Topic: Oddball microphone technique (OMT) - part 4

[Gutbucket]

Sure. I have a couple of them. I think one is a Manfrotto and one is a Impact, basically the same. Standard spigot socket with thumbscrew in the center.  One came with a removable telescopic extension arm, the other I bought just as a foot.  The legs are steel which makes it bit heavy, yet sturdy and it folds up complactly.  I mostly use it as a foot, either on its own as a super low to the floor or table stand onto which the mic bar attaches, or in combination with an extension or two to get up between about 15" and 4'-5' high.   Be aware that there is an alternate version that looks basically the same but is smaller in size, maybe around half the diameter.  Pretty easy to mix them up if just looking at a photo - although If I recall the smaller one features a spigot stud in the center instead of a socket.  Great little versatile folding foot, but I'd say not really wide enough to go unattended if going up, say 3' or higher.  The addition of the two threaded holes in the other two legs which allow it to double as mic-bar just make it that much more versatile for me.  Here's a couple of B&H links that popped up upon a quick search, but you can source it from pretty much everywhere:

Manfrotto version:
https://www.bhphotovideo.com/c/product/546481-REG/Manfrotto_003_003_Backlight_Stand_Black.html

Impact version:
https://www.bhphotovideo.com/c/product/1119713-REG/impact_ls_3sb_backlight_stand_base.html

Smaller diameter Impact version (spec's say 14" diameter instead of 20"):
https://www.bhphotovideo.com/c/product/1651582-REG/impact_ls_bsb_m_mini_backlight_stand_base.html

[Gutbucket]

Here's a photo of the folding foot in use along with a single telescopic extension to create a "short stand", as posted in this thread about a month ago:

[rocksuitcase]

thanks for the links.
I always enjoy the sounds of babbling brooks! Nice array you got there.   

[grawk]

Now that I got my 4018s I’ll have to play with omt4. I ran 4015s din with 4018s pas for umphreys last week and liked how it turned out.

[Gutbucket]

Nice array you got there.   

Except for all the gaffer tape needed on it back then!

Good time up at AmpJam#1 at Spirit of the Suwannee last weekend.  We had a good taping crew with a couple other tapers there running OMT4 type setups.

I was able to get my OMT8 rig back together a few days prior.. without the use of any gaffer tape!  Hurrah to that long-term goal!  Got it all done using shrink wrap, wire-tie zips, pipe clamps, and velcro cable-wraps. Still don't get around to remaking the center attachment hub, but may put that off for now as the current reworked version is working quite nicely.  Will post some pics of the DIY "duck-back" covers I made a couple years ago that attach directly to each windscreen and eliminate the need for a single large umbrella along with the associated windage and visual problems, but fortunately the rain skirted past and they weren't really needed, so I only put up the bigger center one that covers the stereo shotgun for a couple sets.  Will dig up some photos of that.

Reworked and nicely lit without any rain protection needed-

[checht]

Gorgeous shot! Mic pron!

Would love to hear the Mule set when ready.

Regarding center pair config and x/y vs m/s:
When m/s angle is just right and level in mix correct I think it's my favorite.
And x/y pas is drastically easier in the field and post.

I seldom record one show on its own lately, more likely tours/serieses, so the post production time investment is multiplied many fold.

For me, x/y ftw.

[mccordo]

Good time up at AmpJam#1 at Spirit of the Suwannee last weekend.  We had a good taping crew with a couple other tapers there running OMT4 type setups.

I was able to get my OMT8 rig back together a few days prior.. without the use of any gaffer tape!  Hurrah to that long-term goal!  Got it all done using shrink wrap, wire-tie zips, pipe clamps, and velcro cable-wraps. Still don't get around to remaking the center attachment hub, but may put that off for now as the current reworked version is working quite nicely.  Will post some pics of the DIY "duck-back" covers I made a couple years ago that attach directly to each windscreen and eliminate the need for a single large umbrella along with the associated windage and visual problems, but fortunately the rain skirted past and they weren't really needed, so I only put up the bigger center one that covers the stereo shotgun for a couple sets.  Will dig up some photos of that.

Reworked and nicely lit without any rain protection needed-

That was a good time indeed! Always fun to check out everyone's different rigs and look for some new ideas. I taped most of the fest outside of a couple of the early sets and the Headhunters (which was solely due to a stupid mistake on my part related to a change in position and mics due to the strong possibility of incoming rain ). For what was recorded, I ended up using 3 different configurations from the same general area FOB on a stand between 7-8':
DPA 2012 (Ch 1-2/DIN) + DPA 4061 (Ch 3-4/36” split) > MixPre 6
DPA 2012 (Ch 1-2/DIN) + DPA 4061 (Ch 3-4/36” split) + AKG ck63 (Ch 5-6/XY) >  MP-2 > MixPre 6
DPA 2012 (Ch 1-2/DIN) + AKG ck63 (Ch 3-4/XY) > MixPre 6

I'm starting to process everything now after getting back to the real world of work and responsibilities, but should start getting some stuff posted in the next day or so.

[Gutbucket]

^Great to hang with you and the others up there.  You've got some good material there to mess around with.  You know it takes me forever and a day to get anything out, if I do at all, but I did get the Headhunters set and it sounds quite good straight off the recorder.  That set in particular makes for a good example of how the portrayal of "cocktail audience chatter" can come across diffusely in such a way that less of the listener's attention gets drawn away from the music, even when the musical content isn't overly loud in comparison.

[Gutbucket]

Gorgeous shot! Mic pron!

Would love to hear the Mule set when ready.

Regarding center pair config and x/y vs m/s:
When m/s angle is just right and level in mix correct I think it's my favorite.
And x/y pas is drastically easier in the field and post.

I seldom record one show on its own lately, more likely tours/serieses, so the post production time investment is multiplied many fold.

For me, x/y ftw.

^ Thanks Chris.  And thanks for sharing your experience in using the two different types of coincident pairs in the center.  Last weekend while taping I had l a lot of thoughts on X/Y versus M/S in the center position running through my head, and of possible modular optimizations of my setup in the future based on that.  More in a later post to follow..

[Gutbucket]

Got to try a little OMT tonight on a trio with an xy pair in the center and some wide cards spread at about 10", lip of stage (sorta, it was on the ground) about 1.5' from the musicians.  Need to listen to it, but it was a fun experimental little compact setup.

Now this is some bad ass shit here: https://www.youtube.com/watch?v=VxC1xiIkxd4

VibrationOfLife, thanks for that video link.  I'd not seen that one but have followed what Hyunkook Lee has been doing for a long time, both with ambisonics and distributed mic arrays.  Cool stuff.  However, I've yet to be personally convinced that height mics and height playback channels are particularly important for music, even if the goal is fully immersive surround playback.  Capturing height goes past the point of diminishing returns I feel, even more so than the reproduction of it, but I've not properly experienced playback like that from properly recorded material!  That said, I obviously find slicing up the horizontal plane with additional mic channels to be very useful, for both 2-channel stereo and surround.  When I had my full surround playback system in action, routing the surround channel signals that were derived from rear facing mics and/or wide-spaced omnis with some filtering and delay applied to multiple playback speakers distributed around the room was very helpful in creating a truly immersive and realistic sounding diffuse/reverberant ambience with no audibly obvious gaps.  It was more important to have full horizontal playback speaker coverage than to have full horizontal coverage from the mic array.  From that experience, I can see how height speakers might be helpful, but it also convinced me that the diffuse ambient height content feeding them can be quite successfully derived from the other existing mic channels.  Doesn't seem worth the effort to me, certainly not until the horizontal plane is well covered, which does matter and is a difficult enough sell on its own!

I will say that much of what they describe in that video about how solid and dimensional the playback sounds and how the bass reproduction is so much more natural, accurately reflects what I hear from my surround recordings when played back with the appropriate playback array.  The ability to move around and face any direction with my eyes closed and have it sound just like I were doing the same at the event, including an accurate portrayal of the room acoustics in all directions (except up?) is astounding and quite involving!

[Gutbucket]

Ive not encountered any obvious phase issues with the two times Ive run like this. Both times I had the center mics forward anywhere from 4-8 inches. From everything I've read and what Gut has developed / documented. that seems to be the best approach - though others have noticed a smear when all four mics are not on the same plane. After listening to GSW and the LCR approach, I do think I'll go back to running the center as an XY pair a bit more, the single center channel here seems to be missing something that would be additive in a good way

Thanks for the details, impressions and links to the recordings!

I was able to give a brief listen to your God Street Wine recording yesterday, and it sounded quite good on Senn HD650 headphones streaming through my phone.  Love the DPA 2015 sound, which is only improved farther with the addition of the 4011 in center of that arrayand to my ear, and very much liking the resulting solid stereo image.  Although use of X/Y or M/S in the center rather than the single center mic isn't vital in your situation, as neither image placement nor smoothness across the L/R stereo image seems to suffer, it will be interesting to hear what X/Y center does using those mics.  As you put it, "missing something that would be additive in a good way", seems a good description. 

As mentioned, I generally bring up the center Side channel to taste, and there is always a somewhat subjective range of how much is best. With none of the Side channel included in the mix (equivalent to using just a single center channel) it sounds a bit "tighter, drier, and flatter", which can be helpful on some material with a lot of percussion transients, yet also tends to lack the extra bit of depth, dimension and stereo interest.. so I end up using at least a little bit of Side channel in the mix, essentially balancing "tight sharpness of image" against "dimensional openness".  To my ear, it's too much Side channel in the mix (which presumably equates to too wide of an X/Y angle) that causes the mix to start to sound smeared, rather than a bit much forward spacing of the center mic or coincident pair.  That's somewhat counter-intuitive since the Side channel mic remains coincident with the center channel mic, regardless of how far forward the two are placed.

I'll do some more extensive listening to this when I can, along with the Moe at Brooklyn Bowl recording you posted earlier.  I intend to listen particularly for differences between using the 4018VL X/Y pair in the center verses the single 4011 for GSW.

Thanks again for the links to these recordings.  The GST recording is not just an example of how this can sound good, but helps me confirm that the OMT progression remains on the right track and is applicable to higher quality mics like your 4015s, 4018s and 4011s, as well as the somewhat lesser quality miniature DPA mics I'm using.

[F0CKER]

I’ll continue to share what I tape in here. I’ve got a number of shows coming up and appreciate the extra ears and perspectives on the results. On that note


I’m potentially going to a show tonight in a less than ideal room. Big, boomy reverberant. It’s also the Disco Biscuits and the low end will be pronounced for sure.

I’m intending to run the 4018VLs as the main pair spread out a bit like 30-45cm PAS and to my ears the 4018s are quite thin on the low end. I’m debating running the subcards XY in the center to simulate a center Omni to help capture the low end. Has anyone done something similar? Or would it be better to run the 4018s a bit more narrow PAS and put the sub cards on the outside in the traditional OMT config. Thoughts on either approach here?

[Craig T]

Where it isn't possible to locate the center mic(s) forward of the split omnis, is there any guidance on how much delay to apply to the omins in post to mimic the offset? e.g. sound moves 4 inches in about 0.3 milliseconds.

[Gutbucket]

I’m potentially going to a show tonight in a less than ideal room. Big, boomy reverberant. It’s also the Disco Biscuits and the low end will be pronounced for sure.

I’m intending to run the 4018VLs as the main pair spread out a bit like 30-45cm PAS and to my ears the 4018s are quite thin on the low end. I’m debating running the subcards XY in the center to simulate a center Omni to help capture the low end. Has anyone done something similar? Or would it be better to run the 4018s a bit more narrow PAS and put the sub cards on the outside in the traditional OMT config. Thoughts on either approach here?

That's a great question, one I'm still exploring and interested in.

Generally I like to put the more open pattern mics out in the spaced position.  Partly because the spacing in combination with the deeper bass extension of the more open pattern helps in capturing "stereo bass" information down to a lower frequency, but also because the spacing allows more open pattern mics to be pointed more on-axis, even PAS when necessary, while still retaining stereo difference.  The mics with tighter directional patterns can be spaced closer or coincident with each other and will still produce useful stereo difference when used at the same angle.  That's "traditional OMT", taking advantage of the natural attributes of the mics, yet is sort of built atop a foundation of decent room acoustics.

But in a challenging room (boomy, reverberant, a bit too far back) I see advantages of going the other route.  Supercards used in the spaced position and angled for PAS will cut the boom and maximize clarity from the PA.  In the center position, close-spaced or X/Y subcards in PAS will produce far less stereo difference information, but that's probably OK as that essentially shifts things along a trend-line to being more like a single center channel mic, similar to using less Side channel or a very narrow X/Y angle.  If you are using less center pair than outside pair in the mix, that resulting balance will also reduce the boom.

Subcards are very smooth off-axis so they can be angled very widely, even 180-degrees apart, and that would normally be helpful when not spaced very much or at all - as they will be in the center position, however I think you'll want to keep both pairs in PAS or close to it because of the room.

If really boomy and reverberant, consider using the 4011 cardioids in place of the 4015 subcards, arranged with the supercards flanking and cardioids in X/Y or the opposite way around.. both pairs in PAS or close to PAS.

In terms of boom/reverberant reduction, I suspect it goes like this, from maximum to minimum:
1) supercards wide, cardioids X/Y center (max)
2) cardioids wide, supercards X/Y center
3) supercards wide, subcards X/Y center
4) subcards wide, supercards X/Y center
5) subcards wide, cardioids X/y center (min)


My anecdotal experience-

I had good results in a somewhat boomy boxy room running Gefell M21 supercards @ 50cm/90deg + a Gefell M94 cardioid Mid in the center M/S pair.  That arrangement is somewhat like you mention in that the more directional pair was used as the outside flanking pair and the more open pattern was used in the center as Mid.. well sort of like you mention.  After converting the Mid/Side pair output to L/R, the virtual polar patterns of the resulting X/Y pair were actually more supercard like than cardioid, so it was more or less equivalent to using spaced supercards with a supercard X/Y pair in the center.  That made the array very directional with both pairs more or less in PAS (outer pair at 90-deg pointed them maybe 10-deg outside stacks, center pair angle being determined by M/S ratio, which ended up equating to PAS or just inside stacks).
^
I intended to switch that around the other way with the cardioids @ 50cm/90deg + supercard Mid in the center for another show in the same room but unfortunately never got around to doing that.

I decided to set it up first using the M21 supercards in the outer flanking position because years ago I'd successfully used a 3-mic L/C/R arrangement of supercards (ADK TLs set to supercard mode) from the same position in that room, and this arrangement was most similar to that.  I used the folding foot posted about above, flipped over to form an L/C/R mic-bar for both of these setups.

[Gutbucket]

Found an example of the setup above that I posted about in the previous thread -  supercards spaced, cardioid Mid/Side in the center, using the folding foot as mic-bar, in that room.  Here's the post: https://taperssection.com/index.php?topic=191953.msg2373463#msg2373463

And here's a photo of the mic-setup from that post.  Double extension was super-clamped to a stair case railing directly in front of the board, which nicely pushed the mics forward a bit into the room a bit more, but produced that crazy mic-bar angle.  Mics were angled up toward the PA to cut audience chatter.



Here's another of the same setup the following night at a different venue.  Stand vertical this time using both folding feet, one as mic bar as before, the other at the bottom in place of the superclamp, sitting atop a box behind the soundguy to get above heads.