New Predator 4400 inverter.

[llamb]

Originally Posted by Jay2504

I’m wondering if there is some kind of math formula that would let you convert the 12 foot 67db measurement to what the dB would be at 23 feet, which most generator sound levels art measured at? Anyone know?

Not sure it's accurate as I'm not a sound engineer, but my google fu is typically pretty good.

https://www.omnicalculator.com/physi...ce-attenuation

67db at 12' comes out to be a bit over 61db at 23'

[rsdata]

Exactly. That’s why I’m wondering why they decided to change their own standard to make the product look worse compared to their older product.

I believe Harbor Freight is just the importer of product and does not manufacture the products they carry. The predator brand name is probably carried on products made at different factories using each factory's engineering and technical facilities and have no ties with each other.

Honda I believe operates differently but I suspect that is the only example.

[Larry-NC]

Originally Posted by Jay2504

I’m wondering if there is some kind of math formula that would let you convert the 12 foot 67db measurement to what the dB would be at 23 feet, which most generator sound levels art measured at? Anyone know? For what it is worth,in the real world, my SIL has a Champion open frame inverter 4000/3500 watt generator. It is way quieter than my “open frame” Champion of the same wattage. It also has a lower, less objectionable tone. It runs his 15K A/C at less than half throttle. Jay

Loosely, the Sound Pressure Level drops as the cube of the distance from the source.

Intuitively you can see this for yourself. For a perfect omnidirectional point source radiator, consider a sphere at distance X. The energy is spread across the surface of that sphere. You, the ear, are a point on that sphere. At a greater distance, the total energy spread across the sphere is constant, but the energy at any point is reduced because the area is increased.

Since the formula for the surface area of a sphere of radius r is
four-thirds*pi*r(cubed), as r increases, the energy decreases by the cube of the distance.

[Retired1stTimer]

Originally Posted by mikeyk101

Well it looks like Harbor Freight has some new models of the Predator out now. One is the Predator 4400 and looks pretty interesting. It's priced at $599 right now and comes with larger wheels and an attached long handle for moving it. It is also advertised at 77lbs which is over 20lbs lighter than the 3500. It claims that it has a sound output at 67db. Now I wish I had waited as this would be more convenient and have a bit more power.



https://go.harborfreight.com/www58067/

One thing I noticed though is that it seems to be pull start only, no electric start like the 3500.

I may have to check into buying one of these. But looking further into the details of the unit, like almost other generators Harbor Freight sells, the wheelkit and the handle are a separate purchase and does not come with the generator, but is only like $35-40 for the kit. Thanks for the info!

[BriaBeck]

Originally Posted by 5picker

Go big or go home... 9000w dual fuel inverter!
Parallel two for 18,000w!Attachment 252252

Uh... Hey Man... Uh... ya know.... Can I plug in?

[BriaBeck]

Originally Posted by rsdata

I believe Harbor Freight is just the importer of product and does not manufacture the products they carry. The predator brand name is probably carried on products made at different factories using each factory's engineering and technical facilities and have no ties with each other.

Honda I believe operates differently but I suspect that is the only example.

HF doesn't manufacture anything, but they do design (or at least write specifications and then have product built to meet) for many of the products they sell. They usually have several different manufacturers build the same product (that is the reason for the same product having several different SKU#'s) to avoid supply chain problems.

[IDguy]

Originally Posted by mikeyk101

67db falls between a regular conversation level and a vacuum cleaner or hair dryer. That would still be a reasonable level. The difference between the 3500 (57db) and the 4400 (67db) is only 10db. It would be a bit louder but not a tremendous increase. For comparison, the difference between a hair dryer (70db) and a lawn mower (90db) is 20db.

67 db is awful and will annoy neighbors in the whole campground. Decibels means factors of ten. 10 db is ten times louder.

https://www.animations.physics.unsw.edu.au/jw/dB.htm

[Ed from Riverside]

I thought this was a interesting read...

https://www.fs.fed.us/eng/pubs/pdfimage/92231301.pdf

[mikeyk101]

Originally Posted by IDguy

67 db is awful and will annoy neighbors in the whole campground. Decibels means factors of ten. 10 db is ten times louder.

https://www.animations.physics.unsw.edu.au/jw/dB.htm

Well if the sound level of a hair dryer is enough to annoy neighbors throughout an entire campground, that is not the place I want to be. Just normal things I would be doing will end up annoying the whole place and not just with a generator at 67db...

10db does not equate into 10 times louder. Actually a 10db increase means twice as loud. 20db is 4 times as loud.

[mikeyk101]

Here is a chart with info.

[Ed from Riverside]

Originally Posted by mikeyk101

Well if the sound level of a hair dryer is enough to annoy neighbors throughout an entire campground, that is not the place I want to be. Just normal things I would be doing will end up annoying the whole place and not just with a generator at 67db...

10db does not equate into 10 times louder. Actually a 10db increase means twice as loud. 20db is 4 times as loud.

With you there.

I have an ultimate 4550 Furman and in the bed of my truck, with the tail gate up, running my a/c, measured it a couple of weeks ago and did not break 65db at 15 feet. I asked my camping neighbors on either side if it bothered them and i received a no, not at all. so maybe placement of the generator is the key?

[Odyknuck]

Originally Posted by bikendan

Don't believe that comparison. I have a Champion 3500w open frame contractor style generator that's rated at 65db and unless you're over 100 ft away, you can't have a regular conversation. And 67db exceeds the National Park's noise limit and most state park's noise limit.
Totally inappropriate generator for campground usage.

I had that same 3500 generator for my last toy hauler. It was so loud my friends insisted I did not run it at night. It sucked when it was 90 degrees. My current 5th wheel has a built in Onan 5500 and its very quiet in comparison.

[mstred]

Originally Posted by mikeyk101

Ok, never mind. Don't buy this generator or you will be sorry...

Ever notice that there are always people that are experts on everything :-)

[robo44]

Originally Posted by BriaBeck

The problem is, even though it is an inverter, it is still an open frame generator. I'm assuming that the dB rating is probably in "ECO" mode, at only 10% load or there abouts. At 75% or even 50% load, I don't see how this thing could not be worse than fingernails on a chalkboard in a campground setting.

X2,000

[stallsmi]

Originally Posted by mstred

Ever notice that there are always people that are experts on everything :-)

That's why this forum (and some others) sometimes becomes impractical.

[bbmuse]

Originally Posted by bikendan

Don't believe that comparison. I have a Champion 3500w open frame contractor style generator that's rated at 65db and unless you're over 100 ft away, you can't have a regular conversation. And 67db exceeds the National Park's noise limit and most state park's noise limit.
Totally inappropriate generator for campground usage.

I totally agree! It will be too loud as it is now.

[SKND]

Originally Posted by mikeyk101

Well if the sound level of a hair dryer is enough to annoy neighbors throughout an entire campground, that is not the place I want to be. Just normal things I would be doing will end up annoying the whole place and not just with a generator at 67db...

10db does not equate into 10 times louder. Actually a 10db increase means twice as loud. 20db is 4 times as loud.

I think this is a better description of a 10db increase. Note perceived/wattage difference.

A change of 10 dB is accepted as the difference in level that is perceived by most listeners as “twice as loud” or “half as loud”. To produce an increase of +10 dB you need to increase power (watts) by a factor of 10.

[JoeInPA]

I called my local Harbor Freight, and they have some of these in stock, with the most qty in stock tracking pretty much exactly with the rated decibel levels (not always 1:1 higher decibels for higher watt generators), which tells me the quiet ones of all wattage are getting snapped up by campers, and the 65 decibel and louder ones are sitting in the store. Of course, contractors might not care as much about noise, since worksites are already loud, but I still think one way to gauge noise (not to mention quality) on generators is by how many / few are in stock wherever you go. All that said, I am heading over to Harbor Freight after work to have a little look-see for myself.

[BrandonSmith]

As mentioned already in this thread, the predator 3500 is rated 57dB at 23ft away and 25% load (p. 2, Specifications, https://manuals.harborfreight.com/ma...3999/63584.pdf).

The new 4400 is rated at 67dB, at 12ft and 25% load (p. 2, Specifications, https://manuals.harborfreight.com/ma...3175415431.pdf)

HOWEVER, using a sound pressure level calculator to calculate the decibels at the same distance as the 3500 (23ft), the 4400 at 25% load at 23ft is 61dB. And keep in mind, that's at 25% load of 4400W compared to 25% of 3500W.

57dB vs. 61dB: This 4dB difference falls between the "barely perceptible" range and the "clearly perceptible" range. You might notice a difference or you might not. At the same watts, the 4400 may be equivalent - you just don't know until you test and measure.

[Wes Tausend]

Originally Posted by kcmusa

In the audio world, 3db is double the power. ( .1 watt to 1 watt)
10db is 10 times the power (.1 watt to 10 watts) but is only perceived at twice as loud.
But 67db is to much for a campground. Most state parks say a 60db limit.

...

It might be interesting to see what Onan has done OEM on common RV's.

Most full-size Class C's come with a built-in Onan QG4000 4k generator.
This Onan website specs it at:

"68 dB(A) readings at 10 ft (3 m) half load"

And mention that:

"National Park Service sound level requirements 'are' (60 dB(A) @ 50 ft)"

Good thread.

Wes