I'm trying to breathe a bit of life into some old mixes and I'm following the guidelines from the 'HarBal Mastering Tips' PDF. Here's the link:

http://www.har-bal.com/index.php?/mastering-tutorial.php

Towards the end it mentions 'phase issues'. I don't understand this term. I always thought phase issues were caused by multiple mics in the wrong position. If you're working with a mixed, stereo master wave how would you correct phase?

Thanks in advance

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Be or don't be....don't pretend!

Hi.
Older mixes might have phase issues.

You should analyze the mix with some phase analyzer like waves PAZ or phasescope. PAZ is quite expencive but really useful tool.
If theres a little antiphase and it sounds OK both in stereo and mono, then its not a big issue. If the mix sounds rather quiet in mono then you should remove them and make the stereo image more narrow.

There is no "antiphase removal" tool. I think the best way to do it is by using some stereo and phase imagers (waves suffler is quite good).

But maybe there is some better tool for it, im not sure.

Cheers,

m


EDIT:
Now i read the tutorial and it mentioned to work on the phase with s-1 imager, its quite the similar to s-1 suffler, but suffler is better tool for this i think.

Edited by KnobGoblin (13/01/10 03:46 AM)

Quote JSB:

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Towards the end it mentions 'phase issues'. I don't understand this term. I always thought phase issues were caused by multiple mics in the wrong position. If you're working with a mixed, stereo master wave how would you correct phase?

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It's a wonderfully ambiguous term, isn't it?

'Phase issues' can become a problem whenever you combine two or more content-similar signals together.

So yes, it is often mentioned in the context of mixing the outputs of multiple mics together when those mics carry similar signals (such as when there are multiple mics covering the same source, or when mics on different sources are picking up a lot of spill from each other's sources).

In those kinds of cases, the phase issues -- caused by small timing differences between the similar signals they are carrying -- result in colouration caused by comb filtering effects.

In the case of mastering a stereo mix, phase issues may be revealed when reducing the mix to mono (ie mixing the left and right channels together) -- and there are still a great number of mono replay systems around, so it is still important -- or when trying to cut a vinyl record (when significant phase differences result in a vertical movement in the groove, potentially throwing the stylus out of the groove completely on replay and making the record unplayable.

Hugh

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Technical Editor, Sound On Sound

I have never tried Har-Bal but am aware of it's existence, I am actually open minded to it despite, I suspect, quite a few people feeling threatened by such a plug in.(Not that this is an endorsement that it can actually produce good masters, I do not know) I suppose I have not purchased it cause I tend to get the results a client requires without such a tool (and it is is much, much more satisfying)
I also suspect that this tool is lacking the musical sensitivity/affinity of a human being in relation to the source material.

You may wish to install this demo (10 days) to see if it can assist with your stereo phase problems.

http://www.mathewlane.com/DrMS.html

Certainly worth a try as the demo is free for 10 days.

cheers

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Mastering online mastering

Quote Hugh Robjohns:

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In the case of mastering a stereo mix, phase issues may be revealed when reducing the mix to mono (ie mixing the left and right channels .

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I see. That makes sense. So is there a way to correct that? If you find on mono playback things disappear can the mix be salvaged. I'm using Sound Forge 8, by the way.

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Be or don't be....don't pretend!

Quote SafeandSound123:

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I have never tried Har-Bal but am aware of it's existence,

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Ironically I'm not using HarBal either but I stumbled across the 'Mastering Tips' when browsing their site. What's your opinion on those tips by the way? I am no expert in recording or mastering, obviously, but the whole process interests me - especially how minor adjustments can make a massive difference. That being the case, and taking into account room deficiencies, budget monitors/headphones/dodgy ears etc, maybe HarBal can pinpoint something the ears might have otherwise missed.

And thanks for the link.

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Be or don't be....don't pretend!

Quote JSB:

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Ironically I'm not using HarBal either but I stumbled across the 'Mastering Tips' when browsing their site. What's your opinion on those tips by the way?

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Earle Holder (co-developer of HarBal) who I suspect wrote those tips is an extremely experienced Mastering Engineer whose opinions I trust.

Here's his own web site: www.hdqtrz.com


Martin

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YewTreeMagic

Quote JSB:

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So is there a way to correct that? If you find on mono playback things disappear can the mix be salvaged.

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It depends on what is disappearing and why. It's always easier to fix at the mix stage rather than at mastering -- indeed it may be impossible to fix at mastering. And that's why it is important to check the mono while mixing.

Often you can salvage poor mono compatibility by using frequency-selective MS processing, but any processing like that will obviously compomise the stereo sound to some extent too.

hugh

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Technical Editor, Sound On Sound

When you loose important information on folding down a stereo mix to mono, it means certain information is only in the Side channel of the MS signal and not (or not loud enough) in the Mid channel.

Preset 25 "No Loss Mono Fold Down" of my DrMS plugin shows a (tweakable) setting that solves this by saving Side information into the Mid channel by using DrMS's FIELD section.

http://www.mathewlane.com/DrMS.html

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DrMS. Focus on your stereo field.
DrMS spatial processor - native RTAS/AU/VST plugin

Welcome to the forum Mathew.

For the record, I should remind you that we take a dim view on companies using the forums to promote their products (as the Forum Rules explain quite explicitly) -- although they are very welcome to respond to specific enquiries by other forum users.

However, I'll turn a blind eye in this case as I am intriqued by your claims.

Quote Mathew Lane:

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Preset 25 "No Loss Mono Fold Down" of my DrMS plugin shows a (tweakable) setting that solves this by saving Side information into the Mid channel by using DrMS's FIELD section.

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I'm not clear on how this process works. You can't simply take the Side information and add it to the Mid information as this would emphasise the left hand channel of the original stereo information (M+S = L).

So I'm intrigued to know what other processing is being applied -- some all-pass phase shift perhaps to help decorreleate the two signals?

Hugh

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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Welcome to the forum Mathew.

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Thanks Hugh!

Quote Hugh Robjohns:

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For the record, I should remind you that we take a dim view on companies using the forums to promote their products (as the Forum Rules explain quite explicitly) -- although they are very welcome to respond to specific enquiries by other forum users.

However, I'll turn a blind eye in this case as I am intriqued by your claims.

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No worries, I have no intentions to blindly promote my plugin all over the place :-) I found out about this thread as another user linked to my website in this thread saying that it could possibly be the solution to the thread starter's question. I felt some additional information about this specific use could be helpful.

Quote Hugh Robjohns:

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Quote Mathew Lane:

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Preset 25 "No Loss Mono Fold Down" of my DrMS plugin shows a (tweakable) setting that solves this by saving Side information into the Mid channel by using DrMS's FIELD section.

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I'm not clear on how this process works. You can't simply take the Side information and add it to the Mid information as this would emphasise the left hand channel of the original stereo information (M+S = L).

So I'm intrigued to know what other processing is being applied -- some all-pass phase shift perhaps to help decorreleate the two signals?

Hugh

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Indeed you can't just route M into S or the other way around, as S is a more a "mathematical" something rather then a real world signal. Additional processing is applied, that's what DrMS originated from: It started as a mathematical concept I had for routing M into S (Focus) and S into M (Field), and it was further developed from there. First I build a MAX/MSP patch as proof of concept, that made it into the Pluggo version of DrMS (v1 & v2), which recently got re-coded and improved into v3 which now is a true native plugin.

The "No Loss Mono Fold Down" is a preset that actually does the mono-sum as well itself. If you just want to "edit" a stereo mix into a new stereo-version that has better mono-compatibility, simply start from the default setting, activate the Field Depth and add a certain % to taste. The filters in the Field section can be helpful to only work on the region that exhibits the issue (typically higher frequencies that cancel out on mono sum).

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DrMS. Focus on your stereo field.
DrMS spatial processor - native RTAS/AU/VST plugin

Welcome to the SOS FOrums Mathew!

Very interesting indeed - I'm surprised I haven't come across your plug-in before in my travels!

I'm downloading the demo at this very moment


Martin

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YewTreeMagic

Dear All,

Very interesting discussion. Thanks. I am reviewing my recordings now for phase and other problems which led me here.

Just bought the Har-Bal tool mentioned above, recommended by Martin and others, and looking forward to teaching my ears/brain lots more. But a question on the Waves PAZ plugin (also mentioned above) that I have been pondering for some time now:

Q: Would the PAZ position and phase information add to my ear training skills as well as help analyse/improve my mixes? In addition to Har-Bal EQ work that is.

With Har-Bal I am confident I can now get good EQ results across the board. Am I right in thinking PAZ would help me further by giving me direct feedback on position, breadth, and depth of phantom images (as well as phase)? Or would it be a 'distracting toy'?

Thanks all,
Richard
Hong Kong

Hi Richard!

I've found PAZ useful in the past, as its 'lobe' displays do help to train your ears to recognise mono/stereo and phase issues more easily. In my experience it's one of the more informative ones out there.


Martin

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YewTreeMagic

Thanks Martin!

Your reply is exactly what I hoped (feared?) you might say. Definitely confirms my thoughts, and when my ears are half as good as yours, maybe I too can put PAZ behind me.

The (feared?) above refers to the credit card related burning sensation I now have.

Much appreciate your time.
Richard

Edited by RichardHK (22/02/10 01:16 PM)

It's worth trying a few demos of competing software to make sure PAZ is the stereo polar meter you find most useful.

I'm currently using Nugen Audio's Vizualizer on an almost daily basis for nearly all my metering, spectrum analysis, and stereo image checking.

I reviewed it here:

www.soundonsound.com/sos/jan08/articles/nugenplugins.htm


Martin

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YewTreeMagic

Martin, you're a champ.

Downloaded the NuGen Visualiser demo and spent several hours using it on my recent projects, as well as other music files. It really is 'Comprehensive, Detailed, and Intuitive' as their website notes.
Gives me a wonderful warm fuzzy feeling when using several of the tools and actually a no-brainer purchase at that price. Especially as you are using it every day. I will be too. Saved some money and got lots more than expected.

Enjoyed reading your article before going for download. Have my SOS hard copies here and not sure why I missed that review. And not sure why I thought PAZ was the only option for my specific needs. Head now pulled out of sand!

Thanks again.
Richard