10-18-2005 11:39 AM
10-18-2005 12:05 PM
Is it the acoustic data that you are hoping to process or is it vibration on the engine?
Listening to your engine it sounds like a big diesel, whats the engine build state (new, prototpe.....) ,what's the engine application, whats the perceived problem?
600RPM is low for an automotive application, so I guess we can count that out.
Any way its all possible without any of the toolkits but the toolkits save you shed loads of time and you are not so concerned about errors in coding.
10-18-2005 12:58 PM
10-18-2005 01:17 PM
Well a bit light on the build and engine size etc. but here is a suggestion on what to do.
Stop as much of the background noise as possible (such as the speech etc), can be as simple foam.
I would get a sound source to set a calibration level if possble, be carefull in standard rooms / test cells, you can get nodes which make it difficult to repeat noise measurements, make sure you can choose a precise fixed position.
Then pass the incoming noise data into a Window and then FFT, and keep a record the amplitudes for that slice of data at the current speed / load.
Perform a speed sweep / load cycle and you can then see if the noise is related to the rotational speed or not. This will tell you if its a resonant component or gear mesh / torsional issue.
You can use a 3D picture plot, to plot speed versus frequency with ampitude/ intensity as the 3rd dimension, this makes it easy to make a good look at all the data. A waterfall graph tends to be hard to keep a track of.
Be aware that the camcorder isn't instrument quality recording and may mash the noise quite a bit, I would recommend that you sample the data directly using an DAQ board or use a DAT recorder.
10-18-2005 01:57 PM - edited 10-18-2005 01:57 PM
Message Edited by rpursley8 on 10-18-2005 02:58 PM
Message Edited by rpursley8 on 10-18-2005 03:01 PM
10-18-2005 02:59 PM - edited 10-18-2005 02:59 PM
Message Edité par Conseils le 10-18-2005 09:59 PM
10-19-2005 06:18 AM
Thanks for the effort. Can you show me some code?? My FFT results aren't showing anything over 1Hz frequency.
10-19-2005 08:21 AM
10-20-2005 02:54 PM
10-21-2005 05:12 AM