Yes, Low-Noise Adaptors (L.N.A.s) can be used with Y-cables, but please make sure to use one L.N.A. per fan and to place the L.N.A.s between the Y-cable and the fans as shown below. 

Never use one L.N.A. for two (or more fans) by placing it between the motherboard and the Y-cable. The Low-Noise Adaptors could otherwise overheat when used with more than one fan per Low-Noise Adaptor.