Stereo Miking vs. Mono Miking (of soloists/spots)

In light of the endless debates about whether or not to use stereo miking for soloists and, in some cases, multiple musicians in small ensembles, I’ve been trying to wrap my head around the topic. I wanted to present why I feel that stereo miking for soloists—and, in certain cases, several musicians in an ensemble—suits my taste better. And it is also the approach on many of the great (and awards winning) recordings. It might be a long read, but I really tried to capture the idea!

Stereo Miking vs. Mono Miking

Stereo Miking:
- Why?
  Stereo miking creates a sense of space and depth by capturing the spatial characteristics of the instrument in the room. It gives the listener a more immersive experience and a “dimensional” sense of the performance.
  - For a soloist, stereo miking allows the sound to spread naturally across the stereo field, simulating how the instrument might be heard in a real space. For example, the left and right microphones might pick up slightly different tonal colors, reflections, or timbral details due to the physical placement of the performer in the recording space.
- Why Not?
  Stereo miking requires careful microphone placement to avoid phase issues and overly wide or unnatural imaging. It’s often unnecessary in dense mixes or when the focus is purely on clarity and punch (like in some pop or rock recordings or some “broadcast” classical/cross-over).
Mono Miking:
- Why?
  Mono captures a focused, direct sound that can be easily placed in a mix without spatial complexity. It’s great for simplicity and control when you don’t need the spatial spread.
  - For soloists or featured instruments, mono may work well if the recording space doesn’t add desirable acoustic properties or if you want to keep the sound “tight” and centered.
- Why Not?
  Mono doesn’t provide depth or natural width, so the sound may feel flat or one-dimensional, especially in acoustic genres that thrive on spatial realism.

Why Use Stereo Spot Mics for Soloists, Even with a Stereo Main Pair?

Focused Detail on the Soloist’s Performance:
- Main Pair (AB or other stereo configurations) captures the overall sound of the ensemble or room. This provides space and depth, which is crucial for the “big picture” of a performance.
- Spot Mics are placed closer to the soloist, which allows for finer detail and clarity in their playing. This is especially important for soloists who may need to stand out in the mix without being overwhelmed by the room sound or other instruments.
  - For example, a violinist or vocalist will benefit from stereo spot mics because they can capture both the tonal richness and the nuances of vibrato, phrasing, and articulation. The main pair might pick up some of these details but will lack the intimacy needed to truly showcase the soloist’s performance.
Balance Between Ensemble and Soloist:
- A stereo main pair provides the spaciousness and balance of the ensemble sound, placing the instruments in a natural context within the room.
- However, if you rely solely on the main pair for a soloist, they might get lost or sound distant due to the broader perspective of the main mics. Spot mics placed close to the soloist maintain intimacy and definition, ensuring they stand out clearly against the ensemble while preserving the natural room acoustics.
  - This allows the soloist’s sound to cut through the mix in a way that respects both the acoustics and their individuality.
Spatial Control and Flexibility in Mixing:
- Having stereo spot mics gives you more control in the mix. You can blend the soloist’s sound to match the overall spatial ambiance created by the main stereo pair.
  - For instance, if you want a more “intimate” feel for a piano solo, you can turn up the spot mics while maintaining the wider ensemble sound through the main pair.
- Spot mics also allow you to adjust the balance between the soloist and ensemble in post-production, ensuring that the soloist is never buried but still remains within the overall acoustic space.
Capturing the Subtle Elements of Performance:
- Soloists, especially in classical, jazz, and acoustic music, often produce subtle changes in dynamics, phrasing, and tonal quality that are difficult to capture with only a distant main pair.
  - The close stereo spot mics (e.g., one on each side of the soloist, placed around 30 cm apart) can record the tiny variations in sound from the instrument that might not reach the main mics as clearly, such as the expressive change in bow pressure on a violin or the variation in air on a trumpet.
Creating a Natural Interaction Between the Soloist and Ensemble:
- By using spot mics in stereo, you preserve the natural perspective of the soloist as though they are speaking directly to the listener while still capturing the surrounding sound from the ensemble. It ensures that the soloist doesn’t sound too artificial or “separate” from the group.
- The stereo spot mics add depth and dimension to the soloist’s sound without losing the intimate relationship they have with the room and the other instruments. This is much harder to achieve with a single spot mic, which can lack depth or result in too much emphasis on one frequency range.

Summary

In essence, stereo spot mics on the soloist enhance the clarity, presence, and definition of the individual performer while allowing the main pair to continue capturing the broader acoustic space and interaction. It’s the best of both worlds: detailed, intimate representation of the soloist, combined with the natural ambiance and dimensionality of the ensemble. This approach adds flexibility, allows for a more nuanced final mix, and ensures that the soloist remains present and vibrant without being disconnected from the ensemble’s sound.

In short, stereo spot mics complement the main pair by giving you control over individual detail while maintaining the holistic soundscape created by the broader stereo miking.

Double Bass with Two Microphones: Spaced AB vs. One Up, One Down

Spaced AB (Stereo Pair)

Why?
Two microphones spaced apart create a stereo image, giving a sense of the instrument’s width and allowing the resonance and detail of the double bass to come through. This setup captures both the direct sound and some room ambiance, providing depth.
- Example: A spaced AB pair (omni or (wide)cardioid) around the bass body can emphasize the “woody” resonance of the instrument while also capturing the movement of the bow or fingers.
- Stereo AB adds realism, making it ideal for natural, acoustic contexts like jazz duos where the interaction between instruments is crucial.
Why Not?
This setup can introduce phase issues if the mics are too far apart or poorly positioned. It also requires careful monitoring of stereo balance, as the spread might become too wide if overdone.

One Mic Down, One Mic Up

Why?
This technique places one mic near the body (for warmth and resonance) and one near the fingerboard (for articulation and definition). It’s not inherently stereo but allows blending to create a more complex, full sound.
- For instance, blending the two can balance the “thump” of the body with the “buzz” or “zing” of the strings, offering control over tonal characteristics.
Why Not?
Since this setup isn’t inherently stereo, it doesn’t add spatial depth. Additionally, improper phase alignment between the two mics can muddy the sound.

Which is Better in a Jazz Duo?

For stereo imaging and an immersive acoustic experience, I would go with the spaced AB approach. It makes the double bass “breathe” in the mix, complementing the other instruments in the duo.
For focused tonal control, the one up, one down method allows greater flexibility for highlighting specific sonic aspects of the double bass and might be better in louder and more busy groups

In either case, the room acoustics and mic choice (omni, cardioid, ribbon, etc.) play a crucial role in the result. For jazz duos, where space and interaction are key, stereo miking often enhances the organic interplay between the musicians.

To recapitulate the ideas why I started using (and why I mostly prefer it on recordings of others) the stereo micing of soloists:

1. Enhanced Spatial Realism

Stereo miking provides a more natural spatial image of the soloist or musician within the recording environment. This is particularly effective for acoustic music where the sense of space and ambiance is essential. For example:

A soloist recorded in stereo feels more “anchored” in the acoustic setting, with a sense of width and depth that reflects their physical presence in the room.
When using a single mic, the soloist can sound “flat” or disconnected from the environment, as it lacks the stereo cues that listeners associate with a live performance. (and you can only simulate that with adding artificial reverberation)

2. Preservation of Subtle Nuances

Stereo miking captures fine details of an instrument or voice that might otherwise get lost:

Instruments like a grand piano, a kaval, or a double bass have complex tonal and spatial characteristics that benefit from stereo miking. For instance:
- Piano: Stereo miking highlights the range from low to high notes and the physical size of the instrument.
- Kaval (or other wind instruments): Stereo techniques can reveal subtleties like breath noises and the interaction between direct sound and reflections.
It also allows for more precise reproduction of how the sound interacts with the recording space.

3. Support for Modern Listening Preferences

Today’s listeners, especially those enjoying classical or acoustic music, are accustomed to high-quality stereo playback systems. Stereo miking helps:

Offer recordings that translate well to stereo systems without sounding artificially “mono” or overly dry.
Maintain a sense of intimacy and immersion, even in small ensemble settings.

4. Greater Flexibility in Post-Production

Stereo tracks give more options for mixing and balancing:

With a stereo track, you can retain the depth and realism of the performance while still managing how much the soloist “sits” in the mix.
Even if you prefer a slightly mono-ish focus in the final mix, a stereo recording gives you control to blend the two channels to taste.

5. Aesthetic and Emotional Impact

A stereo image allows listeners to feel the “movement” of the musician, particularly with expressive performances. This sense of physicality can enhance the emotional impact of the music.

Counterarguments and Situations for Careful Application

Of course, stereo miking isn’t always the best option, and understanding these counterarguments can help “defending my choices”:

Phase Issues: Stereo miking can introduce phase inconsistencies, especially when combined with other ensemble mics. Careful placement is critical.
Complexity in Setup: In small ensembles, stereo miking for multiple musicians might introduce clutter, but when done carefully, it can enhance the overall soundstage.
Overly Wide Imaging: If the stereo mic setup isn’t well-calibrated, the soloist’s image might become unnaturally wide or diffuse.

When Stereo Miking Shines for Ensembles

While stereo miking every musician in an ensemble may not always work, there are specific situations where it is highly beneficial:

Close Collaboration with Performers: Stereo miking can capture the intimacy and dynamic interplay between musicians, especially in improvisational or chamber music.

Small Ensembles (e.g., piano trio…): Stereo miking key players ensures each instrument has its own depth and space.

Diverse Instrumentation: Instruments with contrasting tonalities (e.g., kaval, double bass, and piano) often benefit from stereo miking to preserve their unique sonic character and interaction within the ensemble.

Since I am currently in the midst of a project with a double bass player—a sort of “world music/jazz/improvised” duet—and recently had an “interesting” exchange with a sound engineer at a festival, I wanted to gather more thoughts on this topic.

The engineer couldn’t understand why we wanted stereo spaced AB miking on the double bass and tried to convince us to use XY instead (if we must insist on “stereo” on a “mono” instrument – he also feared phase issues). He also argued that, since the bass is a vertical instrument, it would make more sense to at least position the two mics vertically. While his questions have some validity, I’d like to explain what we are aiming for in greater depth. Here’s my detailed answer:

Why a Double Bass is Vertical (Physically and Acoustically)

A double bass is a vertical instrument, so positioning microphones vertically—one at the body and one at the fingerboard—makes sense for capturing its different tonal characteristics.
- The lower body produces the deep, resonant, “woody” sound.
- The fingerboard and strings contribute the attack, articulation, and definition.

This approach aligns well with the idea of “vertical miking” for tonal balance. But it doesn’t account for stereo imaging, which is where AB (spaced pair) shines.

My response to that particular FOH engineer would be (at the time it was – “just do what feels/sounds good to you, and only DI sounds in monitors, please” 🙂 – He let us set-up our spaced pair of CM3s, but I have no idea what was used in the mix – people were enchanted, small venue, half-acoustic sound, anyway):

“The bass might be vertical, but sound doesn’t just shoot up and down—it radiates outward in all directions. A horizontal AB setup captures the whole sound field: the vibrations, the overtones, and the room reflections that make the bass sound alive. It’s not about matching the shape of the bass; it’s about how sound moves in the space. XY, on the other hand, can feel small because it’s too narrow for a big instrument like a double bass. AB lets the sound breathe naturally, giving the bass the depth and width it deserves in the mix.”

Why AB (Horizontal Spacing) Works for the Whole Bass

Horizontal placement captures the entire bass, not just a slice.
Even though the bass is vertical, the sound radiates in all directions, not just up and down. The soundboard vibrates as a whole, and the air it pushes radiates outward. Placing two microphones horizontally ensures you’re capturing the full spread of these vibrations, including overtones and room reflections.
- Example: If you place one mic on the left side and another on the right side (spaced AB), you’ll get the natural blend of body and string sounds along with the instrument’s interaction with the room.
AB provides natural stereo width.
The goal of AB isn’t just to capture the “verticality” of the bass but to create a realistic stereo image that places the instrument spatially in the recording. Horizontal spacing mimics how our ears hear in a room, offering width and depth that align with the listener’s perspective.
AB balances depth and realism.
With AB, you get a wide but balanced stereo image, where both microphones contribute equally to the perception of the instrument. Vertical setups (e.g., “one up, one down”) might sound narrower because they don’t emphasize stereo spread.

I think our live recording below proves the concept well!

The song “Return to the Garden”, from our duo live performance

Why AB is Better than XY for a Double Bass

XY lacks width.
In XY, two cardioid microphones are angled closely together, with their capsules almost touching. While this technique avoids phase issues, it doesn’t create much stereo spread. For a large instrument like the double bass, XY can make the sound feel small and overly centered, losing the sense of space and dimension.
AB captures more room and instrument detail.
Spaced AB uses microphones placed farther apart (often omni or cardioid), which better captures the size of the instrument and its interaction with the acoustic space. This results in a richer, more immersive recording, especially in jazz or acoustic settings where the room plays an important role.
AB is more flexible for post-production.
The wider separation of microphones in AB allows for more creative control in mixing. You can adjust the stereo width or even blend one side more than the other for tonal balance. XY, being so tight, limits this flexibility.

I know I didn’t settle the argument once and for all, and I think the conclusion ultimately depends on individual taste and the circumstances of the session.

I would also include the response I got from Markus Heiland when asking about the recordings of the Gurdjieff Ensemble, specifically how much was stereo-miked, etc. Regarding the project, he mentioned that it was recorded in the great acoustics of the main hall at RSI in Lugano, which contributed to the overall sound. He said that Big AB was used, and that some instruments were so loud they didn’t need spot mics at all. He also added that he stops using stereo spot mics when the panning becomes “ridiculous.”

I hope all of this is helpful and informative. I’m also leaving it here for my own reference, so when I need to explain to another FOH engineer why we want a stereo spaced pair on the double bass, I can recall it! 🙂