M/S - What did I do wrong???

Discussion in 'Location Recording' started by Cucco, Mar 6, 2006.

  1. Cucco

    Cucco Distinguished Member

    Okay - so I just recorded a chamber concert in which I both had to play and record. I only had a few minutes to set up so I had to make educated guesses as to the best positioning. While I'm used to using M/S for smaller chamber groups and solo instruments (acoustic guitar and piano particularly), this particular chamber orchestra was doing BIG works (Finlandia, Karelia and a few others) so the orchestra actually had around 40+ folks in it.

    This is the largest group I have ever recorded with M/S.

    So, here are the details. I am not very pleased with the results that I obtained. I used a Beyer M130/M160 combination (which I've been VERY pleased with on M/S for string quartets and similar).

    Hall -
    Small hall, seats 400 - good acoustics in general with approximately a 1.8 second decay (RT60) measured while no other bodies in the hall (this information was provided to me by the stage manager).
    Stage was NOT specifically designed for orchestra, so a large, recessed cavity is what I had to deal with for the orchestra's positioning (no shells...:-( )

    Positioning -
    I placed the M/S array only a few feet behind the conductor and approximately 8.5 feet above stage level.
    For flanks, I moved a pair of Gefell M296s in place but 12 feet from the stage at the outer width of the orchestra - angled in at about 20 degrees. The main purpose of the spots was to get the LF that I wouldn't from the ribbons and to pick up some ambience.
    I also placed a U195 as the spot for our bass soloist (oh yeah - we had a bassist play the Vivaldi violin concerto....This was VERY cool. I didn't play it as well as he did and I played the violin for over 15 years! Thankfully I gave it up for Lent one year and picked up the horn instead... :lol: )

    So anyway...here's what I don't like.

    In general, I just can't get the balance right between the M and the S. I'm software decoding (phase inverting the right side of the S and mono-ing the M) within Sequoia the same way I always do. I get a lot of ambience, but not as much direct as I want. If I bring up the center, I get way too much mono info and not enough spread. My first inclination would be to move it in even closer, but then I'd be almost parallel with the first violin and the first cello.

    So, those of you who are well versed in M/S and full orchestra - what do you think I did wrong???

    (BTW - don't get me wrong - the recording is acceptable and even good in some spots, it's just that, to me it only hits the 80% mark, and I don't like that. I'll post some clips of the vivaldi soon - it's a GAS!)

    Oh, one last thing - If you need a spot or a direct mic for string bass - the U195 is THE mic for you. OMG - I've used some others before for this task (all sorts of omnis, a couple N**mans, and others, but the U195 gets it all - the attack, the resonance with none of the bloat...simply amazing! I ran it in "flat" mode, no low cut and no "fat" boost switch.)

    Thanks!!!!

    J. :cool:
     
  2. DavidSpearritt

    DavidSpearritt Well-Known Member

    Positioning sounds about right, although a bit close. Remember MS needs to be 1.7 times further back than omni for the same direct-reverb ratio.

    These Beyers have ball ends at the capsule, don't they? I would suspect that you didn't get the capsules close enough. They need to be as close and aligned as possible. This is one of the main reasons the Schoeps MS pairs sound so good, its capsule alignment and small dimensions around the capsule not diffracting the sound too much.

    Are you sure your decoding method is correct. I am amazed there isn't an MS decode plug in Sequoia of all things. Even Wavelab has one.
     
  3. Cucco

    Cucco Distinguished Member

    Thanks David - I bet your assessment regarding distance between capsules (err, elements) is accurate. Due to the shiny silver balls, there is a bit of seperation. It hasn't really posed much of a problem on other recordings, but perhaps the size of the group bears out some of the issues with phasing problems.

    I think the Schoeps fig8 set is on my short list.

    The MS decoding is actually handled by a set of presets in Sequoia. It does it automatically, but what I described was the process which Sequoia uses.

    Thanks!

    J.
     
  4. taro

    taro Guest

    Hi !

    How about the KM120, David ? I read on several forums you said good things about that Neumann... As they are both single capsule fig8 mic, am i wrong thinking the use of the KM120 is a good substitute of the CCM8 for MS recordings? (especially when the budget is too short to go for the Schoeps?;))... and of course, for Blumlein as well, with a pair ?...

    thanks in advance,

    taro
     
  5. RemyRAD

    RemyRAD Guest

    Jeremy, you're recording with my favorite combination for MS. I've not quite had the problem you described. It sounds to me like the Sequoia might be inverting the phase in the MS decode of both microphones? Certainly would cause a problem with the Mono Center imaging in combination with the other microphones. It sounds like you're describing some sort of cancellation of the mono microphone and that's why you can't get the proper balance??

    You may also want to try to do the MS decoding by splitting the output of the figure of 8 track output into 2 inputs into an analog console along with the Mono middle microphone and going through the analog desk and see if that doesn't help through that summing network? Also are you angling the ribbon microphones or keeping their ribbons vertical with relation to the floor? Angling ribbons do affect the sound unlike other types. They should never be positioned horizontally. Red dots pointing towards the ceiling and the floor.

    My favorite sound
    Ms. Remy Ann David
     
  6. Gilliland

    Gilliland Guest

    If you reversed the phase in the M/S decode, the only impact would be to create a mirror image of the stereo. Right would become left, and left right.

    It could be a polarity or phase problem with one or more of the supplemental mics, but I think it's more likely to be a positioning problem.
     
  7. Cucco

    Cucco Distinguished Member

    Thanks for all the input.

    I'll try busing the channels out and doing it manually (although I've never had any issues with the internal processing of Sequoia. I never mind going back into analog though.)

    The wierdness, at least to me, is that I've had wild success with this combo in the past but not so much luck this time. Oh well, practice makes perfect.

    I'm thinking about getting one of those AEA stereo ribbons for the sake of ease. I tried the Royer/Spieden SF12 to not much success, perhaps I'd have better luck with the AEA.

    J.

    PS -
    BTW - Remy, the 130/160 IS a beautiful sound, isn't it? I just absolutely love it on so much...chorus, WW quintet, brass quintet, acoustic guitar, piano...you just can't go wrong with this VERY cheap set of beautiful mics!
     
  8. ghellquist

    ghellquist Member

    Some ideas.

    First the very technical things.

    1 - if your have two mono channels in Sequioa there is already a preset for S decoding. Pan the M channel middle. Rigth click the pan in the S channel and select the preset Convert Side (mono) to Stereo.

    2 - I tend to record everything in pairs, saves a bit of performance on the recording. Then I tend to use a free plugin from Voxengo called MSED. You need to have M on the left channel and S on the right and select Decode. Then there is a mid gain and a side gain. (This plugin I highly recommend).

    3 - unless you have already done it, do time align the tracks. The outriggers are rather far away.

    Next about recording.

    Difficult to say really. Everything seems rather right. Just maybe I would put the MS pair a bit further back. It sort of looks like full 180 degrees between outermost instruments. With a cardioid mid that is a bit too much in my experience, the outermost instruments will be far out from the pattern.

    I´m still learning a lot though.

    Gunnar
     
  9. Cucco

    Cucco Distinguished Member

    Thanks Gunnar.

    Yup, I'm using Sequoia's internal capability for decoding MS.

    I agree, I may have been too close. I wasn't quite at a 180 (or directly between the first violin and first cello). I would say the angle spread between both first stands using the mic as the central point of reference was maybe 130-140 degrees. To the outer row of stands, I would say maybe 160. So, perhaps a bit too close.

    My main goal was to avoid too much reverb as the hall was quite overrun with it.

    I'm going to try again, but this time with a M130 as both the m and the s mic. I know that will give me the rear lobe, but it will allow far easier alignment than the 130/160 does.

    J.

    PS -
    I'll check out the Voxengo plug. Thanks for the tip!
     
  10. OneMegahertz

    OneMegahertz Guest

    Hi Cucco,

    I don't think there's anything wrong with your decoding setup in Sequoia. I've done the same thing before, and it works fine. (Sometimes I tweek the time alignment a little bit, which you can't do in an electronic matrix.)

    My guess is that you simply used a M/S array in a situation for which it wasn't the optimum approach. Because of your close placement, you needed a coverage angle of nearly 180 degrees. I don't think you can really do that with a M/S array having a hypercardioid in the M position. (An omni might have worked, but then it wouldn't have matched your M-130.)

    If you try it with a hypercardioid (as you did), you get to choose between having the orchestral flanks go beyond the array's nominal working angle, and having too much reverberance. Does this match your experience?

    Besides the classic JAES paper on M/S X/Y equivalents by Manfred Hibbing, there's also an AES convention preprint by Michael Williams that discusses this particular issue in excruciating detail. I've attached the abstract below.

    David L. Rick
    Seventh String Recording


    Operational Limits of the Variable M/S Stereophonic Microphone System

    The Variable M/S stereophonic microphone system seems to be a neat solution to modifying the stereophonic recording angle, either during recording or in the postproduction process. This paper shows that angular distortion and the ratio of direct to reverberant sound can vary throughout the range of stereophonic recording angles created by different matrixing values, thus restricting considerably the operational range available.

    Preprint Number: 2931 Convention: 88 (February 1990)
    Author: Williams, Michael
    E-library Location: (CD aes11) /pp8690/pp9003/3013.pdf
    downloadable PDF (449 KB) $5.00 AES Member | $20.00 Non-Member
    hard copy printout $5.00 AES Member | $20.00 Non-Member
     
  11. DavidSpearritt

    DavidSpearritt Well-Known Member

    Yes we have both and I use a KM120 with an MK4 in an MS pair. It works as well as an MK8, because it is small and close capsule proximity is possible.

    Jeremy, rethinking, if your shallow width setting sounds too mono, this is another clue that you are too close, as the others have added. Also, if your M was a hypercardioid, then you are definitely too close, a hyper M allows you to be even further away than a cardioid for the same balance.
     
  12. Simmosonic

    Simmosonic Active Member

    This makes so much sense; I've had similar experiences with MS in the past. Always when there hasn't been enough time or space to put the array where it really needs to be (so it ends up too close), and there isn't a more suitable mic rig available at the time... Thanks also for the AES reference, Mr Rick.
     
  13. mdemeyer

    mdemeyer Active Member

    Guys... I always hear such positive statements about the M130 and M160 here, and am inclined to get them. The other week I had one of those 'windfalls' when I got bumped off my Southwest flight that will just cover buying one of these. But the other would have to wait. I'm wondering, if you could only buy one first, which would you get?

    I have two Schoeps MK8 capsules now for MS and Blumlein (can never remember the spelling on that... sorry if it is wrong), so was thinking that the M160 might be the better add as an instrument spot or paired with the MK8 for MS. I imagine it has a rather different character than my normal MK4 (for MS) which might be interesting. My recording is pretty much all acoustic instruments in real space.

    By the way... the published response of the M160 shows a quite elevated (+3-4 db) 2-8K range. Does it really sound that way? Of does the 'ribbon smoothness' avoid that becoming as forward as it could. I don't imagine it sounding forward based on the descriptions here.

    Or is there anyone who would steer me toward the M130 Fig 8 to start with?

    Michael
     
  14. RemyRAD

    RemyRAD Guest

    Michael, I think I would go with the M160 first as I believe that cardioids are more useful generally than a figure of 8. I generally only use my M130 when I am doing MS and only occasionally use it when I find a situation where it will give me better isolation from a close in sound source that overlaps too much. I love these microphones!

    Peculiar love life
    Ms. Remy Ann David
     
  15. OneMegahertz

    OneMegahertz Guest

    Michael, I agree with Remy on this. I've had a M160 for years, and have somehow never gotten around to buying a M130. Someday the M130 will percolate to the top of my acquisition list, but in the meantime, the M160 has gotten plenty of use. I originally bought it as a stage mic (I'm a cellist), but I've found it works great in many situations where I'd rather not be miking a <whatever> as closely as a need to mic it. Case in point: It's the perfect thing for hanging over a fiddle player on stage using a tall boom stand. You can pull back a little, and because of the hypercardioid pattern it won't get swamped by stage leakage. Just route the fiddle player's pickup to the floor monitors and you'll be fine.

    Don't worry about having too much high end. The top end on ribbons is very different from the top end on condenser mics. Most of what we hate about the top end of condenser mics on things like close-miked saxaphone, trumpet, etc. comes from the fact that these instruments over-excite a high frequency diaphragm resonance that ribbon mics simply don't have.

    David L. Rick
    Seventh String Recording
     
  16. recordista

    recordista Active Member

    Have you tried tinkering with the time alignment of the M & S tracks? Sometimes sliding them to and fro a bit will allow them to lock into position.

    You might also consider a bit of EQ on the S channel, which will produce interesting (and sometimes startling) changes in the image. Start with an LF shelf, just boosting or cutting a little bit.
     
  17. dwoz

    dwoz Guest

    Just thinking out loud here...


    You had very little time to set up.


    Are you sure you haven't switched M for S?


    Might be worth checking out. You are, after all, a french horn player. I'd not put it past you.

    :)

    dwoz
     
  18. Cucco

    Cucco Distinguished Member

    hardy har, har har....

    Yup, I did make sure I had the right ones (I use a green cable - Blue Kiwi - for the Side mic and a black - monster cable for the mid. It helps to eliminate confusion.)

    I've tried a few things with varied, but acceptable levels of succes - including bumping the mid back 2 ms and EQing.

    j.
     
  19. mdemeyer

    mdemeyer Active Member

    J,

    Isn't 2 ms a rather HUGE effective distance to move one of the mics? Unless my brain is toast tonight (which is possible, since I had a recording last night and had to be up at 3:30 am for my flight this morning), that's around 2 feet at the speed of sound. Kind of blows the idea of coincidence completely out the window.

    Am I missing something here?

    Michael
     
  20. RemyRAD

    RemyRAD Guest

    Yes Michael, your other flight.

    I think perhaps Jeremy was referring to micro seconds as you are correct about Millie Seconds, May she rest in peace.

    Still very much alive
    Ms. Remy Ann David
     

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