Sound Deadening

I'm hoping to get some time in the future to work on reducing the hst whine in the 2650.

I found a guy who worked on his 3030. The before and after video he made is listed as private but he seems to have had some measure of success. I personally didn't think it was possible, but he claims it's better.

http://www.tractorbynet.com/forums/kubota-owning-operating/273753-soundproofing-b3030-cab-found-something.html

I downloaded a DB meter on my iphone called SPLnnFFT. It's supposed to be accurate. I came up with a 95 DB max level when driving.

It would be interesting to hear if anyone has had any experience tooling around with this type of project.

skeets said:

I have heard of someone drilling into the ROPS,, ( not something I would do) and used some kind of foam to fill the ROPS and it was said to quiet it down some

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I'd be leary of that as well. Heck, I'm afraid to over tighten my drain bolt by accident

One sound deadening installer I spoke with said the glass would be my weak point. I could insulate everything else, but the sound would penetrate the glass...

Another guy who used a ton of material (not cheap by any means) to insulate his diesel ford whatever, 150, 250, 350, I forget, went all out. He took some serious measurements, loaded up all the different frequencies on his laptop and when was all said and done, he managed to quiet it a modest 3.3 DB. Hardly worth the time and effort.

I have yet to find any quantifiable data on acoustic tractor cabs. Especially kubota. Then again I did start drinking early today so lemme work on that one....

BAP said:

Is it a cabbed tractor or open station?

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Cabbed, Interestingly enough the sound level was 5 DB less outside the cab. You would think the cab would insulate against the sound. in this case it seems to reverberate it.

and by the way, I've tried changing the muffler bearings, no effect. I was thinking about replacing the johnson rod next.

It doesn't make sense not to do a better job with the cab acoustics. I have a tough time figuring out kubota corp. Must be a culture thing. Or their too damn cheap.

I looked at the cab illustrated parts diagram and they do have some sort of sound deadening material in the cab. I'm curious what it's made of. I wonder if just by replacing the stock material with say Dynamat or something similar that we could achieve better results.

lugbolt said:

It's a B2650 not a Grand L or ultragrand "M" series. Sound deadening materials such as Dynamat on the flat sheet metal will help some. Use of Jute could also help a little and Jute also has the benefit of temperature insulation. But you still have a bunch of glass to deal with, all the Jute and dynamat in the world won't help all that much with all the glass, and thin glass at that. If the glass were thicker and less "flexible", it would do a better job of insulating some of the noise-but again, if Kubota were to spend more time and money on the cabin of the B series, it could potentially put the price of the tractor considerably higher than it's competitors.

Kubota can absolutely make a cab that's nearly silent inside (Ultra Grand "M" series is one example), but the cost of doing so, would it put the tractor's cost outside of it's competitors?

All materials have a frequency that causes the material to vibrate. Dynamat-and it's copies-can help change that frequency so that it might vibrate at a frequency that's outside the human ears' ability to hear it. That's one reason it works so well in car audio installations.

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I understand what you're saying. Smaller tractor, smaller price tag, competition. Makes sense I guess from a particular standpoint.

It would be nice to have some upgrades available for those of us who have settled for the cheaper model.

Cost is a factor, but function is more important and worthwhile to invest in the long run. We are talking about protecting our hearing. Not some aesthetically pleasing upgrade. As the old saying goes. Safety first. Especially if we plan to spend 10-20 years owning and operating such a machine.

At the very least we should be able to replace the "stock" sound absorption with higher quality material, which I plan to do as soon as I get some time, but may not be possible for another year or two in my insanely busy schedule. I guess I'm just looking for some hard numbers as far as efficiency is concerned. How many DB"s can I get it down? How can I make this better?

I spoke with a "sound guy" and he said the same thing you did. The glass is going to be your biggest hurdle. Again, I think the option for an acoustical sound cab should have been made an option. Better glass. Heck, I was disappointed where I read in the manual that said "Do not activate the wipers when the windows are dry, they may be scratched" Scratched? From a windshield wiper? What the heck kind of cheap glass is this???

I think that a more discernible crowd would invest the money to protect their hearing. I know I would.

My doctor told me I have to come up with strategies to be able to communicate with my wife better. My hearing is shot, and I'll do anything to prevent any further damage. Its too late for me, but why endanger the next generation who will simply "turn up the radio" to drone out the damaging effects of "the nature of the beast," or simply chug along in their tractors doing their jobs and damaging their hearing just because "its the way it's been done."

The subject has been covered before and I'm sure will be again. I think that covering an older topic offers a unique perspective no matter how seemingly repetitive. Besides, maybe if something is discussed over and over again someone may decide to change the way things are done. Thats the way mods usually work. People keep devising their own solutions until the manufactures says hey, we can make some money off this. Let's do it.

I know that a bunch of folks attest to the noise cancelling abilities of the headphones. One guy chimed in on his $1,000 aviation headset and went on about how great it worked and how long he had been using them sucessfully in a different post.

Bose can't (according to the current NRR testing methods) vouch for its NRR rating. I called bose and the tech said there was no rating applied. I sent an email to the tech support division and they did not reply to my question.

I did a small amount of poking. Most of the terminology was beyond me, nor did I want to invest the time to educate myself on the physics of it all.

I did find one video which was easiest to understand. https://www.youtube.com/watch?v=VTx4JgYsW5s

What I get from it, and the other website reading I did (for whatever thats worth...) is that yes it does cancel out the noise. Constant droning types of noise. Like an airplane. However, it fails in the respect that it doesn't react *quickly* enough to maintain an effective NRR level of protection.

The problem with the tractor situation is that the DB's from the whine fluctuate quickly. Anywhere from the 70's to the mid 90's in DBa. (according to my iphone and the $5 app I used to measure sound for what thats worth) If I drive up a hill, use my FEL, or however I increase or decrease the load, it changes.

The question then becomes just how fast does the technology respond, and how does that apply to the varying DB's a tractor is capable of producing. How effective is it really? Whats the measured passive rating of the bose headphones? No one knows or no ones telling. I did read a few sites where some people claimed it was in the 20's but I haven't yet found anything solid.

I think that if it was worth mentioning they would use it as a selling point. Which they don't. I don't usually trust when people boast about a product without hard facts to back it up. (nothing personal) Whether it be bose, or even kubota. I bought stock in company x. I tell my friends, co workers, and the internet in general how great company x's product is. They sell more of the product, stock goes up, I make money.

I read somewhere that the joker in charge of this scam made some ridiculous amount of $ from the rising stock prices. Its insane.
http://money.cnn.com/2016/09/08/investing/wells-fargo-created-phony-accounts-bank-fees/


To sum it up, I guess the bose headset could work well with a pair of earplugs. That's worth a shot. Thanks for the feedback

Alright. I borrowed a pair of the Bose headphones from a buddy of mine this morning. I fired up the beast. I tried the noise cancelling headphones both with and without ear plugs. Then with my Peltor X-Series NRR 31 earmuffs.

First impressions. The earmuff covers are extremely soft and comfortable. Too soft. I cant get a good seal around my ears. Without using both my hands to press them against my temples, the passive sound protection wasn't that great. I would never rely on them for passive ear protection.

I'll admit when I turned on the switch to activate the headphones it was impressive. The low rumbling sound of the engine was virtually gone. However, when I went up my driveway, cruise control enabled, and moving the FEL up and down to give it a good workout, the screeching was still irritating to my ears. It DID NOT offer a substantial level of protection as compared to my Peltors.

I was using the Howard Leight max ear plugs rated at 30NRR. As expected, it's always better to double up with earplugs. Bose or Peltor.

With and without earplugs, wearing each headset, screeching along in my B2650, the $25 Peltors outperformed the $300 Bose noise cancelling ones. BY FAR. I would not invest in a pair of bose headphones to protect my hearing. In this situation they simply do not offer protection against the HST whine. The engine sound however, was muffled to an inaudible level. In all fairness, i'll give them that.

This myth my friends, is BUSTED.

tcrote5516 said:

Bose headphones are not made for or marketed for hearing protection in any way.

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That was the only point I was trying to get across. When operating a tractor, not safe for our hearing.