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  #31  
Old 03-17-2014, 07:25 AM
AX17609 AX17609 is offline
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Originally Posted by Doug Young View Post
I did a quick demo to try the settings suggested in this article. I recorded with an MS pair, so I'd have both the mono track - the mid mic alone - and then could also compare the results to a stereo micing technique. I also compared a plugin I have in Logic that does something very similar, but applies a more complex EQ to each side - sort of like taking every other band of a graphic EQ and cutting it on one side, then doing the opposite on the other.

So here's the comparison - mono, "stereo, GP-style", Logic's stereoizer, then finally real stereo (MS)

https://soundcloud.com/doug-young/st...coustic-guitar
I love tests like this. I listened to file on headphones. GP-style was so out of balance, that it honestly gave me a headache. The stereoizer sounded much better but manufactured. The real stereo was full and luscious. I wish I got tone like that.
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  #32  
Old 03-17-2014, 09:37 AM
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Originally Posted by rick-slo View Post
The brain will resolve phase and timing differences between the two ears, when possible, into space and direction (ambience).

With one mike (mono recording) the exact same phase discrepancies are presented to each ear and the brain's ability to interpret
it (hear it) as ambience is absent, or at least limited.

Two mikes (stereo) and you have the same phase discrepancies in each mike but each ear hears a different set of discrepancies.
So you could say each specific discrepancy being presented to one ear is at one half the total level of a mono discrepancy which
is presented to both ears. Plus the brain is presented with a variety of signal differences between the right and left mikes with
which it creates space and ambience.

So in stereo some of the one mike phase problems are suppressed to a degree. Plus there is a lot of additional special and
directional information being processed by the brain which helps obscure some of the single mike phase issues.
Interesting, so I get the spacial ambience being better with "timing differences"




Again not try to debate or belabor this just trying to understand, and I find this subject interesting. We actually had this discussion in the Critical Listening class I took online at Berklee

And I can fully understand that with two different mics the ears are going to hear two different sets of characteristics including discrepancies and frequency response . Which is I suppose part of reason why some prefer two different mics for the stereo pair.

And understanding that even with a matched pair there will actually still be minuscule (depending on quality of construction) if probably undetectable by ear, differences. So for the sake of discussion we will say say the matched pair are producing the same responses and would have the same discrepancies.


But with a matched pair it would be as you say "and you have the same phase discrepancies in each mike" .......... But what I am trying to figure out is " But but each ear hears a different set of discrepancies". It doesn't seem possible that the same actual set of discrepancy characteristics can be changed either physically or phychoacoustically and heard differently (other than "timing differences") ?

Wouldn't it still be the same set of discrepancies, but simply at different arrival times ? I could be wrong but.
I guess what I am getting at is... If it is in fact it is the same set of discrepancies at different arrival times .......Wouldn't it follow then that a one mic recording with the track duplicated and time slipped (to the same differences of arrival times) would sound the same as a two mic recording?...even the Ambience which as you say is " timing differences between the two ears, when possible, into space and direction (ambience).

"Also I understand that the two human ears actually hear slightly differently but that difference is also not going change between the time differential of a a stereo and similarly time slipped dual mono.

And for certain there may well be something in the more complex nature of psychoacoustic phenomenon going on I am not aware of. It is pretty interesting that humans can with only 2 ears (theoretically stereo only right to left) actually hear in 3 D

I have often heard people claim that a two mic stereo recording is somehow better and distinguishable from a time sliped ... But I have yet to read a complete solid explanation as far as I can understand, as why that would be.

What we concluded in the Berklee discussion was the only way to resolve the question would be to conduct a blind test and see if in reality people can actually consistently distinguish a difference between a stereo and a similarly time slipped double mono recording and consistently distinguish which is which.
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  #33  
Old 03-17-2014, 09:49 AM
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Originally Posted by ukejon View Post
Kev, I don't know the answer to your question but is it that with one mic placed up by the neck/body joint might not receive the lower bout frequencies quick enough, whereas two mics widely spaced but at the same distance to the guitar or a two-mic coincident arrangement has a better chance of simultaneously catching more of the instruments diverse frequencies (in other words, more "in phase")?
Yes I think there is no question that a close single mic is not going to capture as much of the frequency range as two mic's placed at the same distance. And for sure in order to capture more with a single mic you going to have to place the mic further away , But the frequency issue ( which is a very valid point ) is not what I am questioning it's the phase discrepancy issue as described by Rick that is not yet making sense to me


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Which leads to the novice question "Do lower frequencies travel slower through space than high frequencies, and if so should your neck mics be set back more than the lower bout or body mic?"
as M19 said no the speed of sound in the air is speed of all sound. What does change is the wave length and there in lies the difficulty because as the wave peaks start to get out of alignment or (phase) they begin to start canceling and or (comb filtering) when the same type of wavelegnths get directly opposite i.e. the center of the peak on one, is directly over the valley of another they will cancel completely and there will silence.
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  #34  
Old 03-17-2014, 10:11 AM
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Interesting, so I get the spacial ambience being better with "timing differences"




And I can fully understand that with two different mics the ears are going to hear two different sets of characteristics including discrepancies and frequency response . Which is I suppose part of reason why some prefer two different mics for the stereo pair.

And understanding that even with a matched pair there will actually still be minuscule (depending on quality of construction) if probably undetectable by ear, differences. So for the sake of discussion we will say say the matched pair are producing the same responses and would have the same discrepancies.


But with a matched pair it would be as you say "and you have the same phase discrepancies in each mike" .......... But what I am trying to figure out is " But but each ear hears a different set of discrepancies". It doesn't seem possible that the same actual set of discrepancy characteristics can be changed either physically or phychoacoustically and heard differently (other than "timing differences") ?

Wouldn't it still be the same set of discrepancies, but simply at different arrival times ? I could be wrong but.
I guess what I am getting at is... If it is in fact it is the same set of discrepancies at different arrival times .......Wouldn't it follow then that a one mic recording with the track duplicated and time slipped (to the same differences of arrival times) would sound the same as a two mic recording?...even the Ambience which as you say is " timing differences between the two ears, when possible, into space and direction (ambience).
It is not how closely the two mikes match in frequency response. It is there different positions in relation to the guitar. If you recorded with two mikes that were in the identical position and orientation (superimposed which of course is not quite possible) then each mike's discrepancies would match. Since the mikes are not superimposed their discrepancies do not match. With coincident mic'ing it closer (hence the more mono like sound) than with spaced pairs. Thus in stereo mic'ing each ear receives a different set of discrepancies.
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  #35  
Old 03-17-2014, 10:26 AM
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Originally Posted by rick-slo View Post
It is not how closely the two mikes match in frequency response. It is there different positions in relation to the guitar. If you recorded with two mikes that were in the identical position and orientation (superimposed which of course is not quite possible) then each mike's discrepancies would match. Since the mikes are not superimposed their discrepancies do not match. With coincident mic'ing it closer (hence the more mono like sound) than with spaced pairs. Thus in stereo mic'ing each ear receives a different set of discrepancies.
Ah ha now that indeed makes sense that is the piece I was missing, thank you and for your patience. Kev

So I am now speculating this might be why Doug prefers a spaced pair . And why placement is so very critical ding ding ding
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  #36  
Old 03-17-2014, 12:28 PM
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So I am now speculating this might be why Doug prefers a spaced pair . And why placement is so very critical ding ding ding
I just find spaced pairs to be slightly more "spacious". I often record, actually, using both, MS and spaced pairs, and when A/Bing, I always like them both, and there's something about the focused stereo image of MS that is really appealing, but the spaced pair seems to always win out in the end, even tho it's less stable. My last CD, I recorded with both, but with the MS track as a R88 - stereo ribbon that has the added feature of being a big warm ribbon sound, and mixed them both in.

One thing I find with mic placement is that there's some appeal of "different" at least for me, so I go thru phases. I'll get used to spaced pairs, and then try MS again, and like the different sound. Or get the Jecklin disk out, and go "oh, now, that's nice". Round and round :-) But it's hard to beat the spaced pairs both for sound and the flexibility of mixing. I don't feel as bad about altering the levels on a spaced pair to get the image precisely dialed in as I do with MS, where it seems like I should nail it exactly in the mic setup.
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Old 03-17-2014, 12:30 PM
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Originally Posted by AX17609 View Post
I love tests like this. I listened to file on headphones. GP-style was so out of balance, that it honestly gave me a headache. The stereoizer sounded much better but manufactured. The real stereo was full and luscious. I wish I got tone like that.
Is it still unbalanced? I didn't listen in headphones, maybe that makes the bass on one side more obvious. Maybe someone else could download the track and see if they can do a better job on this than I am. I also wonder, being that this is guitar player, if the author was using this technique more for a rhythm track. With a pick strumming, you'd get more high end energy on the other track, and perhaps a centered image would be less important in a mix.
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  #38  
Old 03-18-2014, 04:43 AM
louparte louparte is offline
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I like the idea.

Of course, I stopped double-mic'ing my guitars three years ago.
I'm not recording solo acoustic guitars though. Acoustic guitars are
only a part of a larger arrangement in my recordings.

If I were recording a project involving a great acoustic player solo,
I'd stereo-mic him or her.
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  #39  
Old 03-18-2014, 06:20 AM
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Is it still unbalanced? I didn't listen in headphones, maybe that makes the bass on one side more obvious.
Yeah, that was the problem. The bass was off to one side and the treble off to the other. It was weird.
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  #40  
Old 03-18-2014, 08:03 AM
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Yeah, that was the problem. The bass was off to one side and the treble off to the other. It was weird.
That is how the GP technique is supposed to work although the degree of it is controllable.
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  #41  
Old 03-18-2014, 11:19 AM
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In a subjective personal preference sense yes, in an objective method for audio reproduction not so much.

Of course everybody tastes are different and of course two mics is a perfectly valid and time honored method. But so is single mic.

To clarify there is nothing inherent or magical about two mics, except time domain difference, that is it.

That said :First the EQing in the article is primarily providing frequency separation not spacial , the panning provides the primary spacial separation. Same as it does in a two mic method. For example that is one reason some producers prefer two different types of mics. Because in a matched pair there will be some very very slight difference of frequency responce because of two different locations. Where a pair different mics with the same location difference the freq. difference will or can be more pronounced or noticeable.

And in a much lesser sense the fact that providing a (distinction) of different freq characteristic (i.e. EQ), can in fact also help reenforce a spacial feeling weather it is from the natural inherent location difference in a matched pair, different mics, or in EQing two duplicated single mic tracks differently. Not to mention the fact that if you slightly time slip one of two tracks creating essentially the same time domain difference as having two mics.

Another additional factor provided by a two mic technique is that a time domain differential is being created and in point of fact introduces some degree of phase difference (arrival time at the mic diaphragm) . Which is in fact in a strict sense is form of distortion. Understanding of course that the amount of distortion we are taking is not intrinsically psychoacoustically either bad or good. After all what we like about tubes is distortion, what we like about analog tape is distortion.
I would disagree with the idea that two different mics only relay time domain information. It's pretty obvious to me that you are capturing information from two entirely different portions of the instrument. It doesn't take much thought to realize that all of the qualities that we attribute to an acoustic instrument change dependent on the perspective point.

If anyone disagrees with that, it's OK by me. The real proof is in the listening, and although I have no imperical evidence to back it up, I can be pretty confident that most critical listeners would prefer stereo micing to any time domain or EQ hocus-pocus that can be done with a single point signal.

I think I can detect that trend even from the low numbers of responders we have in this topic. Publishing something like that is a good way to get people to buy magazines, though.

There just isn't any free lunch.
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  #42  
Old 03-18-2014, 01:26 PM
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I don't thinks anyone disagrees with you at this point.

Below is a typical waveforms of a right and left channel stereo track.
There are obvious differences between the two in frequencies and volume
levels at those frequencies.

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  #43  
Old 03-18-2014, 03:59 PM
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I don't thinks anyone disagrees with you at this point.

Below is a typical waveforms of a right and left channel stereo track.
There are obvious differences between the two in frequencies and volume
levels at those frequencies.

That's a very nice way to graphically illustrate what we hear, thanks.
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  #44  
Old 04-07-2014, 11:52 AM
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This has been a really interesting discussion for me. Once I've finished building my new isolation booth, I plan to try some of this stuff out. Thanks for a lively discussion and the food for thought!

T.
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  #45  
Old 04-12-2014, 07:30 AM
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I would disagree with the idea that two different mics only relay time domain information. It's pretty obvious to me that you are capturing information from two entirely different portions of the instrument. It doesn't take much thought to realize that all of the qualities that we attribute to an acoustic instrument change dependent on the perspective point.



There just isn't any free lunch.
Yes of course and perhaps a bit to declarative of a statement. But to just clarify, I did not did say "two different mic's" I said "two mics". And went on to include some caveat's, to that statement. And now with the part I was not addressing (the different discrepancies) that matched pair might pic up as opposed to a duped single mic technique. The statement is indeed perhaps not accurate in totality.But none the less I still think the significantly largest amount of perceived difference in a stereo recording is time domain and panning.

What would be a truly interesting and confirming test. That would indeed put all this to rest. Would be a blind listening test with a single mic and a pair of the same mics.
Do a time slipped dup of the single with some slight eq. differences, then a stereo track of the pair run dry. Then see if in reality that first, the difference can be consistently identified, and also then if identifying which is actually which, can be accomplished consistently.

Lastly and perhaps it goes without saying he other factor in all this the context of use. If the intended use is for a solo acoustic instrumental track then I think squeezing the last few percent of quality out of stereo recording is certainly the primary goal . As soon as we start adding other instruments into the mix, the priority then begins to shift and increasingly so as more instruments are added.
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