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By James Wren on March 15th, 2010
Sometimes we are asked about the differences between an acoustic camera and a sound intensity probe and which of the two is better for a particular application. There is no straightforward answer as they are quite different pieces of equipment, used for measuring different things. An acoustic camera is a tool used to locate and [...]
By James Wren on January 19th, 2010
I’m often asked what is the difference between free field microphones, diffuse field microphones and pressure microphones.
For a run-of-the-mill ½ inch microphone the short answer is nothing.
However the long answer is a bit more involved.
Basically if the sample rate is 10 kHz or below and an accuracy of ±2dB is acceptable then there is no [...]
By James Wren on October 19th, 2009
The following article will attempt to explain the basic theory of the frequency response function. This basic theory will then be used to calculate the frequency response function between two points on a structure using an accelerometer to measure the response and a force gauge hammer to measure the excitation.
Fundamentally a frequency response function is [...]
By Chris Mason on April 22nd, 2009
Following a discussion in the office about Fourier Transforms we did a little searching on the web. As always, we discovered that the Internet is packed with some great resources on Fourier and his work. So rather than keep all of the information to ourselves we thought we should share it with our readers. We [...]
By James Wren on April 14th, 2008
Most engineers are probably familiar with or have come across the decibel or dB as a unit of measurement. Its most common use is in the field of acoustics where it is used to quantify sound levels. However, as will be explained in this article, it is also useful for a wide variety of measurements [...]
By Dr Colin Mercer on September 12th, 2007
The requirement was to develop a ‘standard’ test for assessing the sound quality of power steering pumps in vehicles. Measurements needed to be objective so that the method would be suitable for evaluating dissimilar vehicles and different types of pump.
Noise is an important consideration when a consumer is selecting a new vehicle. It is therefore [...]
By James Wren on May 23rd, 2007
First, in order to explain resonance we have to explain the terms we will use.
• A resonance is a particular frequency.
• A period is the amount of time it takes to complete one cycle
• The number of cycles in one second is the frequency of an oscillation.
• Frequency is measured in Hertz, named after the [...]
By James Wren on June 6th, 2006
In this note the different types of transducers that can be used with the Prosig P8000 series data acquisition system are discussed. The article deals with the design and function of the different types of transducer and the applications they are normally associated with.
By James Wren on February 20th, 2006
The following note describes an application of the Prosig P8000/DATS system in the refinement of an automotive exhaust muffler design for a major after-market [...]
By James Wren on August 26th, 2005
In a recent article we described how the Prosig P8000 hardware and DATS software had been used to help Dalmeny Racing diagnose a problem with an exhaust [...]
By Dr Colin Mercer on May 17th, 2005
When working with audio signals a common requirement is to be able to equalise, cut or boost various frequency bands. [...]
By Dr Colin Mercer on June 7th, 2001
Accurate measurement of a signal depends on the dynamic range and the overall level of the data acquisition system. The overall level setting may be thought of as determining the [...]
By Dr Colin Mercer on June 6th, 2001
Some devices, particularly digital tape recorders, apply A-weighting to all their data in order to achieve acceptable data compression. This is fine unless you want to analyse the unweighted data or apply a different weighting factor. Using DATS it is a simple task to instruct the WEIGHT module to either simply unweight the data [...]
By Dr Colin Mercer on April 11th, 2001
The Articulation Index or AI gives a measure of the intelligibility of hearing speech in a given noise environment. The metric was originally developed in 1949 in order to give a single value that categorised the [...]
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