Translation guide
Describes a voice that is quiet, deep in pitch, or subdued. Japanese distinguishes between volume (quiet vs. loud) and pitch (low vs. high). The best translation depends on which aspect you mean.
The voice is not loud; it's hushed or soft.
Most common word for a quiet or soft voice. Neutral and widely used.
He spoke in a low voice.
Literally 'low voice', but often implies low pitch. Can also mean quiet volume depending on context.
Can be ambiguous between low volume and low pitch. Use 小声 for clear 'quiet' meaning.
Whispered in a low voice.
Means 'lowering one's voice' intentionally, often to avoid being overheard.
We talked about the secret in a low voice.
The voice has a low pitch, like a bass or baritone.
Standard way to say a low-pitched voice. Often used for men's voices.
He sings in a low voice.
Literally 'thick voice', implies a deep, resonant, or husky voice.
A man who speaks in a low, deep voice.
A deep, thick, and somewhat rough voice. Often used for imposing or rugged characters.
A low, gruff voice echoed.
The voice is low because the speaker is sad, tired, or lacking energy.
小声 (kogoe) is about volume (quiet). 低い声 (hikui koe) is primarily about pitch (low), but can also imply quietness. If you want to clearly say 'speak quietly', use 小声. If you mean 'deep voice', use 低い声.
Directly translating 'low voice' as 低い声 may cause confusion if you mean 'quiet'. Always consider whether you mean volume or pitch.