tools, materials & knowledge for model makers
There are a number of different community noise criteria measurements, some of which are described below: CNEL = Community Noise Equivalent Level This is used to characterize average sound levels over a 24-hour period, with weighting factors included for evening and nighttime sound levels. Leq values for the evening period (7:00 p.m. to 10:00 p.m.) … Read more
Room acoustic modes occur at frequencies at which sound waves in a room resonate (in the form of standing waves), based on the room dimensions. The acoustic modes will “colour” the sound, ie enhance certain frequencies and dull others. Therefore, the standard modal approach for designing a room with good acoustics is to create as … Read more
One of the most important considerations in fan design is that the fan must impart a uniform velocity over it′s entire area. There are several simple relationships between fan capacity, pressure, speed, and power, which are referred to as the fan laws. The first three fan laws are the most useful and are stated as … Read more
When we flow gas through a pipe or over a surface (fluid dynamics) we generate noise and sometimes vibration, this all falls under the title of aerodynamic noise. The noise that is produced can be extreme if there is a feedback system between the noise that is generated and the gas flow. However, even under … Read more