German car magazine AUTO BILD and the sound and vibration measurement company Brüel & Kjær have teamed up to perform really thorough measurements of the noise levels inside the cabin of different passenger cars. In the article Searching for The World's Quietest Car, presenting the results of testing 14 different car models, we found a list of questions and answers about noise in cars that can be useful to gain some insights from.

1) Do bigger wheels roll louder?

"Hardly! An experiment with an Audi A3 showed that when the tyre size was increased from 225/45 R 17 to the next larger variant 225/40 R 18, the road noise only increased by half a sone*. This is hardly audible."

* A sone is the unit of perceived loudness. In contrast to the decibel, which only measures the physically detected sound, the sone provides a more realistic evaluation of how humans experience noise.

Our take on the answer above is that this particular test was made on surfaces in Germany. If testing cars on rougher asphalts/road surfaces as in e.g. Sweden, the noise difference between different wheel sizes is likely to be larger than in this case.

2) Is a four-cylinder louder than a six-cylinder?

"Yes! Under load (when accelerating from zero to 100) a BMW 435i (with a 3.0 litre six-cylinder petrol engine), for example, measures nearly 30 sones, whereas we measured 1.5 sones more with a 428i with the 2.0 litre, four-cylinder engine. One reason, of course, is the power deficit with corresponding consequences for the transmission layout, and the different rev levels."

3) Is a convertible with a fabric roof louder than one with a steel roof?

"Yes! A comparison of high-speed cruises shows that the fabric roof makes about twice as much noise as a fixed roof. More precisely, the MX-5 with cloth cap produces 105.3 sones, its brother with a retractable roof only 80.4 sones."

4) Is a convertible with open roof louder?

"Yes! The moment the retractable roof is open, the wind noise increases dramatically. We could establish up to 18 sones difference."

5) Is a petrol engine quieter than a diesel engine?

"No! At least for the Golf the following applies – a TDI behaves with more restraint during sprinting with the accelerator pedal completely depressed than its equivalent with a TSI engine. The latter achieved higher revs but resulted in more noise."

6) Can you hear the engine at a speed of 100?

"Yes! For this example, we once again picked the Golf 2.0 TDI – its motor hums quite audibly at this speed. Only at 130 km/h and above do the wind and tyre noise drown out the TDI growl."

7) Is a station wagon louder than a sedan?

"Yes! An Audi A3 Sportback (at a constant measured speed of 100) is actually a bit louder than the identical A3 with a boot. In fact, there is only 1.4 sones difference between the Sportback and the notchback."

8) Is the Rolls quieter at the back than in the front?

"Yes! The quietest place in the Rolls-Royce Ghost (at a speed of 100) is at the rear to the right, even if the driver, strictly speaking, has to endure more noise – a difference of 0.9 sones. Only very sensitive people are likely to detect this."

9) Is the rear shelf important?

"No! If there is no plate behind the rear-seat backrest, then you might think that one sound absorbing element is missing. As far as the Audi A3 Sportback is concerned, there is no measurable difference with and without the cover."

10) Does one really only hear the clock in the Rolls-Royce?

"No! The clock is silent. If you can hear something, it’ll be the V12 and the ventilation."

11) Are electric cars the quietest cars in the marketplace?

"No. The electric cars show that a silent motor alone is no guarantee for in-car comfort – noise is also generated by wind and tyres."

Brüel & Kjær is using very sophisticated instruments when producing detailed in-car noise measurements, but if you yourself wish to make your own sound measurements, we would recommend that you get a decibel meter (also called a sound level meter). One great meter that we would recommend you look into is the REED Instruments R8060 Sound Level Meter with Bargraph, Type 2, 30 to 130 dB.

When suddenly facing loud noise and there is no time to put on earplugs or earmuffs to protect hearing, it is essential to know how to effectively use one's hands to protect the ears. However, it seems way too common that people do it the wrong way which can both mean inadequate protection and also even amplify the uncomfortable sounds that you want to protect your hearing from.

It seems especially common among kids to intuitively protect their ears by cupping their hands over the ears. This is not a good way and will not provide sufficient protection. An alternative but only slightly better method is to push on the tragus (see image below) to cover the ear canal. However, by far the best protection using your hands is provided by inserting a finger into each ear canal. These so-called finger plugs can protect the hearing almost as good as earplugs, so can be seen as a great alternative when you didn't bring any earplugs or earmuffs without you and/or when you want to protect yourself from a very quick exposure to loud noise.

This recommendation is supported by a research study. In order to assess which method of natural hearing protection by using one's hands that works best for protecting yourself from loud noise, the company Brüel & Kjær created a head and torso simulator to replicate the response of a real ear and the effects of hands placed over them.

Three methods were evaluated:

1) Cupping a hand over the entire ear

2) Pushing on the tragus to block the ear canal

3) Placing the tip of a finger into the ear canal

Some key findings from the study were:

-- Both holding in the tragus and covering the entire ear gave very similar results. This feels surprising, but could be due to small air gaps still being present, through which sound is transmitted into the ear canal.

-- The level reaching the microphone when using these two methods is hardly affected, and although some of the sound above 2kHz is being absorbed by the hand, the cavity created by cupping the ear or pushing on the tragus is causing an amplification of around 10dB below 2kHz.

-- Pressing on the tragus appears to provide slightly better high frequency attenuation (above 8kHz) than cupping the entire ear, which may be related to the size of the air gap that is allowing sound to propagate into the canal.

-- Placing a finger directly into the canal and blocking it provides the most amount of attenuation of the 3 methods. Above 100Hz this method provides 20-30dB’s worth of attenuation across the spectrum, a considerable reduction in level. Below 100Hz there is an increasing amplification down to 20Hz due to the occlusion effect. This is caused by bone conduction of low frequencies caused by the body (movement of the jaw etc.) reflecting off of the object blocking the canal and being transmitted to the ear drum. This sound would normally escape the canal into the air when not occluded, which is why we don’t normally notice it.

Hence, the conclusion is that when you are in a loud environment and don't have access to or the time to put on any hearing protection such as earplugs or earmuffs, the best method of lowering the sound level reaching your ear is to insert the tip of your fingers into the ear canal. This will provide you with a substantial reduction in noise level (minus the occlusion effect) across the whole audible frequency spectrum. This can be the difference that saves you from hearing damage.

If you are a parent, please teach your children this method of using their finger tips as earplugs, since too many kids tend to cup their hands over the ears when they are suddenly faced with loud noise. There are a lot of everyday noise situations where you will not be able to be there quickly enough to protect them. I am thinking of sudden exposure to industrial machinery, building sites, leaf blowers, excessively loud motorcycles etc.

Source: Natural Hearing Protection: Hands? // Image: Emiliano Horcada

In a recent radio program dedicated to his 90-year-old grandmother, Swedish media personality Fredrik Wikingsson told a story about when she asked him a question about sound.

'What is the most beautiful sound in the world?' she asked.

Fredrik started to guess, but he couldn’t figure out what the answer was.

There are so many beautiful sounds in this world, but the one sound that she places on top of all the rest is the sound of a telephone ringing in the home of a lonely person. When that intense silence is broken and the ringing carries the promise of human interaction.

The tale is moving and it reminds us all how important it is to keep creating that sound. How about creating it right now? Pick up the phone and call a relative whose silence you would like to turn into a vibrant and joyful conversation.

And please also leave a comment below: Which is, to you, one of the most beautiful sounds in the world?

The fast-paced urbanization across the world is a fact and society faces a great challenge in terms of managing the urban soundscape. There is indeed a lot of beauty in the eclectic sounds of city life, but the noise levels have unfortunately gotten out of hand. And it's detrimental to our well-being.

Soundhawk, a company set out to reimagine the listening experience, has compiled data on some decibel levels in the American cities of San Francisco, Los Angeles, Chicago, New York City and Boston:

These noise levels can certainly have a negative impact on the citizens' quality of life in these cities. Commuters of New York City have to face 106 decibels in the subway. And 92 decibels at an average Boston restaurant does not call for a relaxing dining experience. It's interesting to note that restaurant reviews are increasingly factoring in the sound experience as part of the review. And it's getting more common for people to avoid certain restaurants because of the noise level.

While there are a lot of great challenges in terms of taking measures to reduce the noise pollution in urban centers, there is a growing movement of people and institutions alike speaking up against noise. It's essential that this dialogue about sound and noise in our society is not only kept alive, but also intensified.

If you wish to join the movement, it is recommended that you get a sound meter/decibel meter to be able to do your own noise measurements in local environments that you find uncomfortable. Hard decibel data makes the case more credible when you then contact whoever is in charge and start a dialogue about how things can be improved.

The growing grass-roots movement against noise pollution has every opportunity to influence, and even drive, a transformation of society. However, we have to become even better at seeking the empathy of others - hearing-related issues are strangely enough still very underestimated and lacks the 'status' of other health conditions - and we have to put forth arguments that are supported by solid data.

As previously described in the post Tired of Cabin Noise? Here Is Your Guide to Getting a Quiet Car, the choice of tires is very important. Merely changing tires on a car can potentially improve the driving experience quite dramatically in terms of the level of road noise inside the cabin of the car.

The range of tires available in each market will differ and there are constantly new tires being launched, so it's tricky to provide specific recommendations. Instead, I have compiled a checklist on different dimensions to consider in your hunt for the quietest available tires that fit your car.

So, here goes your guide to selecting quiet tires that can provide you with a less noisy driving experience.

1. Wheel size
The smaller wheels, the less road noise will be generated. E.g. 16-inch wheels are quieter than 18-inch ones. The reason being that the thicker the tire is in terms of height of rubber rolling on the road, the less noise will be created. 16-inch wheels will leave more room for a thicker tire than the 18-inch ones. You need to look in your car owner's manual to find out what wheel sizes that fit your vehicle. Visually, it seems to have been established in the automotive press and among car owners that larger wheels look better, so if you are looking to reduce road noise, you will need to forego the looks and instead focus on the driving experience that you're looking for.

2. Tire width
Again, look in you car owner's manual to find out how narrow tires that you can mount on your vehicle. The smaller the area of rubber rolling on the road, the less road noise will be generated. Hence, go with the narrowest possible tire dimension that the car manufacturer recommends for your vehicle.

3. Speed & weight specifications
Something that most car owners will miss taking into consideration when picking out tires is that there are different tires for different maximum speeds and for different weight specifications.

The core description of a tire can look like this: 195/65R15. The first number '195' refers to the tire width in millimeters, the second number '65' is the aspect ratio. Tire manufacturer Yokohama describes the aspect ratio as follows:

"Often referred to as the profile or series, the aspect ratio of a tire is determined by dividing a tire's section height by its section width when the tire is inflated to maximum air pressure, mounted on the approved measuring rim, and under no load".

In layman's terms, the higher the aspect ratio the thicker the layer of rubber that rolls on the road.

The 'R' means radial construction and the last number '15' refers to the rim diameter, thus meaning a 15-inch wheel size. BUT don't stop here. After this main piece of tire description, a tire comes with an additional identity, which could look like this: 82H.

The '82' is the load index and the 'H' is the maximum speed that the tire is made for. Look for a chart of load index and maximum speed respectively and pick a tire that works for your specific load size and your driving habits. The higher the load a tire is built for, the noisier it is likely to be because it will be harder and sturdier. For similar reasons, the faster speed a tire can be used for, the noisier it is likely to be.

A lot of car owners are driving with tires that are unnecessarily hard and noisy. If you e.g. never exceed 118 mph (or 190 kph), then why use tires with the speed symbol V meaning a maximum speed of 149 mph (or 240 kph). Check what different speed and load index variants that are available for the tire model that you're wanting to get.

4. Weather conditions
Choose tires that fit the weather conditions you will be using them in. For winter tires, go with studless/non-studded ones since studded tires will be noticeably noisier. Although, if you'll be driving in very bad winter conditions, you need to consider safety aspects and carefully evaluate the noise dimension as part of the overall equation.

The studless winter tires on offer in Scandinavia (and I assume also elsewhere) are made of a rubber composition softer than that on summer tires, making them quieter. It therefore feels attractive to drive with them year-round, but experts consistently conclude that non-studded winter tires are dangerous to drive on hot surfaces so it is only advisable to use them during winter-time.

I have little experience from all-season tires and how they rate in terms of noise, compared to winter and summer tires. If anyone reading this has insights to share, please comment below.

5. Materials and patterns
There is a wide range of different rubber compositions and tire patterns respectively available in the marketplace. It is advisable to read about the noise ratings from tire manufacturers' own tests (there are regional noise rating systems in place that tire manufacturers follow; be wary though - I have discovered that these decibel/dB ratings may not necessarily accurately mirror how the tires perform on public roads), read tire reviews in your local market to find out about the ones with the best noise ratings, and speak to local car and tire dealers to gain expert insights. You need to find out which tires that roll quietly in your particular surroundings; the road conditions and asphalt roughness/smoothness differs widely across the world.

Softer rubber compositions will generally be quieter but then you'll also need to evaluate the ratings in road handling and fuel consumption. And some patterns will be quieter than others, but it's hard to draw any overall conclusions in terms of patterns without actually comparing tires and concluding the relative quietness/noisiness.

We as car owners will have to gather collective insights from industry experts, the automotive press and amongst ourselves to find out which tire that may be best suitable to go for. You might also need to do some experimenting and trial-and-error yourself. If you have some personal insights that could be of interest to the rest of us, please leave a comment below.

If you wish to do your own noise measurements inside your car, get a decibel meter/sound meter. A sound meter will produce more accurate results than a smartphone app and it can become a very valuable tool in your endeavour to shave noise. For safety reasons, avoid doing the measurements on your own. Bring a friend who can place the sound meter in different sections of your car; e.g. holding it by your left ear when you're driving, in the front-center section and in the backseat.

Please, leave a comment below if there are additional dimensions you think should be considered and feel free to share any of your own insights from testing different tires.

Philosopher Alain de Botton wrote on Twitter that "most of our childhood is stored not in photos, but in certain biscuits, lights of day, smells, textures of carpet".

I can totally relate to that.

Another fantastic source of childhood memories are the sounds we loved when growing up. One area that induces a lot of my personal memories in terms of time spent with family and friends, places and contexts are the sounds of video games. Especially games from the 80's.

I browsed around on YouTube and found some wonderful compilations of the most iconic video game sounds.

Let's start out with these 5 iconic sound effects in gaming. Do they ring a bell?

Here is a Top 10 list of great video game sounds.

I also found an excellent compilation of the Top 10 Arcade Games of the 1980's and 1990's.

Out of all the games I played when growing up, there is one with that extra nostalgia-inducing, emotional value: The Great Giana Sisters that I played on my Commodore 64. Listening to this intro brings me back a lot of wonderful memories.

So, now I'm curious. Which gaming sound brings back the most vivid childhood memories for you? Please, leave a comment below.

Guest post by Ze Zhou

Sound is quality.

If a product is supposed to be silent but isn’t, it’s lower quality. If it’s silent when it’s supposed to make a noise, it’s lower quality.

The solid “thunk” of a car door and the silence inside the car are both expressions of quality. The distinctive tick of a high-end wristwatch is quality. The refrigerator that makes just enough of a low hum to prove that it’s working is quality.

Sound has been a factor in product quality for decades, if not centuries. However, factors are conspiring to change the fundamentals of creating a fitting sound profile for a product. Consumer preferences and government mandates are making energy efficiency and environmental sustainability higher priorities. They require new designs and new materials, such as carbon fiber composites, that can alter a product’s sound profile.

New materials and designs are challenging for engineers. With no accumulated knowledge to rely on, they cannot make credible predictions about a new material’s acoustic performance before the design goes to prototyping and production.

As we wrote in a previous blog post on Elevating Sound, the automotive and aerospace industries are compensating by integrating acoustic simulation technology into their design processes. Airbus, in particular, has successfully “democratized” access to sophisticated acoustic simulation technology by extending it beyond analysts to front-line design engineers. The company has implemented high-end acoustic simulation software on its network that enables engineers to submit calculations then receive answers via an in-house developed automation platform.

Airbus, of course, also has something in the range of 10,000 engineers who design one aircraft at a time. How can an appliance company with 100 engineers designing 10 products at once follow its example?

A lot more easily than you might think.

Aerospace and automotive companies have more resources, but many of those resources are consumed by their products’ greater size and complexity, not to mention the regulatory requirements they have to meet. They have to infuse acoustic simulation technology into every facet of their design processes because any change to a design at any point in the development process can have huge consequences.

For example, if engineers add mass to an aircraft design, it affects the whole product’s fuel economy. The company needs acoustic simulation everywhere in their design process because it needs to know long before prototyping and production what effect the sound-related modification has on the final design.

By comparison, the appliance company may only have 100 engineers, but it also doesn’t have to evaluate every single change as exhaustively as Airbus does. Dishwashers and refrigerators aren’t as complex as aircraft. Not as much rides on each design change. Where the aerospace engineers need as much certainty as possible, the appliance company’s engineers may only have to be able to make credible estimates of how design changes will affect their product’s performance and sound profile.

So rather than investing in a top-to-bottom acoustic simulation program, the appliance company could take one of several lower-cost but still effective measures.

The first and most obvious solution is outsourcing, which is as simple as sending computer-aided design (CAD) models to an analyst firm and receiving results back. This approach would keep overhead expenses manageable for a company that doesn’t often make substantial changes to its products but wants to maintain their sound profiles. They might only need occasional acoustic simulation to verify their sound profile.

Companies that re-design more often and more extensively, or who don’t want proprietary design data outside their own walls, need an in-house solution that won’t break the bank.

One option is to contract with an outside analyst to create acoustic models of each product according to the company’s design best practices. Engineers can use the models as benchmarks to estimate the effects of new materials and designs on the products’ sound profiles.

Some companies need a more interactive system that enables engineers to run simulations. These companies can purchase a single license of an acoustic simulation solution, train one or two engineers to use it, then use them as an in-house service bureau to support the rest of the engineering staff.

Whatever solution a company chooses, the underlying point is that with the advent of new materials and design imperatives, most manufacturing companies need some form of acoustic simulation to maintain their products’ sound profiles. A consumer product probably won’t fail because of a flawed sound profile, but it will definitely be at a disadvantage against competitors with well-crafted sound profiles.

Manufacturers need to know in advance whether the shutter click of the digital SLR camera sounds enough like a mechanical SLR to satisfy serious photographers. They need to know the dishwasher is quiet enough to run at night without waking up the customer’s kids, or that the cap of the rollerball pen makes a satisfying “click” to justify its $300 price tag.

Integrating acoustic simulation technology into their design processes provides manufacturers with that insight. They don’t need the resources of a multinational aerospace company to do it. They just need to know their options.

Ze Zhou is a senior application engineer and product marketing manager at Free Field Technologies, an MSC Software company.

Guest post by Doug Tews

Numerous posters on this site have expressed the desire for finding quiet, comfortable cars for driving on European roads. As a US citizen working and living in the UK for over 8 years (and with an engineering background), I might share a few important matters I’ve discovered. I will also share my own personal experience of adding additional sound deadening materials to my UK car; what it accomplished – and what it did not.

Streamlined designs reduced wind noise

Decades ago, wind noise was a significant noise component in road vehicles. In those days, glass was not flush mounted. Items like chrome moldings surrounding the glass created turbulence resulting in wind noise. Turbulence around door mounted mirrors was also a notorious noise maker. However, today’s streamlined designs have significantly reduced such turbulence along with its accompanying noise. The desire for more fuel efficient vehicles lead to these streamlined designs, but with pleasant byproduct of also reducing wind noise. In many of today’s cars, air rushing past the vehicle is still often heard through the doors, but can be quieted by adding sound deadening materials to the door panels.

Acoustic vs. conductive road noise

In today’s cars, road noise is perhaps the single biggest contributor to noisy interiors. Road noise originates from tires running over noisy road surfaces. However, what is not typically recognized, is there are two totally different components to road noise, each requiring a different form of treatment: acoustic noise and conductive noise.

Acoustic noise, as the name implies, is transmitted from the road surface through the air to the car body where it can be heard by occupants inside. This noise is fairly easy to treat by adding sound deadening materials to the floorpan, sheet metal surrounding the cabin and especially the doors.

However conductive road noise is an altogether different problem. This is noise in the form of vibrations conducted from the road surface, through the tires and suspension into the car interior. A great percentage of road noise can enter a car interior via this path. Unfortunately, the only treatment an owner can perform is obtaining quieter tires. A significant issue today is the popularity of low profile tires. The problem: the wheels are very large with very little rubber. Often a significant improvement in noise and ride can be achieved by switching to smaller wheels with higher profile tires. (The outer diameter of the tire is the same. You simply have more rubber on a smaller wheel.) This can make a significant difference, but ultimately the effectiveness is limited by the car’s suspension…and that is the single biggest issue in today’s cars.

Subframes vs. unit-body construction

In the States, most cars made before the mid 1980’s had full-frame suspensions. The tires and suspension components were attached to a steel frame via rubber bushings. The frame in turn was attached through additional rubber bushings to the chassis. In essence, the suspension was “double isolated” from the car chassis. However, nowadays most cars have so-called unit-body construction. In an effort to shave off weight, manufacturers eliminated frames. As a result, the suspension components are now fastened directly to the chassis. Road noise therefore, has a more direct path into the car’s interior.

For luxury cars like Cadillac, this became a big problem. Owners complained bitterly about the increase in noise levels and clunkier ride. The use of larger and better bushings helped, but simply couldn’t match the isolation found in the older cars with frames. Eventually manufacturers responded with the addition of subframes. Unlike the full frames of yesterday, these were smaller and lighter. But like the old frames, they made it possible to much better isolate the suspension components from the chassis and car interior.

I recently had a firsthand experience illustrating the difference subframes can make. In a trip back to the States, I rented a Toyota Corolla. Though bigger than my UK Auris, it is still a smaller vehicle than an Avensis. As soon as I started to drive I was amazed. At speeds up to 20 mph the car was totally, completely silent. There was not a trace of any road noise whatsoever. Nothing. In contrast, as soon as my Auris (and most other small European cars) start to roll, road noise immediately invades the interior. After investigating this, I discovered the US Corolla now has a subframe. The difference was amazing.

Alas, because cars in the UK are far more expensive than in the US, I doubt we’ll see this technology appearing in the smaller cars here. The only exceptions I’m aware of are the Mercedes A & C classes along with the BMW 1 & 3 series vehicles. Of course, these can be pricey. I suspect larger cars like the VW Passat undoubtedly have subframes. But not everybody wants such a relatively big car.

Of course subframes alone don’t guarantee a quiet car. Other appropriate sound deadening measures are required too. However, I wondered, could extensive sound deadening treatment have any effect on conductive road noise? That leads into my own personal experience and what I discovered…

The challenge of silencing conductive road noise

After moving to the UK, I came to the realization that owning a larger comfortable vehicle (even a used, older one) was out of the question due to soaring petrol costs, taxes and insurance. My experience with US Toyotas was so good, I thought the Auris would be appropriate for me. I was able to purchase a 3 year old model with only 15,000 miles on it for a very good price. It was the top trim level loaded with many options. Regrettably, a short test drive on a relatively smooth road was insufficient to reveal the car’s true characteristics. After purchasing the car and gaining experience, it became a significant disappointment. Road noise in particular was horrendous — and the ride was brutally stiff. It didn’t take long for me to start hating the car. However, it was a good buy and Toyotas are dependable, so I decided to see if I could improve things.

First on the agenda was wheels & tires. Although 16 inch tires were standard on the Auris, my top line version came with 17 inch wheels. On eBay I was able to purchase a set of brand new 16 inch wheels for the Auris. I got all four wheels for the price of one. I then had Michelin MXV4 tires put on. My research indicated these were some of the finest tires available for a quiet, smooth ride. After putting the new tires on the new, smaller wheels, the difference was unbelievable. Although nothing can be done about the stiff suspension, the ride was very significantly less harsh and noticeably quieter. The overall improvement in comfort was well worth the expense.

Then came the big project: massive soundproofing. I found a company in the middle of the country that specialized in this sort of work. They put in a double thickness of Dynamat on all metal surfaces, including boot floor, all doors, door panels and roof and bonnet. It was extensive, and expensive.

The results? Unfortunately mixed. First, at motorway speeds the car is noticeably quieter, especially on quiet road surfaces. On a quiet road, one can go from 30 mph up to 50 mph with hardly any discernible increase in noise. Going up to 70 mph does see some increase, but that is primarily just a more distant airflow noise. At about 71-72mph engine hum starts to become the most notable distraction. Before the soundproofing, the car was otherwise so noisy, the engine hum was masked.

However at lower speeds around town (and on noisy highway surfaces which are very common here), the soundproofing was a major disappointment. At speeds below 30-35mph, the improvement was marginal. As soon as the car starts to move, even at 10 mph, road noise intrudes into the cabin. At these lower speeds, virtually 100% of the noise was from conductive road noise.

The importance of suspension design

What was learned? Even massive amounts of sound deadening materials can do little to silence conductive road noise coming through a cheap suspension into a unit-body car. The sound deadening did eliminate all booming from sheet metal that was being excited by the stiff suspension. However, that was a relatively small component of the overall noise.

Having all the sheet metal thoroughly dampened did considerably reduce acoustic noise at higher speeds. On a motorway this can make a very significant difference, but mostly on quieter road surfaces (which are rare here in Britain). Unfortunately on noisy road surfaces, the conductive road noise is so enormous, the greatly reduced acoustic noise was only of very limited benefit.

Between all the the sound deadening, new wheels and tires, I spent over £1500. Was it worth it? I would say yes, but only just. At lower speeds around town, the noise levels are still disappointingly high…and aggravating.

The single biggest improvement (and most cost-effective) was the new wheels and tires. Although sound deadening helps, it’s of limited effectiveness at low speeds. Again, massive soundproofing can do little to stop noise being transmitted into the interior via a cheap, stiff suspension.

The only way we’ll see any significant improvement in this area is for manufacturers to pay more attention to conductive noise in their suspension designs. Although better unit-body suspension designs are possible, manufacturers have discovered there is no better solution than having subframes for really good road isolation.

Therefore, if a person is shopping for a quieter car, finding one that incorporates subframes is extremely important. Earlier I mentioned the wonderful isolation I experienced in that US Toyota Corolla. At highway speeds, most noise I could hear was coming in via the doors – and that is treatable. Therefore, if one took that car and treated it the way I did with my UK Auris, it would probably be as quiet as a luxury vehicle. However, if a lot of noise is coming in via a car’s suspension, there’s little one can do.

Guest post by By Ze Zhou and Philippe Hebert.

Long before Rolls Royce boasted that the only thing passengers could hear inside their cars was the dashboard clock ticking, silence was literally golden in automotive design. Nothing has changed. As Elevating Sound reported in the blog post The Price of Quiet Driving, the quietest cars on the road are the priciest – Lexus, Mercedes, BMW, Volvo – while the loudest are economy models.

A quiet ride, however, is increasingly conflicting with an equally important design imperative: fuel economy.

Government mandates, fuel prices and the public’s growing concern for the environment have made mileage a key factor in vehicle design. Oak Ridge National Laboratory has determined that reducing a car’s mass by 10 percent increases mileage by 7 percent. The EPA says that for every 100 pounds taken out of the vehicle, the fuel economy is increased by 1-2 percent. There are also cost benefits to mass reduction. Using 10 to 20 percent fewer materials in a vehicle can reduce its costs by 5-15 percent.

As a result, auto manufacturers are experimenting with new designs, drivetrains and materials to decrease vehicle weight and improve gas mileage.

The problem is that lighter vehicles are also noisier vehicles. New lightweight materials like fiber-reinforced plastics (FRPs) and lightweight metals vibrate more than conventional materials – primarily steel – and can create more noise in passenger compartments. Though lightweight materials can also be used as noise insulation, engineers need a comprehensive view of their designs’ noise profile to identify noise sources and the best ways to mitigate them.

Engineers have known for years how steel deflects, vibrates and blocks noise in different applications. That knowledge had enabled them to approximate their designs’ acoustic properties and make vehicles consistently quieter. Their approximations were based on performance benchmarks accumulated through decades of working with steel.

Those benchmarks held up for all of those years largely because steel is an isotropic material, meaning that it has a uniform composition and behaves consistently under loads. Once engineers had benchmarks for steel’s performance in different applications, the benchmarks didn’t change because steel didn’t change.

Benchmarks derived from steel do not apply to new metals, and benchmarking doesn’t work at all with composite materials such as fiber reinforced plastics (FRPs). While steel is isotropic, composites are said to be "anisotropic", which means that their structure and behavior under loads can vary widely.

The behavior of a composite material is different depending on the direction considered in the material. It is very stiff if the material is solicited in the fiber direction, while it will be very soft if it is loaded transversely to the fibers. Another challenge set by composite material is the fact that in addition to their anisotropy, their microstructure – fiber orientation or fiber content – can vary over the entire part.

In addition to composites, automotive engineers are often dealing with other new materials with unfamiliar properties. Companies are experimenting with laminate metals in auto bodies and using visco-elastic materials for interior sound dampening.

Automotive design engineers are not used to dealing with so much variability in their materials. So how can they incorporate lightweight materials into vehicle designs to increase fuel efficiency while making them quiet enough to please customers?

The answer is new vehicle design processes built around simulation technology that accurately models a vehicle’s sound profile from the beginning of the design process all the way through production.

Finite element acoustic simulation technology has been around for almost 20 years, but has been too complicated and expensive to use throughout the design process. Acoustic analysis has been confined to teams of highly trained Ph.D. analysts working in research departments, as opposed to design engineering. There were few solutions on the market because acoustic simulation required so much computational power that few companies could afford it.

Acoustic simulation’s price and complexity have dropped over the last several years. Automotive companies have steadily adopted acoustic simulation solutions such as MSC Actran, but the best example of integrating acoustic simulation into design processes might be at the aerospace company Airbus. It can serve as a model for automotive companies, which are only now starting to deal with noise issues at the level that Airbus and its predecessor have for almost 40 years.

Airbus is the successor to the consortium founded by French aerospace company Aérospatiale and the British Aircraft Corporation to develop the supersonic Concorde airliner in the 1970s. The Concorde was a technological success, but it was so loud that few airports would grant it landing rights.

Partly because of its predecessor’s experience, Airbus has worked steadily over the last 15 years to “democratize” access to acoustic simulation technology among its design teams. Today, acoustic simulation is fully integrated into Airbus’ in-house engine noise optimization processes.

Design engineers at Airbus’ Tolouse, France headquarters use Actran at the beginning of the process to get a broad idea of which designs and material use will yield the best balance of silence and fuel economy. As they get closer to a final design, they can adjust the parameters for optimal performance. This system eliminates guesswork and needless iteration. It avoids costly late-stage errors through constant simulation that reveals when an idea is going awry.

Airbus design engineers can initiate acoustic simulation calculations to determine, for example, engine noise levels at various speeds, temperatures and altitudes, and how changing the design of the nacelle liner design would affect them. Working in a simulation model on the network, they change parameters then submit them for calculation. MSC Software’s Actran runs the simulation and reports the results back to the engineers.

Airbus also uses acoustic simulation to manage interior noise by making material choices for fuselage design. Engineers use the acoustic simulation solution to virtually design the acoustic behavior in the cockpit or cabin, and the noise transmission from exterior to interior. They can compare noise levels between designs using traditional aluminum or newer composite materials on the fuselage. The resulting insight into their designs’ sound profiles gives Airbus engineers the ability to balance noise with fuel efficiency considerations through the process.

It’s easy to see how the Airbus model would apply in the automotive industry. The heart of the design process would be a simulation model created by various design groups working in a common data format. Part and assembly models would include the properties of their constituting materials. Every design engineer would be able to run acoustic simulations against the design and material property data in the model through desktop or server-based applications.

This on-demand access to acoustic simulation technology gives engineers previews of their designs’ sound profiles well before they commit to expensive prototypes. Armed with advanced knowledge, they can experiment with different shapes and masses to reach a balance between a quiet ride and fuel economy.

Ze Zhou is a senior application engineer and product marketing manager at Free Field Technologies, an MSC Software company; Philippe Hebert is an application engineer at e-Xstream Engineers, also an MSC company.

Guest Post by Katherine Bouton.

People often ask me what hearing loss feels like. I tell them I can only describe what my hearing loss is like. We all experience hearing loss differently, depending on the degree and nature of the loss; the kind of correction we have, the kind of person we are, the relative difficulty of the challenges in our daily hearing environment.

When I’m with a friend or family member in a quiet place, my hearing loss seems negligible. When I’m with that friend or family member in a restaurant – or even at my own dinner table with five other people – my hearing loss seems overwhelming. I can follow very little of what’s said. When I worked in an office, hearing loss dominated my every waking moment. Now that I work at home, it’s less of an issue.

My hearing loss, like most people’s, is actually two different things. Without my hearing aid and implant, I don’t hear much. I might hear that someone is talking, but not what they’re talking about. I might hear a fire engine going by, but it could be the television in the other room.

My hearing loss without any correction is primarily peaceful. I’m very lucky not to have tinnitus, because the silence is indeed silent. The cover of my book “Shouting Won’t Help” describes perfectly how that uncorrected hearing sounds. Cut off from the world, but not stressing about it.

But when I put on my hearing aid and implant, the sudden noise even in a quiet room is enough to make me jump. Both devices seem to come on at a higher decibel level than I need and then adjust themselves. That means there’s a brief flash of loud sound, which is even worse if I’ve accidentally turned the volume up before I put the device in.

Neither instrument is good at regulating background noise, the bane of every hearing aid wearer. Think how often you’ve seen someone take out their hearing aid in a noisy restaurant, because the din is overwhelming. Doing what the ear does naturally – filtering out unwanted sound – has so far stymied the acousticians and manufacturers of hearing aids and cochlear implants.

Still, when it’s quiet, my instruments allow me to hear birds chirping, a stream gurgling, a friend talking. And I’m getting better at hearing all the time. A year ago, my son called on the phone. I had no idea who he was. He kept saying, “It’s Will.” I kept saying “You want to talk to Will? He isn’t here.” Now I would at least know who was calling, if not what he was saying.

I’ve had serious hearing loss for a little more than a decade, but I first lost my hearing in my left ear when I was 30, in 1978. I spent years in denial – my hearing isn’t that bad, I don’t need a hearing aid. I could hear with my right ear and that seemed sufficient.

My hearing loss, of unknown origin, went through periodic unexpected drops. My hypothesis is that the drops were connected to periods of stress, when my immune system was compromised. If the hearing loss is caused by a virus – one possibility – that virus would have a chance to get the upper hand under stress, and I’d lose another 10 decibels of hearing.

In 2002, my hearing had gotten so bad that I had no choice but to get hearing aids. I got two. The one in the left ear merely provided balance – no real sound. But the one in the right ear worked well for me for about three years. During that period, when I was once again tested for everything, the doctor still had no diagnosis. Ever optimistic – ever in denial – I continued to believe that someone would find the cause, would reverse the progression. I began researching hearing loss myself, delving into my health history hoping for a clue.

I continued to work but I communicated by email whenever I could. I didn’t participate in meetings. I saw as few people as possible. And of course there was anger. Anger at my hearing, anger at my colleagues at work, anger at my husband. I was short with my kids, estranged from my friends. I was angry with the hearing aid industry for not coming up with better products, at my audiologist for not being able to make me hear again. At science, at the world.

The following year I got a cochlear implant – but mine was not a joyful eureka moment. All that negative stress made it hard to adjust to the implant.

Shortly after that, I left my job. Despite the implant and hearing aid, I couldn't do the work I loved and I wasn’t interested in doing the work offered as a substitute. In January of 2010, I was out of work. I was deaf. Rock bottom. The only way to go was up. Anger helped, surprisingly.

Anger was my original incentive for writing “Shouting Won’t Help.” I’d show them, I thought. Not a good premise for a book. Luckily, I moved on.

I spent two years reporting the book. It’s a memoir in part, but it is also an exploration into the science of hearing loss and the possibility of regeneration of hair cells, into the hearing aid and cochlear implant industries, and into noise and the damage it does. I wanted to write a reported book because there were so many facts I wanted to know. I figured if I wanted to know them, others would too. There were no books out at that time about the practical aspects of mid-life hearing loss.

These days I accept that hearing loss is part of who I am. I’m no longer pretending I can hear; I’m no longer living a lie. Because I write and speak about hearing loss, it’s a big part of who I am. But it’s by choice. I own my hearing loss. It doesn’t own me.

That doesn’t mean that I don’t have occasional fits of what the blogger Gael Hannan calls "ear rage". Hearing loss is always there, and sometimes it ambushes you. The anger you feel in response seems out of proportion to the event, but that’s because even as you’ve seemingly been doing okay, that anger – and its concomitant depression and anxiety – has been simmering. Every once in while it reaches the boiling point.

New York-based writer Katherine Bouton is the author of "Shouting Won’t Help: Why I – and 50 Million Other Americans – Can't Hear You" and the What I Hear blog on Psychology Today. She is a former editor and writer at The New York Times.

Elevating Sound warmly recommends Katherine Bouton's book "Shouting Won’t Help: Why I – and 50 Million Other Americans – Can't Hear You".

Hearing loss is a hidden disability and there is a pressing need to close the empathy gap in society in order to better understand and support the people who experience and live with hearing loss and other hearing-related conditions, such as tinnitus and hyperacusis.

This is an important and gratifying read for people experiencing hearing loss and who are currently going through Elisabeth Kübler-Ross’s five stages of grief: denial, anger, bargaining, depression and acceptance. Likewise, it is an essential read for friends and family members of people living with hearing loss. The book will expand your mind and enable you to better understand what it means to be living with hearing loss via the personal memoir of Katherine Bouton as well as the persons she interviewed for the book. As more people learn about the depths of this invisible disability, they will be able to help and encourage those experiencing hearing loss to find their way to personal acceptance.

The premise of the book as told by Katherine Bouton:

I know. I've been there. "Shouting Won't Help" shares my experience. I began to lose my hearing when I was 30, from unknown causes. The loss was progressive and by the time I was 60 I was profoundly deaf in one ear, and with severe loss in the other.

When I started thinking about this book, I had been struggling with increasingly severe hearing loss for much of a decade. I was depressed, angry, stalled in my work, isolated from my family and friends. My reaction was in no way unique.

Hearing loss is a hidden disability, one often borne in secret. It affects friendships, family, and professional lives. Many people have told me their stories. In the book, I share theirs along with my own, in the hope that others will come to see that there is a path to acceptance, a way to return to life. Life after deaf.

Forty-eight million Americans have some degree of hearing loss—17 per-cent of the population. If you’re among them, or if you’re married to someone with hearing loss, or if you're a friend, a colleague, a relative, this book may help in coming to that elusive state of acceptance. The first step, acknowledgment, is a major one -- major both in effort and reward. I hope this book will help you find your way there."

It's very fascinating to see new progress being made in the area of acoustic levitation, which will see far-reaching value-adding applications in chemical and biological processes. Before we look at an interesting video, let's talk about what it is.

Defining Acoustic Levitation

Wikipedia defines acoustic levitation as follows:

Some methods can levitate objects without creating sound heard by the human ear such as the one demonstrated at Otsuka Lab.

By 2013, acoustic levitation had progressed from motionless levitation to controllably moving hovering objects; an ability useful in the pharmaceutical and electronics industries.

There is no known theoretical limit to what acoustic levitation can lift given enough vibratory sound, but current technology can only lift a few kilograms."

A Multitude of Applications

The ability to levitate multiple objects and manipulate them in a 3D space will find many useful applications in chemistry and biology as well as science overall. There are a lot of chemical and biological processes that can be disrupted by contact with a surface and acoustic levitation is the optimal solution to alleviate that issue.

The fact that levitation can be achieved without the need for magnetism or buoyancy is a great advantage for science. So instead of being limited to magnetic objects, scientist can react anything by leveraging levitation.

Three-Dimensional Mid-Air Acoustic Manipulation

We found a fascinating video demonstrating the beauty of the latest advances in acoustic levitation.

The research team at the University of Tokyo employ ultrasonic speakers at a sound frequency that is not audible to humans.

On Google+, Martijn Vreugde explains the sound-based levitation technology used:

The acoustic axis of the ultrasound beam in these previous studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers.

In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays. We experimentally confirmed that various materials could be manipulated by our proposed method."

Why are some toys so noisy that they can damage your kid's hearing?

That's a question I wish I didn't have to pose as we have just entered the year 2014. And this is in the US - a market known for its tough product-safety regulations, where manufacturers are under a lot of pressure of being sued if their products end up inflicting injuries on people.

A Flawed Acoustic Standard

The reality is that until as recently as 2009, toy manufacturers were not required to follow any guidelines regarding the sound level of toys. But since then, all toys are required to meet the acoustic standard set by the American Society of Testing and Materials (ASTM) (ASTM F963-08). This acoustic standard states that the sound-pressure level produced by all toys, except close-to-the-ear toys, shall not exceed 85 decibel/dB at a distance of 50 cm/approx 1.6 feet from the surface of the toy.

This standard has a serious flaw though - while the maximum noise level is based on a 50 cm distance from the child, most kids play with toys by holding them or sitting right next to them, not at 50 cm/1.6 feet away. Anyone who has kids of their own can confirm how they, especially the younger ones, tend to hold their toys very close to the head/ears.

Noise Testing that Reflects Real Play

I was glad to find out that the non-profit organization the Sight & Hearing Association challenges the toy industry by putting together a list of the loudest/noisiest toys in the US marketplace. The mission of the Sight & Hearing Association is to enable lifetime learning by identifying preventable loss of vision and hearing.

On an annual basis, right before the busiest toy-shopping season, the Sight & Hearing Association (SHA) teams up with the University of Minnesota to test a range of toys for potentially dangerous noise levels.

As mentioned, most kids play with toys by holding them or sitting right next to them. Not at a 50 cm distance (approx 1.6 feet), which is what the acoustic standard bases its noise limit on. Therefore, the SHA tests toys in a way that better reflects real play situations based on how kids usually hold their toys. That way it is possible to get an understanding for just how loud these toys can get for kids. Decibel levels are recorded in two different situations - directly near the ear (0 inches) and at arm's length (25 cm/10 inches - half the distance of the one used in the acoustic standard).

Excessively Loud Toys - A Clear Health Hazard

The testing, which takes place in a sound-proof acoustic chamber, has identified a large number of toys whose noise level was greater than 100 dB in intensity when measured right next to the speaker.

So what does 100 decibel mean? How loud is too loud? According to the SHA, over 100 decibel is "like a chainsaw in the ear canal".

As a guiding principle, sounds that are 85 dB or louder can permanently damage hearing. The louder a given sound is, the less time of exposure it takes to cause damage to the auditory system.

The SHA explains that "a sound at 85 dB may take as long as eight hours to cause permanent damage, while a sound at 100 dB can start damaging the inner ear’s hair cells after only 15 minutes of exposure. According to NIOSH, part of the Centers for Disease Control, the permissible exposure time (the amount of time you should listen) is cut in half with every three decibels over 85 dB".

So let's repeat this - a sound at 100 dB can start damaging the inner ear's hair cells after only 15 minutes of exposure. Our hypothesis at Elevating Sound is also that when it comes to babies and really young kids, their auditory system is extra sensitive to loud noise, which could cause damage after less than 15 minutes of exposure. And the toy retailers sell a range of toys, targeting young kids, with a noise level greater than 100 dB coming out of the speaker.

The obvious conclusion is that we are putting our kids at a severe risk of having their hearing damaged at a very early age. And the toy industry is making it hard for parents to protect their kids as they unknowingly pick out toys from the shelf that are highly inappropriate to be played with.

Noisy Toys Lists - or the Kid Toy Hall of Shame

The Sight & Hearing Association puts together annual Noisy Toys lists, which also in some regards should be seen as a Hall of Shame.

The number 1 spot of the 2011 Noisy Toys list was awarded to Fisher Price's Disney Cars 2 Shake 'N Go Finn McMissile - a toy whose noise level reached 124 dB. According to the National Institute of Occupational Safety and Health (NIOSH) guidelines, at such a noise level a person starts to risk hearing damage in merely four seconds. So after four seconds of holding this Fisher Price toy close to the ear, a kid can get a permanent hearing damage.

At second place of the 2011 Noisy Toys list came Disney Princess Follow Your Dreams, a play-a-sound book meant for a toddler 18 months or older. The noise level? 118 dB!

Below, you will find information on the top 5 loudest toys from the 2013, 2012 and 2011 Noisy Toys lists, based on decibel/dB ratings at 0-inch distance from the speaker. The respective toy manufacturer in brackets. You will notice that some of these toys are really popular, top-selling toys with a large number of kids being exposed to them, which makes it even more of a concern.

2013 Noisy Toys List - Top 5

1. Disney Baby Einstein/Take Along Tunes (The Baby Einstein Company, LLC) - 114.8 dB - Elevating Sound comment: we did notice that this toy does have a volume control with two set levels, so the 114.8 dB is probably the sound level when the volume is set to high (see YouTube video below)
2. Twister Dance Rave (Hasbro) - 107.9 dB
3. B. Meowsic (Piano) (Maison Joseph Battat, Ltd.) - 106.8 dB
4. Doc McStuffins - Talkin' Check-up Set (Disney, Jr. Just Playing) - 102.8 dB
5. Road Rippers - Road Rockin' Ricky (Toy State Industrial, Ltd.) - 101.2 dB

Click here for full Sight & Hearing Association’s Noisy Toys List 2013 with additional details per toy.

2012 Noisy Toys List - Top 5

1. Disney Pixar Toy Story Talking Figure Buzz Lightyear (Mattel, Inc.) - 111 dB
2. Nickleodeon Teenage Mutant Ninja Turtles Leonardo’s Electronic Sword (Playmates Toys) - 109.2 dB
3. Dora the Explorer/Dora’s Desert Friends (Publications Int’l., Ltd.) - 108.2 dB
4. Barbie Little Learner Laptop (Oregon Scientific) - 108 dB
5. Playskool/123 Sesame Street Let’s Rock Grover Microphone (Hasbro) - 107.3 dB

Click here for the full Sight & Hearing Association’s Noisy Toys List 2012 with additional details per toy.

2011 Noisy Toys List - Top 5

1. Disney Cars 2 Shake N Go! Finn McMissile (Fisher Price) - 124 dB
2. Disney Princess Play-a-Sound Follow Your Dreams (Publications, Intl.) - 118 dB
3. Hot Wheels Super Stunt Rat Bomb (Toy Quest) - 116 dB
4. Disney Cars 2 Shake N Go! Professor Z (Fisher Price) - 114.1 dB
5. Toys Story 3 Matchbox Garbage Truck (Mattel, Inc.) - 113.2 dB

Click here for the full, condensed Sight & Hearing Association’s Noisy Toys List 2011.

I'm left with a few fundamental questions...

• WHY do these toys need to be so loud?
• Is there a notion that these toys will not be fun enough to play with if the noise levels were to be reduced to more reasonable and ear-safe levels?
• Or is this rather a result of toy product developers lacking basic skills about noise and how it can impact the auditory system of kids, in conjunction with sub-standard suppliers of speaker technologies?

This has got to stop. Elevating Sound would be very interested in getting comments from toy manufacturers as to how they see the future of toys and noise levels, and why we have this issue still in the year 2014.

We need to do a much better job at protecting the well-being of our children - us consumers can use the power of directing our purchase decisions to toy manufacturers who safeguard the hearing of kids, and toy manufacturers need to step up their game and take much more responsibility for the potential consequences of the products they launch into the marketplace.

Advice to Parents: How to Avoid Noisy Toys

There's legal regulations and then there's common sense. In a marketplace, where some toys are excessively loud, the best advice to parents is to always listen to a toy before buying. And if a toy seems too loud to them, then it will likely be too noisy for their kid/s.

The Sight & Hearing Association provides the following advice for parents of a small child:

• Listen to a toy before you buy it. If it sounds loud to you, it’s too loud for your child.
• If you wish to buy toys with sounds, look for toys with volume controls so that you can control the volume
• If you already own a noisy toy or receive ona as a gift and would like to keep it, try putting clear packing tape (or glue) over the speaker on the toy. This will help reduce the volume. Check if the volume has been sufficiently reduced, which could transform your health-hazardous toy into an ear-safe toy that can be played with without damaging the hearing.
• Report a loud toy. The Sight & Hearing Association has a special e-mail address at reportatoy@sightandhearing.org.

Excessive noise coming from a dishwasher can be a real nuisance. In small- to midsized kitchens, the noise level can be so overbearing that it's uncomfortable to be in the kitchen when the dishwasher is on. And in many modern homes with open/integrated kitchen-living room layouts, a noisy dishwasher can disturb conversations, watching TV and other activities.

Thankfully, there are manufacturers of household appliances that are getting better at developing quieter product offerings. As we live in an overwhelmingly noisy society with ever fewer quiet spaces, there is a strong sense of people wanting their home to be a peaceful place for relaxation and contemplation.

The increasing global consumer need for quiet products is still largely unfulfilled, but it is very promising to see that manufacturers are beginning to realize the great commercial potential of taking leadership of the quiet space in their respective category/categories.

In the area of dishwashers, Bosch is doing an excellent job and the German manufacturer offers the quietest dishwasher in North America - the 24" Bar Handle Dishwasher 800 Plus Series - Stainless steel SHX9PT75UC. The noise level lands at only 38 decibels (dBA), which is fantastic. It will be so quiet that you may not even notice that it's on.

Bosch promotes itself as being the quietest dishwasher brand in the US, which is based on an average of sound ratings on major brands' websites. Major brands are defined as the Traqline Top 10 Brands.

Under the heading of "Explore the Science of Quiet", Bosch does a great job at explaining how every part of the dishwasher has been optimized to be quiet.

They describe 7 noise-reducing features:

1. Layers of Insulation - Multiple layers of sound-absorbing insulation that dampen noise.
2. EcoSilence Motor System - Frictionless, brushless motors contain motion and reduce noise by 25%.
3. Solid Molded Base - The base absorbs sound while minimizing vibration.
4. Triple Filtration System - Grindless system filters out food particles, so there's no need for a loud internal food disposal.
5. Detergent Tray - Optimized for tablets, this tray holds detergent in place for a dedicated spray jet to directly dissolve the tablet and minimize spraying the door. (Note: dishwasher also works with powder and gel tablets)
6. Spray Arms - Spray arms project water towards your dishes, reducing noise.
7. InfoLight - So quiet, you might not know it's on. This light lets you know. / TimeLight - This light shows that a cycle is running and counts down until your wash cycle is complete.

Bosch really wants consumers to understand what different decibel levels mean so that they will understand just how quiet their quietest dishwasher is. See below a chart found on the Bosch website, where users can experience the difference between a Bosch dishwasher and other familiar sounds.

Go to the website and click on the different bars to hear it for yourself.

If you are looking for a quiet dishwasher to keep aggravating noise out of your kitchen, Bosch seems to be the way to go.

Happy dishwashing! :-)

We are launching a new, regular feature on Elevating Sound called the Tinnitus Dialogue.

Tinnitus Dialogue will be a peer-to-peer advisory series on issues related to living with tinnitus and hyperacusis. The aim is to offer a supportive voice to help you and your loved ones manage your condition/s and embrace life.

As the founder of Elevating Sound, my passion for sound stems from the fact that I was struck with tinnitus and hyperacusis around 24 years ago - at the age of 16 - after having regularly attended loud concerts.

I have personally experienced how I would have benefitted from more interaction with people who are going through the same experiences as I do. These days, there are many forums online where tinnitus can be discussed, and I hope that the Tinnitus Dialogue feature will become a valuable, helpful and high-quality addition.

On Elevating Sound, you will find insightful and helpful articles about tinnitus and hyperacusis, mixed with the Tinnitus Dialogue peer-to-peer advisory section where things will be discussed with others who are in the same position as yourself.

Our focus is quality of content, which there is a great need for in the area of tinnitus. I'm sad to see how the Internet is being littered with so much tinnitus spam from people who are trying to capitalize on the fact that there is still no cure for tinnitus. On the other hand, I very much admire any of the serious efforts out there to share knowledge and provide valuable information and support to people with tinnitus.

Back to the Tinnitus Dialogue. On a regular basis, a new question will be posted. I will start out by providing my perspective on the particular question and then you as part of the Elevating Sound community will be able to add your thoughts and perspectives in the Disqus comment section.

I'm truly hoping that this could grow into a very supportive peer-to-peer advisory section where we strive to help each other by sharing our personal experiences and words of love.

I believe in the power of people/patients exchanging insights and real-life experiences to figure out a way forward to tackle one’s own challenges. Especially as medical professionals lack many of the answers that we are seeking. Also, at times of hardship, empathic support from others who are in the same situation as you becomes very meaningful.

Besides inviting those of you with tinnitus and hyperacusis as well as your friends and family members to participate in the Tinnitus Dialogue, we also wish to extend a warm welcome to any researchers or healthcare professionals who wish to join and share their knowledge and experience. We should all come together to move our collective knowledge and experience forward to learn more about tinnitus and hyperacusis.

What questions would you like to see discussed in the Tinnitus Dialogue? Please, let us know by emailing us at hello@elevatingsound.com

We look forward to hearing from you!