Chassis Ears - An amazing tool (1 Viewer)

[bloc]

Hello all,

I recently used a new-to-me tool to help track down a drivetrain noise and figured more people should know about it. I spent months trying to figure this out, and as soon as I had the tool wired up on the truck, it was completely obvious where my issue was.

Also, I wanted the board's ideas on a way to make the output of it more useful to everyone.

It's called Chassis Ears by Steelman.

Basically it is a set of wired microphones that clip to objects on your drivetrain or chassis, then run them to the control box, where you have a knob to select which mic you want to hear, and a set of headphones. This allows you to pinpoint squeaks or rumbles, and critically, compare them to the other side of the vehicle since often in the early stages of a failure it won't be completely obvious what you are listening to is bad.

Here's the system. Usually it comes with six microphones.

In my case I had reasonably eliminated the engine/transmission/transfer/driveshafts/differentials as the source of my sound. If you want to see my thread on that it's here: New driveline noise after lift - https://forum.ih8mud.com/threads/new-driveline-noise-after-lift.1228472/page-5#post-13722710

I needed to attach the microphones to each hub in a way that would solidly transmit the sound to the mic, then through the system. For the rear, I originally used the caliper bracket, but the second time I set it up this bolt head worked great. Then I strung the wires with zip ties along the rear LCA, into my slider, then up to the front door on that side.

 

[bloc]

For the front I went to a brake line bracket bolted to the knuckle. I would have preferred getting the mic clipped somewhere on the knuckle itself, but didn't see a good spot that would be secure, not get too hot from brakes, and stay out of the way of anything moving, including the knuckle swinging around during steering. Turns out the bracket worked great for transmitting sound.

Then string the wires out of the way to the same location under the door as the rear wire.

Going through the door jamb

Then, the box with all wires, ready to go drive.

Basically you set up your mics in a way that is logical to you, then click through them as you drive. For me, logical was clockwise starting at the front left. I learned the hard way to avoid having the unit on when coming to a complete stop and getting that last little bit of inaudible brake squeak.. I can't even hear it externally, but it comes through the mic attached to the hubs very very well, and is ear splitting. So wait until you are moving.

 

[bloc]

This is what you'll get when driving.



The audio is worse than I wanted because the mic on my phone was picking up the very noise I was trying to track down.


So.. a question for the board.

What is a good way to take a Mono audio out signal and get it into an iphone as though it were a microphone.. so I can use voice recorder or the regular camera app but without using the regular microphone's processing? I tried the basic lightning/headphone adapters and they didn't work. Other stuff on amazon gets terrible reviews and has the same problem. There seems to be a $100 audio converter that might do it.. but is there a cheaper way? The whole point is to get good audio to post here on the board.

If I can come up with a good way to do this I'll post audio of my vehicle now that it has a new bearing in the rear.


Either way.. I have no affiliation but wanted to put this potentially game-changing and not very expensive tool out there to help others.

 

[linuxgod]

Ditto.

I bought a set of these for under $100 after seeing @bloc's post. It was about 10 degrees in my garage when I hooked mine up so I did not take photos. However my setup was very similar, except I hooked the fronts up to (I believe) the brake caliper bolts. I used all 6 mics and also tried to put one on the front and rear diff, just to rule out diff noise that was migrating. Video of my results at Bad rear wheel bearing? - https://forum.ih8mud.com/threads/bad-rear-wheel-bearing.1239216/page-3#post-13668620.

I agree a good mic-to-microUSB/lightning connector adapter would be awesome. My son held my phone up to the headphones, but it just didn't capture the intensity of the sound anywhere near as well as putting the cheap headphones the kit came with on my head.

 

[linuxgod]

Ok so to your original question, what about one of these? At that point I think you'd just need a 3.5mm headphone wire. You might only get one channel of audio instead of 2 but I think it might work, and it's <$25

Amazon product ASIN B08Q38FVQP

 

[RobW0]

This one is not cheap but looks like it might work well.


Amazon product ASIN B07G9N111W

 

[bloc]

Ok so to your original question, what about one of these? At that point I think you'd just need a 3.5mm headphone wire. You might only get one channel of audio instead of 2 but I think it might work, and it's <$25

Amazon product ASIN B08Q38FVQP

Doesn't seem available anymore, and my gut is looking for the mic signal it won't work anyway.

This one is not cheap but looks like it might work well.


Amazon product ASIN B07G9N111W

Same, it's probably looking for the actual microphone signal.



Doing some digging it looks like a headphone to RCA cable and a $30 "UCA202" can get the job done, if using the official lightning to CCK usb camera adapter. Might be able to get it working with my ipad pro plus adapters I already have. Will post if I figure that out.

 

[Fisher23]

Thanks for post that !


Wow I really could have used that to find out ARB sent me the wrong upper bushing on my BP51 rear shock causing a squeaking issue !!

 

[bloc]

Thanks for post that !


Wow I really could have used that to find out ARB sent me the wrong upper bushing on my BP51 rear shock causing a squeaking issue !!

Yeah, I didn't really cover it but you can clip these things anywhere you can run the microphone wire safely. Not necessarily to the driveshafts themselves, but easily to the transfer output and diff housing. Or each shock. Or each end of a given shock. It really is a very powerful tool for tracking down issues.

They do make more expensive wireless versions, but the main advantage is it simplifies the install. In a shop environment I could see it being worth the investment, but for the shadetree people the wired version works great.

 

[linuxgod]

Yeah, I didn't really cover it but you can clip these things anywhere you can run the microphone wire safely. Not necessarily to the driveshafts themselves, but easily to the transfer output and diff housing. Or each shock. Or each end of a given shock. It really is a very powerful tool for tracking down issues.

They do make more expensive wireless versions, but the main advantage is it simplifies the install. In a shop environment I could see it being worth the investment, but for the shadetree people the wired version works great.

Yeah I had the exact same thought. If you're a shop charging for diagnostics the wireless ones are probably worth the extra $100-150 as you could just zip tie them and be done without needing to fish wires everywhere. But for occasional use the <$100 option is killer