Experiment activity is an essential part of science learning. <em>Suling </em>(flute), a traditional musical instrument from West Java, can be used as a learning media for sound wave concepts. Technology-based mobile can be used as an experimental tool is <em>Phypox</em>. This study aims to report using a combination of <em>Suling</em> and <em>Phypox</em> in experiment activities. The designed activity aims to engage students in critical thinking. The instrument for measuring critical thinking consists of five questions based on the critical thinking aspect: interpretation, analysis, evaluation, inference, and explanation. The study used a one-group pre-and post-test design on 32 8th-grade students at one of the junior high schools in West Java Province, Indonesia. The study procedure is a pre-test, discussion of <em>Suling</em>’s concepts, introduction to <em>Phypox</em> application, experiment activity, presentation, and post-test. Data analysis uses the normalized gain to compare the pre-and post-test. Experiment activities help students to understand frequency, open organ pipes concepts, and investigate the speed of sound produced by <em>Suling</em>. The study found a significant change in the pre-and post-test scores of students after experimenting, so it could be interpreted that the experimental activities using <em>Suling</em> and <em>Phypox</em> affected critical-thinking students.