Correlation Meter in Voxegno Span. How much is it important in mixing?

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Mohammadyarahmad
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Post 17 Jun 2024

Hello,
I have recently watched a mixing course which the tutor monitored the Correlation meter in Span constantly in every track.
Capture.JPG
Honestly, I haven't used that in my music production.

How much is it important to check that the meter is on the right side?
What's the main purpose of that?

Thanks
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Popey
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Post 17 Jun 2024

If it goes too far out of phase it might not sound correct if played on a mono system.

Its not something I personally monitor constantly but I will play through my track in mono to see if anything dissappears from the track.

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selig
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Post 18 Jun 2024

I learned how to use one many years ago, found it easy to hear phase weirdness so never used the meter. Doesn’t hurt, but it also is not something to get glued to and worry about every crossing into negative territory. Maybe a good idea for learning how to identify issues by ear (try intentionally flipping the polarity of one side of a stereo track and listen while watching the meter).
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dioxide
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Post 18 Jun 2024

I find these kinds of things useful for spotting things that are potentially problematic. I have some finished tracks that have Thor sounds with the Chorus set to 100% and when these are summed to mono the level of that synth drops by 4db or something, which isn't great if it's a lead sound. So it's worth checking the phase meter to spot anything like this and then you can solo the track to see what is causing it.

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selig
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Post 18 Jun 2024

dioxide wrote:
18 Jun 2024
I find these kinds of things useful for spotting things that are potentially problematic. I have some finished tracks that have Thor sounds with the Chorus set to 100% and when these are summed to mono the level of that synth drops by 4db or something, which isn't great if it's a lead sound. So it's worth checking the phase meter to spot anything like this and then you can solo the track to see what is causing it.
100% wet means no dry signal at all, and many stereo effects involve phase offsets of some sort. FWIW, with chorus at 100% my correlation meter shows swinging around zero ±25% or so, nothing seriously out of phase at all. You can't chase all mono compatibility issues, no stereo mix will collapse to mono without some changes. If you hit mono and something changes, you don't need a meter to show it because you hear it, right? A 4dB drop is pretty obvious sounding! So if you hear the lead drop, and you decide this mix MUST sound good in mono, you go to the lead and start making changes which could include simply panning things more towards center so you don't loose the original sound/effect.

Looking at Thor's chorus effect, as SOON as you add ANY chorus the meter swings up and down above and below zero. You can't really get around that. Even the delay does this when using modulation. You can even see this with a synth and panned/detuned oscillators to some degree. The new Stereo Tool even does this, just saying it's not entirely a bad thing to see.
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dioxide
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Post 18 Jun 2024

I just mean to say this kind of meter acts mostly as a warning light. As you say you'll hear it when collapsed to mono but for these tracks I wasn't in the habit of doing this. So if you spot something odd on the meter then it's time to investigate further.

splitpen
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Post 18 Jun 2024

The correlometer from voxengo I find myself more usefull for this part. The tool shows the phase in splitted bands which are tweakable in number of bands. Handy tool to to keep an eye on the phase in the low end. Like Giles mentioned above, it could be usefull to often hit that mono button and listen if your track translation in mono has the vibe and power of your stereomix.
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selig
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Post 18 Jun 2024

splitpen wrote:
18 Jun 2024
The correlometer from voxengo I find myself more usefull for this part. The tool shows the phase in splitted bands which are tweakable in number of bands. Handy tool to to keep an eye on the phase in the low end. Like Giles mentioned above, it could be usefull to often hit that mono button and listen if your track translation in mono has the vibe and power of your stereomix.
unless you are cutting vinyl, the only purpose of this meter is mono compatibility. And yes, you should be checking mono compatibility just in case, but I don't ever worry too much about a mono mix not sounding like the stereo mix, as it never does.
BUT, in the rare case when I check a mix in mono and I don't like what I'm hearing, I don't need a correlation meter to tell me I don't like what I'm hearing!

Yea, I'm being cheeky, but I believe this to be true - if you check the mix in mono and it's close enough for you, that's all you need to do. I'll also add that any extreme scenarios shouldn't come as a surprise to anyone, you should already know when you added that super wide stereo instrument that you may need to keep your 'ear' on that sound.

Most of the time (because I don't have to worry about vinyl) I LOVE having that weird stereo stuff in the mix. Bottom line: it's not like it's 100% a bad idea to mess with phase in a mix, but I WOULD say it is 100% a bad idea to do it without knowing you're doing it. So if the meter helps someone to attain a higher awareness of phase issues, then it's doing it's job IMO! Otherwise, if it sounds OK in mono, forget what the meter is showing you!
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Mohammadyarahmad
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Post 19 Jun 2024

selig wrote:
18 Jun 2024
splitpen wrote:
18 Jun 2024
The correlometer from voxengo I find myself more usefull for this part. The tool shows the phase in splitted bands which are tweakable in number of bands. Handy tool to to keep an eye on the phase in the low end. Like Giles mentioned above, it could be usefull to often hit that mono button and listen if your track translation in mono has the vibe and power of your stereomix.
unless you are cutting vinyl, the only purpose of this meter is mono compatibility. And yes, you should be checking mono compatibility just in case, but I don't ever worry too much about a mono mix not sounding like the stereo mix, as it never does.
BUT, in the rare case when I check a mix in mono and I don't like what I'm hearing, I don't need a correlation meter to tell me I don't like what I'm hearing!

Yea, I'm being cheeky, but I believe this to be true - if you check the mix in mono and it's close enough for you, that's all you need to do. I'll also add that any extreme scenarios shouldn't come as a surprise to anyone, you should already know when you added that super wide stereo instrument that you may need to keep your 'ear' on that sound.

Most of the time (because I don't have to worry about vinyl) I LOVE having that weird stereo stuff in the mix. Bottom line: it's not like it's 100% a bad idea to mess with phase in a mix, but I WOULD say it is 100% a bad idea to do it without knowing you're doing it. So if the meter helps someone to attain a higher awareness of phase issues, then it's doing it's job IMO! Otherwise, if it sounds OK in mono, forget what the meter is showing you!
How do you fix issues when your track doesn't sound good in mono?
How much sound drop(dB) is normal in mono?

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selig
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Post 19 Jun 2024

Mohammadyarahmad wrote:
19 Jun 2024
selig wrote:
18 Jun 2024


unless you are cutting vinyl, the only purpose of this meter is mono compatibility. And yes, you should be checking mono compatibility just in case, but I don't ever worry too much about a mono mix not sounding like the stereo mix, as it never does.
BUT, in the rare case when I check a mix in mono and I don't like what I'm hearing, I don't need a correlation meter to tell me I don't like what I'm hearing!

Yea, I'm being cheeky, but I believe this to be true - if you check the mix in mono and it's close enough for you, that's all you need to do. I'll also add that any extreme scenarios shouldn't come as a surprise to anyone, you should already know when you added that super wide stereo instrument that you may need to keep your 'ear' on that sound.

Most of the time (because I don't have to worry about vinyl) I LOVE having that weird stereo stuff in the mix. Bottom line: it's not like it's 100% a bad idea to mess with phase in a mix, but I WOULD say it is 100% a bad idea to do it without knowing you're doing it. So if the meter helps someone to attain a higher awareness of phase issues, then it's doing it's job IMO! Otherwise, if it sounds OK in mono, forget what the meter is showing you!
How do you fix issues when your track doesn't sound good in mono?
How much sound drop(dB) is normal in mono?
This is how I've always understood it…

Here's the thing about mono compatibility - no stereo mix is likely ever going to be 100% mono compatible. That's not the goal with a mono check, the goal is to make sure nothing important is unexpectedly lost. I say "unexpectedly" because when you add a stereo source or effect you must assume there COULD be some issue down the road.

Here are some examples of sounds that change with a mono check.

1-Let us start with a mono sound panned hard to one side. This is not uncommon in a mix, but may be a bit on the extreme side, but it will prove to be illustrative I believe.
That sound will drop 6dB when making it mono. That's right, 6 freaking decibels. So do we stop panning sounds hard to one side? Hell no, we accept that no mono mix will sound the same as the stereo version and we hope for the best.
3-4dB drop is more typical with a 'wide' stereo type effect due to destructive interference, but remember there is ALSO constructive interference which is why those sounds don't totally disappear.
This is but one reason we put important things dead center, because they are the ONLY signal that will survive a mono check untouched. Now the effects on the vocal etc. are another story with regards to mono compatibility.

So it's safe to say a sound panned away from center becomes progressively less mono compatible. The correlation meter will even go negative when you pan the sound, confirming this fact. So take those negative readings with a grain of salt…

2-Polarity inversions in the wrong place can of course cause complete cancellation when summed in extreme cases. And making a stereo mix mono is basically summing two channels into one. Watch out for "stereo" (not real stereo) effects that use polarity to create the width (more common with vintage devices or emulations).

3-Phase shifts can be worse than polarity because it won't affect every frequency equally like a polarity inversion. An extreme example would be a HAAS type of effect combined to mono just becomes a static flanger or chorus effect. This comb filter response boosts some frequencies and cuts others, making it more difficult to hear if the source doesn't fall exactly on one of the dips/boosts. So this one is the most difficult to predict the amount of level change since it can be so 'source dependent'.

I hope I've not misspoken on any of this here, this is off the top of my head first thing in the morning. I'd love to hear from others on the same subject - one power of a forum IMO is the ability to hear about the same subject from different perspectives! That's how I learned studio engineering, by watching different engineers work the same gear/room over time, and while they pretty much had the same goals, they all approached and described things from their different perspectives. It was especially helpful when guys from NY and London came to the studio, since they had a more radically different take on things compared to the local Nashville guys. And all approaches potentially have something valuable to offer IMO!
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Mohammadyarahmad
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Post 21 Jun 2024

selig wrote:
19 Jun 2024
Mohammadyarahmad wrote:
19 Jun 2024


How do you fix issues when your track doesn't sound good in mono?
How much sound drop(dB) is normal in mono?
This is how I've always understood it…

Here's the thing about mono compatibility - no stereo mix is likely ever going to be 100% mono compatible. That's not the goal with a mono check, the goal is to make sure nothing important is unexpectedly lost. I say "unexpectedly" because when you add a stereo source or effect you must assume there COULD be some issue down the road.

Here are some examples of sounds that change with a mono check.

1-Let us start with a mono sound panned hard to one side. This is not uncommon in a mix, but may be a bit on the extreme side, but it will prove to be illustrative I believe.
That sound will drop 6dB when making it mono. That's right, 6 freaking decibels. So do we stop panning sounds hard to one side? Hell no, we accept that no mono mix will sound the same as the stereo version and we hope for the best.
3-4dB drop is more typical with a 'wide' stereo type effect due to destructive interference, but remember there is ALSO constructive interference which is why those sounds don't totally disappear.
This is but one reason we put important things dead center, because they are the ONLY signal that will survive a mono check untouched. Now the effects on the vocal etc. are another story with regards to mono compatibility.

So it's safe to say a sound panned away from center becomes progressively less mono compatible. The correlation meter will even go negative when you pan the sound, confirming this fact. So take those negative readings with a grain of salt…

2-Polarity inversions in the wrong place can of course cause complete cancellation when summed in extreme cases. And making a stereo mix mono is basically summing two channels into one. Watch out for "stereo" (not real stereo) effects that use polarity to create the width (more common with vintage devices or emulations).

3-Phase shifts can be worse than polarity because it won't affect every frequency equally like a polarity inversion. An extreme example would be a HAAS type of effect combined to mono just becomes a static flanger or chorus effect. This comb filter response boosts some frequencies and cuts others, making it more difficult to hear if the source doesn't fall exactly on one of the dips/boosts. So this one is the most difficult to predict the amount of level change since it can be so 'source dependent'.

I hope I've not misspoken on any of this here, this is off the top of my head first thing in the morning. I'd love to hear from others on the same subject - one power of a forum IMO is the ability to hear about the same subject from different perspectives! That's how I learned studio engineering, by watching different engineers work the same gear/room over time, and while they pretty much had the same goals, they all approached and described things from their different perspectives. It was especially helpful when guys from NY and London came to the studio, since they had a more radically different take on things compared to the local Nashville guys. And all approaches potentially have something valuable to offer IMO!
Awesome explanations,
Thanks
I would really appreciate your opinions about these:

0. How about phase inverting of one side? For example, invert the left/right channel. This will bring the Correlation meter of Span to the right side.

In your opinion, is it necessary to :
1. Cut below 20Hz in every track, instead of doing it in the master
2. Make below 50Hz mono
3. Use mid/side EQ

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selig
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Post 22 Jun 2024

Mohammadyarahmad wrote:
21 Jun 2024
Awesome explanations,
Thanks
I would really appreciate your opinions about these:

0. How about phase inverting of one side? For example, invert the left/right channel. This will bring the Correlation meter of Span to the right side.

In your opinion, is it necessary to :
1. Cut below 20Hz in every track, instead of doing it in the master
2. Make below 50Hz mono
3. Use mid/side EQ
0. What is the original source, mono, stereo, panned mono?
1. I only cut when needed, I never “cut 20Hz” for any general reason.
2. I’ve actually never done this. One of the exciting things of the move to digital in the 1980s was no longer needing to do this - I enjoy the freedom!
3. Mid/side EQ is a great way to deal with poor mixes in mastering. Today we deal with them by going back to the mix since that is typically going to give a far better result. My issue with Mid/Side is how quickly it can destroy the stereo image. Look at it this way - going to extremes, too much “mid” is just mono (easier to do with panning). Too much sides and the panning is lost - going to extremes too much sides and panning is totally lost, all you end up with is the L-R panned to each side with one side inverted. Not only is all panning lost, but the signal is totally cancelled in mono (the ultimate in non-mono compatibility).
So seeing the extremes, it’s easy to understand how quickly you get part of the way to either undesirable end point.

So in cases where you have no other option, it can be better than nothing. Otherwise I would suggest using it as sparingly as possible unless your panning isn’t important (like for an ambient wash of sound that just needs to fill the sound stage).
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Mohammadyarahmad
Posts: 114
Joined: 15 Jan 2023

Post 01 Jul 2024

selig wrote:
22 Jun 2024
Mohammadyarahmad wrote:
21 Jun 2024
Awesome explanations,
Thanks
I would really appreciate your opinions about these:

0. How about phase inverting of one side? For example, invert the left/right channel. This will bring the Correlation meter of Span to the right side.

In your opinion, is it necessary to :
1. Cut below 20Hz in every track, instead of doing it in the master
2. Make below 50Hz mono
3. Use mid/side EQ
0. What is the original source, mono, stereo, panned mono?
1. I only cut when needed, I never “cut 20Hz” for any general reason.
2. I’ve actually never done this. One of the exciting things of the move to digital in the 1980s was no longer needing to do this - I enjoy the freedom!
3. Mid/side EQ is a great way to deal with poor mixes in mastering. Today we deal with them by going back to the mix since that is typically going to give a far better result. My issue with Mid/Side is how quickly it can destroy the stereo image. Look at it this way - going to extremes, too much “mid” is just mono (easier to do with panning). Too much sides and the panning is lost - going to extremes too much sides and panning is totally lost, all you end up with is the L-R panned to each side with one side inverted. Not only is all panning lost, but the signal is totally cancelled in mono (the ultimate in non-mono compatibility).
So seeing the extremes, it’s easy to understand how quickly you get part of the way to either undesirable end point.

So in cases where you have no other option, it can be better than nothing. Otherwise I would suggest using it as sparingly as possible unless your panning isn’t important (like for an ambient wash of sound that just needs to fill the sound stage).
Sorry, I haven't had access to the internet.
Thanks for the responses and sharing your brilliant experiences <3 :clap:

0. The source is stereo and what's the difference between the others?

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