We live in a 10-unit condo building with (mostly) wonderful neighbors, too, but there are always a few noisy tenants (and it's an older building, so the noise really carries!) so I definitely feel your pain!
Our noise policy includes specifications for "house hours" and then "after house hours."
Here is the actual policy from our House Rules:
• House hours are Sunday through Thursday 8 a.m. to 10 p.m., and Friday/Saturday 8 a.m. to 12 a.m.
• *Residents shall not play any musical instrument, radio, stereo, television, or cause any other noise at a level that would disturb any other residents.* Noise levels must be kept below 80 dB (vacuum cleaner sound level) during house hours unless previously approved by the board of directors.
• No one shall make any noises in the building or adjacent grounds that may disturb the occupants of other units after house hours. Noise levels must be kept below 40 dB (standard conversation voice level) after house hours.
• Residents are encouraged to inform other residents of any planned social gatherings within a unit or on the back deck that may result in elevated noise levels.
Determination of excessive noise levels during social gatherings is left to the mature discretion of the residents.