A Weighting Sound

A weighting sound is the most generally used filter when making overall noise measurements. The attenuation of the sound signal with an A-weighted filter corresponds to the fact that the human ear is not as sensitive to sound of the lower frequencies as it is at the higher frequencies. The A-Weighted Sound Level is a … Read more

Community Noise Criteria

airbus a400

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

Frequency, Wavelength and Speed

waves

Understanding frequency, wavelength and speed is fundamental to everything around us. From noise and vibration, chatter on a lathe tool to the light we experience from objects. Waves move energy from one place to another without any accompanying matter. Sound waves, ocean waves and electromagnetic waves are some of the examples; other, more complicated types … Read more

Room Acoustics

room acoustics

Room acoustics is a huge subject in it’s own right, but I wanted to share some basics. A basic level of knowledge will help if you are trying to reduce the noise levels in a workshop or position your speakers in the optimal location. The trend of creating large open living areas that are decluttered … Read more

Acoustic Chambers and Rooms

acoustic rooms and chambers

There are a number of different types of acoustic chambers and rooms.┬áSome are defined very specifically and others more loosely. These rooms are mainly used by noise and vibration measurement specialists. Acoustic chambers and rooms are quite specialist rooms to design, build, operate and maintain. Often the design of these rooms will be done by … Read more

Vibration Damping

CAD of a shock absorber and over type spring

Vibration damping is the dissipation of energy in a system, either through time or distance. Damping will reduce the vibration amplitude. Hence reducing the radiated sound or reducing the vibration and hence improving the tactile quality. The term is generally applied to the vibration of a structure owing to the internal dissipative properties of the … Read more

Mill Stiffness = Top Finish

end mill finish with SX2.7 and bracket

Mill Stiffness = Top Finish is a fundamental equation for any milling machine big or small. Increasing stiffness reduces vibration. I increased the column to base connection stiffness with this mild steel plate. The fundamental design principle was to add a thick plate and increase the bending stiffness of the plate using beams. So the … Read more