my piano roll is muted

[quaint mirage]

now when i place a new note over my pattern my pattern is still muted but the new note i place has a sliding up sound

[lost yew]

See the little triangle on the bottom-right corner of each of those notes?

[quaint mirage]

yes

[lost yew]

Those indicate slide notes, which don't make noise by themselves, but instead causes regular notes to, well, slide to that note