Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
The event occurred almost immediately after climbing through 10;000 MSL to a higher ATC assigned altitude.  I heard what I would describe as a moderately loud 'poof' sound.  The aircraft lurched a bit and there was a definite vibration.  In a few seconds I smelled a somewhat noxious and certainly unusual odor.  The Captain called out the abnormal indications on the EICAS which included the left engine's N2 vibe icon and red ITT indications.  The vibration was reduced by retarding the left thrust lever.  We referenced the QRH and the Captain and I decided against a full shut down given the EICAS indications and that the vibration was very insignificant at about idle.  The Captain informed Dispatch and the Flight Attendant of our return.  ATC was advised of our need to return and an emergency was declared.  We landed safely and without further incident.  We promptly got the passengers off the airplane at a gate.
CRJ-200 First Officer reports a compressor stall climbing through 10;000 feet that results in high N2 vibration and high ITT.  The thrust is reduced to idle and the flight returns to the departure airport.