Outrigger benefits - anyone got a theory?

[MichaelPatrick]

Main center mics (coincident or near-coincident) carry a whole mix, so people rarely EQ mains except to remove rumble or to correct something unpleasant.

For outriggers the only "rule of thumb" I've been able to come up with is that their low-mids can make recordings much more spacious and interesting. How do you use outriggers to compliment center mics? Do you EQ them? What benefits do you get from them?

[dtf]

Hi Micheal,

This is really not such an easy question to answer briefly. I think one has to establish first what we really mean with outriggers (there are actual debates...) and distinguish the several situations in which engineers use them and how they do it.

When talking about classical music recording, using outriggers makes most sense with orchestras. They do add a sense of space, but also help greatly with improving the sound as their placing is beneficial for e.g. the strings and brass.

I know it's not a great answer, but I would never use outriggers to add something - they are part of the recording concept to begin with.

Dirk

EDIT: By the way, as a rule, I never EQ mains or outriggers. But if it is necessary, I will.

[MichaelPatrick]

Originally Posted by dtf

This is really not such an easy question to answer briefly. I think one has to establish first what we really mean with outriggers (there are actual debates...) and distinguish the several situations in which engineers use them and how they do it.

When talking about classical music recording, using outriggers makes most sense with orchestras. They do add a sense of space, but also help greatly with improving the sound as their placing is beneficial for e.g. the strings and brass.

I know it's not a great answer, but I would never use outriggers to add something - they are part of the recording concept to begin with.

Dirk

EDIT: By the way, as a rule, I never EQ mains or outriggers. But if it is necessary, I will.

Thanks Dirk. This is helpful. I agree that orchestras are the main use, and I've also used them on large choirs.

P.S. when I say "add" something, I mean only that any sound additional to the main mics must be positive and not negative for the recording. In this way even spots should also "add" something positive.

[studer58]

This is potentially a very useful thread ! In my orchestral recordings I invariably use a pair of outriggers for 'enlarging' the left/right width or reach that the main pair would otherwise be unable to do on it's own...as dtf has outlined here. A main pair alone gets the orchestra, but the outer edges can be fuzzier (compared with the players closer to the conductor) than I'd like them to be. That stated, there are occasions when the addition of the outriggers can "lighten up" the overall sound, compared with the solidity that results from a well placed pair alone. I assume this is due to phase issues between the main pair and outriggers, although the distances between them should theoretically rule out destructive phase cancellations ? The only option we have usually is to flip the outer pair's phase, but that often doesn't work either, and is too drastic a measure. What I'd love is a continuosly variable "phase pot" which could introduce a progressive phase shift, as I'm sure a 90 degree or 270 phase shift would restore the imaging solidity of the mix without the 'out of the room' experience of a 180 phase flip. Anyone care to shed more light on this issue, especially with regard to whether this incremental phase adjustment is possible via software or hardware ? Aren't there some DI boxes around that accomplish this for combining the direct vs miked signals of electric instruments yet avoiding the cancellations or suck-outs that can occur ? Deling od spot mics is a well known technique, but I've never heard of it being advocated for outriggers...would it approximate the same result as the aforementioned phase shift ?
Ray

[studer58]

erm..."Deling od spot mics" = Delaying of spot mics....

[CPTenorII]

I am not totally sure what you mean by outriggers. I assume you mean a pair of omnis split over the cardioids. This is a very effective setup assuming the room and equipment are good. If not done properly, it can highlight phase issues. Also watch out for noise as omnis frequently add to the noise floor noticeably.

The extra pair of omnis is terrific in large rooms. It allows you to narrowly focus the cards for detail pickup and use the omnis to add room space. For choral recordings, it can either enhance or ruin diction, depending on the room and placement.

[rumleymusic]

I assume you mean a pair of omnis split over the cardioids.

He means a pair spaced very wide on either side of the main array. Polar pattern has nothing to do with it, except for discussions of personal preference. I personally use both omnis as mains and outriggers, though I do like the Schoeps mk21s for support when I am able to use them (they are not mine :( ).

I use them to add presence to the recording, by the time you capture the outer edges of the orchestra with the main pair, the sound is so diffused and mixed with the reverberent sound, it becomes very thin.

I like to use very clean mics as the mains, and something with a little "sound" to it for support. For me, that is the best of both worlds.

And I don't know about anyone else, but I always delay the outriggers to the mains, I think it just sits better when mixed.

[MichaelPatrick]

In my findings, the "spaciousness" that outriggers can add to a recording includes front-to-back depth in the soundstage that helps put woodwinds and horns in the back and strings in the front.

Daniel just said he always delays outriggers to the mains because "it just sits better when mixed." I've also noticed that changing the delay can really alter the final recording, so I experiment with delays when mixing them. I don't think I have ever put the outriggers ahead of the mains, but I do try out a variety of tiny delays (i.e. under 10ms) and tune the mix in fractions of a millisecond so that the stage sounds really interesting, alive and still natural.

[fifthcircle]

I find that I'm using a pair of outriggers more and more. Even for the chamber recordings that I do where I normall would not have used them in the past, I find that it helps add a sense of depth and dimension.

Ultimately, though, I find that thinking of the overall mics in terms of a system is absolutely required. How will the space of the omnis work with the image of the main pair. This is part of the reason why I'm not doing as much blumlein recording anymore. It is really difficult to get the blumlein image to work with the spaced image of the flanks. I still will do it, but it requires much more controlled situations.

Raising and lowering the level of the outriggers will indeed make the sound wider or narrower, but the downside is that the same action can also bring in phase issues- especially with smaller ensembles. It can also help bring in room sound in a very pleasing way.

For my outriggers, I switch between omnis, omnis with balls and subcardiods. Each brings in a different focus to the final sound and the use of them for me depends on the room I'm working with.

When it comes to EQ and reverb treatment in a mix, it really depends. I do what it seems like the recording calls for. Sometimes it is EQd and sometimes not. It really depends. Sometimes they'll get a bit of verb to tie their sound in with everything else, but just as often, they'll be unprocessed.

--Ben

[MichaelPatrick]

Originally Posted by fifthcircle

...For my outriggers, I switch between omnis, omnis with balls and subcardiods. Each brings in a different focus to the final sound and the use of them for me depends on the room I'm working with.

Ben, I have to ask what "omnis with balls" means ?

1. something a bull carries between his legs
2. an Acoustic Pressure Equalizer for omni microphones (image below)

[panatrope]

As a minimalist (AKG C426B in Blumlein or Schoeps CMC54/58 M-S pair) I have recently taken on the use of outriggers (omnis previously AKGC460/CK62, Audio Technica AT3032 Rode NT45 and now Schoeps MK2S) in the following situations:

- for orchestral work when microphone placement is limited by audience location - the main pair is closer than optimum so the outriggers cover the outer strings and just give a more presence to horns and brass (as if they need it!) and usually help along the basses (something that recording engineers who have previously indulged in bass practices are unfortunately prone to do);

- where a small group needs close placement (due to soft instruments such as period bands) and the outriggers allow you to treat the ambience separately from the main content.

There are many other examples. The key disadvantage is that one tends to then record multitrack, and waste lots of time in post arguing with oneself over the various balance possibilities. (Time rises exponentially as the number of microphones, and the exponent is greater than 2 ...)

But with the right mics (the judges decision is final and no correspondence with DPA fanboys will be entered into) in the right position and in the right balance it really makes a difference.

[CPTenorII]

Originally Posted by MichaelPatrick

In my findings, the "spaciousness" that outriggers can add to a recording includes front-to-back depth in the soundstage that helps put woodwinds and horns in the back and strings in the front.

Daniel just said he always delays outriggers to the mains because "it just sits better when mixed." I've also noticed that changing the delay can really alter the final recording, so I experiment with delays when mixing them. I don't think I have ever put the outriggers ahead of the mains, but I do try out a variety of tiny delays (i.e. under 10ms) and tune the mix in fractions of a millisecond so that the stage sounds really interesting, alive and still natural.

Why would you delay the outriggers? The whole point is to make sure that both pairs are aligned exactly to avoid front-to-back timing issues. Delay would artificially alter the acoustic form. The mics are intended to create a wider and more-detailed sound picture. The only reason I can see to delay a second pair is if it was not aligned with the first. Even then, they may play well together with no alteration. The best handling in my opinion and experience, is to walk the room to find the best places for pairs.

[fifthcircle]

Originally Posted by MichaelPatrick

Ben, I have to ask what "omnis with balls" means ?

1. something a bull carries between his legs
2. an Acoustic Pressure Equalizer for omni microphones (image below)

That would be choice number 2.

[mixedupsteve]

Originally Posted by studer58

Aren't there some DI boxes around that accomplish this for combining the direct vs miked signals of electric instruments yet avoiding the cancellations or suck-outs that can occur ?
Ray

http://www.littlelabs.com/ibp.html
They have a JR version also.

[studer58]

Originally Posted by mixedupsteve

http://www.littlelabs.com/ibp.html
They have a JR version also.

Thanks mixedupsteve, that's the box which was lurking in the dim recesses of my memory...! Hmmm, $630 US....I wonder if there's a software equivalent out there ?
Ray

[iluvatar]

Originally Posted by studer58

Thanks mixedupsteve, that's the box which was lurking in the dim recesses of my memory...! Hmmm, $630 US....I wonder if there's a software equivalent out there ?
Ray

The IBP Jr. is the same thing w/o the DI and streets for about $365.

-Dan.

[panatrope]

Originally Posted by CPTenorII

Why would you delay the outriggers? The whole point is to make sure that both pairs are aligned exactly to avoid front-to-back timing issues. Delay would artificially alter the acoustic form. The mics are intended to create a wider and more-detailed sound picture. The only reason I can see to delay a second pair is if it was not aligned with the first. Even then, they may play well together with no alteration. The best handling in my opinion and experience, is to walk the room to find the best places for pairs.

The use of delay is an interesting topic, and is always decided on a case-by-case basis. However on the occasions I have used delay it is always with the intent of preserving the spatial image of the main pair, using the idea of first wavefront/Haas precedence to ensure the spotter/outrigger contribution arrives in the mix several mS after the main pair. If it doesn't help it doesn't get used.

A reverse case (delaying the main pair) occurs where I have a main pair in front of the stage, with an omni room pair deep in the hall because that's where the better room sound is. Because the separation is such that that the sound from the stage arrives at the omnis a considerable time after being picked up from the main pair, to the point where it can become two separate sounds, a delay is placed in the main pair so the time difference between the two paths is below the point where the two sounds can be heard separately. Seems to work reasonably with both large and small ensembles. Helps to have a VERY quiet hall .... and audience!

[phil.]

Originally Posted by fifthcircle

How will the space of the omnis work with the image of the main pair. This is part of the reason why I'm not doing as much blumlein recording anymore. It is really difficult to get the blumlein image to work with the spaced image of the flanks. I still will do it, but it requires much more controlled situations.

Yes! I second this opinion and only use outriggers if there is enough time to set up and monitor carefully.

Ben, what are the main factors you listen for when trying to get an image from the outriggers that goes well with your main pair? Are you using any particular techniques in order to make both work together harmoniously.

Thank you,

Phil.

[mixedupsteve]

Originally Posted by studer58

Thanks mixedupsteve, that's the box which was lurking in the dim recesses of my memory...! Hmmm, $630 US....I wonder if there's a software equivalent out there ?
Ray

I think they have one. Also google "PHASEBUG" thats a freebe if you have windows VST

[rumleymusic]

Why would you delay the outriggers? The whole point is to make sure that both pairs are aligned exactly to avoid front-to-back timing issues.

If they were aligned, they wouldn't be outriggers. Whenever you space and combine mics on a channel, you run the risk of phase cancellations. Front to back, side to middle, it doesn't matter, direct sound will reach one mic before it reaches another. Delaying the sound of the outriggers to the main pair as you would any spot mic helps keep the main pair in focus and does nothing to diminish their effectiveness, at least not that I have experienced.

[aracu]

"Delaying the sound of the outriggers to the main pair as you would any spot mic..."

Do you mean that you delay the spot mics and outriggers similarly to your main pair? Seems strange to me since they would have an opposing relationship in time to the main pair. Maybe I don't understand you correctly.

[dtf]

Originally Posted by rumleymusic

If they were aligned, they wouldn't be outriggers. Whenever you space and combine mics on a channel, you run the risk of phase cancellations. Front to back, side to middle, it doesn't matter, direct sound will reach one mic before it reaches another. Delaying the sound of the outriggers to the main pair as you would any spot mic helps keep the main pair in focus and does nothing to diminish their effectiveness, at least not that I have experienced.

I am not familiar with this idea. Outriggers have been part of e.g. Decca's orchestra recording technique since decades, way before the time that delaying was possible (without significantly diminishing quality).

In another post the Haas effect was already mentioned. Phase cancellations are everywhere in spaced microphones, the question is: are they a problem? Natural hearing is full of comb filters, and more importantly our reproduction in stereo or surround is also full of comb filters. There is masking in the time domain as well to some degree.

I perceive all microphone systems with outriggers as a complete main system - sure imaging will be affected by the outriggers, but you know this and make sure the combination of e.g. tree and outriggers delivers the desired result. Any delaying will destroy this and will introduce real phase issues resulting in annoying comb filters. Of course, sometimes it might work.

Best,
Dirk

[MichaelPatrick]

You've made some really interesting observations. In my experience delaying spots (not outriggers) makes more of a difference than delaying outriggers. Spots sometimes have weird combs that color the source in an unflattering way, and that's all I try to correct. I don't worry much about numbers - I listen for the tone and sometimes alter the delay by a few milliseconds up to ~20ms, depending on placement.

Originally Posted by dtf

I am not familiar with this idea. Outriggers have been part of e.g. Decca's orchestra recording technique since decades, way before the time that delaying was possible (without significantly diminishing quality).

In another post the Haas effect was already mentioned. Phase cancellations are everywhere in spaced microphones, the question is: are they a problem? Natural hearing is full of comb filters, and more importantly our reproduction in stereo or surround is also full of comb filters. There is masking in the time domain as well to some degree.

I perceive all microphone systems with outriggers as a complete main system - sure imaging will be affected by the outriggers, but you know this and make sure the combination of e.g. tree and outriggers delivers the desired result. Any delaying will destroy this and will introduce real phase issues resulting in annoying comb filters. Of course, sometimes it might work.

Best,
Dirk

[Audiop]

Originally Posted by panatrope

The use of delay is an interesting topic, and is always decided on a case-by-case basis. However on the occasions I have used delay it is always with the intent of preserving the spatial image of the main pair, using the idea of first wavefront/Haas precedence to ensure the spotter/outrigger contribution arrives in the mix several mS after the main pair. If it doesn't help it doesn't get used.

A reverse case (delaying the main pair) occurs where I have a main pair in front of the stage, with an omni room pair deep in the hall because that's where the better room sound is. Because the separation is such that that the sound from the stage arrives at the omnis a considerable time after being picked up from the main pair, to the point where it can become two separate sounds, a delay is placed in the main pair so the time difference between the two paths is below the point where the two sounds can be heard separately. Seems to work reasonably with both large and small ensembles. Helps to have a VERY quiet hall .... and audience!

Up to what distance does it work for you without delaying the mains?


/Peter

[fifthcircle]

Originally Posted by phil.

Yes! I second this opinion and only use outriggers if there is enough time to set up and monitor carefully.

Ben, what are the main factors you listen for when trying to get an image from the outriggers that goes well with your main pair? Are you using any particular techniques in order to make both work together harmoniously.

Thank you,

Phil.

It really depends on the group that I'm recording. Don't get me wrong, I use flanking mics a lot. I am just a lot more careful as to what the center pair is.

The blumlein pair has a very exact stereo image. You can pinpoint anything in it- that is just the way it works. On the flip side, your flanks are a very widely spaced set of omnis or subcards. The image there is anything but exact. To make those two things work together is mighty tough.

Now, a pair like an ortf pair or a pair of subcards that are spaced in the 14-18 inch range gives you a good image, but nowhere near as exact. When you combine this with the image of the flanking mics, things seem to work together a lot better. (at least in my opinion). I have a similar thought process when deciding the size of a decca tree to use and then how that affects the width of the outriggers.

Just a few thoughts...

--Ben

[rumleymusic]

Do you mean that you delay the spot mics and outriggers similarly to your main pair? Seems strange to me since they would have an opposing relationship in time to the main pair.

Exactly. I know it is not common practice, but I have found it works quite well. It is not even a phase issue really, even with spots it usually a balance issue because the 3 to 1 rule is most likely in effect considering the size of an orchestra. I do not like the warped and sometimes unrealistic sense of space that extra mics can add to a recording. Making sure the sound reaches the main pair first, even from the sides, is a good way to avoid this. And I have never had a problem with the outrigger delay interfering with the spots. Even spot mics have an opposing relationship in time with each other and I usually delay those about 20% longer than the time the first reflections hit the main pair (per DPA's recommendation). You will not get the huge channel separation that some people might like, but the full, rich, and expansive sound is still there, and without the main pair being over shadowed (or the last chair violins being over emphasized ).

I guess it is a matter of personal taste.

[aracu]

"The blumlein pair has a very exact stereo image. You can pinpoint anything in it- that is just the way it works. On the flip side, your flanks are a very widely spaced set of omnis or subcards. The image there is anything but exact. To make those two things work together is mighty tough."

Interesting. It's hard to add anything to a well placed coincident pair without also having some comprimising effect on it's stereo image. Sometimes a close and far coincident pair can strengthen each other.

[panatrope]

Originally Posted by Audiop

Up to what distance does it work for you without delaying the mains?


/Peter

I usually do not delay the mains if the outriggers are parallel to the main pair or about 5m into the auditorium. However, once the distance between the on-axis area of the main and the outrigger exceeds about 10m, then I would start to think about it. The instance I talk about has a separation in excess of 15m.

BTW, the main pair is usually M-S (Schoeps MK4/MK8). But I occasionally use M-S Blumlein (AKG C426B). Reducing the S component decreases image width and reduces focus on the edges. I then use the outriggers to drape the edges - and some air - around the M-S image. When it works, it is quite satisfying.

[7rojo7]

Ultimately, delay, is what gives you depth.
I like to have a solid image, before I start balancing it.
Depends a lot on the space in which one records.
Once, for a demo, I recorded a classical gtr in a dance studio, ex 'sala nobile' (parlor), with a L/R AT ATM825 at 40 cm from the instrument, L/R plane horizontal centered at the left edge of the hole, angled a little towards the neck.
I would pick that room to record classical gtr, with what ever mics and whatever placement. It is no longer available. My recording (ATM 825/Tascam DP-1) would be unobtainable without that room (or one similar).
There are so many variables. I often recieve funny looks from clients when I walk towards the corner of a room whispering what seems like demonic prayers or shamanistic sentences, only to find the Q of the corners and critical distance. Develop mono ears.
Ultimately, delay, is what gives you depth.
I still align everything to the center array (for me, it's almost always xy over mono) the delays that already exist are more than enough to contend with, without complicating the matter too much.
When we hear something, the reference is always 'center of the universe'. Our heritage as preditors gives us an 'arrogance', we search for sound as an instinct to find prey, we will never be objective concerning sound. Jeep mixes vs. Shosticovitzch quartets, as equally stimulating sonically, Shosticovitzch on a jeep system is da bomb.
Anyway, to have many different 'pathlengths' is not a good idea, critical distance serves as a guideline to space mics so that their diverse pathlengths don't interfere with one another and that simple off axis response of the mic overlaps with its neighbors in a more or less mathematical unforgiving way. Air is air and sound moves through air for our practical purposes, no reason to pretend any differently. Delaying mics is like delaying the different arrays of an FOH system, it's more or less scientific.
We have the job of making a bunch of mics seem like a pair of ears connected to a primevil brain (reptile) anything else is outside the work of a recordist and enters in the realm of documentary. Otherwise it's very precise what needs to be done. Most often there's not enough time to get it done properly, but this can be overcome with a little extra preparation. Making all those calculations on the fly, having enough experience to use those calculations to your advantage, devising a scheme to fit everyone's needs and doing it before you've even seen the the space, guided by descriptions of the space and the program to be pereformed there within and to get it right and deliver it with your name on it for all time. If the other side delivers on the performance: This is what great recordings are made of.
Better to have too much and not use what isn't needed than to not have enough and end up smirking at your client (for the last time)

[studer58]

y xx z
... .... ...
..... ....... ........
aa ...............a ............. ...............

Imagine that xx is the main pair and y and z are the outriggers. A sound emanating from position 'aa' on the stage is going to reach mic 'y' much more quickly than it does 'xx', so delaying makes some sense, but a sound emanating from 'a' is likely to reach both of 'xx' and 'y' at around the same time, since it's origin is equidistant from both. So the delay applied to mic 'y' to account for the earlier arrival of 'aa' is not applicable to the sound coming from point 'a' My point is that your delay applied to mic y is an approximate at best, and unfairly discriminates against the closer sounds vs the more distant ones (ie the ones coming from region 'aa' and further off to the left and rear). There can't be an appropriate one-size-fits-all delay for the outriggers ? Wouldn't one expect a time or dimension distortion of the soundfield by picking some arbitrary delay time and applying it to the outriggers ? Discuss and debate.
Ray