A filter device (301,501,501,601) comprises an acoustic wave propagating substrate having an effective coupling coefficient k² and having a first filter (310,310',320,320',330,340,340',340'',...,510,620) and a second filter (350,360,360',360'',...,370,370',380,380',520,630) disposed on the acoustic wave propagating substrate. The first filter (310,310',320,320',330,340,340',340'',...,510,620) comprises a first electro-acoustic transducer (310,310',320,320') and a first acousto-electric transducer (330,340,340',340'',...), both disposed on the acoustic wave propagating substrate. The first acousto-electric (330,340,340',340'',...) transducer comprises N₁ many electrode pairs, wherein N₁ ≧ C/k². C is a constant having a value in the range from 1 to 2. The first electro-acoustic transducer (310,310',320,320') is acoustically coupled to the first acousto-electric transducer (330,340,340',340'',...). The second filter (350,360,360',360'',...,370,370',380,380',520,630) comprises a second electro-acoustic transducer (350,360,360',360'',...) and a second acousto-electric transducer (370,370',380,380'), both disposed on the acoustic wave propagating substrate. The second electro-acoustic transducer (350,360,360',360'',...) is electrically coupled to the first acousto-electric transducer (330,340,340',340'',...). The second electro-acoustic transducer (350,360,360',360'',...) comprises N₂ many electrode pairs, wherein N₂