Listen to the racket! Try picking knock out of that at high RPM :lol:

Not an easy car to tune.

Sound file is 22KHz, Mono, recorded via Line-In, as tapped directly into my knock sensor. Filtered to only include 4KHz to 8KHz.

Right-click, Save-As:

http://www.kickflop.net/temp/noisiest-engine-ever.wav
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PS: So... has anyone determined a non-Subaru part number for a proper direct replacement of our knock sensor? As I recall, the OEM ones are marked up about 300%.
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You might try to turn down the gain a little. The nice thing about recording the sound is that you can analyze later, like a datalog.

The slanted lines just below 6 kHz are indicative of knock. The frequency seems a little low for an EJ20. Is this from an EJ25?

http://i12.tinypic.com/2i6iddl.jpg
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It's an EJ20.

Those trace "indications of knock" have been around as long as I can remember. They don't go away with an octane increase nor do they go away with timing retarded further (my timing is already truly conservative -- I am not one of those "crank up the timing!" guys).

My compression, after 12,000 hard miles on this setup while analyzing the sound files with Cool Edit Pro and Gram, is as tight as day 1 and my plugs have never shown a hint of detonation.

If I sound defensive, I'm not trying to be. Just stating what I have seen with my own eyes instead of theory.

Unfortunately, nobody else shares their .wav files like this.
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If you're making these recording for analysis, and not just for your listening pleasure, I suggest that you not filter out the higher frequencies. Knock creates sound at higher frequencies, in addition to its fundamental frequency, which can be used to confirm knocking.

http://focus.ti.com/lit/an/spra039/spra039.pdf#page=8
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I keep the originals. I'll check out the PDF.
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