תַּגְבִּיר אֶת הַוּוֹלְיוּם
When we speak in English of raising volume, we mean making the volume more powerful or stronger. That’s the literal meaning of the active-causative Hebrew verb לְהַגְבִּיר listen and repeat, which is used in the expression:
לְהַגְבִּיר אֶת הַוּוֹלְיוּם
to raise the volume
רוֹצִים לִשְׁמוֹעַ חֲדָשׁוֹת, תַּגְבִּיר אֶת הַוּוֹלְיוּם!
(We) want to hear (the) news, raise the volume!
…when spoken to a male, or, simply:
Volume, in the auditory sense, can be translated to קוֹל listen and repeat, while in the physical sense (measured in liters, gallons, etc.) it’s נֶפַח listen and repeat. However, ווליום is what people say when they refer to the volume button on the radio.
To lower or reduce is לְהַנְמִיךְ listen and repeat. Its root is נ.מ.כ meaning low, while the root of להגביר is ג.ב.ר meaning strength or might.