That has nothing to do with lmms. You propl. have a config-program, for your head-phones, where you can set the default volume, if not you have to set the volume on your pc/ MAC for the particular out (normal green on pc's)
Depending on your soundcard, there will be various advanced settings to do that.
Besides that, since you are new here, Welcome to the forum jakecj02! Here are all our important links:
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In case you like to introduce yourself to the rest of the community, this is the right place
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