Calculate psychoacoustic indicators

This example shows how to calculate psychoacoustic indicators. The following indicators are included:

• Loudness of stationary sounds according to ISO 532-1.

• Loudness of time-varying sounds, according to ISO 532-1.

• Monaural and binaural loudness of stationary sounds according to ISO 532-2.

• Sharpness according to Zwicker and Fastl, “Psychoacoustics: Facts and models”, 1990.

• Sharpness according to Zwicker and Fastl, over time.

• Sharpness according to DIN 45692.

• Sharpness according to DIN 45692, over time.

• Roughness and roughness over time according to Daniel and Weber, “Psychoacoustical Roughness: Implementation of an Optimized Model, 1997.

• Fluctuation strength according to Sontacchi, “Entwicklung eines Modulkonzeptes für die psychoakustische Geräuschanalyse under MatLab”, 1998.

The example shows how to perform these operations:

• Set up the analysis.

• Calculate indicators on loaded WAV files.

• Get calculation outputs.

• Plot some corresponding curves.

Set up analysis

Setting up the analysis consists of loading the required libraries, and connecting to the DPF server.

# Load standard libraries.
import os

# Load Ansys libraries.
from ansys.sound.core.examples_helpers import download_accel_with_rpm_wav, download_flute_wav
from ansys.sound.core.psychoacoustics import (
    FluctuationStrength,
    LoudnessISO532_1_Stationary,
    LoudnessISO532_1_TimeVarying,
    LoudnessISO532_2,
    Roughness,
    RoughnessECMA418_2,
    Sharpness,
    SharpnessDIN45692,
    SharpnessDIN45692OverTime,
    SharpnessOverTime,
)
from ansys.sound.core.server_helpers import connect_to_or_start_server
from ansys.sound.core.signal_utilities import LoadWav

# Connect to a remote DPF server or start a local DPF server.
my_server, my_license_context = connect_to_or_start_server(use_license_context=True)

Load the WAV files used in this example

Load the signals from WAV files using the LoadWav class. They are returned as a list of Field objects, where each field corresponds to a channel.

# Load a first signal from a WAV file: recording of a flute.
path_flute_wav = download_flute_wav(server=my_server)
wav_loader = LoadWav(path_flute_wav)
wav_loader.process()
signal_flute = wav_loader.get_output()[0]

# Load another signal from a WAV file: recording of an acceleration inside a car cabin.
path_accel_wav = download_accel_with_rpm_wav(server=my_server)
wav_loader = LoadWav(path_accel_wav)
wav_loader.process()
signal_car_acceleration = wav_loader.get_output()[0]
# Note: This signal contains a second field (RPM profile) that is useless in this example.

# Get file names, for later use.
file_name_flute = os.path.basename(path_flute_wav)
file_name_car_acceleration = os.path.basename(path_accel_wav)

Calculate ISO 532-1 loudness for a stationary sound

Create a LoudnessISO532_1_Stationary object, set its signal, and compute the loudness according to standard ISO 532-1.

loudness_ISO532_1_stationary = LoudnessISO532_1_Stationary(signal=signal_flute)
loudness_ISO532_1_stationary.process()

Get the ISO 532-1 loudness (in sone) and loudness level (in phon).

loudness_ISO532_1_sone = loudness_ISO532_1_stationary.get_loudness_sone()
loudness_ISO532_1_level_phon = loudness_ISO532_1_stationary.get_loudness_level_phon()

print(
    f"\nThe ISO 532-1 loudness of sound file {file_name_flute} is "
    f"{loudness_ISO532_1_sone:.1f} sones "
    f"and its loudness level is {loudness_ISO532_1_level_phon:.1f} phons."
)

The ISO 532-1 loudness of sound file flute.wav is 39.6 sones and its loudness level is 93.1 phons.

Plot the ISO 532-1 specific loudness, that is, the loudness at each Bark band index.

loudness_ISO532_1_stationary.plot()

Calculate ISO 532-1 loudness for a time-varying sound

Create a LoudnessISO532_1_TimeVarying object, set its signal, and compute the loudness.

loudness_ISO532_1_time_varying = LoudnessISO532_1_TimeVarying(signal=signal_car_acceleration)
loudness_ISO532_1_time_varying.process()

Get percentile loudness and loudness level values.

N5 = loudness_ISO532_1_time_varying.get_N5_sone()
N10 = loudness_ISO532_1_time_varying.get_N10_sone()
L5 = loudness_ISO532_1_time_varying.get_L5_phon()
L10 = loudness_ISO532_1_time_varying.get_L10_phon()

print(
    f"\nThe sound file {file_name_car_acceleration} has the following percentile "
    f"loudness and loudness level values:\n"
    f"- N5  = {N5:.1f} sones.\n"
    f"- N10 = {N10:.1f} sones.\n"
    f"- L5  = {L5:.1f} phons.\n"
    f"- L10 = {L10:.1f} phons."
)

The sound file accel_with_rpm.wav has the following percentile loudness and loudness level values:
- N5  = 16.4 sones.
- N10 = 15.6 sones.
- L5  = 80.4 phons.
- L10 = 79.6 phons.

Plot the ISO 532-1 loudness as a function of time.

loudness_ISO532_1_time_varying.plot()

Calculate ISO 532-2 loudness for a stationary sound

Create a LoudnessISO532_2 object, set its signal, and compute the loudness according to standard ISO 532-2.

loudness_ISO532_2 = LoudnessISO532_2(signal=signal_flute, field_type="Free")
loudness_ISO532_2.process()

Get the ISO 532-2 binaural and monaural loudness (in sone), and loudness level (in phon).

loudness_ISO532_2_sone_monaural = loudness_ISO532_2.get_monaural_loudness_sone()[0]
loudness_ISO532_2_phon_monaural = loudness_ISO532_2.get_monaural_loudness_level_phon()[0]
loudness_ISO532_2_sone_binaural = loudness_ISO532_2.get_binaural_loudness_sone()
loudness_ISO532_2_phon_binaural = loudness_ISO532_2.get_binaural_loudness_level_phon()

print(
    f"\nThe ISO 532-2 loudness of sound file {file_name_flute} is:\n"
    f"\tMonaural loudness and loudness level: {loudness_ISO532_2_sone_monaural:.1f} sones, "
    f"{loudness_ISO532_2_phon_monaural:.1f} phons.\n"
    f"\tBinaural loudness and loudness level: {loudness_ISO532_2_sone_binaural:.1f} sones, "
    f"{loudness_ISO532_2_phon_binaural:.1f} phons."
)

The ISO 532-2 loudness of sound file flute.wav is:
        Monaural loudness and loudness level: 28.2 sones, 87.7 phons.
        Binaural loudness and loudness level: 42.3 sones, 93.2 phons.

For comparison, display the values previously obtained with the ISO 532-1 standard. The two standards rely on similar auditory principles but differ in the way they estimate the loudness.

print(
    f"\nThe ISO 532-1 loudness of sound file {file_name_flute} is "
    f"{loudness_ISO532_1_sone:.1f} sones "
    f"and its loudness level is {loudness_ISO532_1_level_phon:.1f} phons."
)

The ISO 532-1 loudness of sound file flute.wav is 39.6 sones and its loudness level is 93.1 phons.

Plot the ISO 532-2 binaural specific loudness, that is, the binaural loudness at each center frequency of equivalent rectangular bandwidth (ERB).

loudness_ISO532_2.plot()

Calculate sharpness, roughness, and fluctuation strength

Calculate the sharpness.

sharpness = Sharpness(signal=signal_flute, field_type="Free")
sharpness.process()
sharpness_value = sharpness.get_sharpness()

Calculate the sharpness over time and plot it.

sharpness_over_time = SharpnessOverTime(signal=signal_flute, field_type="Free")
sharpness_over_time.process()
sharpness_over_time.plot()

Calculate the sharpness according to standard DIN 45692.

sharpness_DIN45692 = SharpnessDIN45692(signal=signal_flute, field_type="Free")
sharpness_DIN45692.process()
sharpness_DIN45692_value = sharpness_DIN45692.get_sharpness()

Calculate the sharpness according to standard DIN 45692, over time, and plot it.

sharpness_DIN45692_over_time = SharpnessDIN45692OverTime(signal=signal_flute, field_type="Free")
sharpness_DIN45692_over_time.process()
sharpness_DIN45692_over_time.plot()

Calculate the roughness according to Daniel & Weber’s model, and plot the specific roughness and roughness over time.

# Calculate the specific roughness, the roughness over time, and the overall roughness.
roughness = Roughness(signal=signal_flute)
roughness.process()
roughness_value_Daniel_Weber = roughness.get_roughness()

# Plot the specific roughness and the roughness over time.
roughness.plot()

Calculate the roughness according to ECMA-418-2, and plot the specific roughness and roughness over time.

# Calculate the specific roughness, the roughness over time, and the overall roughness.
roughness = RoughnessECMA418_2(signal=signal_flute, field_type="Free")
roughness.process()
roughness_value_ECMA_418_2 = roughness.get_roughness()

# Plot the specific roughness and the roughness over time.
roughness.plot()

Calculate the fluctuation strength.

fluctuation_strength = FluctuationStrength(signal=signal_flute)
fluctuation_strength.process()
fluctuation_strength_values = fluctuation_strength.get_fluctuation_strength()

Print the calculated indicators.

print(
    f"\nThe sharpness of sound file {file_name_flute} "
    f"is {sharpness_value:.2f} acum,\n"
    f"its sharpness according to DIN 45692 is {sharpness_DIN45692_value:.2f} acum,\n"
    f"its roughness is {roughness_value_Daniel_Weber:.2f} asper according to Daniel & Weber's "
    "model,\n"
    f"and {roughness_value_ECMA_418_2:.2f} asper according to ECMA-418-2,\n"
    f"and its fluctuation strength is {fluctuation_strength_values:.2f} vacil."
)

The sharpness of sound file flute.wav is 1.19 acum,
its sharpness according to DIN 45692 is 1.20 acum,
its roughness is 0.06 asper according to Daniel & Weber's model,
and 0.42 asper according to ECMA-418-2,
and its fluctuation strength is 0.60 vacil.