SfC Home > Communication > Senses > by Ron Kurtus (7 March 2001) Humans and animals can sense a wide range of sound frequencies, pitches or tones. The range of frequencies determines the person's or animal's perception of the world, as well as its ability to communicate. Questions you may have include: This lesson will answer those questions. The frequency of a sound is also known as its pitch. The higher the frequency, the higher the pitch and the shorter its wavelength. There is a range of frequencies that humans and animals can hear or detect. This is also true for any detectors of sound, such as microphones. Frequency is measured in Hertz—which means cycles per second. The abbreviation for Hertz is Hz. There is an upper and lower limit of the frequencies that each animal can hear. The following chart shows a comparison of the range of frequencies or pitches that humans and various animals can hear. Note that a frog and a mouse hear almost a completely different range of sounds.

Range of hearing in Hertz A normal human can hear between 20 Hz and 20,000 Hz. That is quite a range. 20 Hz is a very low pitch sound or very deep tones. 20,000 Hz is a high pitch sound. Besides hearing low frequencies, you can often feel them. An example of that is when you can feel the bass from a loudspeaker. When humans get older, they have trouble hearing the high pitched sounds and their detection range diminishes. For example, I knew an old man who was losing his ability to hear the higher pitched sounds. He could hear my voice fine, but he had trouble hearing his wife, because her voice was at a higher pitch. She often got angry at him, because she thought he was just ignoring her. Dogs and some other animals can hear sounds at higher frequencies than 20,000 Hz. That is why people can’t hear a special dog whistle, while the dog will react to it. Being able to hear the higher frequencies may be useful in hunting for the animal. Cats can hear higher frequencies also, but most are too independent to respond to such a whistle.

Elephants can hear frequencies much lower than the range of humans. Some researchers who were studying elephants in Africa discovered this. The story goes that a herd of elephants they were observing suddenly perked up their ear and ran off in a direction, as if they heard someone calling them. The researchers said they didn't hear anything, but some said they felt something strange in their bodies, just before the elephants ran off. After studying this situation, they found that elephants could make a very low frequency sound that humans can’t hear. Elephants are able to hear this sound coming from up to 5 miles away. It is amazing the distances from while they can communicate with each other. What you hear can affect how you perceive the world around you. The whine of the vacuum cleaner may not bother you, but it can cause your dog to run and hide, because of the painful high-pitched sound that you may not be able to hear. Cats perceive a world where there are high-frequency squeaks of mice hiding in the pantry, while elephants perceive a world of low rumbles of far-away friends.

Meanwhile, we perceive a world somewhere in between.blu-tec robotic vacuum cleaner review The pitch of a sound is determined by its frequency, which is usually measured in Hertz. dyson vacuum cleaner part exchangeAnimals and humans can hear sounds in limited range of frequencies. kenwood vacuum cleaner filterSome animals can hear sounds that humans can’t. The range of sound you can hear determines your perception of the world. There is more to life than you realize Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible. Click on a button to bookmark or share this page through Twitter, Facebook, email, or other services:

The Web address of this page is: Please include it as a link on your website or as a reference in your report, document, or thesis. Download the Noise Thermometer PDF Sound Energy Doubles Every 3 dB Example: if a 90 dB noise is doubled, it measures 93 dB Download the Noise Thermometer PDFReview of: Neato Botvac D75 / D80/ D85Producer: Version:D seriesRating:5Summary:Neato's latest line of robots, named the D series, come in 3 models: the D75, D80 and D85. These are indeed improved from their older siblings, and can be considered as one of the best domestic units in the industry. Improved brushrolls, lower sounds levels, higher dust capacity and bigger filters are just a few perks Neato brags about. If you’re looking for a good robot vacuum cleaner, then you’ll surely going to have a blast with the new Neato Botvac D series, which will be released starting with the first of July 2015. If you’re reading this, I bet you are already acquainted with the Botvac line, more specifically Neato’s Botvac 85, which I’ve reviewed a while ago.

In this new series, you’ll find the D85, D80 and D75 which are awesome models packing each a powerful take on cleaning. This is what you’ll learn from me in the following minute or so: how good are new Botvac D models, compared to other robotic vacuum cleaners how good are new Botvac D models, compared to the older Botvac models what are their strong and weak points where to find good deals The LCD panel display is something commonly shared among all Neato vacuums. But their latest product comes with more sensitive controls, 24 oz (0.7 liters) of dust collector space and reduced noises. Different bristles and brushes can be easily attached, allowing fast replacement and use. The new brush system is much more efficient in comparison to previous versions of the product. But let’s have a closer look to these features: Suction is enhanced in the D Series. Its new filters enable and the capture of debris and dirt with extra performance, thus a better airflow can be deployed.

No matter the type of surfaces vacuumed, the suction system allows for the robot to perform on uneven grounds. Vacuum robots with such capabilities spend less time vacuuming, thus being much more efficient and allowing of their batteries. Speaking of batteries, the vacuums in this series can be charged under both 110V and 220V voltages. The batteries themselves have a 6-months limited warranty (a 1-year warranty is granted for the whole unit). They consume 1 Watt on standby and 2 Watts while charging. This means batteries will last longer, for longer cycles and bigger vacuumed areas. You can also program these vacuum robots to operate every day in any appointed time. As mentioned above, the Neato Botvac D packs a dust collector capacity of 24 ounces. Although it can’t be compared to common uprights, bear in mind that the capacity of any robot vacuum cleaner is designed considering autonomy issues. In other words, they are built to work every day, keeping your house clean all the time.

It’s a new radical change that’s promised to revolutionize the way home vacuuming is done. And now you too can be one of the pioneers having a piece of this great upcoming future. As mentioned, the filtration system includes enhanced larger filters. They operate with higher performance retaining much more dust and debris particles than its predecessors, ensuring that even allergic users are not affected by the vacuuming operation itself. This gives you great tranquility knowing that your home’s environment and air quality will also be enhanced by the continuous cleaning provided by these vacuuming systems. The D Series is very light, weighing only 9 pounds. Dimensions are 12.7 x 13.2 x 3.9 thick which makes it extremely compact, light to carry and set up anywhere you want. Its distinctive D shape grants it enhanced navigation, enabling it to clean near corners and edges, under tables, beds, wardrobes, cabinets, chests, couches and many tricky spots which are sensed through it advanced laser sensor, which guide its operation.

If there are any operational defects, you can quickly exchange Neato for another one. And if problems occur to the battery such as short circuits or the battery doesn’t function properly, you can exchange it for a new one without having to exchange the whole product package. Main accessories include specialized brushes and boundary markers. The brushes ensure your D Series model renders your vacuum robot extremely efficient, especially if your house includes different ground levels and formats and if you own pets. Speaking of pets, Neato‘s specialized brushes are provide great hair pickup. As for the boundary markers, you can program your vacuum robot to stay off your pet’s areas or your children’s bedrooms. The D series have noise reduction capabilities, thus you can have your robot vacuum operate even at nighttime. This is  awesome, as you can wake up to a freshly cleaned home. Something you probably never thought of doing before. The D Series are praised for their great suction, low noise and long lasting batteries.

The navigation is also something homeowners really admire, since these D Series vacuum robots hardly ever miss a spot. One con most homeowners have is that the vacuum dust compartment. Although is it much bigger than the previous versions, they still wish it was bigger, so to store more dust and debris. But the makers sacrificed extra space for more compactness and autonomy. There’s also the issue with the remote control – Neato vacs don’t have remotes. Model Comparison (D85 vs D80 vs D75) Botvac D comes in 3 models: D85, D80 and D75. Thus, you might start to wonder which one is right for you. 2 main factors usually differentiate one from another: the combo brushes, designed specifically for pet hair, and the number of high-performance filters. D85, as the bigger number implies comes with 3 high-performance filters, all others have only 1. If this is a key feature for you, then the D85 is definitely the right choice. As for the combo brush, only D85 and D80 have this.