I looked back through your thread, and couldn't find a reference to me mentioning insufficient power.
It may have been in one of the links I provided, but I wouldn't know where to begin to look.
A bad or malfunctioning PSU is a possibility, how to check
Something else I thought of, did this start after
you arrived in Japan?
Excerpts from dv7 Manual | Section: Power Cord Set Requirements | Sub-section: Requirements for specific countries or regions
Requirements for specific countries or regions
Country/region Accredited agency - Accredited agency - Applicable note number
Japan - METI
3. The appliance coupler, flexible cord, and wall plug must bear a “T” mark and registration number in accordance with the Japanese Dentori Law.
The flexible cord must be Type VCT or VCTF, 3-conductor, 1.00-mm˛ conductor size. The wall plug must be a two-pole grounding type with a Japanese Industrial Standard C8303 (7 A, 125 V) configuration.
Operational power supplied by a Country other than where the machine was built for can cause a lot of problems.
But, If you, and your Father are living on base or "American soil" its possible because of agreements that your "Japanese" power is already being converted to "American". It can get rather confusing.
Try not to go the cheap route, worst case can be a fire in the device.
The METI link is a search there for Power Requirements.
The Beat Audio setting could be causing the noise, you will have to take the time to check different settings to troubleshoot.
Any device or its settings can be suspect.
It won't hurt to keep the DPC running.