Need help with Mono, Stereo, Stereo Image, and M/S

[Nevs]

There are a few concepts I have been struggling with lately, and I was hoping some of the knowledgeable folks on this forum could help me with it.

I am having a hard time understanding the concepts of Mono, Stereo, Stereo Image, and M/S. I know what Mono and Stereo IS, Mono is just one signal going through one channel, and stereo is a slightly altered version of the same signal being sent through the left and right channels. However, I don't fully understand how to implement them into sound design and into a song.

For example, in Massive, in the voicing tab, there is the "Pan Position" controller with Mono in the center. I find most of the sounds I make sound better when I set the position closer to "Full Inv" or "Full". However, I've read and heard countless times that bass sounds should be in Mono. I've never heard an explanation as to why this is and what range of frequencies they are referring to. Are we talking only keeping Sub Bass (below 100 hz) in mono? are we talking about things below 500 hz? And why exactly is this the case. Could I layer a sub bass (100 hz and below) and set this in mono and have another bass on top of it (100-200 hz and beyond) and have this in stereo?

Are there certain elements you would not want to pan? I use the pan position on every sound I make because I feel like it adds to the sound. Is this going to cause any problems when trying to layer, for example, a pad and a lead together when they are both fully panned?

Next, I don't understand what the term "Stereo image" means. Are there any methods of visually being able to view the stereo image? Is the stereo image going to clutter up other elements when its fully panned? I've found I am a very visual person and I always have a copy of Voxengo Span open whenever I am producing and designing sounds, so a way to view the image would be helpful to me in my understanding of it.

Finally, Mid/Side processing is something I can't seem to get a grip on. in the case of an EQ that can do M/S processing, how is it different from using the standard EQ? I realize it changes 1 channel to be the mid, and the other to be the side in a stereo signal, but what does this mean and how does it change the sound? I can't tell much of a difference when playing around with it.

Hopefully this isn't too much for one post, I'm eager to learn

[FAARE FACED]

However, I've read and heard countless times that bass sounds should be in Mono. I've never heard an explanation as to why this is and what range of frequencies they are referring to. Are we talking only keeping Sub Bass (below 100 hz) in mono?

We are talking about having the sub in mono only. This is important for your track to sound the best possible on a huge system. The mid part of your bass should be in stereo, and this can be particularly usefull to make it sound bigger and more powerful.

Next, I don't understand what the term "Stereo image" means. Are there any methods of visually being able to view the stereo image?

iZotope's Ozone Imager allows you to see and change the stereo image.
You might want to have a look at this : http://www.youtube.com/watch?v=c4Aq0K05DPc

[Nevs]

However, I've read and heard countless times that bass sounds should be in Mono. I've never heard an explanation as to why this is and what range of frequencies they are referring to. Are we talking only keeping Sub Bass (below 100 hz) in mono?

We are talking about having the sub in mono only. This is important for your track to sound the best possible on a huge system. The mid part of your bass should be in stereo, and this can be particularly usefull to make it sound bigger and more powerful.

Next, I don't understand what the term "Stereo image" means. Are there any methods of visually being able to view the stereo image?

iZotope's Ozone Imager allows you to see and change the stereo image.
You might want to have a look at this : http://www.youtube.com/watch?v=c4Aq0K05DPc

Thanks! Which frequencies would make up the mid part of my bass? am I safe to pan things over 100 hz without causing issues on a bigger system? Would multiple stereo, fully panned, instruments (for example: A pad and a lead playing at the same time) cause conflict? In other words, does panning the position and putting something into stereo alter the frequency range of the sound? or does it just color the sound. I'll take a look at the video you sent me.

[YeahItsMe]

Mid-Range is technically like 200Hz->7kHz, so it depends more on the frequency range your bass is sitting in.

I don't think anything below 600Hz should be panned. In my experience, a lot of time 300Hz-500Hz is just mud.

It's one thing to make it sound fat with compressors and a tiny bit of delay/reverb, but I wouldn't pan anything below 600hz unless it's a lead that hits down there.

[lightshapers]

I've read and heard countless times that bass sounds should be in Mono. I've never heard an explanation as to why this is

mainly due to club sound systems being mono.

also due to problems arising if the low end is too wide when cutting vinyl. if its too loud/wide it will cut too big a groove/troughs and the needle will jump

generally keeping anything below 300hz mono is not a bad idea

. Are there any methods of visually being able to view the stereo image?

waves paz is useful for judging stereo image

[YeahItsMe]

generally keeping anything below 300hz mono is not a bad idea

I believe Culine does ^^^ at either 350-350Hz

Make the sub have Weight and the mid-range(or anything above 100Hz) beefy! This is where Multinand Compression &/or frequency splitting will come in handy

[YeahItsMe]

Just read this is the iZotope Ozone manual:

What is Mid-Side Processing?
At the mastering stage, Mid-Side processing separates an ordinary stereo recording into its center and side elements (mid-side). This allows you to apply Ozone's processing to separate areas of your soundstage independently.
Now that your mix is divided into it's Mid and Side components, you can easily hear the separate elements that make up your soundstage. You can think of the "Mid" channel as the phantom image between your two speakers, or center channel of your audio. This is often composed of low frequency material and lead instruments (drums, bass, lead vocal, horns, etc). The "Side" channel will contain the remaining elements of your mix that exist at the edges of your soundstage (reverberation and/or instruments that are panned to one extreme side).

[outbound]

Just read this is the iZotope Ozone manual:

What is Mid-Side Processing?
At the mastering stage, Mid-Side processing separates an ordinary stereo recording into its center and side elements (mid-side). This allows you to apply Ozone's processing to separate areas of your soundstage independently.
Now that your mix is divided into it's Mid and Side components, you can easily hear the separate elements that make up your soundstage. You can think of the "Mid" channel as the phantom image between your two speakers, or center channel of your audio. This is often composed of low frequency material and lead instruments (drums, bass, lead vocal, horns, etc). The "Side" channel will contain the remaining elements of your mix that exist at the edges of your soundstage (reverberation and/or instruments that are panned to one extreme side).

A very versatile tool.

@OP an example would be say you have a reverb send that you can hear is very wide. But it is muddying up the sound with the other instrument which are all panned dead centre. M/S EQ would allow you to EQ out the masking frequencies in the mid (centre) to make things clearer but still keep those same frequencies at the side.

[SunkLo]

To clarify mid/side, mid is the shit that's coming out of both speakers, side is what's coming out of one but not the other. When audio gets put through a mid/side matrix it just calculates the common signal between both channels and separates it into the mid channel, leaving the content that's panned out in the side channel. Now if you have something panned halfway right, some of it will be in mid and some will be in side. It makes sense if you think about how panning works, which is just increasing the volume in one channel or the other, so having having the left channel be half as loud as the right to achieve a 50% right pan, means it'll take the half that both channels share for mid, and the remaining isolated half for side. (Note: I'm completely ignoring panning laws here, which you don't really need to understand.)

As for stereo field or image, that just describes the sum of elements and where they exist on the left to right continuum. You can do some psycho-acoustic tricks to increase the perceived stereo field. For example in the real world, if a sound wave approaches from the left, it will hit your left ear before your right ear. So adding some micro delay to the right channel can increase that perceived sense of space. Also doing things like eqing left and right or mid and side channels differently will help to increase that separation. The psycho-acoustic analog of this in the real world is high frequencies being absorbed by your head or ears as it hits from a certain angle. This is what makes binaural recordings so effective when wearing headphones. What wikipedia has to say about the Head Related Transfer Function.

The reason for keeping bass frequencies in mono is because bass is non-directional. You can move your sub around the room and not really hear a difference but this is not true for your high frequency drivers. This is part of the reason you're supposed to align your monitor tweeters at ear height. Also as mentioned above, a lot of club systems are still running in mono, probably to ensure uniform sound delivery throughout the venue. This can cause some pitfalls with the stereo techniques I talked about above due to phasing. Adding delay or other processing to different channels can cause certain parts to phase cancel when summed to mono. This phase cancellation is partly what causes the separation effect in the first place.

You can try it yourself, get a stereo plugin that allows you to invert just one channel of a stereo signal. If you listen on headphones it'll sound super wide and inside your head. But if you hit the mono switch on your daw, you get silence. You'd feel like a goof if your snare disappeared when you played it at a club because you tried some fancy stereo tricks on it. So be careful about phasing and periodically check mixes in mono to make sure they're not falling apart.

In addition to checking on headphones and mono, there are meters to help you figure out how things are going stereo-wise. The above-mentioned iZotope Ozone has one, as do many other free and commercial metering plugins:


Source and explanation here.

Panning can be a very helpful tool in a mix, as you can place clashing elements at opposing sides of the stereo field to reduce conflicting frequencies. It can also help you save headroom by not having to have certain parts so loud. Of course there's the creative aspect of laying out your sound stage, and also psycho-acoustic merit to having everything in its own perceived space in the virtual physical environment you're simulating. BUT there are mixing engineers who swear by L-C-R mixes, in other words only panning things either hard left, center or hard right. The idea is, if you can get a mix to sound good in L-C-R format, it'll sound good in any environment. This is a bit of an extreme approach and can sound weird on headphones, but the underlying principle is a valuable lesson. Save your panning for the end of your mix, or regularly check in L-C-R and mono to see how things are stacking up. If you can get things sounding great and balanced in mono, with a few tweaks and some panning, you can have a nice lush stereo mix that still sounds good playing on a laptop down the hall or on the stereo of a cab parked beside you.


TL;DR: I'm reeeally sorry for how big this post is. Also, chicken poutine.

[YeahItsMe]

Good read. Helped me out a bunch. Like I understood the concepts, but not how they worked together and against each other. This is especially helpful for club mixing, which is what I've been looking into: making my songs mom-compatible

[YeahItsMe]

When checking for mono-compatibility, should I make the master stereo track to mono then check for phasing/sounds cancelling?

[charles1]

I disagree that "bass is always mono" should be a hard and fast rule. I have at times used very strong panning for a very brief amount of time on my basslines. I automated it to pan in sync with the wobble LFO rate. So in other words, one wobble would come out of one side, and then the next would come out of the other side. In order to do this, you shouldn't have a random panning rate - I would sync it. You should also use it very briefly (ie, don't have your whole bassline be panning, only a small fraction of it)

[outbound]

I disagree that "bass is always mono" should be a hard and fast rule. I have at times used very strong panning for a very brief amount of time on my basslines. I automated it to pan in sync with the wobble LFO rate. So in other words, one wobble would come out of one side, and then the next would come out of the other side. In order to do this, you shouldn't have a random panning rate - I would sync it. You should also use it very briefly (ie, don't have your whole bassline be panning, only a small fraction of it)

I agree*, if the mix and bass sound good when it is summed to mono and there isn't any cancelling in the low frequencies then it shouldn't have to be mono'd just for the sake of it. (Especially in your example where the stereo plays that sort of role in the mix) I wouldn't recommend cutting that track to vinyl (Stereo bass panning being cut sounds very scary indeed ) and it may limit how loud the master can be pushed but if that's how the music is intended then let it be, let that bass roam free and wild!

*Edit : I was agreeing with "charles1's" disagree'ance not the original comment made.