Do you sing harmony with your vacuum cleaner? Some people will find that question strange, but a lot of you will know exactly what I mean. You may be vacuuming away and notice that the sweeper has a constant pitch. You can hum along with it a 3rd up or down. Or you could get wild and try some 5ths or even 2nds. I think it's a symptom of frustration that you don't have anyone to sing ACTUAL harmony with.
So you turn to appliances, car dingers and horns, etc. Though there is (probably) no permanent harm that can come of such behavior, it may please you to learn that you can now sing harmony … wait for it … with yourself! Yeah, yeah, I know. You experimented in high school with recording into your smart phone or boom-box-type recorder, and then sang along with it. But that was cheesy. You may have even frightened your friends with 4-part vocal-bouncing experiments using two or more portable tape recorders, resulting in grotesque semi-audible, music-like hissing noise. But that does not approach the kind of thing possible today! It's even easier and much less painful … to all involved.
All you need is a computer (since you're reading this, I'm assuming you already have one), and a microphone you can plug in to said computer. You CAN do this with a $ 5.00 mic going straight into your sound card, especially if you want to try this like RIGHT now. But if you have a USB mic, things will sound much better. You can pick a decent one up for between $ 20 and $ 50. The only other thing you need is recording software, and there is even a program you can download FREE. It's called Audacity, and is amazingly capable for such an inexpensive (did I mention, "free"?) Program.
Audacity will get the job done. You can find a step-by-step on that on the Home Brew Audio website. I actually use Reaper (by Cockos) to do my multitrack recording. It, too, is affordable. It's free for evaluation period, which is 30 days. But it won't ever stop working! Cockos knows that it sometimes takes longer than 30 days to evaluate. When you are ready to buy Reaper, it will only cost you $ 40 for a full license, unless you start making $ 20K per year with it! Yeah, you heard right. The full license, which costs $ 150, is the exact same software, with the exact same functionality and capability as the $ 40 "discount" license. Cockos merely stipulates that when you start making $ 20,000 a year using Reaper, you'll need to pay for the full license. It's all on the honor system! That kind of thing is really almost unheard of. Even at such a low price-point, though, Reaper really is far more flexible and capable than Audacity in the realm of tracking and mixing audio. Either way you decide to go, you can create some truly stunning, dare I say, "mind-blowing" harmony sounds with just this modest home recording setup.
Check out some of the really cool self-harmony things you can do with just your computer, a mic, and some cheap software at the Home Brew Audio website.