I also realise now why we started using the 3Dio more often. The Soundman is a great binaural microphone but the problem it has is that it makes a lot of self noise. So you can get a lot of static, and for ASMR where you are listening to quiet sounds, you can really hear the static.
So although we really love this microphone, we tend to stick with the 3Dio since we don’t have to remove the static on the 3Dio. It is a lot quieter.