Mysterons – Portishead

This compelling groove is heard throughout most of the song, which features on the band's critically-acclaimed debut album, Dummy (1995). Portishead drummer, Clive Deamer, plays a clever, funk-inspired beat with a crescendo roll beginning on beat 4 of each measure. I first thought that the roll must have been overdubbed because you can hear the hi-hat sound on the 'and of 4' – which is impossible to play with only two hands. Studying some live footage shows how he achieves this seemingly impossible feat. There are 3 broken down versions of the beat below to help you learn the roll technique.
Step 1:
To begin, get comfortable with the basic groove. Note that there is a ‘Z’ on the stem of beat 4. This buzz stroke is played by dropping the left stick until the bounces fade.
Step 1 @ 60 BPM
Step 2:
Add 4 sixteenth-triplets on the snare after the buzzed stroke, leading with the right hand.
Step 2 @ 60 BPM
Step 3:
Double up all of the snare notes that were added in step 2, creating a 9-stroke roll.
Step 3 @ 60 BPM
Step 4:
Add increasing force to the double strokes to create a crescendo, as seen in top image.
Studio version:
Live version: