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The Twentieth Annual Interactive Audio Conference
BBQ Group Report:
This Ainít Your Momís Horn Tone
Participants: A.K.A. "CarTunes"

Rian Chung, DTS

Randy Stephens, Cirrus Logic
Adam Smith-Kipnis, Samsung Michael Jessup, Dolby Labs
Phil Brown, Dolby Labs Larry Przywara, Cadence (Tensilica)
Michael Vulikh, P-Product Yipeng Liu, Cadence
Miguel Chavez, Analog Devices Bobby Lombardi, G-Technology
Josh McMahon, Realtek Mikko Suvanto, Akustica
Facilitator: David Battino, Batmosphere  
  PDF download the PDF

Brief statement of the problem(s) on which the group worked

As the car evolves into a personalized computer on wheels, changes driven by audio will be needed to increase safety and improve both comfort and user experience. The journey will become the destination.  The car itself will become the place where passengers will have new experiences, while increasing their productivity as workers.

Cars will be able to turn themselves into: theatres, karaoke rooms, meeting rooms, schools, museums, amusement parks, and gaming systems among other things.  In addition, the introduction of self driving cars will present new challenges and opportunities to all OEMs, Tier 1s and 3rd parties.

Our team’s thinking targeted the model year of 2026 to take into account the long design and manufacturing cycles of cars. Recognizing the financial burden that longer running cars incur within OEM, we recommended an open system that enables other sources of revenue through upgrades and subscriptions.

A brief statement of the group’s solutions to those problems

The car will become a personalized computer on wheels, and therefore will adopt computer technologies applicable to its environment. Driverless vehicles will become more commonplace, driving a shift in media consumption and productivity enhancements will be demanded. 

We identified three main areas of investigation, safety, entertainment and communication.  Additionally we saw potential for audio algorithms and overall improvements.


Safety features will require:

  • Short Range Inter-car communication
  • Improved internal and external sensors
  • External alert tones
  • Simulated engine or other car proximity noise
  • ADAS sensing of visual and auditory cues

Safety examples could be:

  • An Amber Alert triggering a dashcam to lookout for specific license plates
  • The car could listen for, and share, automotive sounds related to potential malfunctions for diagnostic purposes.  That audio could be added to an event data recorder.
  • Understand how song selection affects driving style.  Manual override for an automatic mood setting.


The entertainment system will need to evolve to include:

  • Active noise control
  • Engine sound enhancement
  • Hand-off from car to smartphone and vice versa
  • Internal and external microphone arrays, speaker arrays
  • Algorithmic improvements
  • Open platform to enable app-store purchases, upgrades, etc
  • Virtual and Augmented reality engine
  • Personalized auto-tuner/sound systems that learn user patterns / preferences (i.e. baseball game playing, specific songs). Karaoke (Car-aoke) with autotune.
  • Time compression of music based on destination arrival time so that song finishes just as you arrive.
  • Engine Sound Enhancement will be more frequently requested based on evolving customer expectations.


  • Internal and External advances, through specially designed microphone arrays will improve communication and safety.
  • Short range inter-car communication to signal more information than just a honk. Would spam be a concern? Are there ways to prevent spam or harassment (perhaps legal constraints)?
  • In-cabin communication (driver to third row or second row). For example using microphone arrays and Beamforming algorithms (audio zoom).
  • Passenger specific audio infotainment / localization (audio zoning).  The problem is that cars are tuned once and don’t change depending on the number of occupants or the entertainment desires of the occupants.  For low frequency information, close proximity subwoofer can be used to contribute to audio zoning.
  •  Embedded data within the horn sound for driver to driver communication (masked data)


  • Improve ANC instead of heavy acoustic insulation as a way to reduce vehicle weight to lower carbon footprint (ANC).
  • There will be additional challenges and opportunities with automobile tuning controls and features, being provided from downloadable apps, and associated and managed on mobile devices, as opposed to directly in the car.
  • It should be possible to update the feature set easily to ensure that the system is not outdated.  For example, current model Tesla’s receive over the air updates.
  • Algorithm requirements for some of the above include:
    • Audio Zoom - Long range DSP-based focus for microphones
    • ADAS (Advanced Driver Assistance System) Display
    • ANC
  • Silent Horn - Thinking through the potential of a silent horn to reduce noise pollution we concluded that…
    • A silent horn could carry data:
      • General alerts
      • Customized messages
      • Emoticons (Visual and audible)
      • Other...
    • The audibility of a data carrying horn sound serves 3 purposes:
      • prevents abuse, spam, hacks
        • Limit data to a defined set
        • Prevent it from being used for advertising purposes (popups while driving, or spoken messages)
      • sends the data
      • sends the alarm in case receiver doesn’t contain the system
    • Beamformed horn - Targeted horn honk could be an interesting area of exploration

Expanded problem statement:

The following is our vision of the OEM Audio system model 2026:

  • Safety
    • ADAS
  • Infotainment
  • Communication
    • In vehicle communication
    • Better Hands Free Support ( Beam forming, Source Separation, Echo Cancellation)
  • Ambient Noise affects speech recognition, music enjoyment and conversations (audibility), cognition
      • Engine Noise
      • Road Noise (tires)
      • Radio Noise
      • Wind Noise
      • Street Noise
      • Distracting passengers
      • Traffic Noise
      • Outside warnings, alerts(sirens, police). Noise incidence (directionality) from outside noise affected noise or other system design considerations.
      • Outside noise cues at times ( i.e. for people with hearing noise or deaf) do not provide enough information
  • Pedestrian sound alert are more and more important especially with quieter cars. Context awareness needs to be consider to avoid noise pollution.
  • Transducer and speaker reliability for outside pedestrian detection
  • What is the correct system partitioning within a car infotainment system (display, audio, apps processor…..)
  • How much will the phone itself replace current car electronics? (what can and what cannot be introduced)
  • There is a need to Increase the accuracy of voice recognition system
  • There is a need to have a smarter (occupancy dependent) surround sound rendering\
  • Smart Transducer control that sense internal pressure
  • Active  audio reinforcement system (voice and music itself) (i.e. Meyer sound - constellation system )
  • For Self Driving Cars:
    •  D-box theatre, Party Mode
  • Augmented reality could enable replacement to traditional car entertainment technologies for all audiences, (on road virtual meetings)
  • Bluetooth intelligent / localized sharing of playlists including proper management of multiple bluetooth devices
  • Exciters on the seats
  • Negative side of using phone in cars:
    • Dialing is difficult
    • Phone ergonomics are not design for automotive use
    • A phone is a distraction
    • Speech recognition doesn’t work
    • Audio quality is not excellent (questionable with the newer bluetooth formats)
  • Positive side of using a phone in car:
    • Car sound system sounds better
    • Privacy (capacity take the call somewhere else)
    • Familiarity
    • OS and HW are more frequently updated
    • Current Apps support (no need to redevelop them on a different platform)
  • When using a different and radically different honk, it may get confused with other types of sound.
  • There will be different legal requirements on sound levels.

Average lifetime of a car is increasing. How will this impact system definition?

Expanded solution description

Use Cases:

Silent Sisters
Family trip with a daughter that speaks very faintly seated in the 3rd row. When grandma calls, the driver needs to virtually “pass the phone” to his daughter in the back. He is able to do this by sending the call to the array of microphones and speakers in the vicinity of the daughter. When the call is over, the driver wants to ask his daughter about the call, but has a hard time hearing her. Again, the built in array allows nearfield communication with his daughter without having to shout and wake the other passengers.

Indianapolis Ivan
After attending a NASCAR race, two teenagers are very excited about the sound of the engines. Using the built in HornStar™ app store, they are able to download custom engine sounds to their 2026 Prius vegetable-oil powered car. Since the car is actually silent on the outside, and tends to sneak up on the elderly, they are also able to customize the exterior sounds to alert pedestrians, animals, etc., via powerful external speakers that play custom sound depending on the speed of the vehicle.

Flat Tire Francis
Francis is driving to work and notices that the red light is now green but the driver in front of him is still texting. He tells his car “Honk Polite” letting the fellow in front know that the goddamned light changed color about 5 seconds ago already. A bit later, he notices that the car in front of him has a rear tire that is running low. Since both his car and and the one in front are HornStar™ enabled, he is able to communicate this safely information to the other car.

Alert Amber
Your phone buzzes with an Amber Alert, indicating a child is now endanger. The driver has already told his car to automatically begin scanning license plates when it hears the Amber Alert tone, which now has the license plate number embedded as metadata. If the plate is discovered, the built in wifi automatically uploads GPS position to the authorities.

Hospital Harry
Harry is driving to work, and he has his death metal music up to 11. Unfortunately he does not see or hear the ambulance approaching from behind. Sensors on the outside of his car alert the vehicle to it’s direction, and the music is automatically dimmed and a HUD displays the correct way to maneuver the car. The HUD also gives a graphical indication of the ambulance’s direction and it’s proximity.

Car-aoke Caren
Caren’s friends loves karaoke, but hate long road trips. Caren uses her karaoke-enabled infotainment center to help pass the time. Multiple microphones allow each user to sing along, with patented “Auto-Tune” technology to improve the listener experience. The resulting performance is uploaded to social media via in-car cameras, microphones and wifi.

Otto Driver
Otto loves his new 2026 Apple Pious™ autonomous vehicle. He is able to step into his car, tell it his destination and then sit back, relax and enjoy the ride. He can choose from doing a conference call with his co-workers (Boring!), or watching a film on the HUD with complete hemispherical surround sound, or listen to a custom, context aware playlist that adjusts according to his mood, location and preferences. The experience is superior to anything in his home or office, and he prefers to use his car as his primary mode of entertainment consumption (the new mobile “man-cave”).

Items from the brainstorming lists that the group thought were worth reporting

Name suggestions:

  • Horn Tones
  • The Steering Committee
  • Auto-Tune

Other reference material

  • Tesla User Manual
  • Meyer Sound Constellation
  • ISO 26262 - Functional Safety
  • whistles woo video (UTube)
  • Renault F1 God Save the Queen video (UTube)
  • Tesla Insane Mode video (UTube)
  • Waynes World - Bohemian Rhapsody

section 6

next section

select a section:
1. Introduction
2. Workgroup Reports Overview
3. The Smartest Person in the Room is the Room: Applications for Virtual and Augmented Music Production
4. Audio Of Things: Audio Features and Security for Smart Homes/Internet of Things
5. A Brief History of Time
6. This Ainít Your Momís Horn Tone
7. Protecting Tomorrowís Ears
8. Schedule & Sponsors