Abstract: An apparatus for securing the lid of a container without causing any substance which has collected in the can rim to splash during the recovering process. More particularly this invention relates to an apparatus that secures the lid of a standard gallon or quart size paint can. The invention has an intermediate annular wall and an annular flange such that, when force is applied to the impact surface, as from a hammer or mallet, the lid is secured to the can, and any paint that has collected in the annular ring and sealing groove of the can is prevented from splashing. The apparatus is designed for use with cans or containers of different sizes.

Abstract: A directional microphone system gain adjusts the sum of signals that are received from two microphones mounted spaced apart. The gain adjustment is generally proportional to the product of the two microphone signals. Analog multipliers are used both for multiplying the signals together and also to form a gate that gain adjusts the sum of the signals. Microphone arrays can increase the directionality of this system, and can permit electronic steering.

Abstract: A directional microphone system gain adjusts the sum of signals that are received from two microphones mounted less than an inch apart. The gain adjustment is generally proportional to the product of the two microphone signals. Analog multipliers are used both for multiplying the signals together and also to form a gate that gain adjusts the sum of the signals.