Taperssection.com

Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: noahbickart on October 15, 2018, 10:52:56 AM

Title: M/S Processing for non m/s sources
Post by: noahbickart on October 15, 2018, 10:52:56 AM
Hi everyone:

As I've been thinking about modified PAS and OMT techniques, and doing more multi-microphone recordings, one of the things I'm thinking more and more about is the degree to which a good tape depends on the right mix of direct and reflected sound.

We set up our microphones arrays in such a way to provide a good balance between the “dry" direct sound from the PA and "wet" sound of the room. If done well, yay!! If not, well try again.

But there's an easy way to adjust this stuff in post, by using a M/S plug in on a Stereo L/R signal. With the Magic of modern DAW plugins, there's no need to convert to M/S first.

So, too much ambience/audience chatter? Decrease the S component and/or bump up the M. Recording too Monoish? Decrease the M and/or increase the S.

Here are some great resources:
https://klanghelm.com/contents/products/VUMTdeluxe/VUMTdeluxe.php (This is what I use, as the channel knobs can be L/R or M/S)
https://www.voxengo.com/product/msed/
https://hofa-plugins.de/en/plugins/4u/

**edit to add more resources:**
Here's a good free parametric eq which allows for different EQ setting for M and S:
https://www.ikmultimedia.com/products/trclasseq/

If you prefer a free graphic, the same folks who do MSED make this:
https://www.voxengo.com/product/marvelgeq/

Here's a free VST which does M/S level, eq & dynamics in a single plugin:
https://www.soundonsound.com/news/internet-co-release-free-ms-eq-comp-plug

I find the toneboosters eq to be really easy to work with and is only ~$35:
https://www.toneboosters.com/tb_equalizer_v4.html
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 15, 2018, 12:19:20 PM
Any stereo file can have it's balance re-adjusted in this way. IME lots of live recordings made with narrowly spaced and angled microphones can benefit from some adjustment.  Just listen carefully to determine if it is doing what you want without introducing other problems. 

It can sometimes be helpful to think of this in terms of manipulating the basic Sum/Difference balance between the two channels rather than Mid/Side.  Mid/Side representing the higher-order categorization of the sum and difference components.

And if you want to get really fancy, you can apply inverse EQ curves to the Sum and Difference channels so as to adjust stereo width in different amounts by frequency, without changing the overall frequency balance.  Probably easiest to do that by adjusting EQ of the difference channel to obtain the width result you want (typically by emphasising the low frequencies in the Side channel), then EQing the re-combined output to whatever sounds timbrally appropriate overall.  Otherwise, there are plugins which do that for you, providing controls for varying width by frequency.
Title: Re: M/S Processing for non m/s sources
Post by: noahbickart on October 15, 2018, 01:07:52 PM
Isn’t another way of saying "mid," "sum" and side another way of saying "side," "difference?"
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 15, 2018, 01:25:13 PM
Yes, just different terms for the same thing:
Sum = Mid = L+R
Difference = Side = L-R (and/or R-L)

This past weekend I was considering running a setup using two sideways-oriented Mid/Side pairs, which would have decoded as Front/Back rather than Left/Right.  In talking about this with Nick D over the phone it became confusing describing a sideways-facing Mid and forward-facing Side. 
Title: Re: M/S Processing for non m/s sources
Post by: wforwumbo on October 15, 2018, 06:14:15 PM
All phenomenal information in this thread so far.

First thing I have to say: don't trust that "Nick D" character. He has no idea what he's talking about.

Mid/side processing is also useful for equalization, especially on stereo equalization. Some EQ plugins - I'm pretty sure the default Logic EQ plugin will do it, and I want to say Fab Filter Pro-Q 2 will as well - will also encode/decode and mix in M/S for you as well. Particularly useful if you want to address mid/side differently, and still have the information presented in traditional L/R.

What's interesting to me about M/S, has to do with coherence. The "mid" channel is the amount of "coherent" signal between left and right, while "side" is about "incoherent" or "decorrelated" sound. Practically speaking, this is similar enough (if not identical) to using "sum/difference" terminology - where the waveform aligns in sum it reinforces, and where it does not it cancels.
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 16, 2018, 09:30:25 AM
What's interesting to me about M/S, has to do with coherence. The "mid" channel is the amount of "coherent" signal between left and right, while "side" is about "incoherent" or "decorrelated" sound. Practically speaking, this is similar enough (if not identical) to using "sum/difference" terminology - where the waveform aligns in sum it reinforces, and where it does not it cancels.
^
This! 

And loosely correlates with direct / reverberant, for the sources of primary interest in our recordings.  Which loops back to Noah's initial dry/wet observation.

coherent/decorrelated
direct/reverberant
sum/difference
front/all-other-directions

^
To me, these concepts generally represent more useful ways of thinking about the nature of recording and acoustics than Left/Right
Title: Re: M/S Processing for non m/s sources
Post by: noahbickart on October 16, 2018, 10:17:55 AM
To me, these concepts generally represent more useful ways of thinking about the nature of recording and acoustics than Left/Right

Indeed. And that's why I'm so surprised that while most tapers probably do (or at least know how to do) L/R adjustment in post, so few are willing to use a plugin to adjust the M/S ratio.
Title: Re: M/S Processing for non m/s sources
Post by: Sloan Simpson on October 16, 2018, 10:21:59 AM
Sometimes I’ll high pass or low shelf cut the sides on an audience tape in a muddy room.
Title: Re: M/S Processing for non m/s sources
Post by: capnhook on October 16, 2018, 02:03:24 PM
Sometimes I’ll high pass or low shelf cut the sides on an audience tape in a muddy room.

Great tip, never considered that.  Thanks.

Then MSED....
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 16, 2018, 02:54:57 PM
Whatever works.  If the center bass sum is tighter and you don't want to make a reduction in overall bass level but only wish to tighten things up you can boost the lows in the Mid channel to compensate for the cut you make in the Side channel.

However, in a good sounding situation it's generally advantageous to go the opposite route, boosting the low frequencies of the Side channel.  Two reasons for that- one is that typical stereo mic'ing often leads to weaker than optimal low frequency difference information.  The other is that increased difference at low frequencies is advantageous in taking advantage of the perceptual nature of human hearing, increasing the sense of being there, immersed in the recording space, which is enhanced by sufficinent low frequency difference info.

So try it both ways, cutting the lows in the Side/Difference versus cutting them in the Mid/Sum before going with whatever works better.


Doubtless, folks will find online a lot of info and plugins specifically designed to sum or mono-ise low frequency content, which is a frequency-specific Mid/Side manipulation.  That may have a place in some live music recordings, but mostly comes from other areas which don't apply as strongly to taping-

Vinyl records cannot support strong difference information, especially at the lowest frequencies.. and can't go super low regardless.  Difference information is conveyed via the vertical modulation of the record groove, and a particularly strong difference signal can cause the needle to jump out of the groove.  Also, increasing the playtime per side requires further reduction of vertical modulation depth to squeeze the grooves more tightly together.

EDM and other low synth heavy music typically monoize the low bass content as a way of maximizing low frequency loudness by keeping the woofers in-phase at those frequencies, increasing power transfer though the impedance mismatch between the driver cone area and the air it is pushing, and radio and other broadcast services do the same for somewhat different reasons.
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 16, 2018, 03:37:28 PM
Here's a fun thing to play around with for those of you running two (or more) pairs of microphones and/or mixing multiple sources-

Do an initial mix the way you typically would, then set that aside for later comparison. In listening to the two sources when making that mix, determine which has better clear, direct sound versus which conveys the ambient/diffuse material in a better way. Make a second mix which includes narrowing the width of the more clear/direct source and widening the ambient/diffuse source.  Play around with the width of both in combination to see if you can improve the mix this way, both in terms of imaging clarity and "you are there" feel.

This can sometimes work really well by emphasizing the better qualities of each source, even to the extent that such a manipulation would be too much when either pair is listened to in isolation, yet when combined the two balance each other and blend better with less conflict.. or it might just produce a smeared mess.  Tread carefully and use your ears to find the most appropriate blend of the two.  Generally I'd suggest narrowing the width (increasing the sum) of your closer-spaced/more-narrowly-angled/more-directional source, and increasing the width (increasing the difference) of the wider-spaced/wider-angled/less-directional source.

An opposite approach to that is to listen specifically to the Left/Right stereo imaging locations of each source in isolation, adjusting the width of one so as to match the perceptual sense of the direction to each sound source in the other as closely as possible.  This is more about matching clear and precise specific imaging locations between sources without smearing those apparent locations.  However, in doing this we increase the degree of overlap between the two sources such that other conflicts may arise- congested imaging, timbral issues, less overall sense of envelopment, etc. 

Personally, I find the prior approach more useful most of the time, which in a way is the application of Mid/Side to mixing in a general sense.  But do whatever sounds right, take a break, then compare against your initial straight-up mix to see if what you came up with is actually an improvement or not.
Title: Re: M/S Processing for non m/s sources
Post by: noahbickart on October 17, 2018, 06:30:58 PM
Here's a great example.  wforwumbo made a great recording of Phish in Albany last night, you can find it here: http://bt.etree.org/details.php?torrentId=602184

To my ears, there's just a touch too much room in the recording. So I ran it through the Klanghelm VUMT Deluxe (https://klanghelm.com/contents/products/VUMTdeluxe/VUMTdeluxe.php), and dropped the S signal by 1.5db, and then compensated for the overall decrease in volume by switching the same plugin back to L/R and raising both L and R. It's subtle, but definitely cleans it up a little.

I love being able to use plugins for playback, and that klanghelm one is *always* in the mix
Title: Re: M/S Processing for non m/s sources
Post by: kuba e on October 18, 2018, 05:28:00 PM
This is interesting thread. I would like to ask about phase cancellation when doing M/S equalization for spaced pair of mics:

- If I equalize M/S for lows, the phase cancellation can appear only in the low region (the region that was touched by eq)? Or the phase cancellation can appear in all regions (included regions that was not touched by eq)?

- Is the lower probability of phase cancellation when eq bass than eq height?
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 18, 2018, 07:31:57 PM
Not sure I follow. Is this something you notice this when doing Left/Right equalization?  If not, it's not something you will notice when doing Mid/Side (sum/difference) equalization.  The best practical answer I can give is to listen carefully when you make the adjustment to determine if it is doing anything other than what you want.

Standard (minimum-phase) EQ causes some degree of phase shift which is confined to the EQ'd region.  And as I understand it, the amount of phase shift depends on the gain and Q of the filter.  However, you are unlikely to hear that as cancellation per se.


With regards to spaced microphones and the phase-relationship between channels-
For direct sound arriving along the plane perpendicular to an imaginary line between the microphones, the content in both channels will be coherent and in-phase across the full frequency range. For direct sound arriving from off-axis, and for diffuse/reverberant sound which arrives essentially from all directions equally, the content is in-phase at the lowest frequencies and transitions to increasing degrees phase shift as frequency increases, becoming essentially randomized once the degree of phase shift exceeds 180 degrees.  The frequency at which this trend begins to occur is determined by the spacing between the microphones and the angle of arrival.  This applies to any spaced pair, a near-spaced directional pair of microphones as well as a wide-spaced pair of omnis, the difference between the two being the corner frequency at which that begins to occur, which will be lower for wide-spaced omnis, and considerably higher for a near-spaced pair.  Either way, the sum of the two channels (Mid) favors the in-phase components and the difference of the two channels (Side) favors the randomized phase components.
Title: Re: M/S Processing for non m/s sources
Post by: ycoop on October 19, 2018, 01:02:05 AM
^If I’m understanding that correctly, that explains why my first attempts at pseudo-MS processing showed peaks of around +3 dB from the low end (maybe to around 200 Hz) and the side around 0 dB (though now that I'm writing this I'm not sure what the reference dB is).
Title: Re: M/S Processing for non m/s sources
Post by: kuba e on October 19, 2018, 03:54:49 AM
Not sure I follow. Is this something you notice this when doing Left/Right equalization?  If not, it's not something you will notice when doing Mid/Side (sum/difference) equalization.

Gutbucket, thanks for the answers. I am sorry I asked inaccurately. Just to be sure. E.g.: if we have spaced pair of mics and we sum both channels to mono track, phase cancellation will happen in the resulting mono track (you explained why in the second paragraph).  If I do some Mid/Side manipulation for spaced pair mics, there will be no phase cancellation in the resulting Left/Right tracks?

^If I’m understanding that correctly, that explains why my first attempts at pseudo-MS processing showed peaks of around +3 dB from the low end (maybe to around 200 Hz) and the side around 0 dB (though now that I'm writing this I'm not sure what the reference dB is).

Ycoop, I think it means that the bass is placed in the center of stereo playback. If you try to amplify the bass in the Side channel and weaken bass in the Mid channel, the recording may be more spacious and maybe even clearer. But I do not have experience with it, it will be better for others to advise you.
Title: Re: M/S Processing for non m/s sources
Post by: ycoop on October 19, 2018, 05:48:48 AM
Not sure I follow. Is this something you notice this when doing Left/Right equalization?  If not, it's not something you will notice when doing Mid/Side (sum/difference) equalization.  The best practical answer I can give is to listen carefully when you make the adjustment to determine if it is doing anything other than what you want.

Standard (minimum-phase) EQ causes some degree of phase shift which is confined to the EQ'd region.  And as I understand it, the amount of phase shift depends on the gain and Q of the filter.  However, you are unlikely to hear that as cancellation per se.


With regards to spaced microphones and the phase-relationship between channels-
For direct sound arriving along the plane perpendicular to an imaginary line between the microphones, the content in both channels will be coherent and in-phase across the full frequency range. For direct sound arriving from off-axis, and for diffuse/reverberant sound which arrives essentially from all directions equally, the content is in-phase at the lowest frequencies and transitions to increasing degrees phase shift as frequency increases, becoming essentially randomized once the degree of phase shift exceeds 180 degrees.  The frequency at which this trend begins to occur is determined by the spacing between the microphones and the angle of arrival.  This applies to any spaced pair, a near-spaced directional pair of microphones as well as a wide-spaced pair of omnis, the difference between the two being the corner frequency at which that begins to occur, which will be lower for wide-spaced omnis, and considerably higher for a near-spaced pair.  Either way, the sum of the two channels (Mid) favors the in-phase components and the difference of the two channels (Side) favors the randomized phase components.

Looking back at this last paragraph again and trying to apply it to the EQ and mixing of the pseudo-MS channels that I made for a recent recording of mine that came out with muddy bass and distant sounding mids. Did all this in Reaper. Duplicated the original track and applied the Voxengo MSED plugin to each channel. One channel I set at -24 dB for Mid and the other channel I set as -24 dB side to create individual tracks for mid and side. I then applied the "mud free" preset from the RealEQ plugin on the side channel (which is essentially a high pass set around 150 Hz and band filters at around 300 and 600 Hz with a slight but wide band filter at around 6000 Hz). I further increased the Side track by 2 dB. I think the end result maintains spaciousness and the low end while still bringing out the mids, overall making the recording sound less like there's a thick blanket on top of it.

Doing a lot of work right now trying to wrap my mind around this. Am I correct in thinking that the lower frequency sound that makes it to either channel and is processed as "side" would be more reverberant? So while there's less bass present in the side component, the bass that is present is muddier.
Title: Re: M/S Processing for non m/s sources
Post by: noahbickart on October 19, 2018, 09:21:45 AM
Duplicated the original track and applied the Voxengo MSED plugin to each channel. One channel I set at -24 dB for Mid and the other channel I set as -24 dB side to create individual tracks for mid and side. I then applied the "mud free" preset from the RealEQ plugin on the side channel (which is essentially a high pass set around 150 Hz and band filters at around 300 and 600 Hz with a slight but wide band filter at around 6000 Hz). I further increased the Side track by 2 dB. I think the end result maintains spaciousness and the low end while still bringing out the mids, overall making the recording sound less like there's a thick blanket on top of it.

Can I suggest an easier workflow?

Use MSED in the "thru" mode- you can adjust M/S on the fly.

For different eq on M and S, just use an EQ plugin which allow for different curves for M and S.

Here's a good free parametric:
https://www.ikmultimedia.com/products/trclasseq/

If you prefer a free graphic, the same folks who do MSED make this:
https://www.voxengo.com/product/marvelgeq/

I find the toneboosters eq to be really easy to work with and is only ~$35:
https://www.toneboosters.com/tb_equalizer_v4.html
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 19, 2018, 10:20:18 AM
Am I correct in thinking that the lower frequency sound that makes it to either channel and is processed as "side" would be more reverberant? So while there's less bass present in the side component, the bass that is present is muddier.

Yes, the Side channel will contain more reverberant content.  Not just at low frequencies but across all frequencies.  The Mid channel has reverberant content as well, yet has a higher proportion of direct sound so it will usually sound less reverberant.  And yes there will usually be less very low frequency content in the Side channel

I like approaching each aspect separately, using a tool like MSED in "tru" mode for overall stereo width adjustment, and using a Mid/Side EQ for adjusting the timbre of the direct center-image sound versus the more ambient wide sound.

But a Mid/Side EQ can also be used to adjust width (and to some degree reverberance) by frequency range without changing the overall tone by applying inverse (mirror image) EQ curves to Mid and Side, boosting where the other cuts and vice-versa.  The EQ plugins Noah points to can be used to do that, although you'll probably need to dial in both the original curve on one channel and its inverse on the other yourself.   No unlikely that you might want to adjust both width and tone, but this approach allows you to separate the two.

Does anyone know of a Mid/Side EQ that has an "inverse curve" mode which automatically creates an inverse curve in the second channel?  That would be very useful for this as one could adjust width by frequency with gain being automatically compensated, separating the width/rebererance adjustments from the tonal adjustments.
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 19, 2018, 10:40:29 AM
if we have spaced pair of mics and we sum both channels to mono track, phase cancellation will happen in the resulting mono track (you explained why in the second paragraph).  If I do some Mid/Side manipulation for spaced pair mics, there will be no phase cancellation in the resulting Left/Right tracks?

Might be, but I don't worry about it much unless it presents an obvious problem.

There is no cancellation from simply converting from L/R to M/S and back to L/R again (that's is how FM radio works), but there will be some if you manipulate the M/S ratio in the middle before converting back to L/R again as we are talking about here.  Does it matter?  Your ears will tell you if it does or not.  Usually we're making minor width tweaks which won't stir this kind of thing up too much.  Also, consider that any spaced-microphone configuration will already have phase cancellation combing stuff going on as described above, and doing this mostly serves to shift the combining which is already present around, as much or more so than making it stronger or weaker.  In a way, it's sort of like re-adjusting the distance between the microphones.  Technically it is not the same, but practically it is similar.
Title: Re: M/S Processing for non m/s sources
Post by: kuba e on October 20, 2018, 06:26:03 AM
Thanks GB. I understand. And thanks to all specially to Noah for pointing out this. Mid/Side eq or stereo manipulation looks like good tool for tapers. It helped me with one of my recording. The recording needed a lot of boost of bass. When I did standard eq, it started to sound muddy. So I used only limited bass gain. Now I added additional bass gain only to Mid. It works great, the recording has the required bass and still sounds clear.
Title: Re: M/S Processing for non m/s sources
Post by: kuba e on October 20, 2018, 07:00:28 AM
Ycoop, I think it means that the bass is placed in the center of stereo playback. If you try to amplify the bass in the Side channel and weaken bass in the Mid channel, the recording may be more spacious and maybe even clearer. But I do not have experience with it, it will be better for others to advise you.

I wrote this probably wrong. If the Mid channel is high it should mean that the sound is narrow in stereo playback. But it does not have to be placed in the middle of the stereo playback, it can be on the left or on the right side. On the other hand. If the Side channel is high it should mean that the sound is wide in stereo playback. And it does not mean the placement in stereo playback.
Title: Re: M/S Processing for non m/s sources
Post by: wforwumbo on October 20, 2018, 02:38:11 PM
Just to follow up on this thread...

After Noah mentioned to me his m/s processing on Tuesday’s Phish show (Albany n1), I experimented with it a little bit pre-show Wednesday. I arrived at the conclusion that using MSED and dropping the side just a touch (depending on what I wanted to listen for, I’d vary from -1.5 to -4.5 dB) really helped to strengthen the overall tape. I lost some immersion even just by raw m/s encoding and phase interactions, but I gained a bit of soundstage and image stability, plus I was able to clear out some of the fairly overwhelming room reverberance (TUC is a highly echoic and boomy room). I found this really helped the tape, and actually I applied it to my 16/44.1 masters that I uploaded after Wednesday’s show - I will leave my 24/96 masters untouched re: m/s, but for 16-bit that I knew was going to be first to the draw (and thus widely listened to) I thought it would sound better to the masses listening on their iPhone earbuds and on streaming services.

This has admittedly gotten me to totally rethink how I tape, and what possible coincident and spaced pairs I want to eventually build my rig with...
Title: Re: M/S Processing for non m/s sources
Post by: noahbickart on October 21, 2018, 02:10:33 AM
I can't recommend the Klanghelm VUMT deluxe enough.

https://klanghelm.com/contents/products/VUMTdeluxe/VUMTdeluxe.php

I find it much more precise than the MSED. The metering and gain options are really useful for lots of other applications as well. It's only 22 Euro for the deluxe.
Title: Re: M/S Processing for non m/s sources
Post by: Ronmac on October 21, 2018, 06:44:52 AM
^^^ +1

VUMT sits as the first plugin on each track in my studio projects to insure proper levels prior to any processing.

Simple, elegant and extremely useful. Oh, and it is dirt cheap, as well.

I use the Brainworx  BX Digital EQ3 for my deep-dive EQ and MS needs.

https://www.brainworx.audio/products/brainworx/bx-digital-v3.html
Title: Re: M/S Processing for non m/s sources
Post by: kuba e on October 23, 2018, 12:41:33 PM
Maybe it's also worth trying a linear eq when doing M/S eq. I played with one recording and the linear eq was little better. It could bring a less phase smearing.
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 23, 2018, 03:09:31 PM
Makes sense.  Similarity, for recordings that are made with a Mid/Side microphone arrangement, tweaking time alignment of the Mid channel against the Side channel by a few samples either way can correct for less than perfect microphone coincidence and make an audible improvement.
Title: Re: M/S Processing for non m/s sources
Post by: noahbickart on October 23, 2018, 03:35:54 PM
Similarity, for recordings that are made with a Mid/Side microphone arrangement, tweaking time alignment of the Mid channel against the Side channel by a few samples either way can correct for less than perfect microphone coincidence and make an audible improvement.

How, if at all, does adjusting the time affect phase?

This is one of those philosophical audio questions I've been pondering for years. wforwumbo tries to answer this with equations and logical QED style proofs that lose me. I'm a religion professor after all....
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on October 23, 2018, 04:49:15 PM
Easiest way to think of it is like aligning an AUD and SBD, just to a much finer degree.  By shifting the timing of one channel against the other you shift the alignment of one waveform against the other.  We enter the phase-alignment realm rather than the time-of-arrival realm when such a shift gets things closer than one wavelength at the frequency in question.

In the case of an AUD + SBD mics which are a number of meters distant from each other, the alignment difference is one of milliseconds and therefore in the time-of-arrival perceptual realm.  In the case of a Mid/Side pair of microphones which has an imperfect coincidence better measured in millimeters, the difference is going to be one of microseconds (µs), which is probably a few hundred samples either way.

Sound travels approximately 1 mm in 300µs.  The time difference between samples at 44.1kHz is 22.7µs.  So 13 samples (at 44.1kHz) ~= 1mm.  A misalignment of say 1cm would equate to about 130 samples.

That gives you an idea of the scope of it, but since we probably don't know exactly how far the capsules might have been be out of misalignment, just listen very carefully if adjusting and see if it makes any audible difference.
Title: Re: M/S Processing for non m/s sources
Post by: noahbickart on October 24, 2018, 03:25:46 PM
this might be interesting to people looking for an all in one M/S EQ:

https://www.soundonsound.com/news/internet-co-release-free-ms-eq-comp-plug
Title: Re: M/S Processing for non m/s sources
Post by: capnhook on October 25, 2018, 08:28:35 AM
this might be interesting to people looking for an all in one M/S EQ:

https://www.soundonsound.com/news/internet-co-release-free-ms-eq-comp-plug

Giving it a try, great find noahbickart, I like having M/S, EQ and Compression in a single VST plug-in.

Tried it on a final mix and am pleased with what can be done with it, especially because it's free.

Thanks.
Title: Re: M/S Processing for non m/s sources
Post by: kuba e on December 12, 2018, 06:45:47 AM
Does anyone know of a Mid/Side EQ that has an "inverse curve" mode which automatically creates an inverse curve in the second channel?  That would be very useful for this as one could adjust width by frequency with gain being automatically compensated, separating the width/rebererance adjustments from the tonal adjustments.

You inspired me. Unfortunately, I did not find this plugin. But there is a simple solution for those who use the Reaper. Maybe it's possible in other DAWs too. It is easy in Reaper. We can link gain parameters in side eq with gain parameters in mid eq. And set the scale to -100% for reverse values. We can save this plugin even with linked parameters for future use. This way we can set up most of plugins in Reaper. Input range (slider) of linked parameters should be linear when setting reverse value. In case of this limitation it can be solved by the JS plugins. There is possibility to modify the input ranges and minimal step.

Maybe this can be useful when we do matrix too. First, we can set the correct ratio of e.g. aud and sbd. And when we need to fine-tune the stereo image we can use comfortably a plugin with reverse linked levels (left/right or mid/side). The aud/sbd ratio remains roughly the same and aud or sbd stereo image can be easily shifted or stretched.
Title: Re: M/S Processing for non m/s sources
Post by: Gutbucket on December 12, 2018, 09:08:40 AM
^That's great.  This kind of "automatic inverse compensation" functionality is applicable to a lot of different mixing tasks and should be especially useful for fine-tuning.  The EQ balance between two sources is one good application.  Get each sounding good on their own.  Get the overall mix of the two sounding good. Then use that functionality to retain the same overall EQ balance while playing around with the mix balance of the two across the spectrum.  A "tilt" EQ may be useful there, or one could dial in a specific curve to use more midrange from one source and less from the other or whatever without actually changing the overall EQ balance.

Similarly, I've wished for that kind of "trade-off" EQ for 5 & 7 channel playback to fine-tune the EQ balance between L/R C and the Surround channels.
Title: Re: M/S Processing for non m/s sources
Post by: kuba e on December 12, 2018, 12:05:44 PM
It is a very good idea to play with mirrored eq on two sources while retain the same overall eq. I will try it.

Edit: I tried mirrored "tilt" EQ. It is very nice. And yes, it is very fine-tuning. For whom it is already too subtle (like me), you can try the more extreme settings just to get the idea what could be improved on each source individually.