reference frames

The first episode of Clickspring's series building a John Wilding skeleton clock from raw stock in a home machine shop. It covers making the frames along with the tools needed for the job.

Tech Ingredients builds a pair of large Voigt speakers and explains ported, transmission line and horn designs. It tests them in an anechoic chamber and uses constrained layer damping for the enclosure.

The UK DVSA's one-minute guide to the hazard perception part of the driving theory test, covering when to click and how to score well.