Page 39 - Prosig Catalogue 2005

SOFTWARE PRODUCTS
PSYCHOACOUSTIC ANALYSIS & SOURCE PATH ANALYSIS

DATS Psychoacoustics Analysis Suite DATS Source Path Analysis Suite

• Loudness • Transfer Path Analysis
• Sharpness • Source Contribution Analysis
• Roughness • Path Contribution Ranking
• Fluctuation Strength The interior noise & vibration in a vehicle compartment is caused Training & Support
• Prominence Ratio by various contributing exterior sources - primarily suspension and
engine vibration. This raises two fundamental questions: “Which
In simple terms, psychoacoustics is the study of the relationship sources cause the most audible or tactile interior response?” and
between the physical measures of sound, amplitude and frequency “Which paths are the most critical in transferring energy from
and the human perception of them. the sources to the vehicle interior?” Transfer Path Analysis (also
known as Noise Path Analysis or Source-Receiver Path Analysis)
The DATS psychoacoustics software extension provides a host of attempts to answer these questions by relating the vibrations
functions for the objective description of subjective sounds. measured at different locations around the vehicle to the sounds
Hearing is not purely wave and vibrations measured inside the vehicle.
propagation from one The first stage of experimental Transfer Path Analysis is the
medium to another, it is computation of the Principal Components of the system using
a sensory and perceptual Singular Value Decomposition (SVD). The SVD computation Condition Monitoring
event. When a person hears produces a transformation
a sound, it arrives at the ear (eigenvector) matrix that is
as a wave travelling through used to derive virtual cross
the air, but within the ear it spectra between the virtual
is transformed into neural (vibration) references and
signals by a number of the measured (sound/
mechanisms. These nerve vibration) responses.
pulses then travel to the brain where they are perceived. Hence These virtual cross spectra
for many problems in acoustics it is advantageous to take into are then used to calculate
account not just the mechanics of the environment, but also the Reference Related Auto
fact that both the ear and the brain are involved in a person’s (RRA) spectra at every
listening experience. response position. Each Software
Human hearing can be compared to a spectrum analyzer - the RRA spectrum is related to just the coherent contributions from a
ear resolves the spectral content of the pressure wave. This even particular reference source input.
includes phase information, which provides a significant part of Full Transfer Path Analysis requires not only data at the Source and
the directional sensation of sound. Response locations, but also frequency response (FRF) functions
One good example of the power of psychoacoustics is listening to referenced to the attachment points of the vibration isolators
crackly, hiss-filled, vinyl records; the listener soon stops noticing (anti-vibration mountings). The software estimates the dynamic
the background noise, and enjoys the music, despite the presence forces present at the isolators and determines the contribution
of the hiss in the audible sound. A listener who does this often from each location as perceived at the (driver) response positions.
appears to forget about the noise altogether and may not be The various contributions from the paths are ranked according to
able to tell after listening if there was noise present. This effect is their severity at different frequencies or speeds.
called psychoacoustical masking. Hardware
Analysis functions included

Loudness
Sharpness
Roughness
Fluctuation Strength
Tonality
Prominence Ratio
Prominence Standards
ANSI S1.13-2005
ECMA74 DATS Source Path Analysis Suite
DIN 45681:2005
01-55-799 Source Contribution Analysis software (Requires System Packages
DATS Psychoacoustics Analysis Suite 01-55-872 01-55-622 DATS.toolbox)
Transfer Path Analysis software (includes Source
Contribution Analysis) (Requires 01-55-622 DATS.
01-55-997 Psychoacoustics analysis suite (Requires 01-55-
622 DATS.toolbox) toolbox)

http://prosig.com +1 248 443 2470 (USA) or contact your 39
sales@prosig.com +44 (0)1329 239925 (UK) local representative
A CMG Company