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C00002 00002	WORKING OUTLINE: PROPOSAL TO NATIONAL SCIENCE FOUNDATION
C00005 00003			B. Simulation of Acoustical Environments and Localized Sound Sources
C00009 00004	   III. Relation of Proposed Research to Other Research and Applications
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WORKING OUTLINE: PROPOSAL TO NATIONAL SCIENCE FOUNDATION



   I.	Introduction.
   II.	Proposal - Perceptual Modeling Through Computer Simulation of 
   	Natural Auditory Signals and Reverberant Spaces.
		A. Simulation of Music-Instrument and Vocal Tones.
			1. Analysis-Based Additive Synthesis.
				a. Perceptual Validation of Analysis-Synthesis Technique.
				b. Data Reduction and Higher-Order Algorithms.
					(1) Justification for Data Reduction.
					(2) Current Research with Data Reduction.
						(a) Filtering.
					        (b) Line-Segment Approximations
						    to Data Functions.
					(3) Future Research.
						(a) Wider Range of Timbres.
						(b) Higher-Level Algorithms.
			2. Frequency Modulation Synthesis.
				a. Synthesis and Analysis Techniques
					(1) synthesis
					(2) FM predictive Analysis
				b. Perceptual Correlates FM Technique
					(1) Simple Equation
					(2) Extended equation e.g. multiple
					    carrier and modulation frequencies.
				c. Future Research
					(1) simulation of fixed formants
					(2) FM additive interaction
					(3) Mapping algorithms FM↔Additive data.
			3. Testing and Validation of Tones and Exploration of the 
			   Dimensionality and Properties of Timbral Space.
				a. Naturalness.
				b. Discriminability.
				c. Effects of Musical Training.
				d. Multi-dimensional Scaling.
				e. Categorical Perception.
				f. Perception of Novel Tones.
				g. Context Effects.

		B. Simulation of Acoustical Environments and Localized Sound Sources
			1. Perceptual Model of Enclosed Spaces.
				a. Artificial reverberation in one channel.
					(1) The basic tool: the all-pass network.
					(2) Echo distribution: preceptually relevant
					    density increase; smoothness of decay
					    at both high and low amplitudes.
					(3) Determining effects of absolute values and 
					    relationships between delay and gain
					    parameters. Decay-time, richness,
					    room size.
				b. Multi-channel Reverberation.
					(1) Un-correlated reverberation.
					(2) Naturalness, with both real and synthetic
					    tones.
					(3) Number and placement of speakers for
					    simulation of three dimensional spaces.
				c. Acoustical `tuning' of the simulated space.
					(1) Spectral shaping filters.
					(2) Generalized room response.
					(3) Localized resonances to simulate complex
					    spaces.
				d. Perceptual cues for physical dimensions of the
				   simulated space.
					(1) General: Localization of source as an
					    indicator of room size.
					(2) Specific: Distance from source to nearest
					    reflecting surface.
			2. Localization Cues for Stationary Sources in the Simulated
			   Environment.
				a. Azimuth: amplitude distribution to speakers.
					(1) Investigation of `least discriminable
					    angle' for simulation, possible 
					    asymetricality and remedies,
					    and  possible benefits of speaker 
					    clustering for continuity.
					(2) Energy distribution between speaker
					    pairs other than 2*theta/π.
				b. Distance: ratio of reverberant/direct signal.
					(1) Amount of local reverberation needed
					    for distance cue without noticeably
					    changing  environmental perception.
					(2) Discovery of attenuation function
					    for reverberation with distance.
					(3) Simulation of signals at distances
					    less than the speaker.
				c. Preserving directional information of signal
				   when distance is greater than the echo radius.
				   (Determine range of relationships between amplitudes
				   of local and global reverberation.)
 			3. Simulation of Moving Sound Sources.
				a. Discriminability of changing environmental parameters.
				b. Discriminability of distance, angle, velocity of:
					(1) illusory sources in simulated motion.
					(2) specific features of changing environments.

   III. Relation of Proposed Research to Other Research and Applications
   IV.  Equipment and Hardware
		A. Hardware
			1. PDP-11,45
			2. Special Purpose Processor
			3. Display
			4. Audio equipment- 8-ch recorder, speakers, amplifiers, etc.
		B. Acoustically Controled Spaces
			1. Large acoustically treated room
			2. Small isolation module
   V. Budget and Personnel
   VI.Appendices
		A. The Hetrodyne Filter
		B. Unit Reverberators
			1. First order
			2. Second order
		C. Spectral Shaping Filters
			1. Resonators and Anti-Resonators
			2. The Comb Filter Family
  VII. References