Our Kenmore dishwasher that is 10-11 years old is making a noise like
it isn't going to last much longer, so we are replacing it. I've
looked at several models, but I'm leaning toward a couple of Bosch
dishwashers. One is rated at 52 dB but comes only in black. The
other is rated 54 dB, but comes in black/white/stainless steel.
Stainless steel would match our refrigerator. Is there much
difference between 52 dB and 54 dB in a dishwasher?
Both will be very quiet. Most of us would not hear the difference.
Do some research on reliability though. Bosch is highly rated for cleaning,
noise level, but I've read a lot of complaints about service. Our local
dealer no longer stocks them.
Every 6db is a doubling in the volume, so going from 0db to 6db is
twice as loud, going from 6db to 12db is another doubling of the
volume making 12db four times as loud as 0db, going from 12db to 18db
is another doubling, making 18db eight times as loud as 0db.
(assuming 0 db is the volume you call "normal" or your zero
calibration point which can be any thing you want to calibrate it to).
So for example if you calibrate the sound of a cricket at 10 feet to
0db, then you increase to 18db the cricket will be 8 times as loud as
So a difference of 52db to 54db would be about 33% louder, most folks
would hear that easily.
I went shopping for a furnace the only spec I cared about was db, the
salespeople thought I was nuts. I told them I care less how efficient
it is, I want the quietest one regardless of energy. Unfortunately
the manufacturers could not even tell me their db ratings (Trane,
Bryant, Lennox, etc)
Most could hear the difference if asked to compare the two levels side
by side. However, 1db or less is generally not discernable. And even
if you can tell that one is louder than another, I would doubt it
would be enough to make it a deciding factor in a dishwasher. For
example, here's a link to some common sounds and their associated
db. 50 is a private office or soft music. 60 is conversational
speech 65 is a business office or soft classical music. Considering
that, I wouldn;t worry about 52 or 54 from different dishwashers.
Also, and perhaps more imptortant, is what the noise sounds like.
You could easily have dishwasher A at 52db being more annoying than
dishwasher B at 54 because of what the sound is, as opposed to the
difference in level.
I have a GE Profile that is very quiet, the water sounds like a gentle
water fall. In fact, when I first turned it on, I thought there was a
leak. In general, I think Bosch is over priced and I've heard plenty
of bad stories about problems and repair costs.
On Aug 9, 3:22 pm, firstname.lastname@example.org wrote:
And you could always knock down the sound a little more by packing
some fiberglass between the cabinets and DW on the install provided
your not blocking any kind of fan or anything, also under, over, and
behind. If a Kenmore lasted 11 years why change? I have a Kenmore on
it's 10th year, no problem other than a cherry pit that blocked the
drain once. Never let a cherry pit get in your DW, no fault of
Kenmore on that one.
I've never heard this before. AFAIK, a 10 decibel increase is twice
the volume. It was chosen that way to be a round number, 1 bel.
I verified this by looking the URL's you gave in your second post,
although maybe they don't say it quite the way I have.
http://www.gcaudio.com/resources/howtos/loudness.html does say,
however, that 2 bels, 20 decibels, is about 4 times as loud, and 30
decibels is about 8 times as loud. All of these measures of loudness
or volume -- not sure which is the better word -- are as perceived by
our ears, the ears of healthy people. (Or our ears on average, if
they vary much from one healthy person to another. Maybe that is why
the chart says "about", rather than "exactly".)
The scale is logarithmic because of the way our ears and brain work
together. If we only went by the energy or force or whatever that
went into making sound, it would be misleading. A sound that is the
result of twice as much energy does not sound twice as loud. The
difference seems to be a lot less than that.
Same thing in the opposite direction. When we hear a tiny sound,
maybe the sound of a pin hitting the floor, or a leaf, it's thousands
of times less strong than normal talking, but it doesn't sound like
that to us. The sound is smaller, but not that much. It's still
I've often thought that the reason it works that way is because of the
three bones in the ear, and that one of them is moved when the general
level of sound is higher or lower, to move the fulcrum and change the
mechanical advantage of the ear bones. So that small sounds can sound
louder and loud sounds can sound less loud.
OTOH, it might not be the bones at all but the brain.
One guy with the kind of background to know told me that I'm wrong,
it's not the bones, but typically I'm not yet convinced. I asked
several physics Ph.D's what happened to light after it was no longer
light in a sealed room, and didn't it turn in to the same amount of
heat that it took to make the light in the first place, and all but
one either couldn't say, or thought the answer was no. One thought
the answer was yes, and I'm pretty sure he and I are right.
I guess the reason I think it is the bones is that we could have
gotten by with only 1 or 2 bones, I think, if they were only going to
transmit sound from the eardrum to some nerve. The purpose of the
third bone is not strength. They are all barely attached to anything
else afaik. The purpose seems to me to absolutely be some kind of
regulation, automatic volume control, similar to other mechanical
controls I've seen but forgotten throughout my life, especially before
electronics was so dominant.
The volume control on a Victrola we had for a while was the segmented
door, like the lid on a roll-top desk, that could be pulled in front
of the wooden horn, in models where the horn was not atop the tone arm
but below it in the cabinet. Really only one part involved there, and
the phyical volume control was arithmetic, not geometric or
The iris on a camera, modeled right after the iris in our eyes,
decreases the area available for light to enter by the square of the
diameter. That's it. That's what I compared the bones of the ear
too, but I think they might be more powerful if the fulcrum really
Maybe I asked the wrong question to the guy I talked to about the ear.
Does the fulcrum move? I should have stuck with objective questions
instead of asking about conclusions.
IIRC the steam/speed/power control on a steam locomotive is a little
more complicated than what I expected, but I don't remember if it is
comparable to a 3 part device like the ear.
I'm pretty sure I've seen other mechanical controls more complicated
than an iris or locomotive, maybe involving three parts and but my
memory is a blank now.
If the fulcrum in the ear doesn't move sometimes, we do we have 3
bones and not just one (or two, but I'm not sure what the second does
or would do)?
Since 2db is one fifth of 10 db, it woudl be the fifth root of 2, to
give the ratio; minus 1, to give the fraction louder; and times 100
percent to give the percentage louder. The fifth root of 2 is a
little under 1.2, so a little under 20%. Checking with a calculator I
think 1.15 to the fifth power is a little over 2, so about 15% louder,
though how that converts to the way people would perceive it, I'm
still not sure. I guess we've already allowed for the hearing oddity
of people by using decibels, but now we're converted it back to
loudness -- read that ENERGY -- so I think that removes the advantage
of using bels and decibels. It removes the reason they were invented
in the first place, to provide a number that would correspond to our
hearing, as opposed to the amount of energy used in making the sounds.
So even though I willingly did it at the start of the paragraph, I
think it is misleading to convert back to energy. What we should do
is learn to understand, to have a good feel for what a decibel
represnets. Their purpose is to represent sound, but the problem is
that we don't have ongoing feedback of how loud in decibels something
After measuring and experience and practice and visualizing, we know
an inch when we see one. We can see two inches and know that
something is twice as long as an inch. But even if we memorize the
charts that you yourself pointed us to in your second post, we don't
really appreciate how loud 20 db are, and even less so the ratio of
two levels of sound, or, given one sound and a decibel difference, the
level of the second sound.
I'd say that in general, we can visualize things much more than we can
audiolize things. Maybe that's why there is no word audiolize.
I don't think you're nuts.
I'm glad you just gave me the idea, and I hope by the time I need a
furnace, they will rate them by loudness. They probably won't,
I have a 3 speed indoor furnace fan, only adjustable by connecting a
different wire to the power. It's too loud, but it's set on the
slowest speed. I changed it anyhow, on the slim hope the schematic or
the color was wrong, but they weren't.
And some of the posted info. was wrong/incomplete!
Several comments reference to Decibels.
1) The decibel is of course one tenth of a Bel. The Bel is defined as
"The logarithmic ratio of two powers (volumes)". It is a unit of
comparison named after Alexander Graham Bell a Scottish immigrant who
invented the telephone in Canada.
2) If you double the power (volume of sound etc.); The logarithm of 2
is 0.3; or 0.3 Bels. Which is of course 3 Decibels!
3) The third thing wrong is that Bels/Decibels etc. are a 'comparison'
or ratio of two powers, or in this case, two volumes.
It is incorrect to say something is X Decibels.
The question is immediately 'In relation to what'.
So the dish washer is 50 something decibels louder than, what???????
Dead silence? A mouse squeak???? A teenager's ghetto blaster at full
volume?? A loud motorbike next door????? A radio plying very quietly
as you drop off to sleep????
Decibels have to be referenced to something.
Anyone reading car magazines such as Car and Driver may have noticed
that they will say that the sound level inside the cabin of a certain
vehicle is say 75Dba. While another vehicle which is twice as loud,
say, has a sound level of say 78Dba.
That tells us that the measurement (comparison) is Decibels and that
it is in reference to some agreed standard of "Zero Dba".
There are number of different references used by different industries/
types of technology.
The reason for Decibels is; a) Convenience; think back to adding and
subtracting logarithms in school and then anti-logging the result!
Right; remember that? We 'did logarithms' around about age 14 IIRC.
About grade 8 or 9? b) Logarithmic response is the way the human ear
So if two people are hammering on a wall rather than one person
hammering on a wall it will be TWICE as loud and therefore 3 Decibels
Louder. And humans will be able to perceive the difference in noise
Actually its more correct to say that a doubling of distance from the
source gives you a 6db drop. So increasing 6db gives you a perceived
doubling of the volume, as though you came twice as close to the
source. This is, of course, for a point source sperical wave
emination, (line sources or cylindrical waves have a less than 6db
loss for each doubling up to a certain point).
I work with audio.
I stand by my statement that it you will hear the difference between
52 and 54, all other things being equal like the frequency and pattern
of the noise, etc.
At my mixing panel here when I go from -6db to 0db the difference is
quite a lot.
Agree completely. A 6 Db increase is four times the power and is
clearly discernible by most human ears!
It wouldn't matter if you were changing from one milliwatt to four
Or from one watt to four watts. The change is +6Db.
If I double the power/volume the logarithm of 2 = 0.3 Bel. (i.e. 3
If I double volume again again the logarithm of 2 = 0.3 Bel (another 3
The total increase in volume is four times (doubled it twice) and is
therefore 3 + 3 = 6 Decibels.
When it comes to distance from the source of a noise that is something
different. But you could think of the volume of air between you and
the noise source being twice as wide, twice as high and twice the
distance away. So the sound/volume would probably decrease at at least
a square root rate? Let's not get into that?
Yes in a sphere the power will roll off much faster, than say a
cylinder, I've always heard 6db per doubling for sperical point
Also lets not get into the frequency of the noise coming from the
dishwasher, 1000Hz is perceived much noisier than 100Hz at the same
db. At least this thread dismisses those who would say "its only 2db
difference you wont hear it" db is logrithmic due to the sperical
nature of the emination. Sort of like the difference between a 10
inch pizza and a 12 inch pizza, vs a 16 inch pizza and an 18 inch
pizza, both sets are 2 inches bigger in diameter but 16 to 18 gives
you more extra pizza than the whole 12 inch. If that makes any sense.
I think I would phrase it that doubling the power results in a 3db
But more important is that power and volume are not the same thing.
So there is no contradiction between what I said and what you just
Because of the way our ears and brains work, it takes a lot more than
twice the power to result in twice the loudness. That's a reason,
maybe the whole reason, that Bels and decibels were defined.
If we heard sound in a linear way, we could have measured it using
ergs, or dynes, or watts, I'm not sure what, but one of the already
existing or newly created measures for power.
on 8/10/2007 4:15 PM Jud McCranie said the following:
You can subscribe to the complete Consumer Reports testing results at
$26.00 for one year, or $5.95 per month. If you are a subscriber to the
magazine the annual cost is $19.00.
It is more comprehensive than the magazine in that you can search for
previous testing and results.
I picked up the August issue on the newsstand. I was wondering about
their website - it says that you can subscribe to the website and get
the ratings. But does that include the text? The text in the
articles is just as important as the ratings, IMO.
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