Hiraeth is a Welsh word that has no clear English translation. Oxford and Merriam Webster’s loose definition of the untranslatable noun is “a homesickness for a home you cannot return to, or that never was.” It’s a fitting name for the new release by Richmond post-rock instrumentalists Shy, Low. Cinematic in scope, the blind movies that the quartet imparts aren’t songs — they’re impressionistic soundscapes. There’s an undertow of melancholy in the group’s oceanic, twin-guitar inundations. But like water, each measure and movement flows through an emotional tide of rising and falling. Shy, Low bring its waves of riffs and rhythms to Strange Matter on Friday, Nov. 13. Joining it will be Richmond mathematicians Night Idea and Capital City indie-rockers Clair Morgan. Doors for the 18-and-older show open at 9 p.m. $7. strangematterrva.com.