Convolving a sound with the room's impulse response

Here is the sound as originally recorded (near the mic): mystery sound     sonogram

This is the sound after being convolved with an impulse response from the room (a clap was used for the impulse): convolved sound     sonogram

The most notable effects are an attenuation at higher frequencies (this is also very evident in the sonograms) and a humming sound (at roughly 60 Hz?).