to test how much insulation we need to reduce our acoustic noise (or air currents) problem we've added a simple aluminum-foil plated styrofoam box around the beat breadboard.
There are plenty of holes for all the beams and cables :

• two for incoming beams
• two for the power stabilization
• aux beam from combining beam splitter
• reflected beam from beat PD
• video, power, PD cables,...

Even with all those holes we can already see a reduction with a simple lid on top of it. Due to power outage yesterday we still have no stable system yet, so waiting until tomorrow for measurements.