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Engineering Issues
What client-server connections does AuSIM3D® support? Initially, AuSIM3D® supported a standard serial (RS-232) cable connection to match the ATRON protocol developed for Crystal River Engineering servers.  Today, AuSIM supports USB, Windows-RPC over TCP/IP, and cross-platform TCP/IP.  AuSIM's proprietary USB connection yields a big increase in parameter control bandwidth and ease of use.  Other upcoming developments will focus on the transfer of audio from clients or other peripheral devices to servers, and will implement FireWire and Network (VOIP) based implementations.
Why can't I install AuSIM3Dtm as software on my computer? At this time, AuSIM3D® is hardware/software audio processing technology, and not available for installation on generic PCs. This is due to very specific hardware and software requirements, components and configurations that are currently required.
When AuSIM says the system supports “n” inputs, do you mean "sound sources","analog inputs", or "digital inputs"? “Sound sources” must be differentiated from “Inputs”.
  • A sound source is any event or data stream that is to be placed in aural 3D space. This event or data stream may come from physical source (microphone, radio, tape, - VOIP, etc.), a wave file, or may be locally synthesized.
  • An input is the physical source, comprised of signals originating from pre-recorded wavefiles, generated from signal generators, converted from analog inputs, streamed from IP sockets, or streamed from digital PCM inputs.
  • Analog inputs are live balanced (pro audio) or unbalanced (consumer audio) signals that can originate from any traditional sound generating device, including microphone, radio, or CD player.
  • Digital inputs are live pulse-code modulated (PCM) full-bandwidth digital audio streams at 44.1 or 48.0 kHz and at word sizes of 8, 16, 20, and 24-bits. This includes the digital SP-DIF output of most modern CD-players.
When the data sheets talk about multiple outputs, what do you mean? Three output configurations are possible:
  1. Multiple listeners sharing the same virtual environment from unique perspectives
  2. Multiple listeners sharing the same virtual environment from one perspective
  3. Multiple listeners with independent virtual environments.
AuSIM systems currently support (b) and (c). Support for (a) is not available in the current version of the system, but is a planned addition.
Are headphones required to experience AuSIM’s 3D audio? Yes, at this time, and for the near future, headphones are required. Our system prepares an audio signal for each ear, and assumes each ear is in a fixed position with respect to the speaker. We have plans to develop a tracking system that will keep track of where each ear is with respect to each loudspeaker, but that will be at least a year or two away. Also, our first headphone-free system may be for automobiles, where head position with respect to loudspeakers is relatively fixed.
Can I use different headphones? You can use any stereo headphones but the quality of the headphones directly affects the quality of the 3D sound you hear. Better headphones have better frequency responses that more effectively deliver the high frequencies that contain many of the perceptual spatial cues inherent to 3D sound. Additionally, ear buds and closed/open circumaural headphones all allow a different level of outside sound/noise into the ears.
What are closed headphones? Closed headphones are typically also circumaural and have some kind of hard shell or outer cover that aids in blocking typical ambient room noise out of the ears. You can think of these as a combination of normal headphones and a lighter version of the typical earmuffs that the guy shooting a gun should be wearing.
What are circumaural headphones? Circumaural simply means that it completely encloses your ear (lobe, pinnae, all).
Can I use AuSIM3D® with MIDI? Digital MIDI interface boxes enable users to pipe MIDI sounds directly into the AuSIM3D® audio server. AuSIM has completed alpha development of a system that records a sequence similar MIDI for the play back of live sound movement processing – allowing real-time overwrite/manipulation and other pro-audio recording studio type functionality.
Are AuSIM's products compatible with other audio systems? AuSIM's products work with live analog audio signals, .wav files, and selected headphones and head trackers. As this list is constantly being updated, please check with our technical staff for the latest list.  Our API also maintains compatibility with the Crystal River Engineering (CRE) Acoustetrontm product line.
What is the range of a tracker? Depending on what tracker you buy, their ranges can vary from inches to miles, or in some cases it isn’t an issue.
  • Typical electro-magnetic trackers work in a sphere around the transmitter that can range from 3 to 9 feet. 
  • Ultrasonic trackers typically work within a 5 foot conical range from the transmitter
  • Inertial trackers do not currently calculate x, y, z – instead they measure only orientation; so they have zero relative dimensional range but you can walk anywhere with them, unlimited in range, and they will track your orientation. 
  • Optical technology is the most accurate and has the greatest range of all trackers, exceeding the range required in typical 10-foot caves. All trackers have their limitations, however, that should be noted as they affect their ranges. 
  • Electro-magnetic trackers can suffer from warping caused by surrounding metal or magnetic objects
  • Ultrasonic and optical technology require a line-of-sight from transmitter to receiver that effectively limits motion and thus range. 
  • Inertial trackers are effected/skewed by the movement (“Gs”) of moving vehicles, ships, aircraft, etc. in which you may wish to operate with these trackers relative to the interior instead of the outside world. 
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