The Prepared Piano Plug-Ins by Prosonus

Prosonus Prepared Piano is a sample library / virtual instrument based on sounds produced from a prepared piano a traditional piano altered by placing objects between or on the strings, hammers, or other parts to create unconventional, metallic, percussive, and otherworldly timbres.
The library focuses on experimental and sound‑design‑oriented material, making it especially useful for film scoring, soundtracks, ambient textures, electronic music, and cinematic effects rather than purely traditional piano performance.
The sounds retain an organic acoustic quality since they originate from a real acoustic instrument, but due to the preparation techniques used, many patches sound radically different from a standard piano offering eerie scrapes, ambient drones, percussive hits, warped harmonics, unusual clusters, and unique tonal textures.
This library is ideal for composers and sound designers looking for distinctive, cinematic, and experimental piano‑derived sounds that can function as both musical layers and sound‑effect sources.
A detailed instrument count (e.g., number of samples/multisamples) isn’t always published officially, but independent product reviews describe dozens of individual instruments and layers derived from the sample set.

Specs:

Source Instrument: Prepared piano with various objects inserted/manipulated on strings and hammers to create altered timbres and unusual resonances.
Eerie scrapes and death scrapes
Low ominous drones and whale‑like moans
Percussive hits (log drums, wood thunks, piano kick‑type sounds)
Tuned and untuned melodic/percussive tones
Mechanical and space‑age textures
Clustered piano tones and warped harmonics
Articulation Types: A mix of percussive and tonal elements rather than traditional velocity‑layered piano note samples.
Instrument Count: The library contains multiple unique instrument patches derived from the prepared piano samples (e.g., Log Drums, Mutant Banjo, Power Harp, Woodblocks, etc.).

Formats:

• The Prosonus Prepared Piano library has historically been distributed through Big Fish Audio in downloadable sampler‑ready formats.
• Common formats you may see depending on the release and download options include: GigaSampler / GigaStudio (standalone sampler format)
• Stereo sample libraries (often delivered as .GIG files containing all content in stereo and mono versions)
• Other compatible formats are typically available with Big Fish Audio products, though specific bundled formats vary by purchase option:
• WAV / multi‑format exports
• EXS24 (Logic Sampler)
• Kontakt (requires full version)
• HALion / UVI / Maschine etc.
• Loop and Grooves formats (REX, RMX, Apple Loops, etc.) when offered in multiformat pack releases