Stereo microphones

May 26, 2022
 by Paul McGowan

The deeper we get into the recording arts the more questions arise.

For example, how did the recording industry settle into the idea of using mono microphones to record solo voices and instruments?

For years at the beginning of the stereo revolution recordists relied upon stereo microphones to capture musical performances. Some even went so far as the use what’s known in the industry as a Decca Tree: left, center, and right microphones clustered together. Or, remember the stereo head microphones?

Many classic microphones from years ago, like the AKG C24 and Telefunken’s version of it, were single body stereo devices.

They were for a time, the standard.

And then they weren’t.

My guess is that with the advent in the 1970s of multitrack recorders and control boards with pan pots (balance controls) it was just easier to use a single mono microphone to capture a singer or an instrument and then “place” them where they sounded right in the stereo mix.

The problem is it doesn’t sound real.

It sounds recorded.

One of the advantages of a singer or musician being captured on a single-body stereo microphone is realism. Imagine standing in front of a microphone and singing. Because you’re not a statue frozen in time, you move around as you sing. Your head and voice change ever so slightly. That movement in 6 dimensions (left, right, forward, backward, up, down) is perfectly captured by a stereo microphone.

It is completely lost with the industry-standard mono microphone technique.

Which is why going forward at Octave Records we will no longer be using mono microphones to capture solo artists.

One step at a time we are tearing down the standards by which the recording industry has been built.

I can’t wait for you to hear the difference.

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53 comments on “Stereo microphones”

  1. The Decca tree was the idea of Arthur Haddy, one of the greatest audio engineers ever, responsible for developing full frequency sound recording in the early 1940s. It has been the standard approach for orchestral and choral recording for 70 years.

    The use of mono or stereo microphones for voices also seems to be long established, the number of voices, room acoustics and engineering considerations, being some of the factors. The different sound quality that can be achieved with a single voice through different recording and production techniques is quite extraordinary. One of the most natural I can think of is Barb Jungr (Man in the Long Black Coat) on Linn Records. It helps to have a remarkable voice.

    1. Nice recording, I agree. But, here’s the dilemma, Joan Osborne’s rendering of the same song on Blue Gorilla (Mercury) reveals a remarkably better vocal performance in terms of the breath control and power which the lyrics demand, despite suffering from the usual mediocre recording technique. In a perfect world, which does not yet exist (maybe Paul will in fact achieve perfection), artistry and engineering will finally join together.

      1. Performance is a matter of taste, but the Linn vocal recording is difficult to fault.

        Another favourite vocalist, generally very well recorded by Decca, is Ute Lemper. There is an excellent compilation album “All that Jazz”. Was fortunate to see her in the original London cast of Chicago. She stole the show.

  2. To me it „sounds“ most strange choosing a closely (some 20 cm) placed stereo mic to record a singer’s voice. The recording angle variations now are much much bigger than for the listener in the concert hall sitting at least in a distance of some 20 m or more! It would be better to figure out sophisticated mic arrays capturing the real concert hall acoustics and going for mastering ambiophonic sound.

    1. I am hoping that Octave is NOT going to place that AKG so close to a vocalist that we get those cues, that would be counter productive to their goal. The other issue is going to be the acoustic space. If in the studio (I don’t believe they have a live room), the reverbs will have to be added to those two tracks for that mic. Lets see how it is used.

      My comment to Paul here in this forum went UN-answered, he usually responds.

  3. Bravo for questioning parts, which most so-called professionals never did, because of just doing a job!

    On the other hand there are several who also already learned and produce great, natural sounding recordings again, after we were used to it from the very past. It could speed up the learning curve, talking to them. But certainly you’re in competition, so you have to learn for yourself. Respect for going through this!

  4. great idea.But many years ago,this idea was driven further,using a dummy head with build in microphones into the ears-big desaster.
    i suppose there is no holy grail of mike positioning.
    For me,the best way is made to measument for each session.You are trying to reach the absolute best solution.I am afraid it do not exist.But maybe the best solution,for today,for each event exists

    1. I LOVE binaural music and even gimmicky environmental-sound demos recorded with great mics and a proper dummy head! It can be incredibly realistic. BUT … it MUST be played with headphones for the proper appreciation. I’ve demoed it several times to non-audiophiles, telling them to keep their eyes closed (with a promise that they have nothing to worry about), and typical reactions include suddenly opening their eyes and turning their heads in astonishment (as if the musicians and vocalists had quietly entered the room while their eyes were shut), or suddenly jumping out of their seat or ripping off the headphones because they can’t stand the convincing realism. I even fooled myself once while playing back a binaural recording I’d made myself an hour or so earlier on open-reel tape while still living with my parents during college. My mother had called me from downstairs during the recording. While playing it back later, when I got to that part, without hesitating whatsoever, I removed the headphones and yelled back “Yeah?” – to no response from my mother, because she wasn’t even there! The old ad used to read “Is it real, or is it Memorex?” I’d say “Is it real, or is it binaural?” But if played back over speakers, that misses the whole point of the technique.

  5. Paul, Please, no 6 dimensions! Six directions (left, right, forward, backward, up, down), but only three dimensions. We have too many wild discussions as it is, we do not need to start discussing 6 dimensional space! 😮

    1. Tony,
      Hahaha…I just got home from my wife’s birthday dinner
      & you beat me to it…6 dimensions jolted me too…only 3 axes.

      I know sweet FA about recording, specifically mic design & mic placement in a recording studio.
      However, I believe that if the ‘Cowboy Junkies’ could figure it out back in 1988, David A. Stewart could figure it out in 1989 & Donald Fagen also got it right in 1982, how hard could it be…am I missing something?
      People have been recording music fairly well (& badly) since the 1930’s…surely 90 years of trial by error must’ve yielded some positive, repeatable (tried, tested & true) results that have become permanent best practice.

  6. I remember early stereo recordings were done using a handful of mikes that would be used to capture the central stereo image with a couple used to catch an individual instrument and hall ambience. As mixing boards got larger so did the number of mics used, to often the result was a confusing mish-mosh that was clear but confusing. All those mics only had two speakers (and that phantom center channel) to come out of.

    Record jackets back in the day often went in to great detail about which mic was used where, back then the consumer could actually read the notes without the use of a microscope. I thought the stereo mics an interesting idea that was to soon abandoned, what would we ever do with all those mixer channels? It was an idea that never got fully fleshed out and I’m glad to hear Octave records is picking up the gauntlet.

  7. Looking forward to hearing what the difference will be. You should do a demo recording. Ideally where both types of mics can be placed and that the exact same performance can be captured and mixed both ways. (Maybe that’s not possible)

  8. Most live performers use a single microphone and stand in the middle of the stage and the background singers will stand to one side ,the vocals from both will come out of the mixer in the centre pan position and then into the pa system ,lots of live performers still use a mono amp so the sound from the speakers will be double mono, and the audience don’t care so long as they can hear the performance. Mixing for an audience and a recording are two completely different kettles of fish. Mick Grant, Stocksbridge, uk.

  9. I always thought Todd Garfinkle was pretty interesting when it came to adamant claims about microphone quality and placement. He uses nearly 10,000$ mics and I have a couple of his recordings and met him at a head fi show. Gus recordings are great, so I care not to analyze or question too much. 🙂

  10. Yes, go for it Paul! Some of my favorite classical recordings were the ones made by Telarc years ago with critically-positioned spaced omni mics – very natural and enjoyable sound with the right balance of direct sound and hall ambience for great realistic spectral balance and imaging over speakers in a “typical” listening room. Probably more of a challenge to do it in a small studio due to the necessarily closer spacing of everything – single stereo mics might work best there, augmented with prudent use of spot mics and your high-quality reverb units, both as minimally necessary. The goal need not be for the recording to sound like we listeners are sitting in your actual studio (which we’re not familiar with anyway), but rather, sitting in “A” convincing good-sounding club, recital room or small hall.

    1. Well said, however, I am curious which recordings were spaced omni’s ? I have nearly 150 Telarc recordings in my library. I always thought they were minimal with the use of a Decca Tree in most cases. Which makes the use of THREE omni microphones. Keep in mind, that is not true stereo because it employs 3 channels.

      Most times the placement of it over the music director’s head is not where we really want to be during a live concert setting (O: In an orchestral performance, it ends up being nearly over the top of the string section which to my ears always sounds too up front and close.

      1. I had never heard of the “Decca Tree” until reading this post. After reading up on it, I learned that it is typically used with configurations of 3, 4 or 5 mics, that various types of mics have been or are used with it, and that it was/is very highly regarded by many. I did spot checks of about a dozen of my 40+ Telarc recordings’ technical notes. None of them mention the Decca Tree, nor do they even explicitly mention the pickup pattern type (e.g., omni, cardioid) of mics used – they only list the brand name and, sometimes, the type number. Most classical recordings that I checked either explicitly or implicitly indicated the use of the Schoeps Colette mic series, which can be fitted with any of a number of different capsules. Two recordings explicitly indicated use of capsules M2 (omni) AND M4 (cardioid). One semi-classical used B&K 4006’s (omni). Two jazz recordings listed 4 different types of B&K, AKG, and Beyer mics. Somewhere along the way during the past 45 years or so I somehow got the idea that their regular technique was to use spaced omnis. [Not sure why omnis need the additional clarifier “spaced” – why would anyone use non-spaced omnis? 🙂 ] The technical notes on my oldest Telarc recording (1977, “Michael Murray, The Great Organ, Methuen Memorial Music Hall” direct-to-disc) state “No multiple miking … [was] used to capture the sound of this magnificent instrument”, seemingly implying the use of a single dual-directional-diaphragms stereo mic.

        I dug a bit deeper. Aha! http://www.telarc.com/about/MinimalMiking.aspx . Some excerpts:

        “When [Jack] Renner talks about “minimal” miking, it means using the fewest number of microphones that are absolutely essential to get the job done. This means using only two, three, or four main microphones for recording a full symphony orchestra. Only in extreme circumstances will he employ “highlighting” mics. … ‘That is what I call a distinctive Telarc Sound. That sound is a result of using omni-directional microphones for the main pick-up, and the way they are placed so that the acoustic of the venue and the performing group are successfully integrated into a single, successfully-balanced sonic picture.’ … He often uses two pairs of high-quality Schoeps omni-directional microphones, as well as vintage Neumann M50 omni microphones with tube electronics. … ‘For an orchestral recording, I normally start with the inner pair of mics some ten feet above the floor of the stage, and between three and five feet from the first row of musicians. Then I position my outer mics around twelve to thirteen feet from center stage. From that point, fine-tuning adjustments are made until the desired sound picture falls into place.’ “

  11. Instead of 6 dimensions (or directions) we’re looking for 6 DoF (degrees of freedom) as used in the robotic industry. X, Y, Z and pitch, roll, yaw.

    1. I know those terms well. I led a team that developed a pick and place robotic system that had an accuracy of 4 um ( microns ) and a precision or +/- 1 um. It was used to place thin film wiring layers onto a ceramic substrate to make high performance multi-chip modules for IBM’s big mainframes back around 1990. Great fun when we were doing it. Budget for the program was $750K. Of course $750K was a lot more money in 1990 than it is today. About all you can get for $750K today is a pair of Magico M9 speakers! 😉

      1. That is incredible accuracy! I have several pick & place (aka mounters) from Universal Instruments that has a motor accuracy of 1 micron. Effective placement accuracy is around 11-20 microns which is still one half the thickness of a human hair. Effective speed is 20-30k items per hour. With dual mounting heads and other features they cost me around 250K each (three years ago USD). They will place 01005 but the smallest I’ve done at scale in 0201.

        1. Tim, If I understand correctly you are doing PCB assembly where you are using industry standard body sizes and your volumes are high.

          We had thin fill circuit layouts that were 100 mm square ( 4″ x 4″ ) that were adhered to a very ridged frame. We use dual chevron patterns in each corner and custom alignment software to optimize placement. Obviously, high quality optics and the thing that made it all possible was a proprietary air barring “hand” that was internally designed and built at our research center on the arm of a stock robot. Thru-put was about one unit every 5 to 6 minutes. Totally different ball game than what you are doing.

  12. Paul? PAUL? Is that you talking ‘single point’ stereo? Say it ain’t so ! ((O: Did my personal emailings and conversations with Scott and other’s at PS audio have influence? Or, was it my continuous ‘badgerings’ on the Octave records youTube channel and HERE that got you thinking about FINALLY considering a TRUE STEREO ‘live’ recording? (all in good fun)

    What ever it is or was, I look forward to see what Octave can do with the tried and true recording technique which was once so popular, and all but abandoned. You got the microphone, now lets see how Octave will run with it (O:

    ……….Thanks for the ray of hope.

  13. Before there were stereo mics there were mono mics. Pop and jazz singers sang into mono mics for radio and for recording. Bing Crosby supposedly popularized what became the standard mic technique of working very close to the mic. Stereo came along in the late ’50s, but in short order recording engineers were back to using mono mics. Pop singers had for decades been happier singing at close range into their own mic.

    1. Right, but that makes no sense. That was my point. There are tons of excellent single body stereo microphones. From a singer’s perspective it’s the same. From a listener’s perspective it’s night and day different.

  14. It helps when you have an artist like Frank Sinatra who has mastered the technique of using varying proximity to the microphone to convey emotion. No one has done it better.

  15. Hi Paul, greetings from Montevideo, Uruguay.

    From what I understood from your article, the idea is that the recording sounds as close as possible to what our ears hear in a live performance. I’m right?

    In that case, how should electric instruments such as guitar, bass, and keyboards be recorded? Placing the mic in front of the speakers of the amplifiers (Fender, Marshall, VOX, etc.) as if it were our ears, or with line cables direct to the console?

    Another question. Are stereo mics the same as binaural mics?

    Regards, Fernando.

    P.S. I’m a spanish speaking person. So, sorry for muy poor english.

  16. I hope you’ll consider recording more classical chamber music. It’s perfectly suited to your recording philosophy and techniques, and — at least in summer — you’d have plenty of first-rate players to choose from.

  17. Paul, you wrote:

    “For example, how did the recording industry settle into the idea of using mono microphones to record solo voices and instruments?”

    Answer in my humble opinion: because it simply improved the recorded performance. It places the solo voice front and center, where in most cases it belongs. Yes… it may sound recorded but I would prefer that vs listening to head movement in a multi or stereo mic set up. Agreed, maybe more authentic, but will have to listen to a stereo solo voice recording to be convinced it’s not overkill.

  18. Intuitively and experimentally, stereo mics sound more real. We normally hear an instrument or voice with two ears. Each ear captures a portion of the sound field. Just plug one of your ears and ask yourself, does it sound the same? Of course not. The sound field, especially the parts created by the upper harmonics is complex and varies perceptibly in space. With just one channel you are missing a lot of information that helps define the character of the instrument or voice. Maybe you would not hear a difference with a pure tone, but there are few pure tones in real life.

  19. I’ve long felt that audiophiles were missing out by only concerning themselves with playback. You can only reproduce the recording you’re playing back, and there’s a lot of very badly engineered recordings out there. Frankly, I think the classic “Kind of Blue” recording is dreadful, from the standpoint of how it was engineered in the studio. Paul Chambers sounds like they put him down the hall.

    Garbage in -> garbage out.

    I’ve been doing location recording for 40 years. Nowadays it’s mostly my wife’s string quartet. I get to bring it back live and hear at home what I first experienced live.

    I don’t have the budget of a recording label, but I do get very good results. S’matter of fact, proper use of very inexpensive equipment can still bring very enjoyable results.

    I run a pair of modified Oktava cardiod mikes in an ORTF configuration. I invite y’all to visit a web page I put up with a recording of the Dvoark Piano Quintet in A Major. There’s a photo on the page showing the performers and the microphones.

    The tracks are all the original 24/96 resolution. I use a Focusrite Clarette USB audio interface feeding a laptop PC.

    The piano player chose to not open the lid on the piano, fearing that he would over power the string players, but I feel he was mistaken. This microphone technique only records the performance as it was. I can’t “fix it in the mix.” Still it’s quite enjoyable.

    http://temescalquartet.com/Dvorak_Piano_Quintet/

    I encourage y’all to get a pair of decent microphones, a USB audio interface and a laptop PC, go out and bring it home live. It’s shocking at how good of a recording you can do with inexpensive gear.

    1. Man after my own heart! Thank YOU! I have been on the LIVE, TRUE STEREO band wagon for years. You can find my comment to Paul up the list a bit. Seems my messages to Octave personnel have made it through?

      I will GLADLY check out your recordings, as I have used the ORTF scheme for a number of years. I am ‘cheating’ a little now with a single point MS mic of good quality and record straight into a ZOOM H4n at 24/96. I recorded a college symphony orchestra (70 musicians) with an historic Skinner organ we maintain. FANTASTIC!

      Anything MORE then 2 channels is NOT stereo! Thanks for your dedicated, stereo principal approach to live performances.

      1. I wish more audiophiles would investigate location recording.

        People drop enormous sums on cables, power conditioners and any number of things that aren’t even in the signal path. Even the very best playback systems are only half the audio chain.

        When you bring it home live, THEN you get to know just how good your rig is.

    2. Hello Russ. JUST listened to your recording, now THAT is what I am talking about! Nice intimate setting, the acoustic of the room and all. I DO agree that with the strings closer to the mics, you could have suggested ‘half’ stick on the piano to give it a bit more presence.

      Very fine playing here!

      Interesting, as in a full orchestral recording, the piano (in this case), like the brass section, show off the room acoustics due to there further distance from the mic there by breathing into the space.

      Thanks for supporting true live stereo recordings! They are rare today (O:

      1. Before I got the Oktava mikes (modified by Michael Joly), I ran a pair of Behringer C2 condensor mikes for years. They are the very most low-cost mikes that money can buy. I think you can still get them from Sweetwater for $49/pair! Incredible.

        Here are some of the recordings I did with them. Not quite as nice as the Oktava, but good enough to impress the heck out of a lot of people who didn’t know how low cost my mikes were.

        My own favorite tracks are those of the Ravel String Quartet.

        http://temescalquartet.com/audio.html

  20. Not all engineers. When 24 track tape machines came out, Bruce Swedien (Quincy Jones, Barbara Streisand, Paul McCartney, Michael Jackson) said “Ooh! A twelve track stereo recorder!”

  21. You are right, Paul. Recently I acquired a recording of a violin concerto by a renowned violinist and the violin was recorded not only near but louder than the orchestra. So much, that I had lower the volume and certain sections of the orchestra could not be heard. Terrible. I compare that with the DECCA recordings of long ago, the RCA two and three mikes, the Mercurys by the Fine wife and husband team, and others of such times and they had everything : clear, dynamic, lots of air, soundstage. These days there are some recording companies that record without too many microphones and they sound great. Keep up the good work!

    1. I can not stand that ‘effect’ (when a solo instrument is mixed LOUDER then the whole ensemble!) Orchestral music is composed so that a solo violin/flute/woodwinds in general CAN be heard over the accompaniment of full orchestra. A TRUE stereo recording will reveal this, it’s the way it was dynamically written into the score!

  22. I do this all the time on instruments, often using M-S mics. I’ve seen some engineers do it on vocals too. I agree – it can add a 3-demensional quality. It can also amplify minor head movements, which can be distracting.

  23. “That movement… (left, right, forward, backward, up, down) is perfectly captured by a stereo microphone. It is completely lost with the industry-standard mono microphone technique.”

    That’s not entirely true. A mono mic will capture forward and backward movements the same as a perfectly aligned stereo mic (neglecting stereo room reflections). Several years ago I transferred a bunch of 78 RPM (obviously mono) records from the 1940s and was surprised by how much front to back imaging there was, because the musicians were actually placed in the room that way, and recorded with just one mic.

    Also, a stereo mic won’t “perfectly capture” up and down movement. You need a soundfield mic for that.

    I was also surprised by how much musical dynamics those old mono recordings had. More so than most modern digital recordings despite the media having maybe 50 dB dynamic range on a good day! They didn’t use compression back then. Nowadays, most music is compressed to death, except for a small number of audiophile labels.

    I’m grateful that Octave Records is furthering the state of the art.

  24. Very interested to understand how you will do this in detail. Will you use only a single stereo mic or would you use multiple stereo mics arranged along the same axis at different distances?

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