I went to the data sheet and the word filter is mentioned 64 times. Some I think can be altered with software. You'd think so......it would be the correct thing to do. This should not be a 'cable' type discussion. There are measurements that can be taken and people at the companies selling updatable products that can say whether a change affects sound. Chez you asked it also, has any manufacturer when releasing updates for DAPs stated a SQ change? Anyone know?