6. A Fundamental Approach To True Stereo Recording Techniques

True stereo (two microphones in stereo mode) recordings have been adopted since the dawn of stereo, preceded by true mono. Before mixers and gadgets took over with the beginning of electronic manipulations (recording) music was live. It was only through the invention of multi-track recording that music was performed outside of real time. 

When people listen to music for pleasure as apposed to dissecting the material as recording engineers do, the sound is more in relation to the emotional content of the musical performance. Having a good recording may not be the most critical criteria. As we evolve the playback capabilities the quality of the system will appear to make bad recordings sound worse than when played on a budget system, in reality we are more aware of their deficiencies. Playing well-recorded minimal microphone tracks on these systems will on the other hand advance their qualities.

The concept of True Stereo at first glance may seem quite simple, and in today’s modern world, almost primitive, but in truth the complexity and proper its setup is more critical because later manipulations are limited, making it a more perilous task.

There are endless possibilities in the context of any one project yet the ability to get it right may at first seem constraining to the recordist. The knowledge gained through experience is most important here. Thinking outside the proverbial box is of the essence. When we record with multiple microphones we manipulate the sonic input to achieve a desired result. Recording in True Stereo is about manipulating the space to derive these same intentions. Of course we are limited to live performance although editing will allow us to play with real-time. Capturing the information in True Stereo will give us the benefits of enhanced dynamic, harmonic and spatial realism, of course we are still limited by balance and time domain issues which must be considered at all times. When all is executed well the results can be startling as well as addictive.

As we approach any given assignment we must always consider the performers, and the most appropriate space to execute in, always attempting to get the maximum benefit of the total content. Working closely with the musicians is most important, explaining how the procedure is established is paramount. If they understand the basic concept our undertaking will be much easier and rewarding.

I have had the privilege as well pleasure to work with a wide array of musicians in many interesting venues. The experience gained has been critical to just comprehend the possibilities that are obtainable. Every experience has added to my personal knowledge of this craft. Allowing one to be open to all possibilities and practical solutions to various problems will help establish the parameters we need to set.

ORTF (Near Coincident)

The use of the ORTF method has quite a few practical advantages in True Stereo recording. This near coincident technique affords not only a reasonably accurate acoustic geometry and open spatial quality, but also the ability to subtlety space and angle, much like changing the positions of our inner aural senses. In other words we use our own sense of hearing to be our guide. Our ears work more like cardioids with directional frequencies above 700Hz, and slight movements will drastically change our hearing perspective, this is most similar to coincident techniques. There are some phase anomalies, mono compatibility issues, but these occur in the nature of hearing, we do not hear in mono.

I find that literally imagining my head floating in space in the precise position of acoustic harmony. This allows me to open up all sorts of sonic possibilities. Obtaining a spectral balance is often achieved by using your imagination. The use of room surfaces, employing risers, as well as baffling and of course simple positioning of the musicians involved.

The plan of attack is to start with the most (quiet) transparent instrument with in any given ensemble, and working out from this context. Isolating with risers and baffles are good places to start if needed. Creating a sonic picture is all about balance and reflecting the nature of the subject in an interesting way, which will always go far in making the end result to the listener more engaging.

Of course there are a number of other interesting near coincident techniques which are worth exploring; NOS, OSS, Binaural to mention a few.

XY (Coincident)

There are times when either mono compatibility is paramount or the desired results depend on limiting the use of spaced of near coincident techniques. Focusing the sound to a specific space or recording at a distance where more spatial qualities are a determent could find near coincident recording advisable.

I find the sound somewhat narrow but practical considerations may sometimes exist and employing these methods will be of benefit. The uses of Figure eight or Blumlein have their own special qualities that are just as stimulating to the listener, perhaps even more dramatic. Yet I feel often times more limiting with their restricted positioning geometry.

AB (Spaced)

Offering perhaps the most open sound quality improved linearity of bass response with use of omni microphones and the ability to cover a wide spatial area. These techniques are useful in recording large ensembles that tend not to need more directional characteristics. They can give us a very accurate sonic perspective with these sorts of subjects. Careful placement can also give us very interesting results with smaller ensembles again giving us a very open sense of space on playback.

I tend to find the lack of fundamental thrust of sound or being a bit too overly harmonic to be a problem for my own set of preferences, but intended results achieved by these as well as all other minimal microphones techniques are what the recording engineer must always keep in mind.

Recording in True Stereo is not always practical or at times possible, but the knowledge of such practices will only enhance our basic microphone positioning skills. As well as helping improve our ability to develop sonic landscapes.

Ken Christianson, Pro Musica, Chicago

posted on: 2011/09/14
* 12. True Stereo in Perspective
* 11. Room & Boundary Effects for Playback Systems
* 10. Instrument Positioning & Room Manipulations
* 9. Choosing a Space-Acoustical Considerations
* 8. Troubleshooting True Stereo Sound
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