MELISSA BLOCK, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Melissa Block.
MICHELE NORRIS, host:
And I'm Michele Norris.
Time now for your letters. And we begin with a correction. Last Friday, we discussed the dismissal of manslaughter charges against five Blackwater security guards. You may have heard us say the guards had been acquitted. In fact, as several of you pointed out, the guards had yet to be tried. A federal judge dismissed the charges, citing missteps by the prosecution.
BLOCK: A few of you wrote after hearing our story about compression in recorded music and what it takes to squeeze thousands of songs onto your iPod. Our co-host, Robert Siegel, talked to Andrew Oxenham of the University of Minnesota. He studies how the ear interacts with the brain. And Robert asked him where he stands on the debate over whether compression in MP3s reduces the quality of the listening experience.
Dr. ANDREW OXENHAM (Associate Professor, Psychology Department, University of Minnesota): There are really different levels of MP3 coding. You can go from much less data, which people can hear the difference, to higher levels of coding, which take up more space on your MP3 player, but sound better and are basically indistinguishable from the CD. And I would argue that under proper listening conditions, if it's really indistinguishable from the CD, as far as your ear is concerned, then you really haven't lost anything perceptually.
NORRIS: Well, Aaron Andrew Hunt(ph) of Charleston, Illinois, disagrees. He writes: That may be true for people who do not listen very well, but anyone with a keen ear can tell the difference no matter how high the encoding bit rate. He continues: When data is lost, the reproduction of the sound will not be the same. This is especially true for noisy sounds, like percussion instruments, which usually sound extremely unnatural when compressed by the MP3 algorithm.
BLOCK: Finally, Robert Siegel's interviews last week about warranties prompted a number of you to write. Robert spoke with a behavioral economist, who suggested that purchasing a warranty is essentially just buying piece of mind. He also spoke with the chairman of a company that sells warranties on behalf of retailers such as Kmart, Target and Wal-Mart.
NORRIS: Well, Amy Masick(ph) of Yorktown, Virginia, thinks we missed a pertinent question. She writes: Why should we need them at all, especially on items considered durable goods, a term which has now become an oxymoron due to pervasive shoddy workmanship? It is disgusting that the purchase of a $1,000 washer should immediately be followed by the question: And would you like to buy an extended warranty for this machine?
BLOCK: Meanwhile, Andrew Williams(ph) of Chicago was disappointed we didn't speak with customers. He writes: I'm in the middle of a three-month long battle to get Target to honor the three-year extended warranty I purchased on an MP3 player, and I'm continually ignored by the service line.
NORRIS: Well, want to get our attention? Go to npr.org and click on contact us at the bottom of the page. We read some of your letters on air several days a week.