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+--- Thread: Audio Monitor (/showthread.php?tid=10318)
Audio Monitor - GregOConnor - 10-16-2014 13:31
David, I know that this forum category is your blog but wanted to start you on an idea I keep coming back to.
I was reviewing 5 ton trucks at auction for my gijeep.com site and ended up buying a bunch of recoding equipment. cant call it high tec because I bet there are phone apps that can do the same listening and making a graphical or digital file of sound.
My idea is to build a listening device for the bus engine compartment and the towe'd cabin and tow'ed engine compartment. that device makes a record of the sounds in real time and compares the sounds to a file proven to be recorded during normal operation. All done in real time so the operator can puhs the equipment to the limit and back off or stop when issues arise.
Temp gauges we now use are much like a audio graphical display would be. Idiot lights we now use compare input to a normal threshold and are much like a display warning of abnormal sound would be.
sitting in my tractor I can hear issues and some of the sounds are even enhanced when I use ear phones which makes me wonder if there are clues that I miss by not being able to hear all the noise and being able to remember all that is normal.
back on Ernie's forum around 2006 there was a poster looking for a audio file of an 8v92. That got me wondering why he needed it. I think he was just nuts about sound? maybe not.
RE: Audio Monitor - dentmac - 10-16-2014 18:30
Hi
I've been playing with spectrum analyzer for a different and simpler purpose but this one may be closer to what you want. No doubt there are much more sophisticated ones but for $.99? Can't replay just record visible spectrum.
Android app "spectrum analyse".
I simply wanted an app that could hear better then me so I could put the "mouthpiece" end of the phone near air joints to listen for leaks. ( I have a fat head). App I found is "spectrum analyser". (With the R . )Lots of ads bit it seems to work.
RE: Audio Monitor - davidbrady - 10-17-2014 00:30
Hey Greg,
I remember Bennie from the old forum and his quest for engine sounds! I wonder what became of all that...
I did a quick google on engine sounds and eigen values and found this publication: "Vehicle Sound Signature by Frequency Vector Principle Component Analysis".
This gives us an idea of the computation involved. The paper is from 1998. I haven't looked further to see what became of their work. I'm sure there are some software libraries out there to start from; I wouldn't want to write all this from scratch. This is a very interesting topic and project and challenging to say the least. Let's explore how we can simplify the problem.
RE: Audio Monitor - davidbrady - 10-17-2014 15:19
Looks like the state of the software has progressed:
RE: Audio Monitor - GregOConnor - 10-18-2014 12:44
wow this is where the web advances helpful applications. this application looks for patterns. I wonder if something like this is used to look for unauthorized use of copyright music on the web? I need one that looks for anomalies. even something as simple as a decibil measure would help. decibil level increases are a very common with mechanical issues.
I have a dj sound system that mounts on my bus 7600 watts of music. I use a program that reads sound and turns it into a similar graphic chart so we can monitor the wanted sound and eliminate the noise. There are 4 graphic charts that take realtime samples from 4 sides of the bus and allow the operator to compare each chart and look for visual issues. The only warning programmable variable is difference in loudness. All of the sound converted to a visual chart is human monitored. I am fortunate that we have several sound engineer's in our group who can set things up. However. I learned that in Hollywood,"Sound Engineer" is more or less just a sound its self.
I don't want a driver viewable sound produced graph showing me what is going on in the engine compartment or the tow'ed. I rather have a idiot light that warns of an anomaly or blinks on when there is a loud noise. Life got better for me when my backup camera went blank. Now I only look at the tow'ed when Im half way thru a turn. the camera works now but I learned not using it helps me concentrate on where I am going not where I have been.