On Wed, 10 Mar 2010 11:46:53 -0800 (PST), Robert Macy
wrote:

Need a sound recorder for recording noise intrusion from an adjacent
tenant.


Why? A recording would prove nothing. You need to measure sound
levels, not record the sounds. A sensitive microphone would pick up
the smallest of sounds so there would be no way to determine that the
neighbor's noise/sounds were a problem or not. As well, what does your
lease say on noise, and his? If it is not covered, prepair for a long
hard time.

Using Sony ICD-SX700 did not achieve very good results.

What should I use?

I'd use the threat of moving out at the end of my lease.