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Author Topic: Hear for knock  (Read 19598 times)

Offline billman

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Re: Hear for knock
« Reply #15 on: November 10, 2010, 04:14:26 pm »
That was my thought but with a simple passive system. After it it can be driven to a laptop for amplification.
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Offline billman

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Re: Hear for knock
« Reply #16 on: November 11, 2010, 11:33:02 pm »
A kind member of the DIYAudio forum calculated this bandpass filter for me (thanks Frank)!!!

Graph
http://www.vems.hu/files/Billman/BP%20Filter%20Bode%20Plot.pdf

Schematic
http://www.vems.hu/files/Billman/BP%20Filter.pdf
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Offline Kenny Watson

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Re: Hear for knock
« Reply #17 on: November 12, 2010, 06:13:30 am »
What's the point when a $10 set of det cans works perfectly?

The only point where and "electronic" means of knock detection has any use for me is if it can be intefaced to the EMS.

Otherwise some plastic tube and hearing protectors works way better and than any electronics, assuming you actually know what knock sounds like... :-X

It would be nice if the raw knock value could be datalogged in one of the newer firmwares though for sure.
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Offline billman

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Re: Hear for knock
« Reply #18 on: November 12, 2010, 07:45:53 am »
It is easier to use and can be recorded. I also have det cans but cant find a nice spot on the block to mount it.
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Offline GintsK

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Re: Hear for knock
« Reply #19 on: November 12, 2010, 08:23:51 am »
Billman, take into account tolerances of filter parts. Especially capacitors. -20/+80% are usual ones.
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Offline billman

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Re: Hear for knock
« Reply #20 on: November 12, 2010, 08:27:24 am »
No, the values a small so one can use audio capacitors. They have smaller tolerances

i.e. http://cgi.ebay.com/20-NEW-Wima-MKP10-0-27UF-160V-TUBE-AMP-AUDIO-TDA1541-/170561678354

there are also ones with smaller tolerances but they are more expensive.
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Offline gox

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Re: Hear for knock
« Reply #21 on: November 15, 2010, 06:01:58 pm »
Here is the video with how knock sounds...
http://www.youtube.com/watch?v=GGJZ6kKzLus&feature=related
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E30 2.7 - VEMS,KKK K27.2,Schrick,1bar

Offline billman

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Re: Hear for knock
« Reply #22 on: November 16, 2010, 10:13:54 am »
this has been posted before. They filter the sound very nice.
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