The sounds produced from both FIR and IIR part are softer volume than the original , therefore I think the amplification is need to get back the original kind of loud volume to enable student to evaluate the sounds better and also to let student to learn how to implement amplification procedure after filtering process. My suggestion is that after the filtering process maybe the lab should include extra steps to teach us amplifying the filtered signal so that it has the almost same volume or magnitude as the original signal.