Audio mapping: "too near" and "too far"

23 Jan 2012 - 3:45pm
2 years ago
7 replies
957 reads
DamonV
2010

Does anyone know of a good natural audio mapping for "too close" and "too far away"?

Users are using a laser scanning device to capture a 3D shape. The device functions well within a certain range distance from the shape, less so when getting closer or further away from it. The software should provides audio feedback to indicate where the user is in relation to the ideal distance.

My thought so far are to use pitch: high for near, low for far. Would this be a usable mapping? And if so, is it better for indicating the degree of "too close" by increasing the pitch or by increasing the volume?

Notes:
- There is visual feedback as well, but user may not have time to look at the screen.
- The user is there with a patient and may be reluctant to receive overly explicit correctional feedback ("Too far away").

Thanks in advance!
Damon

Comments

23 Jan 2012 - 6:58pm
ericscotteisher
2010

EDIT: I clearly misunderstood what you were trying to do, but the technology below is still pretty cool. : )

 

If you are open to changing your approach, you might find some luck by looking into multiple microphone arrays.Kinect uses this technology for a number of futuristic things. 

"...if we put microphones in different places, the sound will arrive to them in different instants, in that way, we can calculate from where comes the source of sound if we take in to account the difference between the signals that get the microphones and the speed of the sound in the air. But not only we can calculate if the sound comes from one side or another, also can be determined approximately its position..."

http://bit.ly/yOO1LU  - Paper on Approximation 

http://bit.ly/fc25k - Wiki on Independent component analysis

source: http://www.computableminds.com/post/Kinect/multiarray/microphone/how-works/xbox-360
23 Jan 2012 - 5:43pm
martinsz
2011

Hi Damon:

I don't know about standard mappings, but maybe it's not hat important. I think your proposal can work, since the users will be able to learn what the sounds mean by looking at the screen, and after that they'll recognize the sounds easily.

If you want to be sure, a user test might be appropiate.

About the sounds, you have to consider that the two tones are different enough to be recognized as different. Also be aware that other tools in the same space might be making noise or sounds and they don't have to be confused, also, if there's other people in the same room, consider their ears, maybe a volume regulator is a good idea, and try different sound textures to find the most appropiate with the general aesthetic of the tool, and the most respectful with peoples ears.

In other words: It's allright but don't make another beepity beep annoyance ;)

Martín.

PS: I can't send messages by email, I have to log in to the site... does anyone know how to change that?

23 Jan 2012 - 6:15pm
Moses Wolfenstein
2010

If the audio component is going to be persisent I might recommend considering rhythm rather than pitch. It's not entirely uncommon in video game design and tends to be pretty effective. Think about sonar as a metaphor: the frequency of beats increases as the user approaches the target/optimal distance. One concern with any audio feedback using either pitch or rhythm in a context like this is the potential for it to become annoying. Crafting the right sound can definitely be tricky.

24 Jan 2012 - 3:48pm
Jochen Wolters
2010

This reminds me of electronic "parking assistants" in cars that, when activated, beep at steady intervals. The pitch remains constant, but the frequency at which the beeps repeat increases the closer the car gets to an obstacle. A constant sound means "STOP NOW!" ;)

In cars that have these devices for the rear and back bumpers, the system usually uses two pitches that are easily distinguished, for indicating which end of the car is about to run into something. To add a bit of final polish, some premium car makers position the beeps in the passenger compartment via the onboard stereo system's fader and balance capabilities for a perfectly natural mapping.

For your application, you could try using two distinct pitches, one for "too close", one for "too far". I'd probably start out testing with a close:far::high:low pitch mapping.

Increase the frequency (not the pitch) of the beeps the closer the device is being moved towards the allowed distance range, and while the device is in that range, stop the beeps entirely. That way, the system provides guidance when the user needs a gentle nudge, while being silent once experienced users have learned how to properly position the scanner.

As Martin and Moses mentioned, though, use pleasantly soft and smooth sounds and a reasonable maximum beep repetition frequency to minimize the annoyance for the user and anyone else close by. And make sure that there are no similar sounds in the environment where this device is used, that could be confused with this distance control. (And also that, in turn, the distance control cannot be mistaken for another device, either.)

You might also consider to allow the user to temporarily switch off this audio guide completely, if the visual distance control is sufficiently prominent on the control panel.

As for this visual feedback, have a look at electronic guitar tuners, who use a similar widget for indicating how far off the current string's tuning is from the target frequency.

24 Jan 2012 - 3:59pm
Alan Hogan
2007

I must agree with the feedback you have been getting so far, namely:

  • If pitch differentiates “too close” and “too far,” then the closer pitch must be higher, as any musician would tell you.
  • Frequency of beeps, similarly, would be higher the closer you are, for similar reasons. The sonar analogy is a good one.

24 Jan 2012 - 6:00pm
DamonV
2010

This is great, thanks for all the feedback!

Damon

27 Jan 2012 - 7:06am
lukus
2010

I think frequency of bleep would provide a good solution.

  • Convention already dictates that (a) increasingly frequent bleeps, equals closeness, (b) decreasingly frequent bleeps equals distance.
  • If the user is in a location that is 'just right' - it would be fair to provide the user with no audio feedback.
  • This would provide the user with a prompt if they move out of the correct area - but wouldn't distract them unnecessarily when they're located correctly.
Hope this helps
Luke

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