Some of the characters do actually encode sounds, typically in the right side of the character. However, the encoding is more like a memory aid than it is phonetical. 中 (zhong1), 钟 (zhong1), 种 (zhong3/zhong4); 艮 (gen3), 跟 (gen1) 根 (gen1), but 很 (hen3). And it doesn't always work: 立 (li4), 位 (wei4), 拉 (la1).