One of my favorite startups showcased at the this year’s CES was Simply Amplified. They make 3D printed smartphone amplifiers. You can take a look at their assortment here.
You set your smartphone down into the cradle portion of the object, and the natural shape of the object (based on the golden ratio, I’m told) amplifies the sound from the device. It’s key to point out that this device is not powered in any way – no batteries, no power plug. It just has a little hole where your phone speaker is so it can naturally channel the sound. By default they are designed for iPhones, but they also can include an adapter for the more popular Android handsets if you need one.
They have a kickstarter going to improve their production process. It seems like a great product and team, I’m rooting for them.