It’s been nearly a week since PBS’ broadcast of the White House concert of music from the civil-rights era, and its sounds and images keep popping up in my brain.

Among the maladies to which music lovers are especially susceptible, hearing damage caused by prolonged exposure to loud sounds is perhaps the most pernicious. When you're young, you normally don't think about the consequences of cranking up the volume, but if you do that routinely, you are sure to suffer some form of hearing deficit in your later—or, in some cases, not so later—years.

Playback Designs was founded less than three years ago. However, with the release in 2008 of its MPS-5 Music Playback System—a slim, full-featured SACD/CD player and DAC that costs $15,000 and is built in the US—the company has since established itself as a significant player in high-performance digital audio.

Playback Designs was founded less than three years ago. However, with the release in 2008 of its MPS-5 Music Playback System—a slim, full-featured SACD/CD player and DAC that costs $15,000 and is built in the US—the company has since established itself as a significant player in high-performance digital audio.

Playback Designs was founded less than three years ago. However, with the release in 2008 of its MPS-5 Music Playback System—a slim, full-featured SACD/CD player and DAC that costs $15,000 and is built in the US—the company has since established itself as a significant player in high-performance digital audio.

Playback Designs was founded less than three years ago. However, with the release in 2008 of its MPS-5 Music Playback System—a slim, full-featured SACD/CD player and DAC that costs $15,000 and is built in the US—the company has since established itself as a significant player in high-performance digital audio.

Playback Designs was founded less than three years ago. However, with the release in 2008 of its MPS-5 Music Playback System—a slim, full-featured SACD/CD player and DAC that costs $15,000 and is built in the US—the company has since established itself as a significant player in high-performance digital audio.

Playback Designs was founded less than three years ago. However, with the release in 2008 of its MPS-5 Music Playback System—a slim, full-featured SACD/CD player and DAC that costs $15,000 and is built in the US—the company has since established itself as a significant player in high-performance digital audio.