In Turkey, children are accepted to conservatory music departments after fourth grade and fine arts high school music departments after eighth grade by taking a musical talent test. For students with high musical aural skills to know about their potential and be directed to the related education institutions there needs to be a valid test. This study was, therefore, conducted to develop a valid internet-based test to assess music perception of children with design-based research. Design-based research includes a series of iterative stages that involve continuous data collection, analysis, and improvement, rather than a linear process in development and implementation activities. Voluntary-basis selected schools in the pilot city's first through fourth grades (both public and private schools) were invited to join the preliminary test. A total of 433 students participated in the online test. The test has seven categories including pitch discrimination (single, two, and multiple tones), tempo, length, melody, and rhythm. For item analysis, two separate sequential samples were collected. The results were evaluated according to psychometric test development principles. The initial results show that the music perception test (AMAT) is a valid and reliable instrument. The test is open to public use and can be reached at: https://aummat.anadolu.edu.tr/amat/