I am the builder , I will answer several question, yes these will work even if amplified ,for the amplified section is fed the audio signal then goes to the preamplifier -internal Xover ,these Filter which = cleans the audio band of noise ,not the same as a RC filtering in a Xover ,for one there is much times spent using various size capacitors for the the filtering ,and your speakers ohms, impedance determine which resistors I use ,which BTW these parts are night and day better then then 95% of the Xover parts in most speakers including anything at $25 k for example.once these are runin at least 100 hours they then start to open up. And get better to 300 hours.
Tony gee of humblehomemade Hifi capacitor helped me over 4 years ago ,today these are a very well thought out design ,to Ass ume the answer is self defined. 1st try them ,then make a call. Magico A5 is the 1st company to use these superb Mundorf Ultra resistors ,Yes even more defined then the path audio resistors I have directly compared them, and the Duelund copper foil oiled paper need no introduction .and head shaking is a good thing when the music sounds good !!