System/Library/PrivateFrameworks/MediaExperience.framework
MXDuckingSource.h
@interface MXDuckingSource : NSObject
@property (readonly, nonatomic) unsigned int type;
@property (readonly, nonatomic) unsigned long long ID;
@property (nonatomic) float duckVolume;
@property (nonatomic) float duckFadeDuration;
- (void)dealloc;
- (id)initWithType:(unsigned int)a0 ID:(unsigned long long)a1 duckVolume:(float)a2 duckFadeDuration:(float)a3;
@end