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det cans, listening for knock

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has anybody used DIY det cans and give some insight , a lot of people say they do better job than some " modern electronic " ones .

Can't say I ever have personally. I know some people swear by them, but I can't personally see them functioning as well as a professional audio knock detection system with that uses digital signal processing. I guess the price point is somewhat appealing though.

Any of our members had personal experience with them? Good? Bad? Please comment :)

I've used them before and it really would surprise you how good they are Andre, might be worth making a set purely for testing, once you've got the hose into the ear piece you can run a smaller piece of vac line from that directly to your ear.

I use electronic det cans on a daily basis, like I said I've used these and also the electronic and prefer the electronic det cans. When I'm hooking a car up to the dyno I'm usually adding multiple sensors so there's wires going everywhere, if I was using the 'DIY cans' the inflexibility of the hose would cause issues as you need to plan your hose route properly. You can't afford to close the hose so you need to avoid kinks in the line and also you can't shut it in a door or window like you can with cables.

That said, they are a really useful piece of equipment. In an ideal world the car would have all the sensors fitted so all that would be needed would be these. That would make for a simple installation, allowing you the luxury of picking a good route.

Since your using a flattened copper tube you can just loosen a nut and instal it virtually anywhere on an engine, with a knock sensor you need to find a suitable threaded hole. This can also be a limiting factor as generally you'll only have good access to the top of an engine, getting bolted to the block with a clear run for your hose will be difficult. With being bolted to the top you'll get more valve train noise, but the noise volume compared to electronic is lower, however knock is very clear through them, even just the light crackles you get before full knock is clear and audible.

I've been using analog det cans, looking quite similar to those shown, have built a modified hearing aid with the microphone glued to a sheet metal clamp and now and finally using the Plex knock Monitor v2.

Det cans: For me simply not loud enough (Chris250 tip with the vac lines straight into the ears may help facing that issue)

DIY electronic cans: too much noise and interfering signals on high rpm/engine noise. The microphone got simply overmodulated and you hear a low of cracking noises

Prof. knock setup: Great! For me, doing this for only 2 years on a sideline job and hobby, this was the first setup I became confident with using it for knock detection. Especially if your new at listening at knock, those features like flashlights, beeps and a display showing you the sensor signal giving you the confidence and feedback you may need while listening for knock.

Especially comparing my DIY electronic knock setup to the professional, it makes a whole lot of difference listening to a filtered engine noise, than to an unfiltered one.

In any case: An electronic setup is only as good as its calibration. So I guess it's not as bulletproof as analog det cans, you can't do much wrong with except to mounting.

I tested knock sensor wired up directly into the mic jack of my lap top with a 2w 100k resistor on a 2jz ge with low pass and high pass filter i can clearly hear everything inside the engine, just cant make it knock yet cuz its completely stock maybe advance it a bit and clamp a fuel pipe :D

I use det cans for listening knock a lot, and sometimes i prefer them better than audiable phormula knock detection system.

Most of the time I use this det cans for engines where it is very difficult to mount audiable knock detection system in porper possition.

With det cans is possible to hear engine knocking very well.

but You need to remember not to close the tube into car doors

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