A grand piano offers an extensive dynamic range from pianissimo to fortissimo, varied substantial tonality, and deep resonance with its 88 touch-responsive keys, long horizontal strings that extend away from the keys, large horizontally-mounted sounding board, and pedals for changing the volume and tone as well as sustaining notes.
This acoustic, stringed instrument comes in three sizes: the baby grand which is around 4 feet 11 inches (1.5m), the parlor or boudoir grand which ranges from 5 feet 7 inches to 7 feet 3 inches (1.7 – 2.2m), and the concert grand which is the largest at around 7 feet 3 inches to 9 feet 10 inches (2.2 – 3m). The longer the strings are, the richer the sound and the lesser inharmonicity of the strings, which translates to a significantly reduced “harshness of tone.” In this regard, the concert grand piano has that exceptional sustaining tone quality, which is why it is the musician’s choice for a concert hall performance.
Capturing the full versatility of expression and natural timbre of the grand piano would require not just the skills of the pianist but also the acoustics of the room, the quality of equipment for recording, the type of microphone used, mic positioning, and other factors that should be taken into consideration such as when playing solo or with a band and the genre of music played.
Things You Should Know Before Miking Grand Piano for Live Recording
Recording sounds coming from an instrument as powerful as the grand piano can be challenging. Great care should be taken in choosing the type of mics used, and in order to do so, it is important to know the quality of sound produced by the piano. The frequency range of a grand piano with 88 keys is 27.5 Hz (A0) to 4,186 Hz (C8). Changing the dynamics is dependent on the force used to strike the keys and will affect tone quality or harmonic content. When the key is struck gently, it will produce a soft sound because it has fewer higher harmonics, but when it is struck heavily, it will produce a louder sound because it has many higher harmonics. Softer notes will sound a little dull while louder notes sound brighter.
As the dynamics change, the tone quality from bass to treble also changes. The bass part of the piano has 50-60 harmonics (5,000 Hz), the middle region has 20 to 30 harmonics (7,000 Hz), the treble part has less than 10 harmonics (10,000 Hz), and the highest couple of notes have one harmonic. The bass notes will sound full and rich, while the treble notes will sound thin and weak.
Types of Microphones Used for Miking Grand Piano Live
Microphones vary on how sensitive it is to sounds coming from different directions or angles about its central axis.
1) Condenser Cardioid Microphone
It is great for studio recording as it can pick up a large frequency range, has a good response to short, high-level peaks or transient peaks, and is sensitive to loud sounds. With cardioid mic, it can best capture sounds coming from the front, not so much from the sides, and totally rejects the sounds coming from behind it; its sensitivity pick-up pattern is an upside‑down heart‑shaped or apple-shaped pattern.
With the lid of the grand piano open, you can put two condenser cardioid mics 11 inches above the strings and directed downwards, and make sure they are far apart, so phase alignment is properly maintained. Keep in mind that when it is close to the hammer action, the sound gets brighter while moving farther away will decrease the brightness. Another technique you can use is placing one large-diaphragm cardioid mic inside at the rounded end of the piano’s body for the smoothest and richest sound. You can also use two small cardioid condenser mics three feet from the piano and five feet above the floor for a more natural piano solo sound.
2) Boundary Microphone
It is a small-sized omnidirectional condenser microphone with the diaphragm placed parallel to the surface, so it will pick up the vibrations from the sounds reflecting off the surface it is mounted to. It will record the audio coming from all directions or sides of the microphone with equal gain. This boundary mic can capture sounds from multiple sources and in reverberant rooms.
The mics can be placed inside the grand piano on the underside of the lid. To get a balance between the bass and treble strings, you can use two mics. Please ensure they are secure so that with the lid closed, there is no danger of mics falling off onto the strings. It is also advisable to use a layer of foam or anything to avoid picking up the mechanical sounds from the hammer key action.
3) Contact Microphone
This mic can sense and pick up vibrations directly from the surface through contact to detect low-level sounds. Its contact plate is placed on the vibrating part of the musical instrument. Double adhesive tapes are used to secure the mic. The background noise would not be a problem because it essentially records only the instrument to which it is attached. It is almost insensitive to vibrations in the air, so it is perfect for recording in a challenging or less than ideal environment. Keep in mind that is has none of the reverberation that other mics have.
It is quite easy to amplify sound with this one; however, if the pedals or the key’s hammer action is noisy, there is a chance it might be picked up.
Guidelines on Miking & Recording Live Grand Piano Playing
Microphone Positioning & Placement
Knowing the structure of the grand piano that you are going to amplify or record is important in where and how the mics should be placed. Once you know what each type of mic is good for, it will help you position them inside or outside, depending on what would deliver the best results. Closing the piano lid is good for isolating the sound.
Playing the piano and positioning the mics at different distances from the acoustic instrument should be done in order to determine which one would deliver the kind of sound that you want. Record and take note where the mics are so you can evaluate properly.
Every mic and piano are different. I would suggest that you can walk around the piano with the opened lid while the piano is playing. And try to listen to the piano with only one ear with other ear been covered up to find the sweet spot for placing sweet spot for miking the grand piano. Try to record the live grand piano playing from the spot sweet you found and test the audio quality to verify it.
Room Acoustics
The acoustics of the room where you are going to record playing the grand piano is an important factor to consider and evaluate as it will affect the quality of the sounds produced and recorded. Room acoustics is basically how sound propagates or behaves in a closed or semi-closed space. The elements that come into play include the source of the sound as well as the receiver, the structure or geometry of the room, and the material of the wall and the floor. This means that every room would have different acoustics.
Concert halls are perfect for playing the grand piano as it is specifically designed to enrich the sounds or music. Reverberation time is the most used parameter for room acoustics, and a concert hall has 0.9 to 1.3 seconds at 500 Hz. If you are playing the grand piano in a place other than the concert hall, you should check its acoustics so you know the quality of sound that you will get and what type of mic you should use.
Playing the Grand Piano Solo or Playing with a Band
When playing the piano solo, it will be easier to make the necessary adjustments to get things right with the kind of mic used and its placement. However, when you have many instruments when miking for recording, it will be more complicated and challenging. The sounds from other instruments might bleed onto the mic that you are using for the grand piano. Closing the lid of the piano with the mic inside might help isolate its sounds from the rest. Look also into how unidirectional mics can help in miking the piano.
Genres of Music
The kind of music you will play on the grand piano should also be taken into consideration when recording as each genre might require a different location. Miking techniques would also differ from producing the best audio quality
Classical music might be suitable for a natural ambiance and will need two omnidirectional microphones in front of the instrument. With pop or jazz, the mics should be closer to the piano or inside it with one near the bass and the other near the treble side. Change the position of the mics, as well as its distance from the piano, will affect the timbre and ambient sounds captured.
Conclusion
Capturing the subtleties, nuances, and power of the grand piano will depend mostly on the type of microphone used, its placement, as well as the acoustics of the place. You can try different techniques to help determine which one can capture the best audio quality in order to give justice to the amazing sounds that only a grand piano can deliver. Take into consideration the different factors that can affect the recording so that you can cover all bases and avoid unnecessary problems.
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