The modern violin is engineered for projection, with a focused radiation pattern designed to carry over an orchestra. The Baroque violin, by contrast, speaks with a different voice and projects sound in a fundamentally different way. Its lower-tension gut strings, shallower neck angle, and lighter bass bar result in a less powerful but more complex and diffuse sound field. The instrument doesn't project sound forward as aggressively; instead, it radiates energy more uniformly, creating a fuller sound in the nearfield and interacting more intimately with the acoustics of the performance space.

This is compounded by the playing technique. The absence of a chin rest means the instrument is held more loosely against the player's collarbone, reducing the damping effect of the body and altering the instrument's vibrational modes. The resulting sound is less about raw power and more about nuanced color and resonance, a quality that close-miking can easily misrepresent by capturing an unbalanced slice of the spectral output.

The spectral signature of a Baroque violin is defined by the interaction between the gut strings and the period bow. The lighter, convex bow design encourages a different approach to articulation. It produces transients that are less aggressive than those from a modern Tourte bow, with a softer attack envelope that blooms into the note. This results in a sound that is rich in lower-order harmonics but has a delicate, complex high-frequency texture that can be easily masked or rendered harsh by improper microphone choice or placement. The goal is not to capture a bright, modern sheen, but the airy, textured sound of horsehair on gut. Therefore, stereo techniques like ORTF or spaced pairs positioned several feet away are often superior to close spot-miking, as they capture a more natural blend of the instrument's direct sound and the crucial early reflections that define its timbre.

The harpsichord is a machine for making music, and its sound is intrinsically mechanical. Each note begins with the sharp, high-frequency transient of a [{] plucking a string. This initial attack is broadband, percussive, and rich in inharmonic content. Immediately following this pluck is the resonant bloom of the string's energy transferring to the large soundboard, which acts as the primary acoustic radiator. Capturing both the transient detail and the resonant body of the instrument without one overpowering the other is the central challenge.

The mechanical action itself is a significant source of noise. The sound of jacks returning, plectra resetting, and the damper felts touching the strings creates a low-level percussive bed. These are integral parts of the instrument's voice, but placing microphones too close to the keybed or action can result in an exaggerated, distracting level of mechanical noise that is out of proportion with the musical tone.

The large lid of the harpsichord plays a critical role, acting as both a reflector and a barrier. When fully open, it projects the soundboard's resonance forward and upward toward the audience. However, it also creates a significant acoustic shadow. A microphone placed directly in front of the player, level with the keyboards, will receive a sound that is heavily filtered by the case, lacking the high-frequency detail radiating from the soundboard. Conversely, microphones placed too high above the strings may capture an overly bright, thin sound dominated by the plectrum attack and lose the woody warmth of the soundboard's lower-midrange resonance.

A common solution involves a spaced pair of microphones looking down at the soundboard from the side, past the lid's edge. One microphone is often aimed toward the bass strings and the other toward the treble, capturing a balanced stereo image. This placement minimizes the pickup of direct mechanical noise from the action while avoiding the lid's acoustic shadow.

Understanding the physical acoustics of these instruments is the first step toward capturing their unique historical character. The goal is to record not just the notes, but the complex interplay of mechanics, materials, and resonance that gives them their voice.