I 2nd what Raindrops suggested.
Additionally, may I recommend that the first few times you close the door on the crate and turn the radio on, leave....that the radio can become paired with your leaving and may actually wind up being a conditioned punisher. LOL. When the radio goes on, Dad leaves. The radio is a predictor of something not good is about to happen. (unless she couldn't care less if you leave. That's sometimes the possibility) You could have the radio on when you're already in the room for a while, then leave. You can also mix things up so that sometimes the radio goes on when you leave, sometimes not, sometimes when you return. That way the radio doesn't become a cue. If you want her to feel soothed when you're gone and you think the radio helps, then use it. But I'd have it on also when you're there some of the time. (I recommend Bach):musical-note: lol.
Also, I would suggest if she's not showing that she's super comfortable in there with the door closed that before you start leaving the area, stick around in the same room...unload the dishwasher or putter around in there. When she's comfortable with the door closed for longer and longer spells, then try going to another room but only for a short time. Come back, increase duration of absence. Don't let her out while she's whining but wait for a lull. Anyhow...you get the idea. Gradual conditioning. Pretty soon she'll be comfortable in there with the door closed for an hour or more. Good luck.