@seb-harmonik.ar Thanks for your answer! I tried your recommendation and it solves the problem despite my initial thought that the problem would appear with more than two filters, but it doesnt. Cheers!

I am creating sounds by exciting bandpass filters with a short impulse and summing the outputs together. The more filters I use the more there seems to be a clipping sound at the very beginning. When I visualize the sound wave I realize the gain of the first crest of the first wavelength is higher than it shoud be when compared to the next wavelenght. When I just have one filter the output is fine. I attach the patch and the sound wave with one filter and with four filters for illustration. How can I correct that first crest? Has it got anything to do with the phase? Cheers!