Weird crest in first wavelength when summing bandpass filter outputs

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]1

I got an answer on another forum. It is a phase problem. I solved it by changing the phase of every other bandpass filter by multiplying the output by [*~ -1]. Hope this helps someone.