Download and install software
Label the (4) USB sound cards. Plug in the sound cards one at a time, waiting for it to be ready before plugging in the next. It should automatically install device driver/software.
Right-click the speaker icon in bottom right of taskbar > select "Recording devices". Your sound card microphones should appear when ready to use. Make note the name of each microphone/sound card so you know which one is which. (mine are "USB PnP Sound Device", see pic)
Place microphones at each corner of the vehicle or problem area and using extension cords, connect to the microphone plug on the usb sound cards (label each microphone wire so you know which sound card is recording which corner). Tape wire to vehicle so it doesn't flap in the wind.
You may have to adjust the microphone level up or down depending on how loud the sound is you're looking for and your background noise level.
Right-click speaker in taskbar > select "Recording Devices" > Right-click the microphone > select "properties > select "Levels" tab > adjust accordingly
- Open Alis software
- Click the "wrench" in top right to configure settings
- Under "General Properties" tab, Select "choose" to choose a directory to save the recordings
- Under "Java Sound Properties" > Other options > select "Record in WAVE format"
- Under "Java Sound Properties" > Detected Input Lines > select the USB microphones you're using (mine are "USB PnP Sound Device") and make sure the "Enabled" box is checked for each one you want to record
- Make note the Line Input ID for each microphone.
- Click green check mark to exit configuration settings.
- Click Green circle button to start recording, Red Square to stop recording
Your recording will be separated into each track by the Line Input ID you noted earlier and will be found in the folder you chose
- Open Audacity
- Open the audio tracks by finding them in the folder you saved them in, and drag them into the audacity window. (Pop-up window will ask import method, select "Make a copy of the files before editing"
- You can now compare the sound wave for each track looking for anomalies.
As you can see, all 4 of mine look the same, so I applied a high pass filter (I played around and tried a bunch of different stuff until I could pinpoint the sound I was looking for)
Select "Effects" > Scroll down and select "High Pass Filter" > select your cutoff frequency
I chose 16k Hz w/ a 12dB rolloff
After zooming in (left-click in the range window pane of each track zooms in, right-click zooms out, make sure to zoom in the same on each track), you can see the difference on the bottom track (all have the same HP filter applied).
If I play each track individually, with the HP (16k) filter applied, I can only hear the noise I'm looking for in the bottom track. In my case, that corresponds to "4 - USB PnP Sound Device" which corresponds to the right rear corner in my case.
Now I know where to look for the problem on the car. So I'm going to replace the microphones at different spots at the right rear and check the wheel bearing, brakes, and cv, and hope it's not a diff bearing.
Hopefully this helps me and you.
2008 Sandstorm FJ
-Offroad pkg, trail gear sliders, 35x12.5x17 Nitto Trail Grappler on 17x9 Level 8 Bully Pro, Icon 2.5 Ext. Travel Coilovers, Light Racing UCA, MetalTech Long Travel Rear w/ Icon 2.5 remote res , EM rear UCA, MetalTech rear LCA, Icon panhard bar, 1/2" Bandi lift, Man-a-fre skids, TC A-arm skids, FJToyman shock skids, CB w/ Bandi mount, AFE HT exhaust, Demello front bumper, Warn M8000 w/ synthetic, 4.56 Gears, ARB locker, Safari Snorkel