaking in an ambiguous fashion...but mostly because stereo recording has me a bit confused. I've learned my hypers on my oktavas were worthless for tree frogs! I do like the sound of my camera mic from time to time [dvx]. I'd like to recreate or improve on that when I video from a distance. When the mic is too far away for a descent recording! Maybe panning and fading in post is all I need to learn?
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The easiest way to achieve what you desire is to set your matched pair of mics up in an X Y pattern and plug one to each channel on your camera. There are adapters available to screw on to the end of your boom for this. In post just be sure to pan one track left and the other right and you will have your stereo. This will work great for recording your ambience and tree frogs etc. but for dialogue in movies you will usually want it in the center channel so a mono recording would be better.
Here's a good explantion
http://www.transom.org/tools/recording_interviewing/200106.stereomicrophones.jtowne.html
 
Barry_Green said:
Dual Mono would be taking the exact same soundtrack and putting it on both channels.

Stereo soundtracks (at least in the context of a live recording) would have two mics placed at different places in the room, recording the event. Having two separate mics at different places will yield some separation to the soundtrack, and can make it more approximate what it would sound like had you actually been there and listened to it with your own ears.
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Sorry, namesake, I'd have to disagree a bit here...

"Stereo" means "solid", and in audio terms, refers to a re-creation of a soundscape in which one can determine relative locations of things... say, a car passing left to right, locations of different instruments in an orchestra, a scream from the rightr, off in the distance.

A stereo "image" can be created in two ways: by recording in stereo, or by mixing mono sounds to stereo. Stereo mic techniques (there are many, some of the more popular ones here are ORTF, XY, A-B) involve precise positioning of a pair of mics such that the soundfield is captured with some degree of accuracy, and when played back, the listener will know from sound cues where things are located.

I won't go into detail about the techniques right now - they've been described here, and in other places, a lot - but some involve the mics being in exactly the same location, but pointed in different directions; some involve mics placed wide apart, and some fall in-between. "Stereo mics", of course, consist of two mic capsules in the same mic body.

Mono sound gives no indication of relative location of the emitter of the sound (though it can give some distance information). "Dual Mono" refers to two audio tracks that are recorded without any spatial relevance to each other - e.g., two boom mics that follow talent for dialog - which when combined don't form a consistent stereo image. So "dual mono" tracks may be different sounds, or may be the same sound recoreded to different channels - what's important is that they don't form a proper stereo image. In most editors, therefore, dual mono means "panned center by default, with no linking of volume"; while "stereo" means "panned hard left and right by default, with volume of left and right linked".

Using a good stereo recording technique will result in a good stereo image off the bat. To SYNTHESIZE a stereo image, you record or find a number of mono tracks, then use all types of post-production techniques (panning, modifying EQ and gain, reverb, etc.) to place the sounds in various locations in the soundfield. Of course, you can mix these, say, combining stereo ambience tracks with mono dialog panned to an appropriate location in the soundfield.

When you're using a DAW or Video Editing system, the terms "stereo" and "dual mono" really mean "track handling convenient for stereo" and "track handling convenient for mono". You can record two mics, say lavaliers that have no special spatial relationship, to a stereo track - but you won't have stereo; you'll have two mono tracks treated as stereo. You can record two mics placed in a precise XY relationship to dual mono tracks - and you won't (by default) have stereo (since they'll both be panned center by default, rather than left and right)[Of course, you can then pan these left and right, keep the volume the same, and have stereo playback - recording well-placed stereo mics to dual mono doesn't destroy the stereo image; the same information is recorded, but defaults to dual-mono playback].

To get "stereo", you must:
1) Have a stereo image, generated either by recording proper stereo, or by mixing various sources to stereo; and
2) Play this image back with a "left" track panned left, a "right" track panned right, and the volume level of L and R matched.

As a caveat - "stereo" can technically involve more than 2 speakers; surround sound is all technically part of the world of "stereo" techniques - but today's nomenclature distinguishes stereo from surround, and tends to use stereo to refer only to 2-track stereo.

-Barry

P.S. Probably the best reference for all issues of stereo (from human perception to recording techniques to mic selection to mixing to playback is "The New Stereo Soundbook" by Ron Streicher & F. Alton Everest - see http://www.stereosoundbook.com/
 
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TRUE stereo requres identical microphones in certain configuration, or a matched set (for MS stereo). This is because both amplitude and phase diffrences make the illusion of space, if the mics are different their differing characteristics throw the image out of whack. For this reason some mics are available even as matched sets, where the factory tries to find two mics that are identical twins as much as possible.

Hypers are not used in any traditional stereo setups, but certainly they can be used in narrow-angle xy setup and tried with ORTF. Those would be the setups for collecting sounds in nature. If you have the full set of Octavas the omnis are perfect for AB and Jecklin disk.
 
ozduc said:
For someone that professes to do sound design I think you have a very poor understanding of the meaning of mono and stereo. Barry's explanation is a lot closer to the truth than yours.
It has nothing to do with whether or not 2 sound files are interleaved. In fact it has nothing to do with files at all. For instance, take an analog tape recording that was made with 1 microphone patched to 2 seperate tracks on the machine. Here you have 2 identical tracks or a DUAL MONO recording. Now Plug 2 mics into the same tape machine, one to each channel, and set them up in an opposing direction and you will have 2 tracks with similar recordings but not identical. Here you will have a STEREO recording.:thumbsup:
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I'm not sure what you're talking about. Why would you make (your version of) a dual mono recording? If what you're saying is correct, the only reason to record 1 signal to two tracks is if you want an ms configuration. What I assumed the guy was talking about was when one looks at a pair of audio files on their harddrive and tries to say, burn them to a cd. Now some burning software (jam) will burn multiple mono files to a cd, others (toast) won't put the signals back together, so you need a stereo interleved file. That's what I assumed he was talking about because he seemed to be at a beginners level. And please, I know what a stereo recording is and no you don't have to have Identical mics to do one. I record acoustic gutars stereo with two different mics all the time.
 
This is what I was talking about. And yes, that song is called Secret Love. I'ts part of a metal opera my friends and I are writing. That's what happens when four recording engineers are bored over christmas time.:)
Picture1.png
 
I think the biggest confusion most people have is thinking that the same signal cloned onto another track and panned is stereo. As stated before it is just dual mono, and for that matter no different than just pushing up the fader.

Perhaps the more important point to consider is that most recordings you hear are made up of a combination of mono and "stereo" sources. I would argue that generally most recordings consist of a large number of mono sources and a few stereo or multi-mic'd sources.

Generally the sense of space in a given recording is created by selective panning and eq of mono sources to create a "stereo" recording. The most valuable real estate in a mix is dead center and far left and right, so be very selective about what you place in those spots.
 
conrad,

Not to be rude or anything, but I don't think the original posters question really had anything to do with output file formats.
 
I think you're right tigeba. I figured he got a mutimono file and didn't know what to do with it. I've ran into people having that problem before.
 
conrad_johnson said:
I'm not sure what you're talking about. Why would you make (your version of) a dual mono recording? If what you're saying is correct, the only reason to record 1 signal to two tracks is if you want an ms configuration.
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Not so. Quite often on a set you may have one boom mic recording dialogue, in which case you would send it to 2 channels with one side being 6db lower than the other to protect against over modulation. (Dual mono recording)

conrad_johnson said:
What I assumed the guy was talking about was when one looks at a pair of audio files on their harddrive and tries to say, burn them to a cd. Now some burning software (jam) will burn multiple mono files to a cd, others (toast) won't put the signals back together, so you need a stereo interleved file. That's what I assumed he was talking about because he seemed to be at a beginners level.
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I didn't get that at all from his post, in fact he didn't even mention anything about files. He was asking what stereo is and the difference between stereo and dual mono.
This has nothing what so ever to do with NLE's or files on a hard drive. Stereo and mono have been around long before the days of NLE's and digital sound files.

conrad_johnson said:
And please, I know what a stereo recording is and no you don't have to have Identical mics to do one. I record acoustic gutars stereo with two different mics all the time.
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With an explanation like the following, I wasn't so sure you really understood.

conrad_johnson said:
Dual mono is only referring to whether or not the stereo file is interleaved or not. They are both a stereo signal, just one (stereo) is treated as one file and the other (Dual mono) is treated as two seperate sound files.
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They are NOT both a stereo signal. Dual mono is exactly what the name implies. 2 mono signals, not a stereo signal.
 
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