noise-cancelling headphones

[beaucham <beaucham@xxxxxxxxxxxxxxxxxxxxxx>]

When conducting listening tests in labs with significant
background noise due to computers, etc., it seems like
noise-cancelling headphones would be a good solution.
I see on Amazon the following items:

    Type              Cost    %sales
1) Bose               $299     63
2) Sennheiser PXC 250 $130     20
3) JVC HANC100        $150      5
4) Sony MDR-NC20      $106      5
5) Panasonic RP-HC70  $28       3

Are any of these suitable for listening tests? What are their
drawbacks?

Jim Beauchamp
jwbeauch@uiuc.edu