Sencore SP395 Operation Manual
SP395 SoundPro Audio Integrator Form7492 Operation Manual
SP395
SoundPro
Audio Integrator
Operation Manual
(Firmware version 1.32)
3200 Sencore Drive, Sioux Falls, SD 57107
http://www.sencore.com
mailto:sales@sencore.com 1.800.736.2673 or 1.605.339.0100
SP395 SoundPro Audio Integrator Form7492 Operation Manual
WARNING
PLEASE OBSERVE THESE SAFETY PRECAUTIONS
There is always a danger present when using electronic test equipment.
Unexpected voltages can be present at unusual locations in defective
equipment and distribution systems. Become familiar with the equipment
with which you are working, and observe the following safety precautions.
Every precaution has been taken in the design of the SoundPro SP395 Audio
Integrator to insure that it is as safe as possible. However, safe operation
depends on you, the operator.
1. Never exceed the limits of the SoundPro SP395 as given in the specifications
section or other special warnings provided in this manual.
2. Always be sure that your equipment is in good working order. Broken or
frayed test leads or cables can be extremely dangerous and may expose you to
high voltages.
3. Remove test leads immediately following measurements to reduce the
possibility of shock.
4. Do not work alone when working under hazardous conditions. Always have
another person available in case of an accident.
5. Never assume that a cable shield is at earth ground potential. Both static
and electrical voltages can be present on a cable’s sheath.
6. Always follow standard safety procedures.
When in doubt, be careful.
Sencore reserves the right to make changes in specifications and other information contained in this publication
without prior notice, and the reader should in all cases consult Sencore to determine whether any such changes have
been made. This manual may not be reproduced, and is intended for the exclusive use of Sencore users.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
SP395
SoundPro
Audio Integrator
Operation Manual
(Firmware version 1.32)
3200 Sencore Drive, Sioux Falls, SD 57107
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
TABLE OF CONTENTS
SAFETY PRECAUTIONS ...................................................................... inside front cover
DESCRIPTION................................................................................................................ 1
Introduction ............................................................................................................................1
SP395 Audio Integrator Features.......................................................................................... 1
Specifications......................................................................................................................... 4
Front Panel Control Descriptions ......................................................................................... 9
Right Side Panel – Input Description................................................................................... 9
Left Side Panel – Output Description ................................................................................10
SP395 Audio Integrator Accessories .................................................................................11
Firmware Add-on Test Functions ....................................................................................... 13
OPERATION................................................................................................................. 14
Power ON/OFF Switch ........................................................................................................... 14
Power Input Jack.................................................................................................................... 14
Battery.................................................................................................................................... 14
Installing/Removing Battery............................................................................................... 15
Battery Charging & Battery Life .........................................................................................15
User Interface – Control Knob................................................................................................ 16
Menu Navigation .................................................................................................................... 16
Menu Overview ......................................................................................................................17
Inputs & Outputs ....................................................................................................................18
Audio Inputs....................................................................................................................... 18
Audio Outputs....................................................................................................................19
Audio Monitoring Output.................................................................................................... 19
Input Gain Control - Preamplifiers ..................................................................................... 20
Menu Toolbars .......................................................................................................................21
Top Tool Bar......................................................................................................................21
Bottom Tool Bar................................................................................................................. 22
Headphone/Speaker Monitor Control ...........................................................................22
Memory Control ............................................................................................................23
SPL .............................................................................................................................. 24
Sound Level Meter .................................................................................................................24
LEQ ........................................................................................................................................26
Dosimeter............................................................................................................................... 27
Sound Study Graph................................................................................................................ 29
Acoustics ..................................................................................................................... 31
Real Time Analyzer................................................................................................................ 31
FFT Analyzer.......................................................................................................................... 35
Energy Time Graph................................................................................................................ 38
Reverb Decay Time................................................................................................................ 43
Multi-Band Decay................................................................................................................... 47
TDA - Time Delay Analysis......................................................................................... 50
Main Output & Generator Control ................................................................................. 23
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Noise Tools.................................................................................................................. 57
ALCONS ................................................................................................................................57
RaSTI .....................................................................................................................................60
STI-PA.................................................................................................................................... 63
Noise Curves.......................................................................................................................... 65
Transmission Loss ................................................................................................................. 67
Audio Stethoscope .................................................................................................................69
Tech Bench.................................................................................................................. 70
Level/Freq. Meter ...................................................................................................................71
Signal Generator ....................................................................................................................72
Amplitude Sweep ................................................................................................................... 74
Distortion Meter...................................................................................................................... 76
Phase Meter........................................................................................................................... 80
Crosstalk Meter ......................................................................................................................81
Speakers ...................................................................................................................... 82
Speaker Polarity..................................................................................................................... 82
Speaker Distortion.................................................................................................................. 84
Impedance Meter ................................................................................................................... 86
Impedance Sweep .................................................................................................................87
Cable Tester........................................................................................................................... 90
Tools............................................................................................................................. 92
USB Preamp Display & Controls............................................................................................ 92
USB Preamp Operation..................................................................................................... 93
USB Output Operation....................................................................................................... 94
Utility Function ............................................................................................................ 95
Audio Scope........................................................................................................................... 95
Save Settings .........................................................................................................................97
Setup & Calibration ................................................................................................................98
Setup – Unlock Firmware .................................................................................................. 98
Setup – General ................................................................................................................99
SPL Calibration................................................................................................................ 100
PC Interface/About............................................................................................................... 101
Computer Interface ................................................................................................... 102
Uploading Memories to the Computer.................................................................................. 102
Upgrading Firmware in SP395 ............................................................................................. 103
TerraLink Software: Real-Time Computer Interface............................................................. 104
APPENDIX A
dB SPL Scale .......................................................................................................................105
APPENDIX B
ANSI Weighting Curves........................................................................................................ 106
APPENDIX C
ANSI Balanced Noise Criterion Curves................................................................................ 107
APPENDIX D
Serial Protocol for Accessing SP395 Memories................................................................... 108
WARRANTY AND SERVICE
INFORMATION......................................................................................inside back cover
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
DESCRIPTION
Introduction
The Sencore SP395 SoundPro Audio Integrator is a quality, high-end audio and acoustic
analyzer designed for audio professionals, commercial audio installers, and audio system
engineers. Its audio analyzing functions make it attractive for virtually anyone involved with
audio acoustics or audio systems testing.
The Audio Integrator employs a powerful DSP
engine. All functions, filters, and processing
are implemented in DSP firmware algorithms.
As each function is selected, loaded into
internal memory and executed, the analyzer
takes on a completely new personality. Over
25 different test functions become possible in
one instrument.
The SP395 is especially good at multi-tasking.
It employs independent input, DSP processing,
output, monitor, and USB circuit sections. For
example, you can run the Sound Study Graph
to record SPL over time, while monitoring the
input in headphones, and simultaneously
feeding the input signals to a PC through the
USB audio interface.
The Integrator uses precision 24-bit A/D and
D/A converters, and internal 64-bit processing.
The input and output amplifier stages are fully
balanced, low noise, high-resolution gain
stages. The result is precision measurements
for accurate audio/acoustic analysis.
SP395 Audio Integrator Features
The SP395 provides multiple audio analyzing features including:
• Sound Level Meter or (SPL) Sound Pressure Level: Measures loudness of ambient
sound according to ANSI Type 1 A and C weighting networks and ANSI Class 1 octave
and 1/3 octave band filters. Selectable slow, fast, impulse, or peak sound level
measurement averaging modes.
• Leq: Measures linear averaged Sound Pressure Level over a specified period of time to
determine if noise standards are being met.
• Dosimeter: Measures noise dosage level according to ANSI S1.25-1991 and ASA 98-1991
specifications for noise studies, machinery noise evaluations, and occupational noise
analysis.
• Sound Study Graph: Analyzes and records SPL noise levels over a specified time period
from 1 minute to 24 hours, and graphs the results. Automatically runs multiple sound
studies storing up to 40 sound study tests.
• Real Time Analyzer (RTA): An audio spectrum analyzer which graphs the dB level of
each audio octave or 1/3 octave band. Fast DSP audio analyzing can be used for live music
or sound analysis. An ANSI X curve weighting network for motion picture theater setup is
included. RTA graphs can be stored to memory or compared with the “difference” mode
for before and after analysis.
• FFT Analyzer: Digital signal processing with three FFTs that graph the dB sound level
with 1/6 or 1/12 octave band resolution to 20 kHz. RTA graphs can be stored to memory or
compared with the “difference” mode for before and after analysis.
• Energy Time Graph: Graphs the arrival of sound energy to the microphone input and/or
shows the decay of sound energy in dB over time. Starts with sound initiated from the
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
SP295 generator or an external sound pickup such as a handclap. Valuable in setting time
delays from speaker to listening positions and analyzing sound decay for reflections or
decay time.
• Reverb Decay Time (RT60): Measures and computes reverb decay time or the time it
takes the sound in a room to decrease 60 dB. The measurement computes wideband RT60
(20Hz-20 kHz) or the RT60 of any octave band.
• Multi-Band Decay: Measures, computes and displays the reverb decay time RT60 for
seven audio octave bands simultaneously to identify differences in room sound absorption
characteristics in each band.
• Time Delay Analysis: Times a swept audio generator (20-20,000Hz) and tracking audio
1/12 octave band level meter, with a variable filter Q of 6 to 150, graphing the detected
level. Measurement eliminates room reverberations or echoes for accurate frequency
response testing of speakers or microphones.
• Speech Intelligibility: Measures speech intelligibility using the most popular industry
standards including ALCONS, RaSTI and STI-PA. A CD with the proper test signal for
these tests is provided.
• Noise Curve: Measures noise in a room and characterizes it to a numeric value taking into
account how the human ear hears. Performs standard NC or NCB (balanced noise curves),
RC (Room Criteria), and PNC (preferred noise curve) ANSI tests.
• Transmission Loss: Measures sound transmission loss through a partition. Computes
STC, RW and OITC standard transmission loss measurements by comparing 1/3 octave
RTAs from the source and received sound.
• Audio Stethoscope: Combines the microphone input and sensitive audio preamplifier with
the audio monitoring headphones to form an audio stethoscope. Weighted filters and
octave or 1/3 octave band filters may be selected.
• Level/Freq. Meter: Measures two channel left and right audio input levels from -120 dBu
to +40 dBu and sine wave frequency from 10 Hz to 32 kHz. Measures dBu, dBV, Vave,
Vrms, Vp-p and dBr.
• Signal Generator: Generates audio test signals including sine wave to 22 kHz, square
wave, pink noise and white noise with variable output level. Also outputs octave or 1/3
octave band limited pink noise.
• Amplitude Sweep: Plots the frequency response of audio equipment by sweeping the
generator through its frequency range and graphing the amplitude input level of each 1/12
octave.
• Distortion Meter THD: Measures THD+N (Total Harmonic Distortion plus Noise) of an
incoming signal by comparing the level of the incoming signal with the level of harmonics
and noise.
• Distortion Meter IMD: Measures IMD (Inter-modulation Distortion) of an incoming
signal by outputting a multi-frequency output test tone and measuring the distortion
components. Performs SMPTE IMD and DIN IMD tests.
• Phase Meter: Measures the phase difference between left and right input sine waves of the
same frequency.
• Crosstalk Meter: Measures the amount of dB isolation between the left and right input
audio sources or the signal bleeding from one channel into the other.
• Speaker Polarity: Determines the polarity of the speakers to determine proper wiring.
• Speaker Distortion: Tests speaker distortion, using the THD+N test function, to identify
speaker defects or performance problems.
• Impedance Meter: Measures the impedance of an audio device or component such as a
speaker. The frequency of the test is variable. Also indicates watts or amplification
required at a particular voltage.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
• Impedance Sweep: Plots the impedance of a load by sweeping the generator through its
frequency range and graphing the impedance at each 1/12 octave step.
• Cable Tester: Provides a cable attenuation test at 1 kHz and 20 kHz, and a polarity test to
identify defective or improperly wired cables.
• USB Preamp Control: Serves as a calibrated USB microphone preamp. Use as a sound
card for a PC based analysis program or to route audio from a PC to the Audio Integrator
main outputs.
• Audio Scope: Provides a voltage vs. time graph of the audio waveform to look for
distortion or clipping.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Specifications
SoundCore™ Module
Sound Level Meter (SLM): Measures ambient sound energy levels at microphone input
Displays true RMS SPL
Averaging: Meets ANSI S1.4
Slow
Fast
Impulse
Peak
Avg – Equal time-averaged SPL
Sound Study Graph (SSG): 1 minute to 24 hour continuous recorded SPL measurement
“Strip Chart Recorder”
Peak or Avg mode
Auto-Saves to internal memory
SPL/SSG Measurements
Weighting networks: ANSI Type 1 A, C, Flat, octave, or 1/3-octave band filtered
Level Range: 25-140 dBA with MIC-TP2 mic
Level Accuracy: ±0.1 dB at 1 kHz with MIC-TP2 mic
Level Resolution: 0.1 dB
Frequency Range: 20 Hz to 22 kHz
Real-Time Analyzer (RTA): Plots sound energy levels vs. octave band filtered spectrum
ANSI-compliant 1/3 octave digital filter-based
FIR Filters: Full octave, 1/3 octave frequency resolution.
Weighting networks: Flat, A, C, X-curve, difference mode.
FFT Analyzer (FFT): Plots sound energy levels vs. octave band filtered spectrum
ANSI-compliant 1/12 octave resolution
Three 1024-point cascaded FFTs
Weighting networks: Flat, A, C, difference mode.
RTA, FFT Analyzer
Display range: 30 dB or 15 dB window within 0 dB to 165 dB range, adjustable in
5 dB steps
Level range: 25-140 dBA with MIC-TP2 mic
Level accuracy: ±0.1 dB at 1 kHz with MIC-TP2 mic
Level resolution: ±0.1 dB
Frequency range: 20 Hz – 22 kHz
Frequency accuracy: ±0.5 dB 10 Hz to 22 kHz, ±0.2 dB 100 Hz to 16 kHz
Averaging: 1 sec, 3, sec, 6 sec, 10 sec, 30 sec, 60 sec, equal time-weighted,
peak hold
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Energy-Time Graph (ETG): Graphs impulse sound decay energy vs. time or distance
Identifies arrival time of direct sound and audio reflections
Displayed in mS (milliseconds), ft (feet), m (meters)
Decay time ranges: From 0-15 mS to 0-7680 mS
Calculates RT10-RT60 from cursor points on decay curve
Accuracy: Better than ±1% of full scale
Reverb Decay Time: Calculates time for residual pink noise test signal to decay 60 dB in
room
Also RT10, RT20
Range: 0-15 sec
Accuracy: ±2% of full signal
Resolution: 1 mSec
Weighting networks: A, C, Flat, octave, or 1/3-octave band filtered.
Ambient Noise: Ambient noise level must be at least 26 dB lower than test signal
RT60 Time: Extrapolated from Decay Time measurement.
Impedance Meter:
Accuracy: 1 ohm to 50 ohms, ±2%, 50 Hz – 12.5 kHz
1 ohm to 8 kohms, ±10%, 20 Hz – 20 kHz
Speaker Polarity: Tests absolute speaker phase (polarity) by analyzing a proprietary
waveform
Shows polarity of mid-frequency wavefront
Range: 0-100 ft, speaker to SoundPro
Cable Tester: Tests XLR, 1/4”, and RCA audio cables, balanced and unbalanced
Performs analog transmission test to test transmission loss at 1 kHz and 20 kHz
Resolution: 0.1 dB
Performs polarity test
Signal Generator:
Signals: Sine, square, gaussian white noise, pseudo-random pink noise,
band-filtered pink noise
Frequency Range:
Sine: 1 Hz to 22 kHz; fine, 1/3 octave, or one octave steps
Square: 1 Hz to 6 kHz; fine, 1/3 octave, or one octave steps
Noise bandwidth: Full (20 Hz to 20 kHz), octave, or 1/3-octave band filtered
Frequency Accuracy: 50 ppm; 0.005%
Level range: -35 dBu to 17 dBu
Maximum Sine Output Level: Balanced: +16 dBu
Unbalanced: +10 dBu
Level Accuracy: ±0.1 dBu at 1 kHz, ±0.2 dBu, 16 Hz to 20 kHz
Typical: ±0.05 dBu at 1 kHz, ±0.1 dBu, 16 Hz to 20 kHz
Sine distortion: < 0.01% THD at full-scale output
Audio Monitor: Source independent channel for monitoring
Software volume control
Headphone or built-in internal speaker output
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
TechBench™ Module
Level Meter: Stereo level meter reads in dBu, dBv, Vp-p, Vrms, or dBr
(reference)
Frequency Range: 10 Hz to 22 kHz
Auto-level ranging.
Level Range: -120 dBu to +40 dBu
Level Accuracy (–85 dBu to +40 dBu): ±0.2 dB, 10 Hz to 22 kHz
Typical: ±0.01 dB, 100 Hz to 16 kHz; ±0.05 dB, 10 Hz to 22 kHz
Level Resolution: 0.01 dBu
Frequency Counter:
Frequency Range: 16 Hz to 40 kHz
Accuracy: ±5%
Resolution: 1 Hz
Amplitude Sweep: Graphical display of 1/3 and 1/12 frequency response
User adjustable frequency range
Impedance Sweep: Graphical display of 1/3 and 1/12 octave impedance values
User adjustable frequency range
Distortion Meter: THD+N – Computes Total Harmonic Distortion plus Noise
Compares level of output harmonics and noise to single test frequency
Test Frequencies: 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz
IMD – Computes Inter-modulation Distortion
Compares levels of output sum and difference frequencies to dual test frequencies
Test Types: SMPTE 60/7kHz, DIN 250/8kHz.
Inputs: Speaker, microphone, line level.
Range: 0.02% to 50% THD+N
Accuracy: ±5% of reading
Phase Meter: Shows the phase difference in degrees between 2 sine waves
Crosstalk Meter: Displays the amount of isolation that exists between two audio
sources
Displayed in dB
Audio Scope: Shows audio signal on an oscilloscope-like screen
Dual-trace, auto-triggering
AC-only input coupling (down to approx. 3 Hz)
X-Y mode for phase display
Sample rate: Hz
Accuracy: ±1 display pixel
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Speech Intelligibility Module: (RaSTI and STI-PA test waveforms included on CD)
ALCONS: Computes Percent Apparent Loss of Consonants
RaSTI: Calculates Rapid Speech Transmission Index
STI-PA: Computes Speech Transmission Index using STI-PA method
(STI for Public Address)
Time-Delay Analysis Module:
Time-Delay Analysis: Measures frequency response using log-swept sine wave.
(TerraLink software included)
Noise Curves Module
NC Curves: Displays Noise Criteria data, based on ANSI standard S12.2-1995
(ASA 115-1995)
Displays limiting band, SPL by octave band
RC Curves: Displays Room Criteria rating
PNC Curves: Displays Preferred Noise Criteria rating
STC/NIC Measurement: 1/24th octave Sound Transmission Class/Noise Isolation Class
measurement
Multi-Band Decay Module
Multi-Band Decay: Displays seven octave-band filtered RT60 measurements
simultaneously
Audio Stethoscope Module
Audio Stethoscope: Filters incoming left input audio through to the headphone or
speaker
Filters: Flat (no filter), A or C ANSI Weighted, octave, 1/3 octave filters
Audio Hardware
Sample Rate: 48 kHz
Input Gain Ranges: -50 dB to +50 dB
Maximum Rated Input: +40 dBu
Preamplifier
Distortion: -90 dB THD+N
Phantom Power output: 48 VDC ± 1 VDC
ADC/DAC
Cirrus Logic: CS4224 48 kHz 24-bit 105 dB Audio CODEC
USB Preamplifier
Burr-Brown Texas Instruments® USB Audio CODEC
USB 1.1 full-speed
USB isochronous data format
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Standards
Sound Level Meter: ANSI S1.4-1983 (ASA 47-1983)
Leq: ANSI S1.43-1997
Dosimeter: ANSI S1.25-99 (ASA 98-1991) Class 2
Digital Filters: ANSI S1.11-1986 1/1, 1/3 octave digital filters
All filters, weighting networks, response rates, and algorithms meet or exceed ANSI
Type 1 specifications
General/Environmental
Input Impedances
XLR and balanced inputs: 40 kohms nominal
RCA unbalanced inputs: 20 kohms nominal
Output Impedances
XLR and balanced outputs: 300 ohms nominal
RCA unbalanced outputs: 150 ohms nominal
Non-Volatile Memory: 40 graph data storage locations
Display: 64x128 pixel blue LCD with backlight
Size: 9 1/2" x 5 1/2" x 2 1/4" (HWD)
Weight: 2 lbs. 5 oz.
Temperature Range: 5°C to 45°C, non-condensing
Power
Battery: Li-Ion pack provides over 5 hours of service, depending on usage
AC adapter/charger: 120/130/230/240 VAC, 9-12VDC, 800 mA (Nominal 9V)
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Front Panel Description
1. Display Screen: Provides a visual
interface to the user of all instrument
functions and test results.
2. Left Side Panel: Contains
Computer, USB and analog audio
jacks and speaker. See Left Side
Panel Description section for details.
3. Right Side Panel: Contains power
input jack, audio input jacks, on/off
switch and contrast control. See
Right Side Panel Description section
for details.
4. Control Knob: Provides navigation
through instrument menus. All test
operations and user selections are
performed using this control. This
control is both rotated and pressed.
Rotate the control to move the
screen cursor or increment through menu selections. Momentarily pressing inward
(clicking the control knob) makes a selection or change.
Right Side Panel – Input Description
1. Left Analog Input: Combination XLR and ¼ inch Balanced Microphone /Line input.
Used as main input for most tests. May have 48 Volt Phantom Power switched to jack by
instrument. Used as Cable Test Input.
2. Right Analog Input: Combination XLR and ¼ inch Balanced Microphone /Line input.
May have 48 Volt Phantom Power switched to jack by instrument.
3. Power Adapter Input: Powers the instrument and charges the internal rechargeable
battery. Use a Sencore approved adapter nominal 9V @ min 800 mA. (Center pin
positive)
4. Power Switch: Turns the instrument power on or off. Down is Off.
5. Contrast Control: Sets the contrast of the display screen for best viewing.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Left Side Panel – Output Description
1. RS232 Computer Interface Connector: Serial DE-9 connector. Interfaces instrument to
computer for use with automation software and for the purpose of updating unit firmware
to factory changes.
2. USB Audio Connector: Provides USB connection for digital audio signals.
3. Stereo Headphone (Hdpn) Output Jack: ¼ inch headphone jack. Provides stereo audio
monitoring with headphone.
4. RCA Phono Audio Output Jack: Provides unbalanced audio output through female
RCA phono jack.
5. Balanced mono Audio Output Jack: Provides balanced audio output through a ¼ inch
headphone jack (TRS).
6. Balanced XLR Audio output: XLR jack male, Provides a balanced mono audio output.
Jack also used for Cable Test output.
7. Internal Speaker: Provides audio output to monitor input audio to instrument or audio
generated and output by instrument.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
SP395 Audio Integrator Accessories
Sencore
Part #s
133G527
13G122
13G123
Description Photo
TerraLink Viewer Software /Speech
Intelligibility Audio CD provides
TerraLink – viewer only capability – along
with the audio CD files needed for the
STIPA and RASTI speech intelligibility
tests.
supplied
XLR Audio Cable – a microphone cable
for interfacing balanced audio inputs and
outputs to the SP395.
supplied
USB Cable – a 6’ connection cable (type
A to type B), connects the unit’s USB
connector to a USB port on a computer
PC USB port.
supplied
Serial Interface Adapter Cable – a 6’
computer serial interface adapter cable
13G124
17G65
39G1156
(straight through), connects between the
unit’s RS232 jack and a computer serial
port.
supplied
Lithium Ion Battery – install battery to
power the instrument. The battery is
removable, supplies up to 5 hours of
continuous power per charge, depending
on use.
supplied
Standard Measurement Microphone
meets or exceeds ANSI Type 2
specifications. Microphone Holder Clip
mounts on a standard microphone stand
and holds the test microphone.
Both are supplied.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Impedance Test Cable 1/4 inch mono
plug to clip connections – provides a test
39G1171
60G80
lead connection when using the
Impedance Meter and Impedance Sweep
test functions.
supplied
AC Power Adapter/ Charger plugs into
the SP395 to charge the battery or to
provide AC operation.
supplied
Soft Carry Case padded carrying case to
CC309
SPPMIC1
optional
SPSW-TL
optional
transport unit; includes extra storage
capacity for supplied accessories.
supplied
Precision Low Noise Microphone –
meets or exceeds ANSI Type 1
specifications
optional
Software – provides a real-time PC
connection/interface with the instrument.
Plots memories and displays FFT, RTA,
SSG and SLM Meter results in real-time.
(Requires purchase and authorization of
an UNLOCK code from Sencore) Included
as part of the Time Delay Analysis (TDA)
Firmware Add-on Module. optional
Terra Link Software Unlock
Code
http://www.sencore.com mailto:sales@sencore.com 1.800.736.2673
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Firmware Add-on Test Functions
The Audio Integrator comes standard with a solid core of audio analyzing tests. These tests are
fundamental to most audio and acoustic analysis work. The core tests are referred to as the
SP395’s “SoundCore” measurements.
The Audio Integrator contains, in its internal operating software or firmware, instructions for
performing many more audio and acoustic tests than provided by the standard “SoundCore”
measurements. These additional tests may be purchased based upon individual user and company
requirements. The additional available tests are divided into packages or “Firmware Modules”
for easy implementation or purchase.
Firmware Module Function Menu
TechBench Amplitude Sweep TechBench
TechBench Distortion Meter TechBench
TechBench Phase Meter TechBench
TechBench Crosstalk TechBench
TechBench Audio Scope Utilities
TechBench Impedance Sweep Speaker
Noise Curves NCB, RC, PNC Noise Tools
Noise Curves Transmission Loss
(RW, STC, OITC)
Speech Intelligibility ALCONS, RASTI,STI-PA Noise Tools
Time Delay Analysis TDA TDA
Audio Stethoscope Audio Stethoscope Noise Tools
Multi-Band Decay RT60 Multi-Band Decay Acoustics
The optional functions are available for use upon purchasing the firmware module and entering
the supplied unlock code. The functions contained within a single firmware module may appear
on more than one menu. The table lists the firmware modules and the functions they contain,
along with the Audio Integrator menu that the function appears in.
To purchase an unlock code for a firmware module, contact Sencore. For instructions on how to
unlock a firmware module, see the Setup & Calibration section of this manual.
Specifications, accessories and software add-on test functions are subject to change without
notice.
Noise Tools
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
OPERATION
Power On/Off Switch
The power switch is mounted at the top of the right side panel. The power switch turns the Audio
Integrator on or off, whether the unit is powered by the internal battery or the AC adapter.
When you turn on the power switch, the unit begins initialization. During this time software is
loaded from memory locations within the Audio Integrator including updates. The unit is ready
to use as soon as the main menu screen appears, no warm-up time is needed. The Audio
Integrator can be powered off at any time – there is no required shutdown procedure.
Power Input Jack
The Power Input Jack is located in the center of the right side panel. The DC Input Jack requires
the input of a DC voltage to power the instrument and charge the internal battery. The SP395
requires a 9-12v DC power adapter, regulated or unregulated, rated at a minimum of 800ma. The
input connector is a 2.1mm coaxial power connector with the positive polarity voltage on the
center pin of the connector.
An AC power adapter/charger is supplied to power the Audio Integrator and charge the internal
battery. Use only the Sencore-supplied power adapter, if possible. Using an improper AC adapter
can damage the unit and/or improperly charge the battery. Using an improper AC power
adapter/charger voids the unit warranty.
The AC plug symbol in the display screen beside the < (back) field indicates the
unit is powered form the AC power adapter/charger.
When the AC power adapter is plugged in, the battery level indicator
shows an AC power plug symbol. When the AC power adapter is
removed, the indicator shows a battery symbol with a relative battery
charge level.
Battery
A lithium-ion rechargeable battery is supplied with the Audio Integrator. The battery is charged
whenever the AC adapter is plugged in, or can be charged using an
external charger.
Battery operation is indicated with a battery symbol near the < (back) field. The
symbol indicates the approximate charge level of the battery.
Battery operation is indicated in the Audio Integrator screens with a
battery symbol located in the upper left of the screen adjacent to the <
(back field). The symbol also indicates the relative charge of the
battery. It the battery symbol is filled to the top, the battery is at or near
full charge. A battery symbol that shows little or no fill indicates that
the battery is nearing a discharge level in which it must be recharged.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Installing / Removing Battery
The battery can be removed for replacement. The battery is installed in a small compartment in
the bottom rear of the Audio Integrator. To remove the battery you must open the battery door or
cover plate. Unscrew the thumb screw holding
the plate to the instrument case. The door
contains a cutout so if you push the door away
from the screw the door can be hinged open. Use
the nylon strap that surrounds the battery to lift
it up and out of the compartment. The battery
terminals plug into the small circuit board lining
the top side of the battery. Gently pull the circuit
board away from the battery to disconnect the
battery from the circuit board.
To install a battery, reverse the removal process.
The battery is polarized and needs to be installed
correctly. Line up the flat side of the battery
with the flat side of the circuit board. Push the
board male connector pins gently and straight
into the battery terminals. Seat the battery into
the instrument, close the battery door and secure
it by tightening the retainer screw.
The battery may be removed from the rear battery compartment.
Warning: Observe proper polarity. Do not plug the battery into the connector board the
wrong way, or the battery may be damaged.
Battery Charging & Battery Life
The battery is charged anytime that the AC adapter is
plugged into the Integrator. It charges at the same
Charger Charge Time
Charge in Integrator 6.0 hours
rate, whether the unit is turned on or not. You can
also charge the battery in an external lithium-ion battery charger. You cannot overcharge the
battery, as long as you charge it in the instrument or use an approved external charger. The
battery requires about 6 hours to fully charge.
The Audio Integrator uses different amounts of
battery power, depending on what functions are
being used. The phantom power uses a significant
amount of power. Also, the headphone monitor
Battery Life
Maximum run time 5.5 hours
Phantom power on 4.5 hours
amplifier consumes power when it is enabled. Expect 4-5 hours of run time on a full charge.
Warning: Storing the unit with the battery in a state of discharge for long periods of time can
shorten the life of the battery, or possibly destroy it. We recommend that the battery be kept
charged at all times. The battery cannot be overcharged, so it is fine to leave the instrument
plugged in, or to leave the battery plugged into an external charger when not in use.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
User Interface – Control Knob
All the Audio Integrator operations and user selections are performed using the front panel
control knob. This control is either rotated or momentarily pressed (clicking) the control knob.
Turning the control knob moves a display highlight (white box with dark text) between menu
options and fields on the screen. Clicking a highlighted choice selects it. To exit from a function
and return to the previous menu or screen, highlight and click on the “<” symbol located in the
upper left corner of the display.
To change the value of a selected field, click the control knob. The highlighted field will either
toggle to a new value (fields with only a few possible values) or will change to an underlined
“control lock” (data with many possible values).
To change the value of a “control-lock” field, click the control knob to “lock” (underline) the
field and then turn the knob to change the value. When the desired value is shown, click the
control knob again to unlock the control highlight. Turning the knob then moves you to the next
field
All user selections are made using the control knob either by rotating it to select a menu field or
by momentarily pressing or “clicking” the knob to increment values or lock to a field.
Menu Navigation
The main menu with eight main function categories appears shortly after the Audio Integrator is
turned on. By default the first item or category is highlighted. Turn the control knob to highlight
the different menu items and click the control knob to select the item or category. A sub-menu
appears with fields that list test functions that can be selected for that category. To select a
function in the sub-menu, turn the control knob to highlight the desired field or function and
click the control knob (press down momentarily). To exit from a sub-menu back to the main
menu move the highlight to the upper left “<” field and click the control knob.
Click the < field located in the upper left corner of every display to
return to the previous menu.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Menu Overview
All user selections to configure the Audio Integrator are performed with indications in the
display screen. The Audio Integrator includes a main menu with eight categories of tests in
which to choose from. Choosing a category in the main screen results in a submenu. The
submenu lists all the tests available in that category.
Note: Some of the tests shown in the submenu screens may not be included in your Audio
Integrator. These test features may be purchased as Software Additions to your
instrument.
1. Main Menu: Opening menu screen listing eight categories of Audio Integrator tests.
2. SPL Submenu: Appears when the SPL selection is made in the main menu. This
submenu lists the sound level measurements available for selection using the Audio
Integrator.
3. Acoustics Submenu: Appears when the Acoustics selection is made in the main menu.
This submenu lists the acoustic analyzing tests available for selection using the Audio
Integrator. Note: The Multi-Band Decay tests is available as a firmware option. It
appears in submenu but cannot be implemented without purchasing an unlock code.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
4. TDA Submenu: Appears when the TDA selection is made in the main menu. This
submenu shows the TDA test functions available on the Audio Integrator.
Note: The TDA tests are optional firmware add-on test functions.
5. Noise Tools Submenu: Appears when the Noise selection is made in the main menu.
Provides noise related measurements using the Audio Integrator. Note: The ALCONS,
RaSTI, and STI-PA are speak intelligibility tests available as part of the Speech
Intelligibility firmware option. The Audio Stethoscope is available as a Stethoscope
firmware option.
6. TechBench Submenu: Appears when the TechBench selection is made in the main
menu. Provides selection of audio bench testing functions. Note: The Amplitude Sweep,
Impedance Sweep, Distortion Meter,, Phase Meter, and Crosstalk Meter are part of the
TechBench firmware option.
7. Speakers Submenu: Appears when the Speaker selection is made in the main menu. The
submenu provides selection of speaker related tests.
8. Tools Submenu: Appears when the Tools selection is made in the main menu. This
submenu provides a selection for USB Preamp Control.
9. Utilities Submenu: Appears when the Utilities selection is made in the main menu. The
Utilities Functions submenu provides user options to save settings, calibrate and interface
the Audio Integrator. Note: The Audio Scope function is part of the TechBench firmware
add-on option.
All test functions available for the Audio Integrator are listed in the submenus. This includes all
functions which are part of the standard or “Sound core” tests and test functions which can be
added with firmware add-on purchases. If you select a test in the submenu that has not been
added with a firmware purchase, the instruments indicates an “unlock required” message.
Inputs & Outputs
Audio Inputs
The Audio Integrator receives audio signal inputs from a microphone or line input
The input signal jacks are located on the right side of the instrument. There are two input jacks
which are labeled left (L) and right (R). The input jacks are a combination connector which
accepts a balanced XLR connector male input and a ¼ inch stereo mono headphone male
connector. This provides compatibility with most audio microphone cables and line input cables.
Left side input signal connectors are a combination XLR and ¼ inch mono headphone jack
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
The left (L) input should be considered as the main channel input when using the Audio
Integrator. Some test functions, such as the cable test and audio stethoscope, only use one input.
In these cases you always use the left (L) input connector when performing the test.
Be aware that the different test functions of the Audio Integrator are setup for a mic. Level input
and others for a line level input. In each case, the input signal is taken from the left and right
input jacks. For the acoustics test functions, a microphone is normally connected, and for the
TechBench tests, a line level (or lower) electrical audio signal is anticipated by the SP395.
The acoustics functions, which expect input from a microphone, use the microphone SPL
calibration that is stored in the Utilities Calibration section. Electrical functions, which expect
their input from a line level source, use the dBu calibration. Keep this in mind to prevent
potential confusion over measurement results. For example, if a 0 dBu electrical signal is
plugged into the Sound Level Meter, you may see results like +150 dB SPL, depending on the
sensitivity calibration that is stored. Conversely, if you are using a microphone with the
Amplitude Sweep function, you will see very low results, perhaps in the –70 to –60 dBu range.
Audio Outputs
The Audio Integrator provides 3 output jacks for connecting analog audio output to sound
systems. You may use either the XLR, 1/4” TRS, or RCA phono jack. These jacks are located on
the left hand side of the instrument. All carry the same signal. The output range of the Audio
Integrator is approximately -72 dBu to +17 dBu.
The left side panel contains three analog audio outputs including an XLR, ¼ TRS headphone mono, and
unbalanced RCA phono jack.
Use the XLR male output jack when a balanced XLR audio output is needed. The ¼ inch TRS
headphone jack output is available when this connection is desired. This connector is wired in
parallel with the XLR output jack. It provides a TRS (tip, ring, sleeve) balanced audio output.
One side of the balanced output is routed to the RCA phono to form an unbalanced output. Use
this jack when you desire connection to an RCA connection cable.
Audio Monitoring Output
The Audio Integrator provides a headphone output jack for monitoring output audio. It is a stereo
output headphone jack with the purpose of simultaneously monitoring both a right and left audio
channel. The stereo headphone jack powers 32 ohm or grater headphones. The headphone jack
can also serve as a line level output if needed.
A speaker is built into the Audio Integrator for the purpose of monitoring the output audio. The
speaker is located on the left side panel of the instrument. The internal speaker outputs the mixed
left and right outputs taken from the headphone output.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
The audio output from the headphone jack and speaker is routed through separate output
monitoring circuits within the Integrator. Audio to the headphone or speaker is independently
switched on or off in the monitor part of the menu screen. The audio level output to the
headphone and speaker is controlled in the monitor part of the menu screen. Internal generated
audio or audio to the input jacks of the Audio Integrator may be routed to the monitor circuits.
Right, left, stereo, mixed (mono) audio may be selected. See the Bottom Toolbar section of this
manual.
Input Gain Control - Preamplifiers
The left and right audio inputs of the Audio Integrator feed into separate audio preamplifiers and
gain control circuits. These circuits provide audio measurement over a wide range of audio levels
and provide great sensitivity. There are thirteen gain ranges that are available to set the level of
both the left and right input audio signal. The gain ranges of the left and right inputs are
controlled independently in the top toolbar section of the test menu. See the Top Tool Bar
Section of this manual.
The selected input level or gain control setting establishes an overall amplification of the input
signal and best signal-to-noise ratio. The gain setting must be properly chosen for proper testing
results. You should select the range which provides the most amplification without overdriving
the sensitive input pre-amplifiers. The table below defines the clip points of each gain setting,
both in dBu and related for available standard microphones.
Clip Points Table
Gain Setting
Line Input
( dBu)
MIC-TP2
( dB SPL)
MIC-TP1
( dB SPL)
58 -45
52 -39
46 -34
40 -29 110 80
34 -23
28 -16
20 -9 130 100
10 1 140 110
-10 15 160* 130
-20 25 170* 140
-30 35 180* 150*
-40 45 190* 160*
* Beyond microphone maximum level
Note: To get the lowest SPL or noise levels you should use the maximum input gain setting
possible without clipping. In many cases this will be 42-58. At this setting you will have the most
sensitivity, but the input may clip at normal room SPL levels, depending on the sensitivity of the
microphone.
The Audio Integrator provides both manual and automatic range selection for the left and right
audio channels. The auto-gain function selects an input range for best measurement. If the input
level gets within 2dB of clipping, the gain is set to the next least sensitive gain (if possible). If
the input level is below that level at which the most accurate measurements can be made, the
gain is increased in steps until the maximum input gain is reached.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
The Audio Integrator provides an indication when the input level is approaching or overdriving
the input preamplifier. The range number in the top tool bar of the menu blinks. When you see
this select a higher gain setting in the top toolbar for that channel.
Menu Toolbars
The Audio Integrator uses “toolbars” to provide access to often-used features and controls.
Toolbars along the top edge and bottom edge of the screen provide user selections which are
common to many of the test functions. For example, you can adjust input gain, turn phantom
power on and off, and control the generator output and the headphone monitor from any screen
using the top SP395. It is important that you understand the use of the toolbars to properly
operate the SP395. Individual items which can be selected and changed are referred to as fields
in this manual.
Toolbars along the top edge and bottom edge
of the screen provide user selections which are
common to many of the test functions
.
Top Tool Bar
The top toolbar provides a function identification field and is used to control the SP395 inputs.
You can manually select input gain, turn on phantom power, or invert the phase of either channel
independently. You can also enable auto-gain scaling for both inputs.
The Top Tool Bar provides function
identification and selections for the L & R
inputs.
Top Toolbar Icons
1. Back Arrow. Clicking on this icon exits the currently running function and returns to the
function menu.
2. Battery Indicator. When operated on the internal battery, this field shows the relative
battery level, or remaining charge, in the battery. When operated in AC mode, this field
shows the AC power symbol.
3. Screen Title. This is the abbreviated name of the function that is currently running.
4. Function related selection – Not on all menus
5. Left Input Polarity The N/R icon changes the left input from normal (N) polarity to
reverse (R) polarity.
6. Left Input Phantom Power Click to select the icon, then turn clockwise to enable
phantom power (48v), or counter-clockwise to disable phantom power (0v).
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
7. Left Input Gain There are 12 selectable input gain settings. Click and turn to select the
gain for this channel. A blinking value or digits indicate clipping and the need to reduce
the gain selection number.
8. Auto-Gain. Select manual (M) or auto (A). In auto-gain, the gain setting for the channel
is automatically adjusted to prevent clipping and to have enough gain for accurate
measurements. Note that in some functions, such as Leq, you may want to hold the gain at
a fixed level. In this case, choose manual (M).
9. Right Input Gain There are 12 selectable input gain settings. Click and turn to select the
gain for this channel. A blinking value or digits indicate clipping and the need to reduce
the gain selection number.
10. Right Phantom power Click to select the icon, then turn clockwise to enable phantom
power (48v), or counter-clockwise to disable phantom power (0v).
11. Right channel polarity reverse The N/R icon changes the left input from normal (N)
polarity to reverse (R) polarity.
Bottom Tool Bar
The bottom toolbar contains three functional control sections. The sections include:
1. Headphone/Speaker Monitor
2. Memory
3. Output Generator
All or part of the bottom tool bar sections or
selections within each section may be
present in the various test functions of the
Audio Integrator.
The Bottom Tool Bar provides
headphone/speaker, memory, and internal
generator control.
Headphone/Speaker Monitor Control
The five icons at the left end of the bottom toolbar control the monitor output.
1. Monitor Output On/Off The 1/0 icon turns the analog monitor output on and off. This
controls both the headphone jack and the built-in speaker.
2. Level The bar level gauge icon controls the analog output level. Every turning step of the
control knob changes the output level by approximately 1 dB.
3. Speaker On/Off. This icon turns the speaker on and off. The speaker can be turned off,
even when the headphone output is enabled. To hear the speaker output, both the Monitor
On/Off and the Speaker On/Off must be turned on.
4. Source The I/O source icon determines the source for the monitor output. The I selects
the Input for monitoring, the O selects the Output signal (usually the internal digital
generator) for monitoring. Therefore, in Input mode you will hear exactly what is being
received, as selected by the input select field on the top toolbar, and in Output mode, an
exact copy of the digital output signal will be routed to the headphone jack.
5. Mode. The monitor mode field changes between stereo (S), left mono (L), right mono
(R), and the mixed left and right channels (M).
Headphone Warning: Be careful when wearing headphones and changing input connections,
input gain, and phantom power. Although the analog output is usually muted in situations that may
cause high output, unexpected loud volume may occasionally occur at the headphone output. We
recommend turning off the output before changing functions, and in other situations that may cause
loud volume.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
Memory Control
Some test functions support saving measurement data to internal, non-volatile memory. The
SP395 provides memory storage of RTA, FFT, ETG, Dosimeter, Sound Study Graphs,
Amplitude Sweep and Impedance Sweep functions. These functions use the four memory control
icons, in the center of the bottom toolbar. Note that a memory must be empty (cleared) before
measurement data can be stored into it. The Clear (C) icon can be used to erase the contents of a
memory.
6. Memory Number The memory number icon selects a memory location for storing,
recalling, or clearing. There are memory numbers 0 through 39 or 40 locations. When the
memory number field is selected, the type of data stored in that location (or “---” if
empty) appears on the bottom of the graph.
7. Store Click the S (Store) icon to store the results of the current function. The memory
location must be available (empty) before storing results. If the function does not support
memories, the icon does nothing.
8. Recall Click the R (Recall) icon to retrieve the results stored in the current memory
location and to display them on the screen. If the current function does not support
memories, the icon does nothing.
9. Clear Click the C (Clear) icons to erase the contents of the current memory location.
Main Output and Generator Control
The five icons that control the main output and signal generator are located on right end of the
bottom toolbar. Some fields control only the generator, while others control features of the main
output section.
10. On/Off The 1/0 icon turns the generator on and off. This field also controls functions that
use special output signals, such as the transparency test.
11. Level The bar level gauge controls the digital generator output level. Every turning step
of the control knob changes the output level by exactly 1 dB.
12. Waveform This icon selects the generator waveform. It can also select the USB input as
a signal source. The available waveforms are sine, square, white noise, and pink noise.
The USB selection sets up the USB input as a source for the main output.
13. Select Frequency This field changes the frequency of the generator output, as
determined by the Step Size field.
14. Step Size This field selects how the frequency field changes the generator frequency.
Choices are octave steps (Oct), one-third octave steps (1/3), or fine mode (Full). In full
mode the generator frequency is selectable in 1 Hz steps to 10 kHz and 2 Hz steps above
10 kHz.
In some functions the output generator is required to be in set conditions to perform the test
function. Examples include the Impedance Meter, the Cable Tester, and the Sweep tests. In these
functions, some icons on the bottom toolbar will not appear. However, even if generator settings,
levels, and other items are changed, the settings that were in effect most recently will re-appear
when a function is selected that uses the normal toolbars.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
SPL
The SPL main menu selection provides several functions that are used in measuring Sound
Pressure Level (SPL). SPL typically uses a microphone as an input. The standard input for the
SPL tests in the left (L) input.
The SPL tests that are available on the SP395 include:
Sound Level Meter: Measures sound pressure level in dB.
Leq: Measures linear averaged sound pressure level over
time.
Dosimeter: Measures sound dosage according to ANSI or
ASA specifications.
Sound Study Graph: Graphs sound level changes over
time.
Sound Level Meter
A sound pressure level meter measures the
changes in air pressure created by sound
waves and displays this pressure as a dB level,
relative to the threshold of hearing sound
pressure. Weighting curves are added to SPL
measurements to make SPL readings
correspond to perceived loudness. The
SP395’s Sound Pressure Level function
measures the loudness of the ambient sound
level in standard dB SPL measurement units,
auto ranged from 30 to 130 dB (A-weighted).
Use the SLM function when you need to know
objective sound volume, such as when
checking for sound level uniformity, balancing
speaker output levels, or adjusting room sound
levels.
The SPL level is a true-RMS measurement,
using ANSI Type 1 standard display time
averages, ANSI Type 1 standard A and C
weighting networks, ANSI Class 1 octave and
1/3 octave band filters, and ANSI Slow, Fast,
and Impulse averaging. SPL measurements are
made using the supplied microphone
connected to the Microphone Input. The large,
digital display shows the ambient sound level
in standard units of dB SPL and the level is
also shown on an analog bar graph meter (one
pixel equals one dB).
The SLM measurement screen.
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SP395 SoundPro Audio Integrator Form7492 Operation Manual
The following fields and parameters are displayed in the SLM function:
1. Averaging - Three ANSI-standard averaging modes are available. These modes use
exponential decay averaging, in which the more recent sounds have more bearing in the
average.
Slow – 1000 mS exponential decay, time-averaged RMS SPL.
Fast – 125mS exponential decay, time-averaged SPL.
Impulse – 35 mS exponential decay, time-averaged SPL
Peak – Peak, rather than RMS SPL.
Highlight the Averaging field and press the control knob to toggle between these four
modes.
2. Weighting - Standard unweighted (flat), A-weighted, and C-weighted filters are
available. These weighting filters make SPL readings correspond more closely to what
our ears hear. Ten ANSI Class 1 octave-band filters – 31, 63, 125, 250, 500, 1k, 2k, 4k,
8k, 16 kHz; and 30 ANSI Class 1 1/3 octave-band filters are also available. Highlight the
field and press the control knob. Rotate the knob to the desired filter and click to select it.
3. Test Function: Identifies the current test selected.
4. R - Relative (Seat to Seat SPL) Clicking on the “R” (relative) field sets the currently
displayed SPL reading as the relative SPL reference. Then, the numeric dB field will
show the difference between the current reading and the stored reference. This is useful
to show relative seat-to-seat SPL readings.
5. Max – Max Hold Clear The maximum SPL reading is constantly updated and displayed.
To reset the displayed value, highlight and click on the "Max" field.
6. Bar Graph SPL: Indicates SPL measurement in bar graph presentation.
7. Digital Readout: Indicates SPL measurement with a digital numeric value.
SLM Operation
1. Connect a test signal to the audio system input. SPL tests require a constant-level
signal, such as a single-frequency test tone or wide-band pink noise. To use the SP395 as
the signal source, connect a cable from an output connector to the desired audio system
input.
Caution: Preset the amplifier gain to minimum to prevent speaker damage
when the SPL test is turned on. There will be no output until the signal generator is
turned on in the bottom Toolbar.
2. Position the microphone. Position the microphone for SPL testing. For example, when
setting speaker level balance, position the microphone in the center of the listening
position.
3. Select one of the four available ANSI-standard averaging modes:
• Use Slow (1000 mS exponential decay time, time-averaged RMS) for most SPL
measurements. This averages transients and provides the best indication of the sound
level that our ears hear.
• Use Fast (125 mS exponential decay time, time-averaged RMS) to follow fast audio
changes.
• Use Impulse mode, (35 mS exponential decay time, time-averaged RMS) to measure
noise spikes.
• Use Peak mode to show peak SPL, rather than RMS.
4. Select the weighting filter. Select one of 38 filtering modes:
• C-weighting for louder SPL levels, including most system measurements.
• A-weighting for low SPL levels, or for measurements that need to correlate to noise-
induced hearing damage.
• Flat (un-weighted).
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