Bruel & Kjaer 2250

Precision Sound Analyser

Manufacturers' Specifications

The Gracey & Associates 2250 Sound Analyzers include the the following modules

BZ 7222 - Sound Analysis Software
BZ 7223 - Frequency Analysis Software
BZ 7224 - Logging Software
BZ 7226 - Sound Recording Option
BZ 7230 - FFT Analysis Software
BZ 7231 - Tonal Assessment Option

Specifications - 2250 Platform

All our 2250 meters fitted with the supplied microphone and preamplifier and with the instrument at + 20 °C unless otherwise stated

Supplied Microphone
Type 4189: pre-polarized Free-field 1/2" Microphone
Nominal sensitivity: 50 mV/Pa (corresponding to -26 dB re 1 V/Pa) ± 1.5 dB
Capacitance: 14 pF (at 250 Hz)

Microphone Preamplifier: ZC0032
Nominal Preamplifier Attenuation: 0.25 dB
Connector: 10-pin Lemo
Extension Cables: up to 100 m in length between the microphone preamplifier and Type 2250, without degradation of the specifications

Microphone Polarization Voltage
Selectable between 0 V and 200 V

Self-Generated Noise Level
Typical values at 23 °C for nominal microphone open-circuit sensitivity:

Keyboard
Pushbuttons: 11 keys with backlight, optimised for measurement control and screen navigation

On-off Button
Function: press 1 s to turn on; press 1 s to enter standby; press for more than 5 s to switch off

Status Indicators
LEDs: red, amber and green

Display
Type: transflective back-lit colour touch screen 240 x 320 dot matrix
Colour Schemes: five - optimised for different usage scenarios (day, night, etc.)
Backlight: adjustable level and on-time

User Interface
Measurement Control: using pushbuttons on keyboard
Setup and Display of Results: using stylus on touch screen or pushbuttons on keyboard
Lock: keyboard and touch screen can be locked and unlocked

USB Interface
USB 1.1 OTG Mini B socket

Modem Interface
Hayes compatible GSM or standard analogue modems connected through the Compact Flash slot

Input Socket
Connector: tri-axial LEMO
Input Impedance: ≥ 1 MΩ
Signal Source Impedance < 200 Ω
Direct Input: Max input voltage: ± 14.14 Vpeak,
CCLD Input: Max input voltage: ± 7.07 Vpeak
CCLD Current/Voltage: 4mA/25 V
Note: CCLD = Constant Current Line Drive

Trigger Socket
Connector: Triaxial LEMO
Max Input Voltage: ± 20 Vpeak
Input Impedance: > 1 MΩ

Output Socket
Connector: Triaxial LEMO
Max Peak Output Level: ± 4.46 V
Output Impedance: 50 Ω

Headphone Socket
Connector: 3.5 mm Mini-jack stereo socket
Max Peak Output Level: ± 1.4 V
Output Impedance: 2.2 Ω in each channel

Microphone For Commentary
Microphone, which utilises Automatic Gain Control (AGC), is incorporated in underside of instrument. Used to create voice annotations for attaching to measurements

External DC Power Supply Requirements
Used to charge the battery pack in the instrument
Voltage: : 8 - 24 V DC, ripple voltage < 20 mV
Current Requirement: min. 1.5 A
Power Consumption: < 2.5 W, without battery charging.
Cable Connector: LEMO type FFA.00, positive at centre pin

Battery Pack
Type: Li-Ion rechargeable
Typical Operating Time: > 8 hours

Storage System
Internal Flash-RAM (non-volatile): 20 Mbyte for user setups and measurement data
External Secure Digital Memory Card (SD-card): For store/recall of measurement data
External Compact Flash Memory Card (CF-card): For store/recall of measurement data

Clock
Back-up battery powered clock. Drift < 0.5 s per 24 hour period

Warm-up Time
From Power Off: < 2 minutes s
From Standby: < 10 seconds for pre polarized microphones

Temperature
IEC 60068-2-1 & IEC 60068-2-2: Environmental Testing. Cold and Dry Heat.
Operating Temperature: < 0.5 dB, -10 to + 50 °C (14 to 122 °F)
Storage Temperature: -25 to +70 °C (-13 to 158 °F)

Humidity
IEC 60068-2-3: Damp Heat: 90 % RH (non-condensing at 40 °C (104 °F)).
Effect of Humidity: < 0.5 dB for 30 % < RH < 90 % (at 40 °C (104 °F) and 1 kHz)

Mechanical
Environmental Protection: IP44
Non-operating:
IEC 60068-2-6: Vibration: 0.3 mm, 20 m/s2, 10-500 Hz
IEC 60068-2-27: Shock: 1000 m/s2
IEC 60068-2-29: Bump: 1000 bumps at 250 m/s2

Weight And Dimensions
650 g (23 oz) including rechargeable battery
300 x 93 x 50 mm (11.8 x 3.7 x 1.9 ")

Help
Concise context sensitive help in English

BZ 7222 - Sound Level Meter Software

• Conforms with the following National and International Standards:
• IEC 61672-1 (2002-2005) Class 1
• IEC/EN 60651 (1979) plus Amendment 1 (1993) and Amendment 2 (2000), Type 1
• IEC/EN 60804 (2000 ) Type 1
• ANSIS1.4-1983 (R1997) plus ANSI S1.4A-1985 Amendment, Type 1
• ANSIS1.43-1997 Type 1

Note: The International IEC Standards are adopted as European standards by CENELEC. When this happens, the letters IEC are replaced with EN and the numbers are retained. The type 2250 also conforms to these EN Standards

Transducers
Transducers are described in a transducer database with information on Serial Number, Nominal Sensitivity, Polarization Voltage, Free field Type, CCLD required, Capacitance and additional information. The analogue hardware is setup automatically in accordance with the selected transducer

Correction Filters
For microphones of known types, BZ 7222 is able to correct the frequency response to compensate for free or diffuse sound fields

Detectors
Parallel Detectors on every measurement:
A-weighted broadband detector channel with three exponential time weightings (Fast, Slow, Impulse), two linearly averaging detector and one peak detector
C- or Z-weighted (switchable) as above for A-weighted
Overload Detector: Monitors the overload outputs of all the frequency weighted channels

Measurements
X = frequency weightings C or Z
V = frequency weightings A, C or Z
N= number between 0.1 and 99.9

Display and Storage

BZ 7223 - Frequency Analysis Software

• Standards - Conforms with the following
• IEC 61260 (1995) plus Amendment 1 (2001), 1/1-octave and 1/3-octave Bands, Class 0
• ANSI S1.11-1986 (R 1993), 1/1-octave Bands and 1/3-octave Bands, Order 3, Type 0-C, Optional Range
• ANSI S1.11-2004, 1/1-octave Bands and 1/3-octave Bands, Class 0

Centre Frequencies
1/1-octave Band Centre Frequencies: 8Hz to 16 kHz
1/3-octave Band Centre Frequencies: 6.3Hz to 20 kHz

Measurements
X = frequency weightings A, C or Z

For Display and Storage

Measuring Ranges
Dynamic Range: From typical noise floor to max. level for a pure tone signal at 1 kHz 1/3-octave: 1.7 to 140 dB

Sampling for Octave or 1/3-octave Statistics
The Statistics can be based on either LAF or LAS:
• Statistics LAFN1-7 or LASN1-7 are based on sampling LAF or LAS, respectively, every X ms into 1 dB wide classes over 150 dB;
X = 100 for frequency range set to 12.5 - 20 kHz
X = 200 for frequency range set to 6.3 - 20 kHz
Full distribution can be saved with measurement

Measurement Displays
Spectrum: One or two spectra superimposed + A and C/Z broadband bars
Y-axis: Range: 5, 10, 20, 40, 60, 80, 100, 120, 140 or 160 dB. Auto zoom or auto scale available
Cursor: Readout of selected band

BZ 7224 - Logging Software

Measurements
Logging: Measurement data logged at pre-set intervals into files on external SD- or CF-cards
Logging period: from 1 s to 24 hours with 1 s resolution
Fast Logging: LAF or LAeq can be logged every 100 ms, irrespective of logging interval
Broadband Data Stored at each Logging Interval: All, or up to 10 selectable broadband data
Broadband Statistics Stored at each Logging Interval: full distribution or non
Spectrum Data Stored at each Logging Interval: all or up to 3 selectable spectra
Spectral Statistics Stored at each Logging Interval: Full distribution, or none
Logging Time: from 1 second to 31 days (or unlimited) with 1 s resolution
Measurement Total: for the logging time, in parallel with logging: All broadband data, statistics and spectra

Markers
One data exclusion marker and four user-definable markers for online marking of sound categories heard during the measurement. Events can be set manually

Triggers
Markers can be set when broadband level is above or below a specified level

Annotations
On-line annotations with spoken comments or written notes

Measurement Displays
Profile: Graphical display of selectable measurement data versus time
Y-axis: Range: 5, 10, 20, 40, 60, 80, 100, 120, 140 or 160 dB. Auto zoom or auto scale available
X-axis: Scroll facilities
Cursor: Readout of measurement data at selected time

BZ 7226 - Sound Recording Option

The Sound Recording Option BZ 7226 works with all the other software for the type 2250 and requires a CF or SD-Card for data storage.

Recorded Signal
A-, C- or Z-weighted signal from the measurement transducer

Automatic Gain Control
The average level of the signal is kept within a 40 dB range, or the gain can be fixed

Sampling Rate And Pre-recording
Sound is buffered for the pre-recording of sound. This allows the beginning of events to be recorded even if they are only detected later.

Functions With BZ 7222 And BZ 7223
Manual Control of Recording: Recording can be manually started and stopped during a measurement using a pushbutton or an external signal
Automatic Control of Recording: Start of recording when measurement is started. Minimum and Maximum recording time can be preset.

Functions With BZ 7224
Manual Control of Recording (using Manual Event or Back-erase pushbutton, or an external signal): Recording during all of the event, or for preset minimum and maximum duration. A Sound marker is set while recording. Selectable pre- and post-recording time
Manual Control of Recording (using touch screen): Recording for the selected time period (subject to the limitations of the pre-recording buffer). A Sound marker is set for the selected time period.
Automatic Control of Recording: An event can be triggered when a broadband level is above or below a specified level. Recording during all of the event or for preset minimum and maximum duration. Selectable pre- and post-recording time

Playback
Playback of sound recordings can be listened to using the earphone/headphones connected to the headphone socket.

Recording Format
The recording format is 16-bit wave files (extension .wav) attached to the data in the project, easily played back afterwards on a PC using Type 7815, 7820 or 7825. Calibration information is stored in the wav file.

BZ 5503 is included with Type 2250 for easy synchronisation of setups and data between PC and Type 2250. BZ 5503 is supplied on CD-ROM BZ 5298.

On-line Display Of Type 2250 Data
Measurements on Type 2250 can be controlled from the PC and displayed on-line with the PC, using the same user interface on the PC as on Type 2250

Data Management
Explorer: Facilities for easy management of Instruments, Users, Jobs, Projects and Project Templates (copy, cut, paste, delete, rename, create)
Data Viewer: View measurement data (content of projects)
Template Editor: Editor for changing setups in Project Templates
Synchronisation: Project Templates and Projects for a specific user can be synchronised between PC and Type 2250

Users
Users of Type 2250 can be created or deleted

Export Facilities
Excel: Projects (or user specified parts) can be exported to Microsoft Excel.
Type 7810/12/15/16/20/25: Projects can be exported to Predictor Type 7810, Lima Type 7812, Noise Explorer Type 7815, Acoustic Determinator Type 7816, Evaluator Type 7820 or Protector Type 7825

Type 2250 Software Upgrades And Licenses
The utility software controls Type 2250 software upgrades and licensing of the Type 2250 applications

Interface To Type 2250
USB ver. 1.1 or Hayes compatible GSM or standard analogue modem

PC Requirement
Operating System: Windows 2000/Windows XP, Microsoft.NET
Recommended PC: Pentium III (or equivalent) processor, 128 Mbyte RAM, SVGA graphics display/adaptor, sound card, CD ROM drive, mouse, USB, Windows XP

BZ 7230 - FFT Analysis Software


Specifications for FFT analysis are given for the hand-held analyzer with software BZ -7230 installed and fitted with one of the recommended transducers (see Table 2)

FFT ANALYSIS
Sampling Frequency: Downsampling from 51.2 kHz
Frequency Span: 100 Hz, 200 Hz, 500 Hz, 1 kHz, 2 kHz, 5 kHz, 10 kHz, 20 kHz
Lines: 100, 200, 400, 800, 1600, 3200, 6400¹
Zoom Centre Frequency: Can be set so that the Frequency Span is placed in the range 0 to 20 kHz
Spectrum: Averaged and Maximum
Pre-weighting: Z (none), A, B or C

MEASUREMENT CONTROL
Manual Start
Exponential Averaging: With an averaging time of up to 999 spectra, measured with Hanning window and 67% overlap
Linear Averaging: Up to 8388607 spectra measured with Hanning window and 67% overlap

Triggered Start
Transient Signal Type: Linear averaging of up to 32767 triggered spectra measured with rectangular window and 0% overlap
Continuous Signal Type: Linear averaging of up to 32767 spectra measured with Hanning window and 67% overlap. Up to 32767 spectra are averaged on each trigger.
Auto-start: A total of 10 timers allow set up of measurement start times up to a month in advance.
Each timer can be repeated.
Measurements are automatically stored when completed.

TRIGGERS
Delay: From 16383 samples before the trigger time to 300 seconds after
Hold Off: 0 to 300 s
Internal Trigger: Uses the time signal from the measurement transducer. The Internal Level is set in the relevant measurement units External Trigger: Uses the Trigger Input. The External Level is set in the range -18 to 18 V
Hysteresis (Only for External Trigger): 0 to 10 V
Slope (Only for External Trigger): Rising, Falling Pull-up (Only for External Trigger): For Type 2250 serial numbers above 2479653 the Trigger Input is pulled up to +5 V through a 7.5 k resistor when this parameter field is set to On

1. The actual number of lines is one more than stated, to provide symmetry around the centre frequency.

MEASUREMENT RANGE (See Table 2)
The lower limit of the measurement range is influenced by selfgenerated random noise and self-generated tones called spurious signals. The influence of the random part can be reduced to a level below the spurious signals by selecting a small analysis bandwidth (small span and many lines). Therefore, the lower limit is specified as the maximum Peak level of the spurious signal lines.

BZ-7230 has only one measuring range but the spurious level depends on the peak level of the signal. Therefore, two specifications are given. One for high levels, where the upper limit is the overload limit, and one for low levels.

The Typical Frequency Response shows the ±1 dB limits for Direct Input and microphones, and the ±10 % limits for accelerometers.

RPM MEASUREMENT
RPM is measured on the signal connected to Trigger input when Tacho is set to On
Range: 1 to 6000000 RPM
Instantaneous RPM: Instantaneous RPM is only displayed (and not stored)
Average RPM: Displayed and stored together with each Spectrum result. In Linear Averaging it is an average over the same time as the spectrum. In Exponential Averaging it is the last measured RPM
Gear Ratio: 10-5 to 1038. The displayed RPM's are the measured RPM's divided by the RPM Gear Ratio.

OVERLOAD
Instantaneous Overload: Displayed as an icon and indicated by the Traffic Light
Spectrum Overload: Displayed and stored with each Spectrum result

DISPLAY SPECTRA
Two spectra superimposed
Scaling: RMS, Peak, Peak-to-Peak, Power, PSD, ESD
Reference Spectrum: Compare spectrum to stored (measured) reference
Axis: Logarithmic and Linear Y-axis, Linear X-axis
X-axis: Display full frequency range or expand the X-axis until only 20 FFT lines are displayed. Scroll available
Y-axis Display Range: 5, 10, 20, 40, 60, 80, 100, 120, 140, 160, 180 or 200 dB. Auto-zoom or Auto-scale available
Digital Post-weighting: Z (none) or A-weighting

DISPLAY PARAMETERS
Sound: Sound Pressure Level in dB

Table 2 Measurement ranges with the recommended transducers

Transducer	Nominal Sensitivity	Spurious Free Dynamic Range for High Levels	Spurious Free Dynamic Range for Low Levels	Typical Frequency Response Extended Low Frequency OnOff
Direct Input	1 V/V	3μV - 14.1 Vpeak	300 nV - 75 mVpeak	1.5/6.3 Hz - 20 kHz
4189	50 mV/Pa	10 dB - 143 dBpeak	-10 dB - 97.5 dBpeak	6.8/7.8 Hz - 20 kHz,
4191	12.5 mV/Pa	22 dB - 155 dBpeak	2 dB - 109.5 dBpeak	3.6/6.6 Hz - 20 kHz
4193	12.5 mV/Pa	22 dB - 155 dBpeak	2 dB - 109.5 dBpeak	0.56/6.3 Hz - 20 kHz
4950	50 mV/Pa	10 dB - 155 dBpeak	-10 dB - 97.5 dBpeak	4.3/6.3 Hz - 19 kHz
4952	31.6 mV/Pa	14 dB - 146 dBpeak	-6 dB - 101.5 dBpeak	4.3/6.3 Hz - 14 kHz
4397-A	1 mV/ms-2	3 mms-2 - 7.1 kms-2peak	300 μms-2 - 75 ms-2peak	1.25/6.3 Hz - 20 kHz
4513	1 mV/ms-2	3 mms-2 - 7.1 kms-2peak	300 μms-2 - 75 ms-2peak	1.25/6.3 Hz - 10 kHz
4513-001	10 mV/ms-2	300 μms-2 - 710 ms-2peak	30 μms-2 - 7.5 ms-2peak	1.25/6.3 Hz - 10 kHz
4513-002	50 mV/ms-2	60 μms-2 - 141 ms-2peak	6 μms-2 - 1.5 ms-2peak	1.25/6.3 Hz - 10 kHz

Vibration:
Acceleration, velocity or displacement in dB or physical units. SI units (m/s2, m/s or m) or US/UK units (g, m/s or Mil)
Direct: Voltage in dB or V

CURSORS
Readings: Total level within the spectrum.
Frequency Correction: For spectra measured with a Hanning Window, spectral peaks are interpolated to a higher precision
Main: Reads level versus frequency
Symmetrical Delta and Delta: Defines lower and upper frequency limit for any part of the spectrum and calculates the level sum within that frequency range
Harmonic: Identifies fundamental frequency and harmonics in the spectrum and calculates the Total Harmonic Distortion ² (THD)
Reference: Reads the difference between the main cursor Y-value and the reference cursor Y-value

Note 2. Total Harmonic Distortion (THD) is the sum (in %) of all the harmonics relative to the sum of the fundamental and all the harmonics.

LIMIT LEVEL CHECK
Limit Level: Determines the level at which the spectrum is checked
Limit Range: Determines the frequency range for the limit level check
Indication: Two indicators are displayed, latched and instantaneous When the spectrum exceeds the limit level, a recording can be started (license for BZ-7226 required) and a 3.3 V DC signal can be output at the Output Socket

Sound Level Meter Parameters
Sound level meter (broadband) parameters are measured simultaneously with the FFT parameters. However, their measurement starts when the Start/Pause pushbutton is pressed and ends at the nearest whole second after the end of the FFT measurement
Specifications for the Sound Level Meter parameters apply to Handheld Analyzer Type 2250 fitted with Microphone Type 4189 and Microphone Preamplifier ZC-0032

SELF-GENERATED NOISE LEVEL -Typical values at 23°C for nominal microphone open-circuit sensitivity:

Weighting	Microphone	Electrical	Total
"A"	14.6 dB	12.4 dB	16.6 dB
"B"	13.4 dB	11.5 dB	15.6 dB
"C"	13.5 dB	12.9 dB	16.2 dB
"Z" 5 Hz - 20 kHz	15.3 dB	18.3 dB	20.1 dB
"Z" 3 Hz - 20 kHz	15.3 dB	25.5 dB	25.9 dB

• Conforms with the following National and International Standards:
• IEC 61672 - 1 (2002-05) Class 1
• IEC 60651 (1979) plus Amendment 1 (1993-02) and Amendment 2 (2000-10), Type 1
• IEC 60804 (2000-10 ), Type 1
• DIN 45657 (1997-07)
• ANSI S1.4 - 1983 plus ANSI S1.4A-1985 Amendment, Type 1 · ANSI S1.43 -1997 Type 1

Note: The International IEC Standards are adopted as European standards by CENELEC. When this happens, the letters IEC are replaced with EN and the number is retained. The analyzer also conforms to these EN Standards

DETECTORS
Parallel Detectors on every measurement:
A- or B-weighted (switchable) broadband detector channel with `Fast' time weighting, one linearly averaging detector and one peak detector
C- or Z-weighted (switchable) as for A- or B-weighted
Overload Detector: Monitors the overload outputs of all the frequency weighted channels

MEASUREMENTS
X = frequency weightings A or B
Y = frequency weightings C or Z
V = frequency weightings A, B, C or Z

For Display and Storage

Start Time	Stop Time	Overload %
Elapsed Time	Lxeq	Lyeq
LXFmax	LYFmax	LXFmax
LYFmin	LXIeq	LYIeq
LAFTeq

MEASURING RANGES When using Microphone Type 4189:
Dynamic Range: From typical noise floor to max. level for a 1 kHz pure tone signal, A-weighted: 16.6 to 140 dB
Primary Indicator Range: In accordance with IEC 60651, Aweighted: 23.5 dB to 123 dB
Linearity Range: In accordance with IEC 60804, A-weighted: 21.4 dB to 140 dB
Linear Operating Range: In accordance with IEC 61672, Aweighted: 1 kHz: 24.8 dB to 140 dB
Peak C Range: In accordance with IEC 61672: 42.3 dB to 143 dB

BZ 7231 - Tone Assessment Option

LICENSE: Tone Assessment Option BZ-7231 is enabled with a separate license and can be used with the FFT template.

STANDARD
Tone assessment is based on the measured FFT spectrum in accordance with "ISO 1996:2007 Acoustics - Description, assessment and measurement of environmental noise - part 2: Determination of environmental noise levels. Annex C (informative) Objective method for assessing the audibility of tones in noise - Reference method"

SPECTRA ASSESSED
Any displayed sound FFT spectrum (FFT, Ref or Max) may be assessed. Assessment is made as post-processing, i.e., when measurement is paused or stopped.

SETUP ACCORDING TO STANDARD
Default Setup: Setups in violation of the standard are indicated as such on the display, you may then accept to apply the default setup Tone assessment will be made if possible, in spite of standard violations.
Tone Seek Criterion: 0.1 to 4.0 dB in 0.1 dB steps.

TONE AT CURSOR
A sinusoidal tone is available at the Headphone output, to help confirm identified tones
Frequency: Selected by the Main cursor
Gain: -70 dB to +10 dB
Options: The generated tone may be mixed with the input signal, please refer to the Preferences/Headphone Settings.

TONE ASSESSMENT CURSOR
All tones found are indicated in the display

The Tone cursor is initially placed at the most prominent tone, and may then be stepped through the tones found You can also use the Main cursor to step through the tones.

RESULTS
Results are displayed in the Tone Parameter panel and in the Value panel They are not saved with the measurement.
All Tones: Frequency, Tone level Lpti, Masking noise level Lpn, Audibility Lta, Critical Band CB.
Most Prominent Tone: Tone Level Lpt, Adjustment Kt.

QUALITY INDICATORS
In the display, a quality indicator (smiley) will indicate that a hint is available for tone assessment quality. Click on the indicator to see the hint

B&K Help Line - 01438 739 000