best mic arrangement to blend off centre source to main ORTF

Discussion in 'Location Recording' started by tyrolean, Apr 19, 2014.

  1. tyrolean

    tyrolean Active Member

    I am going to record a concert of the 'Armed Man' in a large church.
    The main stereo pair will be flown above+/- conductor position (MC930/ORTF)

    A childrens choir of ~70 will be placed in a side aisle outside the pillars even but level with the choir/orchestra in the Nave. This choir will be angled towards the conductor in the centre aisle/Nave, so at ~45 deg to an imaginary centre line down the church.

    A pair of DPA 4015C (AB@20cm) are being trialled close up to the body of the main choir ~120 & behind the orchestra using a tall 4m cathedral stand almost touching the front row.

    I have been using the 'Sengpielaudio' visualisations ( To get some insight into the best arrangement of a pair of Rode NT55 mics in front of the childrens choir in the aisle.

    I will be trying to reference this pair to the main ORTF stereo pair.

    Am i at all correct in seeing/anticipating a narrower spread in the virtual field between playback stereo speakers as being easier to deal with/more convincing? than a wider localisation?

    Or: what is the best arrangement that will make life easier when trying to fit the childrens choir into the main stereo image?

    I am looking at AB 20cm spacing & orchestra angle of ~125deg

    does that make sense?
  2. TheJackAttack

    TheJackAttack Distinguished Member

    Spaced omnis for the auxiliary mics are ok. Do you really need a stereo pair for the aux microphones? One should be sufficient. Make sure that you add a delay to the aux mic 3ms/meter to the main stereo pair for that particular track. I would also pan it accordingly. You want to add articulation and not volume so don't turn it up too much in the mix. Remember that your main sound will always be the main stereo pair in an acoustic recording.
  3. tyrolean

    tyrolean Active Member

    Hello,....thanks for replying.

    I had considered AB/Cardioid with the NT55's or a single C414xls & I was working from a response to the same question put to 'another place'.

    The reply from 'that place' that got me looking at the Sengpielaudio site was:

    With a children's choir of that size you are probably going to want to have some sort of stereo width, so the NT55s would be sensible (or maybe even all three mics in a kind of spaced trio). Position them to minimise the pickup of the main musical ensembles.

    How you mix the kiddie choir mics into the final sound depends on where they are placed relative to that main ORTF pair. The stereo acceptance angle on ORTF is quite narrow at 90 degrees or so, which means the children's choir will probably appear well off to one side on that main pickup.

    So I'd pan the kiddie choir mics to pull the image back across, panning the NT55 which is closest the ORTF array on to the side of the most ORTF pickup, and the other NT55 panned across to the other side. Adjust to taste, listening carefully to unwanted image distortions caused by spill.
  4. Boswell

    Boswell Moderator Distinguished Member

    This isn't difficult provided you stick to a few straightforward concepts. In principle you can use whatever mic pattern you like on the off-centre choir, but it should be one that can be condensed to mono during the process of setting up the panning. My favourite for this is M-S, as the width control is easier, but with NT55s you will probably have to use cardioid X-Y. I would not use omni spaced A-B on the choir, as it will lead to phasing problems when blending with the other mics. However, the need to delay the choir mics by at least 1ms per foot of distance from the choir to the main pair is important. Remember also that these mics are supplying detail and not main sound.

    The basic process is to start by summing the choir mics to mono (or using just the M mic with an M-S pair) and then panning that source to the place that the main front stereo array says it should be. With M-S, the S channel is then brought up around the mono panned position to give the appropriate width. I like to feed the S signal into two separate L and R inputs so it's easier to compensate for the mixing console's pan laws by giving less gain to whichever S channel is nearer the centre. With an X-Y array, it's a matter of adjusting both the panning and levels of the X and Y channels so they are not equal level nor hard L / R, but it can be much trickier to get an acceptable off-centre image than with M-S. In the past when I have been obliged to work off-centre with an X-Y mic such as a Rode NT4, I have converted its output to M-S and then treated it as an M-S pair.
    TheJackAttack likes this.
  5. audiokid

    audiokid Staff

    Do you guys use your eyes and ears in the DAW for aligning to the mains or stick to an actual measured formula? Should the tracks all line up tight or are you (adding or leaving) a subtle purposeful distance for effect or formula? Whats your rules on this?
  6. TheJackAttack

    TheJackAttack Distinguished Member

    If your mic types are complimentary, the ms/foot is an excellent starting point. Because of time and distance and dispatate sources, it will never visually line up perfectly.

    Sent from my SCH-I535 using Tapatalk
  7. audiokid

    audiokid Staff

    do you still try and line them so you don't hear any distance per-say?
  8. audiokid

    audiokid Staff

    Let me put it a different way:
    Is the object to mix this so it sounds like you (the sole listener) is hearing it (translating) the performance from his/hers perspective or like the mics are hearing it from their locations combined?
  9. TheJackAttack

    TheJackAttack Distinguished Member

    I make it so I dont hear different mic positions. These aux mic positions are for clarity only. Treating them as anything else is counterproductive.

    Sent from my SCH-I535 using Tapatalk
    bigtree likes this.
  10. tyrolean

    tyrolean Active Member

    very useful information and discussion, a few pennies have dropped and i feel clearer about what to do and why i am actually doing it.

    Thank you for taking the time with this.

  11. RemyRAD

    RemyRAD Guest

    I really hate recording children's choirs with condenser microphones. The sibilance just goes crazy. That's why God created ribbon microphones a.k.a. velocity microphones. The only microphones that make children's choirs listenable. Any of them.

    I mean... guys... we're not recording on mushy analog tape anymore, right? So make the kids sound nice. Use ribbon mics. Screw the condenser nonsense. Why must everybody use condensers? Making it sound right & good, is the mark of professionalism. Not what it says on the microphone package. You're there, in the UK! So grab a couple of Cole's! Put at least one on the kids choir.

    Jesus... always condenser nonsense.
    Mx. Remy Ann David
  12. audiokid

    audiokid Staff

    I'm with Remy on this one but it always comes down to budget.
    Budget aside, Royer mics all the way to the finish line makes choirs (well most eveything I do) sound pretty sweet to my sensitive ears.
    As Remy mentioned, children choirs (kids) sibilance is indeed minimized with ribbons. I have great examples of children choirs using a (condenser :whistle:) Royer SF-24 this year. SF12 or any of the unbeatable R series all work wonderful. Buy once and be done with it.
    If anyone is ever interested, PM me. Glad to share a link.
    You will never regret investing in Royer microphones.

    my blumeim two cents.
    TheJackAttack likes this.
  13. TheJackAttack

    TheJackAttack Distinguished Member

    I wasn't aware the OP had other options but quality ribbons are always my first choice.

    Sent from my SCH-I535 using Tapatalk

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