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played right at the start, underneath the drums.



can't tell whether or not it's some kind of transposed down audio of a bass sound or a bass with a high pass etc.

Tbh it could be either of what you said, it also sounds like percussive drums (like bongos) with completely wet reverb. Trial and error methods is all I can reccommend, try both of what you said, and very wet reverb percussion with small decay

Soundcloud

bass with a high pass. you can hear it progress into a bass/synth towards the drop

saying that, you could recreate that particular sound at the very beginning using percussion and reverb