This seemed to help some... let m1 = event?.metaParameters["Sampler_Gain"] as? PHASENumberMetaParameter m1?.fade(value: gain, duration: 0) let m2 = event?.metaParameters["Mixer_Gain"] as? PHASENumberMetaParameter m2?.fade(value: mixSettings.gain, duration: 0) The problem is my gain for the sampler is 0.0005 with ambient. The mixer gain is 0.15 . Calibration is .absoluteSpl at level of 0. The other spatial audio I use .absoluteSpl at level 12 with more reasonable gain values. Maybe its the file but when I read in the file its set to .dynamic . If I use .relativeSpl in any case the speakers blow. Maybe its a captain obvious thing but I'm not seeing it.