Knock sensors

[Terry Martin]

> Tom Cloud wrote:
> 
> >I don't know if he's saying that those frequencies are the
> >resonant frequencies of those blocks -- I cirrusly (a Cloud
> >joke) doubt it  ... I'd think the mass of the 5.0 and 5.8 would
> >make for a much lower resonance than 9.5k or even 6k.  Does anyone
> >know?

I would suspect a harmonic at those frequencies more than resonance.
While resonance is frequently the cause of harmonics, one can produce an
exceedingly energetic harmonic with no resonance at all. 

Terry