It's a little out there, and maybe you're not sure who this guy is speaking to or if they heard you. The spacey voice is a distracted one, a not quite there one, and the perfect voiceover for completing your spacey character.
We know the character, or maybe the actual person, who uses the spacey voice. We often have to nudge them to bring them back to us or repeat ourselves. This doesn't mean they're negative characters, they're just a bit out there. A spacey character has his mind on something, whether it's reality or not.
This is a perfect voice for a character in a video game or in an audiobook. It's a very defining characteristic and the spacey voice is a great way to complete the spacey character. Not the best choice for a narrator or learning piece, the spacey voice will help depict a fictional character's nature.
Remember Jeff Spicoli in Fast Times at Ridgemont High? There's your quintessential spacey voice. This voice shows the character is distracted, maybe because that's their nature or maybe because their a little high on something. There's lots of filler words, like huhs and uhhhs, and you'll definitely hear those pauses. The voice may be a bit softer than others and maybe on the deeper side. We don't dislike it, but we really don't trust it either, because we have trouble connecting to it. Remember the speaker of the spacey voice isn't completelty there with us. But it can be a very effective voiceover.