The resolution for Maxwell's demon paradox is that the demon has limited memory and the demon will eventually run out of information storage space and must begin to erase the information it has previously gathered. Erasing information is a thermodynamically irreversible process that increases the entropy of a system. My question is we can do the same thought experiment without the requirement for any memory, here for example: Instead of high & low energy particles + door, we can put high & low frequency waves in the box and then separate them with a separator that has high pass filter in one direction (located in the upper part of the separator), and a low pass filter in the opposite direction (located in the lower part of the separator). This way overtime low frequency waves will move to one box, and high frequency waves will move to the other box. And because the high frequency waves carry higher energy, we will end up with one box having higher energy content that the other one. No memory is needed here. What I am missing?