Engine sound processing apparatus

An engine sound processing apparatus, comprising:

• an engine sound signal generating section that generates an engine sound signal indicating an engine sound generated in an engine room of a vehicle;
• a signal processing section that includes:
• a reverberation effect applying portion which applies a reverberation effect to the engine signal;
• and
• a mixing portion which mixes the engine sound signal to which the reverberation effect is not applied and the engine sound signal to which the reverberation effect is applied to output a mixed engine sound signal;
• a reverberation effect controlling section that instructs the reverberation effect applying portion to apply the reverberation effect having a reverberation time set in response to a vehicle speed or a width of a diffusion set in response to the vehicle speed to the engine sound signal;
• a mixing balance setting section that sets a mixing balance in the mixing portion;
• and
• a speaker that outputs a sound on the basis of the engine sound signal being output from the signal processing section,
• wherein while in a case that both an increasing rate of an accelerator opening and an increasing rate of an engine speed are positive, the mixing balance setting section sets an occupation rate of the engine sound signal to which the reverberation effect is applied in the mixed engine sound signal to be a rate higher than zero, the occupation rate being increased as the engine speed become higher;
• and
• wherein when other than the case, the mixing balance setting section sets the occupation rate of the engine sound signal to which the reverberation effect is applied in the mixed engine sound signal to be zero.