## On this page # Car Sound Simulator - OSC Messages Last update: 09.03.2026 Car Sound Simulator is driven by OSC MESSAGES sent over UDP, with each action associated with one message. The action name is a KEYWORD, followed by some OSC ARGUMENTS. ## Basic management messages Basic management for the sound generator. #### Messages sent once by state change KEYWORD (Address Pattern)TYPECommentsINIT\_DATAPATHStringData initialization: Data pathINIT\_CONFIGFILEStringData initialization: File nameDSP\_START Starts the CSS Audio EngineDSP\_STOP Stops the CSS Audio Engine (sound off)START\_KEYIntegerPosition of the start key : - 0 : off - 1 : contact - 2 : on - 3 : start #### Messages sent regularly KEYWORD (Address Pattern)TYPECommentsSPEEDFloat (m/s)Absolute vehicle speedRPMFloat (rev/min)Engine speed (revolutions per minute)CHARGEFloat (between 0. and 1.)Throttle loadOUTPUT\_TYPEStringAudio output configuration:- "Stereo" - "2.1" - "4.1" - "4.0" - "Binaural" - "Transaural" SCANMAX\_VERSIONStringUnused## Traffic noise management The exploiting application handles up to 8 traffic vehicles, corresponding to 8 possible synthesis slots. These 8 vehicles must be chosen by the simulator depending on their contribution to the sound scene, for example by selecting the closest ones. Angles are in radians, 0 is a front source, -pi/2 is left, +pi/2 is right. Angles greater than pi or less than -pi are accepted. Note that the specified traffic vehicle speed only serves sound source synthesis. It does not affect the Doppler effect, which is only controlled by the successive relative positions set with the TRAFIC\_UPDATE message. #### Messages sent once by state change KEYWORD (Address Pattern)TYPECommentsTRAFIC\_INITSlot index (int) Vehicle type (int) Distance (float in m) Azimuth (in rad) Absolute speed (float in m/s)Traffic synthesis initialization at slot index. (1<=slot index<=8) Type: - 0 = unknown - 1 = car - 2 = truck/bus - 3 = motorbike TRAFIC\_STOPSlot index (int)Traffic sound synthesis stopped at slot index (1<=slot index<=8)#### Messages sent regularly KEYWORD (Address Pattern)TYPECommentsTRAFIC\_UPDATESlot (int) Distance (float, in m) Azimuth (float, in rad) Speed (float, in m/s)Update of the traffic vehicle characteristics (distance, azimuth, speed) at slot index (1<=slot index<=8).## Harmonic sources management The application handles up to 10 harmonic sources. Each of them can be controlled with the following messages: #### Messages sent once by state change KEYWORD (Address Pattern)TYPECommentsRPM\_USER\_1Value (int)1st specific RPM for a dedicated harmonic sourceRPM\_USER\_2Value (int)2nd specific RPM for a dedicated harmonic sourceRPM\_USER\_3Value (int)3rd specific RPM for a dedicated harmonic sourceRPM\_USER\_4Value (int)4th specific RPM for a dedicated harmonic sourceRPM\_USER\_5Value (int)5th specific RPM for a dedicated harmonic sourceRPM\_USER\_6Value (int)6th specific RPM for a dedicated harmonic sourceRPM\_USER\_7Value (int)7th specific RPM for a dedicated harmonic sourceRPM\_USER\_8Value (int)8th specific RPM for a dedicated harmonic sourceRPM\_USER\_9Value (int)9th specific RPM for a dedicated harmonic sourceRPM\_USER\_10Value (int)10th specific RPM for a dedicated harmonic sourceHS\_AZIMID (int) Value (int)ID is the number of the specific harmonic source. Value is the azimuth angle in degrees for the spatial positioning of the source (between -180° and 180°).HS\_VOLID (int) Value (int)ID is the number of the specific harmonic source. Value is a gain value in dB applied to that source (between -15 and +15 dB).HS\_WIDTHID (int) Value (int)ID is the number of the specific harmonic source. Value is the coefficient of diffuseness of the source, between 0 and 100% (0% means the source has no diffuseness, it can be perceived from a specific direction, 100% means the source is totally diffuse, it is perceived as surrounding and coming from all speakers with the same energy).## Tire noises of the main vehicle Tire noise has to be updated for each wheel by providing information about the current slippiness. #### Messages sent once by state change KEYWORD (Address Pattern) TYPE COMMENTS GROUND\_INDEX int (0-3) 0 = asphalt, 1 = concrete, 2 = grass, 3 = cobblestone SCREECH float x8 4 x wheel slipping intensity between -1 and 1. (float in this order : front left, front right, rear left, rear right) 4 x slipping angle of each wheel in radians (2\*pi-periodic) (float in this order : front left, front right, rear left, rear right) For example: SCREECH 0.2 0.2 0.15 0.15 0.4 0.4 0.1 0.1 WHEEL\_ ADHERENCE int + float x4 4 pairs composed of an int (wheel index) and a float (wheel stickiness coefficient) Wheel indexes are 0, 1, 2, and 3, for front-left, front-right, rear-left, and rear-right wheels, respectively. Wheel stickiness coefficient range is between 0 and 1. For example: WHEEL\_ADHERENCE 0 0.1 1 0.3 2 0.7 3 0.7 0.7 < float stickiness coefficient < 1 : dry 0.2 < float stickiness coefficient < 0.7 : wet 0.1 < float stickiness coefficient < 0.2 : snowy ## Weather management Weather noise management. #### Messages sent once by state change KEYWORD (Address Pattern)TYPECOMMENTSWEATHER\_RAINint (0-100)% rainWEATHER\_WINDint (0-100)% wind## Additional noises Loading orders of additional simulation noises. #### Messages sent once by state change. KEYWORD (Address Pattern)TYPECOMMENTSMOTOR\_PARTIALSstring.motor file to load (path must include slashes '/' instead of '\\')MOTOR\_NOISEstring.noise file to load (path must include slashes '/' instead of '\\')AERO\_NOISEstring.noise file to load (path must include slashes '/' instead of '\\')ROLLING\_NOISEstring.noise file to load (path must include slashes '/' instead of '\\')STARTER\_MOTORstringwav file corresponding to the engine starting noiseHORN0 or 1Triggers the built-in horn sound (sawtooth signal). Note that the sound is triggered on onsets only; several 1s sent in a row only trigger the sound once.INDICATORS0 or 1Plays the built-in turn indicator sound. 0=off; 1=on.## Sound files playing Supported functions: - sendSoundLoad : loads a sound - sendSoundPlay : plays a sound (looping available) - sendSoundStop : stops a sound play - sendSoundPause : pauses a sound play - sendSoundVolume : sets the sound volume There are 10 available slots for sound playback in Car Sound Simulator. The main simulation application has to manage the slot index availabilities. Notes: - the slots indexes are >=1 and <=10 - .wav extension is appended to the file name #### Messages sent once by state change **KEYWORD (Address Pattern)** **TYPE** **COMMENTS** SOUND\_LOAD Sound id (int, 0<id<32765) Loads a file to play with the specified id. File name (string) SOUND\_PLAY Slot index (int) Starts playing the sound <Sound id> at slot <Slot index>. TypeSpat: 0 = not localized, 1=attached to a vehicle, 2 = attached to a point. Gain is linear (directly multiplied with the signal). Azimuth in radians, Distance and DistanceMax in meters. DistanceMax corresponds to the distance from the source where it can no longer be heard. Sound id (int) Play in loop (1 or 0) Gain (float) TypeSpat (int) Azimuth (float, in rad) Distance (float, in m) DistanceMax (float, in m) SOUND\_STOP Slot index (int) Stops playing the specified slot's sound. SOUND\_PAUSE Slot index (int) Pauses the playback of the specified slot's sound. SOUND\_RESUME Slot index (int) Resumes the specified slot's sound playback. SOUND\_VOLUME Slot index (int) Changes the volume of the specified slot's sound. The gain is linear (value directly multiplied with the signal). Gain (float) SOUND\_UPDATE\_POSITION Slot index (int) Updates the position of the sound at slot <Slot index>. Azimuth (float, in rad) Distance (float, in m) ## Error and warning messages Messages sent to the main simulation application when required. #### Messages sent once by state change KEYWORD (Address Pattern)TYPECOMMENTSWARNINGStringSends a warning messageERRORStringSends an error message## Start, stop, state management The main simulation application has to start and stop Car Sound Simulator. #### Message sent periodically to the main application. KEYWORD (Address Pattern)TYPECOMMENTSALIVE-Indicates that Car Sound Simulator is still running## Head-tracking Message sent to locate the position of the listener's head for head-tracked binaural rendering. #### Message sent periodically to the main application KEY WORD (Address Pattern) TYPE COMMENTS HEAD-POSITION X (float) Y (float) Z (float) rotZ (float) rotY (float) rotX (float) Position of the listener's head in space. Distances are in meters, angles in radians. X points to the front. Y points to the right, Z points below. The azimuth angle is then rotZ, with a positive angle when the listener turns their head to the right. Elevation angle is then rotY with a positive angle when the listener raises their head.