NVH News: cost effective Acoustical Imaging, Improving Kundt Tube measurements, ...
To visualize this e-mail in Html, click here: http://ems8.net/a/?E=XTC-DF2H-IB5LS-DD-HTPUNL NVH - N°4/2007 Sound Imaging: PRO-series solution for cost effective Acoustical Holography NetdB PRO-series solution for Acoustical Holography uses NetdB hardware platform and dBVision software: the "image key" from 01dB-Metravib since 30 years. dBVision is the reference software based on Near-field Acoustic Holography providing results with utmost spatial resolution for accurate noise source localization. Moreover, 01dB-Metravib and its partners worldwide will be able to compare and offer both solution in the next future, the choice depending on customer requirements, which can be divided into: Scientific Measurements and Reliable Simulation (Acoustic Holography) or Real Time imaging and quick identification of Noise Ssources and Propagation Paths (Beam Forming). A thorough understanding of the Projects aims and goals is necessary to choose the right method and 01dB-Metravib is ready to help customers understand and decide for the better one. Please contact us at 01dB-Metravib for further explanations. Kundt tube measurements: Can ISO and ASTM standards be improved? From the original method to achieve the sound absorption coefficient of the material using the "standing wave ratio", ISO and ASTM have introduced the much faster "Transfer Function method". The algorithms are easily implemented by FFT analysers, but the conversion of FFT results to 1/3 or 1/1 octave values is made by taking the values of FFT lines to the central frequency of 1/n bands, even if this issue is not explained in the standard. The sound absorption coefficient of a test sample can be derived also by another method which is more "energetically" correct: it is based on the measurement of the reverberation time inside the tube. In fact the transient properties of the sound field in a closed tube show that the succession of wave fronts obeys a simple exponential rule so that the impact of the sound absorption of the termination can be predicted analytically. The PRO-525 system proposed by 01dB-Metravib implement both methods (ISO/ASTM and New one). It has been developed in collaboration with University of Ferrara (Italy). Though a similar procedure was outlined by Beranek, the apparatus used and the processing involved are different, in particular, a new apparatus was developed with both ends possibly equipped by test samples. For more information there is a technical paper available from SAE describing the methodology. Contact nvh department for a copy or download it from our web site. The meaning of "freedom" with NetdB hardware and dBFA suite software? Did you know that our NetdB platform is a Digital Recorder and a "Front End" which can be "fully" controlled using LabView, C# dll (available) or TCP-IP command? Did you know that dBFA suite - Real Time - can act as a server and be controlled using Simple TCP commands? "Freedom" means that either with NetdB hardware platoform or dBFA software suite, or in combination of both, you can build up or customized your own application with few mouse clicks! If you prefer using your LabView environment, you can integrate NetdB in your measuring system and in addition "control and collect" data through the web! Mains features in dBFA software suite Release 4.8 Replay mode Real Time processing on recorded signals Real time frequency Weighting on FFT, 1/N octave spectrum and multi-spectrum Weighted order Overall levels vs. rpm Tacho input Exponential averaging With manual stop Transducers Wide choice of transducers type on Orchestra modules Alarms Remote Control Master/Slave Ethernet & Wifi - TCP/IP protocol GPS Positioning data recording (Garmin protocol) (Speed X,Y,Z - Date - GPS Signal level ) Affordable Sound Imaging Solution from 01dB-Metravib PRO-330: dBVISION system - 6 ch package for Acoustical Imaging. Your dBVision system for the price of a Real Time Analyzer! More info on www.01db-metravib.com or please contact us. EVENTS International Congress of Sound and Vibration: 09/07/07 - 12/07/07 Cairns, Australia SIBRAV: 16-17/08/2007 IX Simpósio Brasileiro de Acústica Veicular (Brazilian Simposium of Vehicle Acoustics) USP, São Paulo, Brasil InterNoise 2007: 28/08/07 - 31/08/07 Global Approaches to Noise Control, Istanbul, Turkey Congress on Acoustics: 02/09/07 - 07/09/07 19th International congress on Acoustics, Madrid, Spain Automotive Testing Expo China: 12/09/07 - 14/09/07 The Shanghai Convention & Exhibition Center, Shangai, China Fan Noise 2007: 17/09/07 - 19/09/07 International Symposium on Fan Noise, Lyon, France Conference on Wind Turbine Noise: 20/09/07 - 21/09/07 2nd International conference on Wind Turbine Noise, Lyon, France --------------------------------------------------------------- Message sent by 01dB-Metravib http://ems8.net/r/?E=XTC-DF2H-IB5LS-DD-HTPU-EETo unsubscribe your email address : http://ems8.net/u/?E=RET-XTC-DF2H-IB5LS-DD-HTPU&EMail=submit@theautochannel.com ---------------------------------------------------------------