'Underwater' Sound From Cubase Track

I imported an Mp3 drum track into Cubase 11 Pro from a source which I’ve used many times. I needed to create a different arrangement by chopping up the track and extending some sections. During the process, there was no problem with playback. I exported the rearranged track. It seemed fine. The track is to be played back from an iPhone through a PA mixer as backing in a live situation. The problem is that when attempting to play the track through the PA mixer, it sounds distorted. The best way I can describe it is that it sounds like it’s being played back under water. I’ve tried everything I can think of, including three different lightning to audio connectors from the phone. The audio plays back fine from the phone itself. It’s also ok when played back through other equipment such as guitar amps, also through the inputs on my audio interface. I’ve tried it through two different mixers, both of which are of good quality. I still get the under water sound. I read online that such problems may be caused by a filter being applied to the audio. I’ve gone back into Cubase and there doesn’t seem to be any effect or extreme EQ being applied to the track. I’ve checked both mixers and no FX or extreme EQ is being applied to any of the channels. Another thing I’ve done is create a drum track for a different song using EZdrummer . It plays back fine through the PA using the phone. It seems I’ve got to the end of the road with this issue. It’s a complete mystery to me, as I’m sure it’ll be to members reading this post. I’d be glad to hear from anyone who has experienced a similar problem or who may be able to offer suggestions as to a solution.