We've made a habit of placing our iPhones in some of our pottery pieces to get a louder play back while listening to music in areas where speakers are not setup. We have vessels that double as home decor/speakers in our bathroom, balcony and studio tables. Try it out with these types of items in your home and rearrange them so they're in areas you might want to listen to music straight from your portable device.
It really is a convenient alternative for getting a louder volume from your portable device without having to plug anything in or compromise your space by setting up unsightly speakers.
Hope you try this idea out for yourself and let us know your experience. We have found that using vessels with a more narrow rim will give the loudest sound. Optimal shape would be a large belly vessel with narrow rim, the example to the left gave a great sound boost.