Probably this post does not get a lot of upvotes but I'd love to see more of this type of content in LW
Actually, this technique is also useful when you want to clap louder (As seen on the spectrum, the peak is higher), I personally found it useful when you would like to force crowds to clap on the same rhythm, where everyone would just follow the most recognizable clap. I can't find any related study to this, but It's quite phenomenal according to my own testing.
If your goal is to clap louder, cup your lower palm and hit it with the fingers of your other hand. When I do this it's painfully loud: not only is it much higher, where human hearing is more sensitive, but it's also just higher energy.
There are some tricks to do this right. Cupping the hands, somewhat misaligning the hands so that the gaps are minimized. You might want to post a photo or video.
Doing this can send out a jet of air above your thumbs. If you send this jet into your mouth, you can change the pitch by changing the shape of your mouth, which I found endlessly amusing as a kid.
Clapping is normally relatively high pitch:
(mp3)
I find clapping annoyingly high, so I usually clap a bit differently:
(mp3)
If you also want to clap lower, the main idea is to maximize the volume of air you trap between your clapping hands. Arch the palms, and try to have the full circumference of your palms collide. It takes some practice, but after a bit it should come pretty naturally.
This is also useful musically, if you're clapping along and want to clap low for some beats (ex: 1 and 3) and high for others (ex: 2 and 4).