Some speakers are definitely better than others for voice. My Maggie 1.6 are pretty good I think, and do a lot of other things well. However, many years ago I had KLH5 and KLH12 speakers that were the best I have ever heard for voice. They were three way, with a pair of very light paper cone midranges, about 3 inches in diameter. When I visited the Smithsonian museum of Science and Industry in Washington DC I noticed that they used KLH5 speakers for the displays which included spoken word audio.
When auditioning speakers, an old trick is to turn off the music and listen to an FM radio station where a man is speaking. The human voice is a "test signal" that we all are familiar with. If voice sounds natural, you probably have a good speaker.
