Polifonia is driven by 10 pilot studies1 that interact with and address the preservation, management, and study of musical heritage (MH)2. Focused on real-world music cases – such as Italian bell heritage, organs in the Netherlands, access to musical heritage for deaf people, and the identification of recurring melodic patterns – these pilots provide a means to validate Polifonia’s computational solutions; to strengthen the project’s outreach; and to integrate new scenarios, early-adopters and stakeholders. They are developed by interdisciplinary teams of researchers from the humanities and social sciences, and from computer science. This deliverable focuses on the mid-term validation of the four pilots that deal with the study of musical heritage: Tonalities3, Tunes4, MusicBo5, and Child6. It is a first step in the pilot validation process which will culminate in the D1.8 deliverable at the end of the project at M407. The main objectives at this stage are to a) present the individual pilot’s validation protocols; b) apply these protocols and present the results obtained so far; and, c) identify the lessons learned from the mid- term validation and address the avenues to be developed, strengthened, and reconsidered in view of the final validation. The validation protocols were designed on the basis of a shared validation framework8 developed in connection with WP5 and presented in detail in the second version of Polifonia’s socio-technical Roadmap at M18 (D1.2)9. This validation framework aims to ensure that: O1: The pilot objectives reflect concrete needs expressed by the target communities and contribute to the state of the art; O2: the methods and approaches are sound; O3: the data on which the pilots are based are of sufficient quality to achieve the desired objectives; O4: the objectives and results expressed are achieved; O5: the resources, methods, and tools provided are made explicit and integrated into the Polifonia Ecosystem, interconnected through the PON and conveyed through the Web portal. The Validation framework is modular in nature. It includes core criteria with which all pilots must comply and specific validation methods for individual pilots or pilot groups.