The well-known LBG algorithm uses binary splitting for generating an initial codebook, which is then iteratively improved by the generalized Lloyd algorithm (GLA). We study different variants of the splitting method and its application to codebook generation with and without the GLA. A new iterative splitting method is proposed, which is applicable to codebook generation without the GLA. Experiments show that the improved splitting method outperforms both the GLA and the other existing splitting-based algorithms. The best combination uses hyperplane partitioning of the clusters along the principal axis as proposed by Wu and Zhang, integrated with a local repartitioning phase at each step of the algorithm.