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The Big Tooter

High atop Mount Oread, in the picturesque city of Lawrence, Kansas, stands a whistle—a whistle with quite a history composed of tradition, controversy, and headache that started about a hundred years ago. The whistle is known as the “Big Tooter.”

March 25, 1912, 9:50 a.m.: a deafening shrill begins. For five earsplitting seconds the power plant steam whistle at the University of Kansas sounds. The sound is so loud it can be heard from one side of the city to the other. It’s the first time the whistle is used to signal the end of each hour of class time.

According to the student newspaper The Daily Kansan, the whistle was not only used to replace the untimely and inconsistent ringing of bells with a standard schedule of marked time, but was also used to remind professors to end their lectures immediately. Prior to the whistle, too often professors would keep students past the 55 minutes of class time, causing them to be late for their next class. With the new sound system in place, even the chancellor had something to say.

“If the instructor isn’t through when the whistle blows,” said KU Chancellor Frank Strong to the student body, “get up and go.”

The Big Tooter Today

For the past 100 years, the Big Tooter has been the deafening reminder to faculty and students about punctuality and when to cover their ears. I can say I was one of those students too, who would purposely alter my walk to class to avoid that sound at its loudest range. But, despite the fact that the steam whistle was excruciatingly loud, it served its purpose as an audio alert. So unique, it was never misunderstood, so reliable it is always trusted.

The Importance of Audition

Control of the volume level is usually still performed by hardware keys, due to the importance. This makes it an interesting control as it is always pseudo-modal. The user enters the mode by using the keys, which loads a screen, layer or other widget to indicate the volume change. Related controls, silence and vibrate, are associated with this mode as well.

From the example above, we see that people can benefit from specific sounds that are associated with contextual meaning. Using audition in the mobile space can take advantage of this very important concept for the following reasons:

Auditory Classifications

Audible sounds and notifications have become so common-place today that we have learned to understand their meaning and quickly decide whether or not we need to attend to them in a particular context.

Warnings

Audible warnings indicate a presence of danger and action is required for one’s safety. These sounds have loud decibels (up to 130 dB) and some use dual frequencies to quickly distinguish themselves amongst all of the external noise that may be occurring at that time. Most often these warning are used with visual outputs as well.

Alerts and Notifications

Alerts are not used to signal immediate action due to safety. Instead they are used to capture your attention to indicate an action may be required or let you know an action has completed. Alerts can be a single sound, one that is repetitive over a period of time and can change in frequency.

Mobile alerts are quite common. They must be distinguishable and never occur at the same time as others. When appropriate, use visual indicators to reinforce their meanings. Use a limited number of alert sounds, otherwise the user will not retain its contextual meaning.

Error tones

Error tones are a form of immediate or slightly delayed feedback based on user input. These errors must occur in the current context. Examples of mobile error tones are often buzzers to indicate:

Voice Notifications

Voice notifications can be used as reminders when you are not holding your device, as well as notifications of incorrect and undetectable input through voice, touch or keypad. Use syntax that makes it clear what is being communicated. Keep the voice notification messages short and simple.

Feedback Tones

Feedback tones occur immediate after pressing a key or button such as the dialer. They confirm that an action has been completed. These may appear as clicks or single tones.

Audio Guidelines to Consider in the Mobile Space

Voice inputs can help for users or situations where eyes cannot be used, but have to be part of a complete voice UI. Don't just perform one or two steps of a process, then require the user to read and provide feedback on screen.

Signal to Noise Ratio Guidelines

When the noise level is +18dB to the signal level, all consonants are confused with one another. (Kryter, 1972).

Speech Recognition Guidelines

Audio accessibility in the mobile space

When designing for mobile as with any device, always consider your users, their needs, and their abilities. Many people who use mobile devices experience visual impairments. We need to create an enriching experience for them as well.

Recently, companies are addressing accessibility needs as standard functions in mobile devices. Before this, visually impaired users were forced to purchase supplemental screen reader software that work on only a few compatible devices and browsers. These are quite expensive starting around $200-$500.

Accessibility Resources

The Importance of Vibration

Depending on our users needs, their sensory limitations, and the environment in which mobile is used, vibration feedback can provide another powerful sensation to communicate meaning.

Vibrate on most devices is coarse, and provided by a simple motor with an off-center weight. Here, it is the silver cylinder between the camera and the external screen; the motor is mostly covered by a ribbon cable. It is mounted into a rubber casing, to avoid vibrating the phone to pieces, but this also reduces the fidelity of specific vibrate patterns, if you were to try to use it for that purpose. To the right, I have removed the motor assembly for clarity. Since our largest organ in our body is the skin that responds to pressure, we can sense vibrations anywhere on our body. Whether we are holding our device in our hands, or carrying it in our pocket, we can feel the haptic output our devices produce.

Common Haptic Outputs on Mobile Devices

Haptic Concerns

Patterns for Audio & Vibration

Using Audio & Vibration control appropriately provides users methods to engage with the device other than relying on their visual sense. The following patterns in the chapter will be discussed.


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