Looking for filters or the effects used for building tension in a trance track

[m4ly]

Hi there,
newbie here who recently tried to find some hobby for couple of spare minutes between family and work time and I have found myself having fun with "producing" some trance music.
I am reaching to you fellow forum members with maybe a dumb but definitively a newbie question put in the Subject: how one can achieve an effect of building (raising) a tension in synth melodies in a trance track.
I am currently going through Demi Hellen youtube videos and this effects sound quite offen when he plays some of his melodies. In this video : https://www.youtube.com/watch?v=E4Ii_ARe_E0&t=855s at 7 min 55 s he previews the created part of the melody and he says: "lets just open the filters.." then one can here this effect of a raising tension in his melody. The same at 16min 10sec.
How can one achieve that?

Best regards

m4ly

[_leras]

Just the main LPF filter on the synth most likely.

[ghettosynth]

Just the main LPF filter on the synth most likely.

Almost certainly. He specifically references the mod-wheel. So it's just the main filter in whatever synth he's using with cutoff mapped to the mod-wheel.