DB or not DB - Generators

**Herk7769** · 05-02-2012, 07:15 AM

Something to remember about "close to" when talking about decibels of noise. Decibels are on a logarithmic scale.

That means if a generator is rated at 30 is compared to a generator that is rated at 40 at full power, the one rated at 40 is 10 TIMES louder than the one rated at 30.

Decibel - Wikipedia, the free encyclopedia

Another way of putting it; if the "sound pressure" on your ears has a power of 1,000 at 30 DB, the 40 DB generator puts out 10,000 pounds of ear pressure at 40 DB.

A "normal" conversation comes in at 60 DB; at 85 DB, permanent hearing damage is guaranteed. The sound pressure of a 747 at takeoff power is 80 DB.

While sound pressure decreases with the "square" of the distance from the source; you can see that a very small increment of sound measured in DB is a LARGE increase in sound pressure.

We won't go into when the DB level of generator "drone" becomes annoying since that is different for different people.

**Herk7769** · 05-02-2012, 12:31 PM

Quote:

Originally Posted by thehamguy1

I looked up the specs on the Champion 73531i and the Honda eu2001i and they're nearly the same. The Champion at 1/4 load is said to run at 54 dB; the Honda at the same load is 53 dB. The Honda weighs 46.3 lbs; the Champion, 48lbs. The Champions have parallel kits available just as the Hondas do, plus they're stackable as Hondas aren't. And at least one buyer said he saw the Champion at Sam's Club in NH for US$499.

Once again I have to say that 1 DB is 100% louder (twice as loud).

bean · 05-02-2012, 01:27 PM

Quote:

Originally Posted by herk7769

Once again I have to say that 1 DB is 100% louder (twice as loud).

Sorry to disagree, Herk...

An increase of 3db is twice the sound "power", 6db is 4 times the sound "power", 9db is 8 times, etc.

At issue is the use of the word "loud". The db scale is used to measure sound because our ears hear "loudness" in a logarithmic scale. In other words twice as much sound "power" does NOT sound twice as loud.

So 4 times the power "sounds" twice as loud (0db to 3db) and 8 times the power "sounds" three times as loud (0db to 6db).

So although the db scale is logarithmic, so are our ears.

Bean

rkswyo · 05-02-2012, 01:32 PM

Quote:

Originally Posted by bean

Sorry to disagree, Herk...

An increase of 3db is twice the sound "power", 6db is 4 times the sound "power", 9db is 8 times, etc.

At issue is the use of the word "loud". The db scale is used to measure sound because our ears hear "loudness" in a logarithmic scale. In other words twice as much sound "power" does NOT sound twice as loud.

So 4 times the power "sounds" twice as loud (0db to 3db) and 8 times the power "sounds" three times as loud (0db to 6db).

So although the db scale is logarithmic, so are our ears.

Bean

So with the 49db of the Honda verses the 53db of my Yamaha, do you think there will be a disernable difference? Really curious to see. The safety guy at work says I won't.

**Herk7769** · 05-02-2012, 01:38 PM

Quote:

Originally Posted by bean

Sorry to disagree, Herk...

An increase of 3db is twice the sound "power", 6db is 4 times the sound "power", 9db is 8 times, etc.

At issue is the use of the word "loud". The db scale is used to measure sound because our ears hear "loudness" in a logarithmic scale. In other words twice as much sound "power" does NOT sound twice as loud.

So 4 times the power "sounds" twice as loud (0db to 3db) and 8 times the power "sounds" three times as loud (0db to 6db).

So although the db scale is logarithmic, so are our ears.

Bean

Oh. I reread that Wiki entry and I think see, generally, what you are saying. What is confusing me is the table to the right in the Wiki article.
The sound "power" seems to go up by a exponential factor of one increment for every DB.

10 DB to 20 DB is 10 times more sound power.
10 DB to 30 DB is 100 times more sound power.

Where I am not following is the "your ear hears" part. If the sound is 100 times more powerful, why is it not 100 times "louder"?

I am going to move all this to another thread called "DB or not DB"

**Herk7769** · 05-02-2012, 02:03 PM

About Decibels (dB)

I think I see what you are driving at and this article explained it so even I, (dense as I am) can understand it. My problem was equating an increase in power as a direct relationship with "loudness."

When talking about power:

3dB represents a ratio of two to one or a doubling of power.

Thus, a gain of 10dB would represent a ratio of ten to one for power
- so 10 dB is 10 times the power

A 40dB power gain would be 10,000 times the power.

However when talking about Loudness:

A 10 Db gain would seem to be about twice as loud
And a 20 Db gain would seem to be about 4 times as loud.
And a 40 Db gain would seem to be about 16 times as loud

ng2951 · 05-02-2012, 04:47 PM

There have not been a lot of comparisons between Honda, Yamaha, and Champion. One I read about shows that at full load all are almost equally as loud at 7 meters.

Still I did find one interesting PDF on the Internet that shows just how different these inverter style gensets are when compared to a contractor style genset.

Check this link Honda EU2000i Generators in Single and Parallel Operation

It really is nice for some college students to show just what real db numbers are...

rkswyo · 05-02-2012, 05:50 PM

I just received the Honda eu3000is today. Took it out of the box, attached the cables to the battery, added oil and gas and fired it up. All I can say is wow! This thing is quiet! As a comparison I pulled out my Yamaha ef2400 and started it up about 10ft away from the Honda. The Yamaha is quiet but the Honda is noticeably quieter. I tried both at idle as well with loads and the Honda is quieter in all. Not a huge difference but noticeable. So I answered my earlier question if the difference between DB and DB is actually noticeable to the human ear. I can say for sure it is to mine. Now I have to get the Yamaha cleaned up and ready to sell. It has served me well and would still highly recommend it. The Honda started the air conditioner on my TT with no problem.

Mad4sax · 05-02-2012, 07:16 PM

Just used a meter to check sound levels around the house. Held it at 5 feet from source.

Birds outside singing 50
TV at normal level 62
Dishwasher running 74
My Yamaha 2000 74 in Eco mode
My Yamaha 2000 88 top idle
My sweet 1 year old baby girl 102 (she was mad)

I only have about 60% hearing so my generator seems very quiet to me.
This is why I used a meter to measure.

**Herk7769** · 05-02-2012, 07:29 PM

Quote:

Originally Posted by Mad4sax

Just used a meter to check sound levels around the house. Held it at 5 feet from source.

Birds outside singing 50
TV at normal level 62
Dishwasher running 74
My Yamaha 2000 74 in Eco mode
My Yamaha 2000 88 top idle
My sweet 1 year old baby girl 102 (she was mad)

I only have about 60% hearing so my generator seems very quiet to me.
This is why I used a meter to measure.

My flight manual says ear plugs required at 85 DB.
You house must be a treat

Keep that baby HAPPY

fast murray · 05-02-2012, 09:03 PM

My old car stereo would hit 141.5 dB back in the day. I didn't wear hearing protection to drive around. People said I'd be deaf by the time I was 18, then 21, and so on. I've grown up and I can still hear but with kids in the truck I don't crank on it. Back on topic, I had always read you had to double amplifier power to see a 3dB increase which sounded twice as loud.

rkswyo · 05-02-2012, 09:53 PM

Quote:

Originally Posted by fast murray

My old car stereo would hit 141.5 dB back in the day. I didn't wear hearing protection to drive around. People said I'd be deaf by the time I was 18, then 21, and so on. I've grown up and I can still hear but with kids in the truck I don't crank on it. Back on topic, I had always read you had to double amplifier power to see a 3dB increase which sounded twice as loud.

Fact is that your hearing has suffered from cranking your tunes. (I did the same thing.) Once the damage is done, it won't recover. I used to do allot of things without hearing protection. I wear hearing protection all the time anymore. I have to at work and it has carried over to home as well. We have annual hearing tests at work as required by OSHA. Thankfully mine has stayed steady. I attribute this to being well informed on the job site and taking that attitude home. They encourage us at work to take hearing protection home with us.

**Herk7769** · 05-02-2012, 10:59 PM

I am 62 and wear hearing aids. While I never was much of a loud music person, I was and still am a fresh air fiend. Wind blast destroyed my left ear and my aviation career put paid to the other one and finished the job on my left.

Ear protection was required (even in the early 70's) and by the time I had 500 hours in the C-130 I was wearing double hearing protection.
Double Protection is ear plugs under ear muffs.

rkswyo · 05-02-2012, 11:08 PM

Hearing loss after the Industrial Revolution greatly increased. Some hearing loss may attributed to old age however most hearing loss is due to repeated exposure of the "loud" things in our daily life.

Namchief · 05-03-2012, 01:54 AM

Snowmobiles in Wisconsin have to be 88 DB or lower by law and trust me it isnt as loud as you would think it would be. I ride Harleys and if just around town I dont worry about it but on long rides I wear ear protection for the wind noise. I think repeated and prolonged exposure will cause damage

bean · 05-03-2012, 06:26 AM

Quote:

Originally Posted by herk7769

I think I see what you are driving at and this article explained it so even I, (dense as I am) can understand it. My problem was equating an increase in power as a direct relationship with "loudness."

Herk, Yeah "loudness" a tricky subject because you would think that two of the same generators running side by side would be twice as loud as one generator. But is ain't so, and this just doesn't "jive" in most people minds.

Thanks for the link,

P.S. Not to confuse the subject, but two generators actually creates less than 2 times the noise "power" because each source of noise is indepenent, so some of the noise cancels out. It will actually be about 1.41 times more noise "power".

Bean

SaskCampers · 05-03-2012, 07:46 AM

Quote:

Originally Posted by herk7769

Something to remember about "close to" when talking about decibels of noise. Decibels are on a logarithmic scale.

That means if a generator is rated at 30 is compared to a generator that is rated at 40 at full power, the one rated at 40 is 10 TIMES louder than the one rated at 30.

Decibel - Wikipedia, the free encyclopedia

Another way of putting it; if the "sound pressure" on your ears has a power of 1,000 at 30 DB, the 40 DB generator puts out 10,000 pounds of ear pressure at 40 DB.

A "normal" conversation comes in at 60 DB; at 85 DB, permanent hearing damage is guaranteed. The sound pressure of a 747 at takeoff power is 80 DB.

While sound pressure decreases with the "square" of the distance from the source; you can see that a very small increment of sound measured in DB is a LARGE increase in sound pressure.

We won't go into when the DB level of generator "drone" becomes annoying since that is different for different people.

I used to work on fighters for over 20 years and when they are chained down to do a burner runup the noise level can exceed 165db. We wore ear plugs and ear defenders and it was still loud standing beside the aircraft. I have included a link to a chart from an F22 which are quiet compared to the older century series a/c.
BLUE RIDGE RESEARCH AND CONSULTING

**Herk7769** · 05-03-2012, 07:55 AM

Quote:

Originally Posted by TheSasks

I used to work on fighters for over 20 years and when they are chained down to do a burner runup the noise level can exceed 165db. We wore ear plugs and ear defenders and it was still loud standing beside the aircraft. I have included a link to a chart from an F22 which are quiet compared to the older century series a/c.
BLUE RIDGE RESEARCH AND CONSULTING

The Wiki chart I was using seemed low to me as well; but the example was repeated in several sources I looked at.

I can only assume the DB was read quite a distance from the plane.

ng2951 · 05-03-2012, 09:15 AM

Ear plugs and muffs can only provide so much protection. When the sound pressure levels get to a certain point they are being conducted through flesh and bone to the unprotected side of the ear.

Lou, our range engineer has dual hearing aids from 105s howitzers. It sure makes arguing with him difficult especially when the batteries need replacing...

MilCop4523 · 05-09-2012, 06:34 AM

Quote:

Originally Posted by herk7769

My flight manual says ear plugs required at 85 DB.

I'm getting out of the Military Police due to hearing loss from working Air Field Security and having to flip on he siren all the time doing traffic.

Guess we are expendable trade because we never got the 85db briefing in any manual.

You may also like: