each modulation frequency allows for two sources within 6 cm of a single detector to be illuminated at once, (two mux 1s, or 4 mux 1s all at once). According to denis the issue is still that one can't be really close while one is far, since the light dissipates over distance and the farther channel will not have a large enough bias
therefore, two optoins
1) could place all four mux1s in the same source location to make a super channel, but could do this already before
2) the harder one will be to allow more than one mux 1 within range of a detector, but constrain the distance to be equal. So if you can't fit any other mux number, then try each one again but pick the one with a closest channel distance to the existing ones,
each modulation frequency allows for two sources within 6 cm of a single detector to be illuminated at once, (two mux 1s, or 4 mux 1s all at once). According to denis the issue is still that one can't be really close while one is far, since the light dissipates over distance and the farther channel will not have a large enough bias
therefore, two optoins 1) could place all four mux1s in the same source location to make a super channel, but could do this already before 2) the harder one will be to allow more than one mux 1 within range of a detector, but constrain the distance to be equal. So if you can't fit any other mux number, then try each one again but pick the one with a closest channel distance to the existing ones,