Dogs yalping has got me at my wits end. [Help][Vent]

Tl;dr: My dogs yalping/howling/barking is completely out of control and I've tried nearly everything. Do you think a citronella collar would be effective?

Please, any help you guys can give me would be tremendous. I've never posted here, but you guys are my last resort. About a year and a half ago I moved back in with my parents for financial reasons. Immediately I recognized a problem. I sleep in a room right next to the backyard and they have a 4 year old German Sheppard who it seems like yalps and barks at everything. Now, I've had dogs my whole life and he is by far and away the worse. It's not the barking so much that I mind (though he does that more than every other dog we've had).

It's the yalping. Or at least that's the phrase I use for his howling, which he does at nearly everything. Way more than any other dog we've had, and more than any other dog in the neighborhood. On Sundays the Catholic Church that's about 2 blocks from my home plays its call to worship twice for about 30 minutes. Okay, no problem there. Except my dog seems to think its the end of the world. And his yalp is just so grating and irritating. This is made worse by the fact that I work graveyards, so when they're playing their call to worship is when I'm trying to get some sleep. Then he yalps at the Ice Cream truck, even when its blocks away and you can barely hear it. And this goes on, intermittently, for hours.

I feel like I've tried every trick in my book. I used to go out there every time he started yalping and give him a light bop on the nose. Nothing hard, just a slight tap. This usually worked for my other dogs. It just seems to have made him worse. I tried the same thing with a water bottle to no avail. I realized that he, being the clingy, needy dog that he is, might respond not the taps/water combined with a complete lack of attention from me. Nope. After months and months of trying this, it's the same if not a little worse. Now this was always combined with body language to let him know that I wasn't please. I upped the ante on the body language a little bit. Still nothing.

Eventually it got to the point where I realized I was getting a serious lack of sleep, which was affecting everything from my job to my social life. It didn't help that I was nearly constantly aggravated at this dog. It literally seems like he's barking at his own shadow. He's 5 now and I'm afraid that he's untrainable. I'm already planning on moving out but A) That decision wasn't overtly influenced by the dog and B) that's not for another 8 months. I didn't want to do a training collar, as we've never had to do one before. And I will not, again, will not get a shock collar. I'm thinking about getting a citronella collar and I just wanted to know you're guys' opinion on them and on whether or not it would be effective in stopping my dogs yalping/howling/barking problem. Sorry I rambled way more than I wanted to, but I just need to vent. Thanks, folks.