MClass Stereo Imager

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dioxide
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15 Mar 2016

How does the Stereo Widening in this device work? Does it use Mid/Side techniques or some other way of widening the sound?

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normen
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15 Mar 2016

Its M/S, yes - meaning it will only work with material that actually has side information already.

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selig
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15 Mar 2016

normen wrote:Its M/S, yes - meaning it will only work with material that actually has side information already.
It doesn't seem to be a strict mid/side encode/decode type device - hard panned instruments stay hard panned even at the widest settings, which is totally unlike what a simple mid/side device would do, which would make center panned instruments disappear and would smear hard panned instruments across the L/R sound stage, right?
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normen
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15 Mar 2016

selig wrote:It doesn't seem to be a strict mid/side encode/decode type device - hard panned instruments stay hard panned even at the widest settings, which is totally unlike what a simple mid/side device would do, which would make center panned instruments disappear and would smear hard panned instruments across the L/R sound stage, right?
Hm, did you try this with actual signal on the right side (i.e. on the other, non-hard panned side)? Because if theres actually no sound coming in to the "silent" side the device might think its working in mono.

Edit: I just tried it with a Redrum panned all the way to the left in a 14:2 Mixer going right into the Stereo Imager at full width and judging from how I tilt my head the right side is indeed rotated in phase ;) So I still think its a plain M/S device :)

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ravisoni
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15 Mar 2016

normen wrote:
selig wrote:It doesn't seem to be a strict mid/side encode/decode type device - hard panned instruments stay hard panned even at the widest settings, which is totally unlike what a simple mid/side device would do, which would make center panned instruments disappear and would smear hard panned instruments across the L/R sound stage, right?
Hm, did you try this with actual signal on the right side (i.e. on the other, non-hard panned side)? Because if theres actually no sound coming in to the "silent" side the device might think its working in mono.

Edit: I just tried it with a Redrum panned all the way to the left in a 14:2 Mixer going right into the Stereo Imager at full width and judging from how I tilt my head the right side is indeed rotated in phase ;) So I still think its a plain M/S device :)
I obviously don't understand mid-side that well yet, but would it be the same thing if we called M/S mono-stereo or mid/side?
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normen
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15 Mar 2016

ravisoni wrote:I obviously don't understand mid-side that well yet, but would it be the same thing if we called M/S mono-stereo or mid/side?
No, stereo means two channels that carry left and right separately, the mid is what is the same in the left and right channel. M/S is a relatively simple matrix that makes left AND right one channel and the mid a separate channel.

I guess the easiest way to understand M/S is when you look at how the mid/side miking technique works, see here: https://en.wikipedia.org/wiki/Microphon ... tereophony

Theres one mic in the middle, either an omni or a cardioid microphone. The mic for the sides is a figure eight microphone that points to the left/right. As you might know the figure eight picks up things from the back with an inverted (180°) phase. Meaning if you mix in the signal of the eight and the mid microphone everything that is picked up from the side that is inverted basically gets canceled out. If you then go and invert the eight and mix it with the mid microphone again everything that is coming from the other side gets canceled out, thats how you get the left and right signal in the end. The same technique is used to get back to a separate mid and side signal from a L/R (stereo) recording to be able to process mid and side separately.

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selig
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15 Mar 2016

normen wrote:
selig wrote:It doesn't seem to be a strict mid/side encode/decode type device - hard panned instruments stay hard panned even at the widest settings, which is totally unlike what a simple mid/side device would do, which would make center panned instruments disappear and would smear hard panned instruments across the L/R sound stage, right?
Hm, did you try this with actual signal on the right side (i.e. on the other, non-hard panned side)? Because if theres actually no sound coming in to the "silent" side the device might think its working in mono.

Edit: I just tried it with a Redrum panned all the way to the left in a 14:2 Mixer going right into the Stereo Imager at full width and judging from how I tilt my head the right side is indeed rotated in phase ;) So I still think its a plain M/S device :)
But if so, in full "sides" mode (for both bands) there should be no center channel energy at all, right? But there IS. So it can't be a "plain" M/S device. And comparing it to a simple M/S device, it's definitely not doing the same thing…
:)
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selig
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15 Mar 2016

ravisoni wrote:
normen wrote:
selig wrote:It doesn't seem to be a strict mid/side encode/decode type device - hard panned instruments stay hard panned even at the widest settings, which is totally unlike what a simple mid/side device would do, which would make center panned instruments disappear and would smear hard panned instruments across the L/R sound stage, right?
Hm, did you try this with actual signal on the right side (i.e. on the other, non-hard panned side)? Because if theres actually no sound coming in to the "silent" side the device might think its working in mono.

Edit: I just tried it with a Redrum panned all the way to the left in a 14:2 Mixer going right into the Stereo Imager at full width and judging from how I tilt my head the right side is indeed rotated in phase ;) So I still think its a plain M/S device :)
I obviously don't understand mid-side that well yet, but would it be the same thing if we called M/S mono-stereo or mid/side?
Technically speaking, it would be most accurate to call it "Mono/Sides", since that's exactly what it's doing.
:)
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normen
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15 Mar 2016

selig wrote:But if so, in full "sides" mode (for both bands) there should be no center channel energy at all, right? But there IS. So it can't be a "plain" M/S device. And comparing it to a simple M/S device, it's definitely not doing the same thing…
:)
Hm, I guess there wouldn't but how could you tell that? I don't think I'd be able to hear "nothing" in the middle just because the signal from the sides are reversed...? After all theres stuff coming out of both speakers. On headphones you get the typical "suck your ear wax out" impression. Technically that is what happens though. Taking my test project from before, when I adapt left and right in volume and pan them both to the middle they cancel each other out - not 100% because I can't get the exact volume difference with the Line Mixer - heres a combi showing the test setup: https://www.dropbox.com/s/nlpdw4oox7b7t ... S.cmb?dl=0

Maybe the initial difference in volume is what confused you? In its original state the left channel is louder, thus leaving a mid signal in the end. I still stick with my assessment that this is a plain M/S device :)
Last edited by normen on 15 Mar 2016, edited 2 times in total.

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dioxide
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15 Mar 2016

Thanks for the replies guys.

Am I correct in saying that the Lo Band and Hi Band are both using M/S to widen the sound (from 0-63) or collapsing to mono (from 0 to -64)?

If I use hard panned drum sounds L and R and turn up the width to maximum it actually loses stereo width as the L signal bleeds into the R and vice versa. It is however louder!

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normen
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15 Mar 2016

dioxide wrote:Thanks for the replies guys.

Am I correct in saying that the Lo Band and Hi Band are both using M/S to widen the sound (from 0-63) or collapsing to mono (from 0 to -64)?

If I use hard panned drum sounds L and R and turn up the width to maximum it actually loses stereo width as the L signal bleeds into the R and vice versa. It is however louder!
Yeah, thats pretty much how to use it. I basically only use it as a cut filter / band splitter or to narrow the bass region if theres lots of bassy guitar / synths panned far left/right, never really was a fan of "widening" using M/S after the fact. Imo thats what the pan knob is for ;)

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dioxide
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15 Mar 2016

normen wrote:Yeah, thats pretty much how to use it. I basically only use it as a cut filter / band splitter or to narrow the bass region if theres lots of bassy guitar / synths panned far left/right, never really was a fan of "widening" using M/S after the fact. Imo thats what the pan knob is for ;)
Thanks. In this case I will be using it to reduce the low frequency content of a reverb to mono, so it will work fine for this. I've always found the widening feature of this device strange as it often doesn't do what you'd like it to. I'll stay away from the widen feature until I understand it I think. I might have a look to see if there are any tutorials on Youtube on using M/S to widen and when this works well.

If hard panned L and R sounds are diminished by M/S or the Stereo Enhancer, when does widening this way work best?

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normen
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15 Mar 2016

dioxide wrote:If hard panned L and R sounds are diminished by M/S or the Stereo Enhancer, when does widening this way work best?
Imo its only useful when you have a complete mix that you can't go back to anymore and think the mixer didn't use the pan knobs emphatically enough :)

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dioxide
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15 Mar 2016

normen wrote:
dioxide wrote:If hard panned L and R sounds are diminished by M/S or the Stereo Enhancer, when does widening this way work best?
Imo its only useful when you have a complete mix that you can't go back to anymore and think the mixer didn't use the pan knobs emphatically enough :)
Thanks. In this case I have the original files so I can widen manually using the pan pots.

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selig
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15 Mar 2016

normen wrote:
selig wrote:But if so, in full "sides" mode (for both bands) there should be no center channel energy at all, right? But there IS. So it can't be a "plain" M/S device. And comparing it to a simple M/S device, it's definitely not doing the same thing…
:)
Hm, I guess there wouldn't but how could you tell that? I don't think I'd be able to hear "nothing" in the middle just because the signal from the sides are reversed...? After all theres stuff coming out of both speakers. On headphones you get the typical "suck your ear wax out" impression. Technically that is what happens though. Taking my test project from before, when I adapt left and right in volume and pan them both to the middle they cancel each other out - not 100% because I can't get the exact volume difference with the Line Mixer - heres a combi showing the test setup: https://www.dropbox.com/s/nlpdw4oox7b7t ... S.cmb?dl=0

Maybe the initial difference in volume is what confused you? In its original state the left channel is louder, thus leaving a mid signal in the end. I still stick with my assessment that this is a plain M/S device :)
My point was it sounds DIFFERENT than a plain M/S device (Jiggery's) or one built in Thor - if you compare to a plain M/S process are you hearing exactly the same results? Solo the Sides, and turn MClass fully wide on both bands - same thing, or different? I'm hearing different - you?

Hopefully this addresses what you're talking about, and I'm not talking about a completely different thing here.
:)
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normen
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15 Mar 2016

selig wrote:My point was it sounds DIFFERENT than a plain M/S device (Jiggery's) or one built in Thor - if you compare to a plain M/S process are you hearing exactly the same results? Solo the Sides, and turn MClass fully wide on both bands - same thing, or different? I'm hearing different - you?

Hopefully this addresses what you're talking about, and I'm not talking about a completely different thing here.
:)
I updated my combi to test for this so you can compare the results for the Stereo Imager and Anansi. Do they sound so much different to you? To me they don't.

Its mainly a level issue between mid and side. I adapted those differences as far as possible. Interestingly Jiggerys device makes the hard-panned drums come out of the other channel as well when the balance of M/S is set to the middle position.

In the Combi you can use "Enable Imager" to turn both Stereo Imager and Anansi to "full side", "Switch Imager" switches between Stereo Imager and Anansi (on is Anansi) and the "Pan Output" knob puts the left/right output either full left/right or both center to check the cancellation or the "missing center information".

https://www.dropbox.com/s/nlpdw4oox7b7t ... S.cmb?dl=0 (Run sequencer to hear the drums)

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selig
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15 Mar 2016

There's a huge difference in that the Stereo Imager does NOT "kill" the center (mid) signal in full "wide" setting, but the M/S (by design) DOES kill the center (mid) signal. You don't even need to listen to know this is not how a mid/side works, but listening confirms what I'm hearing.

Again, to be clear, when you set the Stereo Imager to the widest settings on both bands, you still hear the mid panned signals - this of course is not how a basic mid/side device functions because when you hear the sides on their own you should never hear ANY center/mid signal.
Not sure how we're talking past each other here…
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selig
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15 Mar 2016

normen wrote:
selig wrote:My point was it sounds DIFFERENT than a plain M/S device (Jiggery's) or one built in Thor - if you compare to a plain M/S process are you hearing exactly the same results? Solo the Sides, and turn MClass fully wide on both bands - same thing, or different? I'm hearing different - you?

Hopefully this addresses what you're talking about, and I'm not talking about a completely different thing here.
:)
I updated my combi to test for this so you can compare the results for the Stereo Imager and Anansi. Do they sound so much different to you? To me they don't.

Its mainly a level issue between mid and side. I adapted those differences as far as possible. Interestingly Jiggerys device makes the hard-panned drums come out of the other channel as well when the balance of M/S is set to the middle position.

In the Combi you can use "Enable Imager" to turn both Stereo Imager and Anansi to "full side", "Switch Imager" switches between Stereo Imager and Anansi (on is Anansi) and the "Pan Output" knob puts the left/right output either full left/right or both center to check the cancellation or the "missing center information".

https://www.dropbox.com/s/nlpdw4oox7b7t ... S.cmb?dl=0 (Run sequencer to hear the drums)
Wait - you are converting to mono before hitting the devices and sending a "left only" signal to the devices - check the 14:2 mixer and you'll see you have the signal panned hard left/mono. Remember, this whole idea will "only work with material that actually has side information"… ;)

if you simply remove the 14:2 mixer from your setup you'll hear exactly the different I'm describing - but you'll need a clear "stereo" signal, so pan the snare hard to one side. The result will be that the kick (being panned center) disappears when monitoring the M/S signal, and yet it remains (at a slightly lower level) when you monitor the Stereo Imager. You will also notice that the snare stays left with the Stereo Imager, but has the classic "out of phase" sound from the M/S device. This is the difference I'm talking about.
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normen
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16 Mar 2016

selig wrote:Wait - you are converting to mono before hitting the devices and sending a "left only" signal to the devices - check the 14:2 mixer and you'll see you have the signal panned hard left/mono. Remember, this whole idea will "only work with material that actually has side information"… ;)
:shock: A hard left panned instrument IS side information, its NOT mono.. This was the point of the exercise because you said "hard panned instruments stay hard panned even at the widest settings, which is totally unlike what a simple mid/side device would do, which would make center panned instruments disappear and would smear hard panned instruments across the L/R sound stage".

This is only half true, in fact it DOES "smear" panned instruments to the other side, i.e. the same signal appears 180° phase shifted on the other side, just like one would expect with a M/S matrix. Center doesn't disappear though but I go into that below.
selig wrote:if you simply remove the 14:2 mixer from your setup you'll hear exactly the different I'm describing - but you'll need a clear "stereo" signal, so pan the snare hard to one side. The result will be that the kick (being panned center) disappears when monitoring the M/S signal, and yet it remains (at a slightly lower level) when you monitor the Stereo Imager. You will also notice that the snare stays left with the Stereo Imager, but has the classic "out of phase" sound from the M/S device. This is the difference I'm talking about.
So Stereo Imager always keeps the mid signal, thats the only difference I can tell here. In terms of side signal its 100% a normal M/S device, I updated the combi again to show this. Snare is panned hard, bass drum is center, you can mute each to hear the difference to what happens to mid and side this way.

https://www.dropbox.com/s/nlpdw4oox7b7t ... S.cmb?dl=0

What happens to the hard panned snare is totally, exactly, 100% the same with Anansi and Stereo Imager, the ONLY difference is that Stereo Imager always keeps the mid signal. Which by its name makes sense, it effectively only works on the side signal and makes it louder/more silent. With Anansi it obviously disappears because it completely turns of the mid signal. That wouldn't make much sense for a "stereo widener" though, after all its called "stereo widener", not "mid annihilator".

So still, Stereo Imager is a NORMAL M/S stereo widener, it does NOTHING ELSE than modifying the side signal in an M/S way. Which is my point by the way, I didn't say "Stereo Imager is a M/S matrix", I confirmed dioxides question which was "Does it use Mid/Side techniques or some other way of widening the sound?" by saying "It's M/S, yes". Which is what it is, period.

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selig
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16 Mar 2016

normen wrote:
selig wrote:Wait - you are converting to mono before hitting the devices and sending a "left only" signal to the devices - check the 14:2 mixer and you'll see you have the signal panned hard left/mono. Remember, this whole idea will "only work with material that actually has side information"… ;)
:shock: A hard left panned instrument IS side information, its NOT mono.. This was the point of the exercise because you said "hard panned instruments stay hard panned even at the widest settings, which is totally unlike what a simple mid/side device would do, which would make center panned instruments disappear and would smear hard panned instruments across the L/R sound stage".

This is only half true, in fact it DOES "smear" panned instruments to the other side, i.e. the same signal appears 180° phase shifted on the other side, just like one would expect with a M/S matrix. Center doesn't disappear though but I go into that below.
selig wrote:if you simply remove the 14:2 mixer from your setup you'll hear exactly the different I'm describing - but you'll need a clear "stereo" signal, so pan the snare hard to one side. The result will be that the kick (being panned center) disappears when monitoring the M/S signal, and yet it remains (at a slightly lower level) when you monitor the Stereo Imager. You will also notice that the snare stays left with the Stereo Imager, but has the classic "out of phase" sound from the M/S device. This is the difference I'm talking about.
So Stereo Imager always keeps the mid signal, thats the only difference I can tell here. In terms of side signal its 100% a normal M/S device, I updated the combi again to show this. Snare is panned hard, bass drum is center, you can mute each to hear the difference to what happens to mid and side this way.

https://www.dropbox.com/s/nlpdw4oox7b7t ... S.cmb?dl=0

What happens to the hard panned snare is totally, exactly, 100% the same with Anansi and Stereo Imager, the ONLY difference is that Stereo Imager always keeps the mid signal. Which by its name makes sense, it effectively only works on the side signal and makes it louder/more silent. With Anansi it obviously disappears because it completely turns of the mid signal. That wouldn't make much sense for a "stereo widener" though, after all its called "stereo widener", not "mid annihilator".

So still, Stereo Imager is a NORMAL M/S stereo widener, it does NOTHING ELSE than modifying the side signal in an M/S way. Which is my point by the way, I didn't say "Stereo Imager is a M/S matrix", I confirmed dioxides question which was "Does it use Mid/Side techniques or some other way of widening the sound?" by saying "It's M/S, yes". Which is what it is, period.
OK so we agree these are not the same processes - Stereo Imager is NOT the same as a Mid/Side processor - that was my only point!
:)
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normen
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17 Mar 2016

selig wrote:OK so we agree these are not the same processes - Stereo Imager is NOT the same as a Mid/Side processor - that was my only point!
:)
It IS a M/S processor, albeit one that doesn't allow the mid signal to be turned off completely. I guess you mean "its not a M/S matrix", which Anansi isn't either. Both devices USE a M/S matrix at their core do to M/S splitting and then allowing both signals to be changed in volume.

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selig
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17 Mar 2016

I just didn't want to leave anyone with the impression the Stereo Imager was a M/S device or could be used as one in any traditional way.

We've clarified It's not a "Plain M/S device" as was initially suggested. I kept insisting It doesn't sound the same as a plain M/S device, you kept disagreeing until now.

Bottom line: There's clearly something else going on, which has been the point I've been having a difficult time making clear until now.
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normen
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17 Mar 2016

selig wrote:Bottom line: There's clearly something else going on, which has been the point I've been having a difficult time making clear until now.
Something else than the level of the mid channel? I don't think so at all. Switch through my combinator, whats happening to the side signal is 100% the same as with a normal M/S matrix, I don't hear any difference in sound.

lowpryo
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17 Mar 2016

so, with M/S processing, the wider image comes from the fact that you're removing the "mid" signal, and when that happens, you get some of the L signal bleeding into the right but phase flipped, and vice versa, correct? because the "mid" signal is kinda like the key that decodes the L and R into their own unique channels?

so after reading this, my understanding is that the stereo widener does this, except it's "widest" setting does not fully omit the mid section. as in, there are imposed limits on the on the M/S ratio, whereas on a traditional mid/side device, you can omit the mids entirely. is that where the discrepancy is coming from?

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selig
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18 Mar 2016

normen wrote:
selig wrote:Bottom line: There's clearly something else going on, which has been the point I've been having a difficult time making clear until now.
Something else than the level of the mid channel? I don't think so at all. Switch through my combinator, whats happening to the side signal is 100% the same as with a normal M/S matrix, I don't hear any difference in sound.
Yes, for your one unlikely situation, a signal panned hard left with no other audio signal present, this is true. For every other situation it is not. You have presented the one situation where what you say is true, but seem to dismiss any other possibility. Let's agree to disagree that it is a simple mid/side processor.
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