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Author Topic: Oddball microphone technique (OMT) - part 2  (Read 15593 times)

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Offline EmRR

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Re: Oddball microphone technique (OMT) - part 2
« Reply #150 on: September 05, 2018, 10:33:42 PM »
I've used Blumlein with a center omni for close studio work and been very happy with the addition. 

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Re: Oddball microphone technique (OMT) - part 2
« Reply #151 on: September 05, 2018, 11:16:42 PM »
Not exactly OMT.

But this thread may be of interest to folks here:

http://taperssection.com/index.php?topic=187767.0

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Offline Gutbucket

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Re: Oddball microphone technique (OMT) - part 2
« Reply #152 on: September 06, 2018, 12:34:16 PM »
Playing around with a Phish recording that I did this summer with my Tetramic, I decided to decode it to Blumlein and then also decode a forward-facing cardioid.  I blended the mono cardioid with the Blumlein and I have to say I like how it solidifies the center, without really needing to add much of it.  That said, I don't know that my ears are good enough to tell if I'm causing phase problems or the like.  Anyway, Blumlein with a coincident forward-facing cardioid seems like it might qualify as oddball.  Here's some quick and dirty samples to compare....

Blumlein only: https://we.tl/t-Y1Zh2cfiuC
Blumlein with the addition of the forward cardioid: https://we.tl/t-u12aG1io2p

As ever, I'm interested to hear what others have to say about these.

I'll try and give a listen tonight.

I can see how mixing in some forward facing cardioid with the straight 90-degree angle Blumlein pair would be useful in many cases.  And it's interesting to think about what the addition of the forward-facing cardioid is doing.  In some ways it's similar to  narrowing of the angle between the 8's to something less than 90 degrees, but not exactly.  Narrowing the angle between 8's is equivalent to increasing the ratio of Mid to Side.  It is the same as adding more forward facing figure-8.. similar but not exactly the same as adding more forward facing cardioid.  But I'm getting ahead of myself, let me back up for a moment-

I found that when I was recording from out in the audience using either a pair of ADK TLs or a Peluso P-Stereo in Blumlein that I often liked tightening up the angle between the microphones from the standard 90 degrees to something a bit less.  That helped in solidifying center focus and made for a more-even power-response across the front playback stage.  Otherwise there tended to be a bit too much separation between channels with the microphones angled a full 90 degrees apart.   

When I started using the TetraMic and was able to more easily play around with incremental adjustments to both pattern and angle afterwards while seeing both a graphical and numerical indication of what those actual angles and patterns were, I gravitated towards the same preference, typically preferring an inclusive angle of somewhere between 70 to 80 degrees for a pair of crossed 8's.  However, the pattern/angle combination I most often like best is a crossed pair of super/hypercardioids, using a slightly wider angle between microphones than I'd gravitate to with 8's.  That combination seems to achieve a nice balance of Blumlein-like qualities with more forward-bias that brings the important stuff in front (band and PA) into better focus with increase clarity.

I think what the addition of the forward facing cardioid does is similarly push the virtual patterns towards super/hypercardioid rather than 8s, except narrowing the virtual angle somewhat. 

Obviously each of these variations are similar yet also vary slightly, which IMO is significant.
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Offline Gutbucket

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Re: Oddball microphone technique (OMT) - part 2
« Reply #153 on: September 06, 2018, 12:34:53 PM »
Lucas, If you want to mess around with this a bit more simply as a way to get a good mental handle on how all this stuff works, here is what I'd recommend-

Based on my analysis here of what your addition of the cardioid is doing, try adding some forward facing carioid to the crossed fig-8's as before, except try using an angle wider than 90 degrees between the 8's.  The addition of the forward-facing cardioid essentially narrows the virtual angle, so using more angle on the 8's to start with will help retain ambient stereo width while still getting the advantage the forward-facing sensitivity bias and center focus provided by the cardioid.  It should let you use more cardioid if desired, before things get overly narrow sounding.  How much wider is going to be subjective, it's assessing the general trend in that direction which should be most informative.

All of this is illustrative of the many balancing acts between center-focus/solidity and ambient-width/stereo-openness.  The same balancing act is "baked in" to standard stereo microphone configuration pattern/spacing/angle combinations (which to a limited extent we can tweak afterwards using Mid/Side readjustments).  With these ambisonic recordings you gain more control over finding the most appropriate balance point by ear.  The additional step of introducing a 3rd virtual microphone facing forward can potentially take that to another level..  which I don't think is happening here exactly yet unless you are applying different processing to the 3rd channel in comparison to the other two, such as EQ'ing it differently.  Rather, I think the addition of the forward facing cardioid (or omni or whatever) can be fully explained in terms of Mid/Side and the resulting change of virtual patterns.

Ambisonics is essentially advanced Mid/Side. The addition of a forward facing cardioid (or omni as EmRR mentioned for close studio work) coincident with the Blumlein pair is really no different than changing the virtual pattern/angle.  Assuming the level of both are identical, mixing an omni with the 8's turns the Blumlein pair into a virtual pair of 90 degree X/Y cardioids.  If somewhat less omni is used, that becomes equivalent to a pair of supers or hypers with the same 90 degree inclusive angle.

Mixing in forward-facing cardioid instead of an omni does essentially the same, except it also narrows the virtual angle somewhat, due to the presence of the forward facing bi-directional component of the cardioid in addition to its omni component.

The suggestion of making the angle between crossed 8's wider before adding the forward-facing cardioid, serves to at least retain the 90 degree angle between the resulting super/hyper-ish virtual pair, if not increase it somewhat.  The only real difference between doing this and dialing in a wider angled pair of super/hypers to begin with is the process one goes through in arriving at the end result.  Don't disregard the difference in process even if you can end up achieving the same end result either way.  Different working processes definitely affect our preference as we work toward and settle upon what sounds best.

What would leverage this to the next level and move it beyond an alternate way of making the same Ambisonic Mid/Side readjustment would be EQing the forward-facing cardioid differently from the fig-8 pair prior to mixing them.  Say you EQ the cardioid to achieve best clarity and presence of the direct sound from the PA and stage, while EQing the crossed 8 pair for best ambient correctness.  In addition, to get things correct in an overall global EQ sense,  you'd can compensate for whatever specific EQ works best on the cardioid in your EQing setting for the 8s.  As an example, if you start from an overall well-balanced point of reference with regards to frequency, and then boost midrange/treble in the cardioid for improved clarity and articulation of the sound from the stage and PA, you might want to boost the bass of the 8's even if they didn't need that on their own, in order to compensate "globally" for a better frequency-balance of the overall combination of the forward-direct and diffuse-ambient portions.

That's still essentially making Mid/Side type manipulations, but more advanced ones which equalize the sound arriving from the foreword quadrant differently than than arriving from all other directions.   One of the cool things about single-point in space Ambisonics is that it is all level/polarity based. That means we can potentially split things up into as many virtual microphones as we want and recombine them without phase interaction problems.  One just has to be careful that the processing done to each part does not introduce significant phase differences, so this sort of thing is probably a good place for linear-phase EQ's.  Of course coincidence and lack of time-difference is also ambisonic's biggest constraint, and why spaced arrays which do introduce phase differences become advantageous.


Brief ambisonic aside- Excepting the EQ part, all this is getting close to the first-order Ambisonic control oddity of the "zoom" function, but not quite.  I don't understand the zoom function well, but in my limited understanding, it essentially modifies the W component by shifting it from omni towards a more forward-directional pattern prior to doing the Ambisonic matrixing that derives the virtual mic-patterns.  Don't sweat it if you don't follow that.  It's pretty much above my head too, and I'm likely grossly oversimplifying it.  It's a fun control to mess around with within a rather limited range though.
« Last Edit: September 06, 2018, 12:55:35 PM by Gutbucket »
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Offline Gutbucket

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Re: Oddball microphone technique (OMT) - part 2
« Reply #154 on: September 06, 2018, 12:35:30 PM »
Following up on the above two posts-
Lucas was kind enough to provide the raw A-format TetraMic files of one of these Phish shows to me a few weeks ago (not sure if it was the one he posted links to above or not) for me to assess for him and mess around with a bit.  It's been a while since I used my TetraMic, which is due for a recalibration, and it was fun to dive back into messing around with the virtual microphone settings, homing in on a few good 2-channel decode options.  Below is a portion of my PM to him talking about that, which I'll copy here because it's relevant to this discussion of the most appropriate angle between microphones based on the pickup pattern.  I posted essentially this same information way back when I was first messing with the TetraMic, and it was good to confirm again that it still holds true for me now. 

Essentially, the trend outlined below represents one of the most useful things I found using TetraMic, which has informed my general thinking on coincident 2-channel stereo ever since-

-------------------------------------
For good sounding material, I typically end up somewhere around this trend line of settings:
pattern = 2.0 (fig-8s) / width = 70-80 degrees
pattern = 1.8-9 (hypercardioid) / width = 90ish
pattern = 1.7 / width = 105-115ish
pattern = 1.6 (supercardioid) / width = 120ish
...etc..
pattern = 1.0 (cardioid) / width = 130-140ish
pattern = 0.5-0.8 (subcardioid) / width = 140-150ish

Often several different settings along that trend line work well and it comes down to choosing which is most prefered.

Of course that's just a very generic trend.  I may end up with something significantly different, especially if the recording environment is less than ideal, or the recording is otherwise wonky.
-------------------------------------

^
I'd love to be able to combine several of those options, each targeting a different frequency range.  For example one could have very wide angled subcards for the lowest frequencies and narrower angled more directional patterns higher in frequency.  This would essentially be like the Schoeps Polar Flex system extended to Ambisonic stereo.  It's possible to do so via a lot of manipulation and recombination in a editor, but far more work than I want to do.  What would be great is if that functionality was included in the B-format to virtual-microphone decoding application, where it would be simple and easy to apply with visual confirmation.

[Edit- Another more-basic function which would be very useful in VVM or any ambisonic virtual-microphone decoding application is a single control which would allow one to sweep between the various pattern/angle settings I've listed above, without having to rapidly readjust both pattern and angle separately each time.  One could then simply manipulate that single parameter while listening even with one's eyes closed, and really get a good feel for the incremental variations between them without having to do so in a much slower, clumsier, iterative way.]
« Last Edit: September 06, 2018, 03:01:44 PM by Gutbucket »
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Offline Gutbucket

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Re: Oddball microphone technique (OMT) - part 2
« Reply #155 on: September 06, 2018, 12:36:40 PM »
Not exactly OMT.

But this thread may be of interest to folks here:

http://taperssection.com/index.php?topic=187767.0

Thanks Noah!  I grabbed your files yesterday but haven't had time to listen yet.  Looking forward to doing so.
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Re: Oddball microphone technique (OMT) - part 2
« Reply #156 on: September 06, 2018, 12:46:07 PM »
Lucas, If you want to mess around with this a bit more simply as a way to get a good mental handle on how all this stuff works, here is what I'd recommend-

Based on the analysis above, try adding some forward facing carioid to the crossed fig-8's as before, except try an angle wider than 90 degrees between the 8's. 

This hadn't really occurred to me but I'll definitely play around with it.  Thanks!

Quote
I think what the addition of the forward facing cardioid does is similarly push the virtual patterns towards super/hypercardioid rather than 8s, except narrowing the virtual angle somewhat. 

(Here's where I'll probably mess up the technical side of things...)  Does adding the forward-facing card impact the rear lobes of the Blumlein pair, though?  I definitely see how it impacts the pattern in the front, but aren't the full figure 8 rear lobes still picking up as much as the unaltered Blumlein pair?

Quote
Lucas was kind enough to provide the raw A-format TetraMic files of one of these Phish shows to me a few weeks ago (not sure if it was the one he posted links to above or not) for me to assess for him and mess around with a bit.

The samples above are from the same venue, but a different night (IIRC from what I previously sent you).

Also, if anyone is at all interested in messing with this stuff, the VVMic program is free to download and I'd be happy to share any of my raw A format files.  You could then try all of this out yourself.
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Offline Gutbucket

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Re: Oddball microphone technique (OMT) - part 2
« Reply #157 on: September 06, 2018, 01:18:40 PM »
Does adding the forward-facing card impact the rear lobes of the Blumlein pair, though?  I definitely see how it impacts the pattern in the front, but aren't the full figure 8 rear lobes still picking up as much as the unaltered Blumlein pair?

Increasing sensitivity to the front is essentially the same as decreasing it to the rear in an overall sense.

Consider the cardioid in terms of its basic polar components- an equal sum of a forward-facing figure-8 and an omni.  In that case the figure-8 and omni components combine to produce twice the sensitivity of either alone in the forward direction, the same sensitivity as the omni alone 90-degrees off to either  side, and destructively interfere to create reduced rear sensitivity culminating in a central rear-facing null (or near null).

The same essentially applies to adding the forward facing cardioid to the Blumlein pair.  The main difference is that we're now thinking in terms of combined stereo pattern sensitivity, rather than a single channel polar pattern.

In that overall combined-pattern sense, a Blumlein pair on its own has equal sensitivity in all horizontal directions, making it omnidirectional in terms of stereo sensitivity.

Adding forward cardioid to that shifts the sensitivity bias forward, so the overall combined stereo sensitivity pattern is more subcardioid-like in shape.  Similarly if you overlay a crossed pair of hypercardioids and trace the combined outline of them (ignoring polarity) the overall combined stereo pattern sensitivity is likewise subcardioid shaped.
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Re: Oddball microphone technique (OMT) - part 2
« Reply #158 on: September 06, 2018, 01:22:39 PM »
Also, if anyone is at all interested in messing with this stuff, the VVMic program is free to download and I'd be happy to share any of my raw A format files.  You could then try all of this out yourself.

I encourage anyone interested to take him up on this offer!  It's very enlightening to play around with.  I've been meaning for years to make some of my raw TetraMic files available here but for numerous reasons have never gotten around to doing so.  And I'm happy to discuss the particulars with anyone who does.
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Offline Gutbucket

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Re: Oddball microphone technique (OMT) - part 2
« Reply #159 on: September 19, 2018, 09:24:16 AM »
Copying a couple posts from another TS thread to here, because I feel they do a good job of conveying the philosophy driving the development of OMT and what it is designed to achieve-

Hi. A couple of thoughts:

- If you're coming from a background of recording with spaced omni microphones, I think you'll find that recording with two coincident or closely-spaced supercardioids gives a fundamentally different overall impression. It's not just a variation by degree from what you're used to. The listener's brain goes into a different mode of listening, because the sense of space and the ability to localize direct sound sources are so different between the two kinds of recording. They're both called "stereo" but they're so different in their effect that I sometimes think there should be different terms for the two approaches. (A/B vs. X/Y comes close; "intensity" vs. "arrival time" differences are involved, but those are ugly terms and anyway, those two principles of operation aren't mutually exclusive in most cases.)

With spaced omnis, if the live environment in which you made your recording was rich and spacious, a similar feeling can be manifest when your recording is played back. It's like bringing that _environment_ into the room where the playback occurs; you may feel as if you are wrapped or "enveloped" by that environment, even with only two channels and two loudspeakers. This encourages a mode of listening in which sensuousness and the color of sound are the main offerings. It invites you to turn off certain critical tendencies, and just take a bath in the sound. If the material being recorded is highly complex, it will be blended and softened and the edges rounded off by this type of recording. That can make it more palatable and atmospheric--sometimes primitive and mystical, even--at the cost of some clarity and specificity. That's where judgment and experience come in, since you may not always want that particular tradeoff.

With directional microphones, particularly coincident supercardioids or crossed figure-8s, you can get a very clear "stereo image"--a representation of the direct sound sources that's consistent over space and time, and that involves your knowing (on some level in your brain) where the direct sound sources were relative to the microphones. This offers much better support if you're consciously trying to grasp the specifics of the content that's being delivered. But esthetically it is a very different type of experience. The emphasis is more on the direct sound sources and where they are and what they're doing; the "atmosphere" is reproduced more quantitatively than qualitatively. Its tradeoff is that it puts more of a cognitive burden on the listener, but with a greater payoff in specific information if the listener chooses to engage that way. But it's not usually as intuitively persuasive as a good spaced-omni recording.

There are crossover and compromise approaches. I like certain aspects of both typological extremes, so I'm very drawn to those crossover approaches in many recording situations. Those include the use of "subcardioid" microphones (in the Schoeps line, that would be the MK 21 and MK 22--the so-called "wide cardioid" and "open cardioid" patterns respectively) with an approach to angling and spacing that's derived from ORTF stereo recording.

- "Reach" is a problematic concept, especially where stereo recording is concerned. A fact of physics that surprises a lot of people is that the highest directivity you can get from a "first-order" microphone (with a single capsule and no special signal processing) only gets you a 2:1 "distance factor" relative to an omni. In other words, if you find that the optimal balance of direct to reverberant sound is obtained when an omni mike is 3 feet from something, then a hypercardioid would give you that same quantitative balance of direct and reverberant sound at 6 feet. No first-order microphone pattern can ever give you that same "3-foot balance" at any greater distance; no microphone can "zoom in on" a more distant sound source and make it seem that close.

For a number of technical reasons, a pair of good supercardioids may well be your best choice when you are forced to record in stereo from all the way into the reverberant sound field. Certainly NOT shotgun microphones, which have highly irregular off-axis response at high frequencies, and no better than supercardioid directivity at low and mid frequencies (i.e. they're useful only when they're close enough to the sound source to pick up enough direct sound on axis so that you don't care about the residue of off-axis sound). But even good supercardioids can't compensate for excessive recording distance. Directional microphones are, if anything, more sensitive to their exact placement than omnis are.

- All that said, there's an interesting variant on omnis that can produce surprisingly good results sometimes, and that is to embed the membranes of each microphone in the surface of a sphere (see attached photo). I wonder whether you've tried this technique with your omnis. (Add-on sphere accessories are available for various microphone diameters.) It's another one of those adaptations or compromises that I spoke of, but this one completely preserves the spaciousness and "envelopment" aspects of spaced-omni recording, while increasing the clarity and directness of the direct sound sources.

Just as food for thought.

--best regards

P.S.: The attached photo shows a Schoeps omni capsule mounted on a Colette active cable and surrounded by a sphere accessory. But such spheres can also slide over the capsule when the capsule is mounted directly on the microphone body (amplifier). The important thing is for the surface of the sphere to be "flush with" the front edge of the capsule. -- This technique works only for omni (pressure) transducers. It would block the rear sound inlet of a pressure-gradient (directional) capsule and mess up both its polar response and its frequency response.

P.P.S: I meant to point out--when you're looking in Williams' charts or on Sengpiel's site or on http://www.hauptmikrofon.de/, be aware that supercardioid and hypercardioid have dictionary definitions which any given microphone probably won't fit exactly. The Schoeps MK 41 isn't exactly a supercardioid; it's like 2/3 supercardioid and 1/3 hypercardioid. Neumann calls their small hybrid a hypercardioid, but it's also in between hyper- and super- (with a slightly different recipe from Schoeps). Similarly, Sennheiser calls theirs a supercardioid, but it has about the same pattern as Neumann's hypercardioid, etc., etc.

What I mostly wish to contribute to the thread is to echo DSatz's comments on the fundamental difference in overall listening impression between A/B and X/Y microphone techniques - an excellent observation, well stated.  I especially perked up at the mention of "The listener's brain goes into a different mode of listening, because the sense of space and the ability to localize direct sound sources are so different between the two kinds of recording. They're both called "stereo" but they're so different in their effect that I sometimes think there should be different terms for the two approaches."

The bit below may seem OT at first, but I'll explain further down why I think it applies.

I consider near-spaced microphone techniques commonly used around here as attempts at finding optimized middle-ground solutions which effectively bridge the gap between these two very different modes of recording and listening, without moving beyond the constraint of two microphones and two recorded channels.  This can work very well for live music, where we can achieve a respectable balance between immersive ambience, good clarity and sharp imaging using well considered arrangements of two microphones.  Yet I'm rarely completely satisfied with the results given the necessary compromises.  Once I became aware of how well each aspect can be addressed on their own, albeit at the detriment of the other, those compromise solutions all to often no longer satisfy either listening mode for me sufficiently.  Of course there are plenty of exceptions, but the general trend holds.

I want to try and better optimize for both modes of listening at the same time, so I break the listening experience down further and essentially use separate pairs of microphones optimized to more ideally capture these different aspects, then combine them afterwards.  I feel this results in a better overall result than trying to find a good "middle of the road" optimization using a single pair of microphones.  The trick is that this must be done in such a way that the separate pairs support rather than fight each other, and the devil is most definitely in the details with respect to achieving that.  It's easy to make a mess of it and just complicate things without really improving the end result.  Still, I commonly argue for this somewhat unusual approach here at TS.  That's partly because I feel audience-perspective music recording is a unique recording endeavor compared to other forms of recording- For one thing, audience perspective recording is typically done from a considerable distance from the source.  It represents a very ambient recording situation regardless of whether we like that or not. In addition, we have far less control over the situation and the techniques I'm suggesting provide some additional control and flexibility;  And lastly because I find the presentation more convincing for both "modes of listening" - I can mentally switch back and forth and get a better feel for both than I can with straight 2-channel near-spaced microphone techniques. 

I see these things as possibly being applicable to your nature and ambience recordings as well.

Consider what you are recording and what you want to convey to the listener.  Then consider recording approaches which are optimized for what you want to convey.  If it's relaying a feeling being there in that place with a convincing immersive ambience, a spaced A/B technique with open pattern mics such as omnis is hard to beat.  If its a clear and precise focus on a particular sound within a particular soundscape, a single microphone or a coincident (X/Y, Mid/Side) technique using highly directional mics like the Schoeps MK41's can achieve that.  If you want both at the same time, you may be able to find a "middle ground" near-spaced approach which works for both aspects without compromising either too much. Or you can optimize separately for each aspect, and make a composite recording which better portrays both of them.  All depends on what you want to achieve, and how much effort you want to put into it.

For what you are doing the composite approach would probably mean setting up a spaced A/B omni recording to capture the ambience, and focusing a single MK41 directly on the subject of interest from a not overly distant location.  If the direct sound from subject of interest has stereo qualities to it which you'd like to convey in addition to the atmospheric stereo ambience from the A/B pair, you might consider using both MK41 in a narrow X/Y configuration (or better, a Mid/Side setup using one MK41 plus a figure-8 such as the MK8). Narrow so that neither mic of the pair is very far off-axis from a direct line to the source (which is why a Mid/Side setup works well for this - the Mid microphone is always pointed directly at your source), thus retaining good direct focus on the subject while still getting sufficient direct imaging type stereo-ness. And also narrow because the A/B omni pair will be contributing plenty of the other kind of stereo-ness, meaning less stereo-ness is required from the "direct sound" focused pair for a good overall listening impression.
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Offline kindms

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Re: Oddball microphone technique (OMT) - part 2
« Reply #160 on: September 23, 2018, 07:52:16 PM »
ok Gut etc

thinking of my new 426 as center front and rear (can be run 180)

so what are your thoughts with front rear card or whatever with flanking mics ?

Was wondering if say front and rear cards with say either 414 omni or ck22 omni in either A/B or perhaps Healy ? Constrained to the circumfrence of a human head or maybe 12" split ? (can be adjusted 12" increments up to 4 ft)

Omni----c4+26-----Omni ??

oh and this is 4ft split AKG ck22 with the 426 run hypers at like 65deg

http://taperssection.com/index.php?topic=187967.0

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Re: Oddball microphone technique (OMT) - part 2
« Reply #161 on: September 24, 2018, 10:19:18 AM »
Looks like a cool venue.. As Sam would say- "You look marvelous, dahling".

With any L/C/R microphone setup, I like spacing the L/R pair twice as far or more than I might without using center mic, as long as that's practical.  I'd probably shoot for 2' minimum or as wide as you dare.  If you can't space them as widely as you like for whatever reason, you might try the 414's in subcard instead of omni, pointed out to the sides.  A relatively wide spacing is what produces that nice open and spacious decorrelated ambience, and helps keep the audience sound from competing as much with music in the center of the image.

Using a single forward-facing center channel rather than a stereo-pair (like your 65 degree X/Y hyper pair), I might not go quite as wide as I otherwise would, because the single microphone in the center is more of a point source and I don't want that to come across as a separate "island of sound" in the middle.  A stereo pair in the center sort of helps feather the center in with the omnis, smoothly blending the imaging across the front.

With regards to using the 426 angled 180 degrees apart and facing front/rear- I've never clearly determined the importance of center front/rear microphone spacing, except that I don't want too much (don't want the rear facing mic so far back that there is an obvious delay) and that front/back spacing it is less important than left/right spacing.  I think it might work well dialing in a forward facing supercard and a rear facing cardioid.  That way you get maximum focus on the direct sound in the front facing channel and maximum exclusion of the direct sound from the rear facing channel.

« Last Edit: September 24, 2018, 10:59:23 AM by Gutbucket »
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Offline Gutbucket

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Re: Oddball microphone technique (OMT) - part 2
« Reply #162 on: September 24, 2018, 10:58:56 AM »
Using a single forward-facing center channel rather than a stereo-pair (like your 65 degree X/Y hyper pair), I might not go quite as wide as I otherwise would, because the single microphone in the center is more of a point source and I don't want that to come across as a separate "island of sound" in the middle.  A stereo pair in the center sort of helps feather the center in with the omnis, smoothly blending the imaging across the front.

Expanding a bit on that-
With the mics you now have, I encourage you to try a setup close to what I'm doing.  I really like what it does. This would be six channels total into the DR-680:

Space the ck22 omnis as wide as you can get them, put the 426 in the center facing front/rear, and place your 414's about halfway out between the center and omnis (say at least 12" but less than 24" out from center) as supercardioids facing directly to the sides.

This will give you a different type of directional stereo across the center- not a coincident center L/R pair, but a near-spaced L/C/R stereo triplet.  You'll retain the center forward focus and get some near-spaced goodness. 

When mixing it, try this-
First bring up the 414's in isolation and balance them against each other to center their stereo image. Then mute them.

Next bring up the omnis in isolation and balance them against each other.  Leave them up and bring up the center channel until you get a good balance between the omnis and center mic.

At that point slowly bring up the Left/Right facing supercardioids.  This feels sort of like dialing in more Side to a Mid/Side pair to widen the stereo image, but without loosing center detail and focus.  Sometimes it's seems  like a sort of acoustic zoom control, bringing presence, excitement and "up-frontness".

Then bring up the rear-facing mic to taste.


After you get that sounding good, start over and try the mix a different way-
Get a good balance of the center + sideways supercards first, then bring up the omnis, and finally the rear facing channel. 

The first approach treats the omnis + front-facing center microphone as the primary L/C/R part, sweetening that with the addition of the sideways-facing supercards. The second approach starts with the near-spaced directional triplet as primary L/C/R, and sweetens that with the addition of the omnis and rear facing channel.
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Re: Oddball microphone technique (OMT) - part 2
« Reply #163 on: October 07, 2018, 11:40:24 AM »
so friday night for Warren, Porter, Medeski and RUsso

we had intended to run 4ft split but as we were setting up they gave the 7ft height limit. So figuring that the spit would be an issue at that height we opted for

12" split ck22 Healy > V2
8" forward / rear ck61s
center c426 hyper (again :) ) pointed at the stacks. so fairly wide probably like 100

I mixed it with the ck22 down slightly (signal was hottest), bumped the c426 slightly. left the center forward ck61 alone and dropped the rear 10db. Was gonna ditch the rear in the mix but figured i would leave it in even if just barely noticable

http://bt.etree.org/details.php?torrentId=601986

I think it sounds better over cans vs speakers but probably due to the proximity of the omnis
AKG414 XLS/ST, AKG ck61, ck22, >nBob colettes >PFA > V3, SD MixPre >  TCM-Mod Tascam HDP2, Sony M10
Little Bear tube Pre >Outlaw Audio 2200 Monoblocks > VR-2's

Offline kuba e

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Re: Oddball microphone technique (OMT) - part 2
« Reply #164 on: October 08, 2018, 05:06:11 PM »
Kindms, thanks to you and Rocksuit for your recording. I am listening it via speakers now. It has something that it makes me feel like I am right there. It sounded very pleasant because this.

I also tried to mix near spaced omnis (because it was stealth) with a center microphone. I was afraid of the comb filter. In the end, I mixed very little of center mic. I'm not sensitive for comb filtering, so I was rather careful. Still, the small addition of the center has improved the recording.

I was playing with my old oddball recording. Here is my little observation. Gutbucket advised us to try more methods to mix rear channel. One was just to mix it in. Another was to stereoise the rear channel by M/S with forward mic. Or we can stereoise the rear channel by some other artificial effect (eg.reverberation). I was trying M/S and it was not working well in my recording. It sounded somehow sharp, unpleasant. I remembered that Gutbucket also mentioned that we can try to make artificial stereo of rear channel by plugin for phase shift. I found this plugin. This plugin shifts phase of all frequencies by constant angle. The rear channel is mixed in M/S by phase shift of +-180°  180° . But we can set lower shift by this plugin.
http://www.pcjv.de/vst-plugins/betabugs-plugins/

I think I used +-55°. It sounded better than M/S. It was not so aggressive. I mixed the rear mic into the right channel with positive phase shift and into the left channel with the opposite phase shift. There are two variables for setting - level of rear channel and phase shift. I set up the level as in the previous methods. Phase shift, I set first +-180 ° 180 ° as in M/S, and then I was lowering it than it sounded pleasantly.
« Last Edit: October 10, 2018, 06:33:47 PM by kuba e »

 

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