A leader in the development, manufacture, and world-wide distribution of electronic and electro-mechanical components and systems requested Sound Answers to understand/root cause a noise issue experienced which delayed the release of one of their product lines. Operating acoustic and vibration, static FRF testing, and sound quality measurements were made to determine objective parameters to discriminate between good and bad. The source-path-receiver model was applied focusing on frequency domain analysis to identify the key noise characteristics of the objectionable noise. Countermeasures to reduce the noise of concern were conducted from both the source side (DC motor Ð brush and commutator interaction), and also the path side (housing forces, acoustic cavity modes, modal alignment, and transmission loss). The recommendations made by Sound Answers were accepted by the customer, which helped direct their efforts at launching this product line with an improved motor design and a resolution to their noise concern.