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Sound and Vibration Instrument Hire and Calibration

Bruel & Kjaer 2260D Specifications

Bruel & Kjaer Room Acoustics Analyser
This web page lists the full technical specifications - or click the link to see the 2260 Summary Table
B&K 2260D : Building Acoustics Analyser £ 34 a day *

B&K 2260 with BZ 7204 - Sound Insulation Building Acoustics Software

Specifications with pre-polarized Free-field 1/2" Microphone Type 4189 and Input Stage ZC 0026

Sound Level Meter Standards

Conforms with the relevant parts of the following:
IEC 651 (1979) Type 1 plus Amendment 1
IEC 1260 (1995) Octave and 1/3-octave Bands Class 0
ANSI S1.4 (1983) Type 1
ANSI S1.11-1986 Octave and 1/3-octave Bands, Order 3, Type 0-C, Optional Range

Measurement And Calculation Standards

Measurement and calculations can be made according to the following standards: ISO, DIN, BS, NBE, SS, SIA, NORM, NF, UNI, ASTM and NEN. See Tables 1 and 2

Supplied Microphone

Pre-polarized Free-field 1/2 " Microphone Type 4189
Type: Pre-polarized condenser
Nominal sensitivity: 26 dB ± 1.5 dB re1 1V/Pa
Capacitance: 14 pF (at 250 Hz)

Supplied Input Stage: ZC 0026

Input Impedance: 10 GΩ || <1 pF
Extension Cables: Up to 100 m in length between the input stage and Type 2260 can be driven by the input stage without affecting measurements

Measuring Range

Octave and 1/3-octave: 90 dB A-weighted: 80 dB
Adjustable readings from 70 dB to 130 dB in 10 dB steps (A-weighted: 80 dB range)
Max. peak level 3 dB above full scale reading
Passive Attenuation: Microphone Attenuator ZF 0023 (included) effectively increases all full-scale readings by 20 dB

Under range Indication

Octave and 1/3-octave: 90dB below upper limit for each range setting, corresponding to less than 0.5 dB error


L1 and L2 (Airborne Task) can be measured using 2 channels, which can be connected using any combination of preamplifier inputs and AC inputs. The two channels have independent gain and calibration settings. A correction spectrum can be entered manually for each channel

Frequency Weighting

Lin frequency weighting
A-weighting Instantaneous Fast (displayed, not stored)

Octave And 1/3-octave Band Filters

Conform to IEC 1260 (1995), and ANSI S1.11-1986
Octave Band Centre Frequencies
Nominal: 63Hz, 125Hz, 250Hz, 500Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz
1/3-octave Band Centre Frequencies
Nominal: 50 Hz, 63 Hz, 80 Hz, 100 Hz, 125 Hz, 160 Hz, 200 Hz, 250 Hz, 315 Hz, 400 Hz, 500 Hz, 630 Hz, 800 Hz, 1 kHz, 1.25 kHz, 1.6 kHz, 2 kHz, 2.5 kHz, 3.15 kHz, 4 kHz, 5 kHz, 6.3 kHz, 8 kHz, 10 kHz
Real-time Frequency Range: 50 Hz to 10 kHz centre frequencies

Inherent Noise Level

(Inherent noise is the combination of the electrical noise and the thermal noise from the microphone at 20 °C.) Typical values using a microphone Type 4189 with a nominal sensitivity:
1/3-octaves: 2 dB at 1 kHz, 8 dB at 10 kHz
1/1-octaves: 6 dB at 1 kHz, 12dB at 8 kHz


The analyser contains several detectors working in parallel on every measurement:
Octave Band Filters (8) or 1/3-octave Band Filters (24): Pre-weighted by Lin., each with a detector channel containing one linear averaging detector
Overload Detector: Monitors the overload condition
A-weighted: Broadband detector channel with Fast exponential time weighting. Single-channel only

Internal Generator

Built-in pseudo-random noise generator
Spectrum: Selectable between Pink and White
Crest Factor:
Pink noise: 4.4 (13 dB)
White noise: 3.6 (11 dB)
Bandwidth: Follows measurement bandwidth
Lower limit: 50 Hz (1/3-oct.) or 63 Hz (oct.),
Upper limit: 10 kHz (1/3-oct.) or 8 kHz (oct.)
Output Level: Independent of bandwidth
Max.: 1Vrms (0 dB)
May be set in 1 dB steps 0 to 60 dB
When bandwidth is changed, the level for all bands is automatically adjusted to comply with the set output level
Turn-on time and Turn-off time: Equivalent to RT = 70 ms
Repetition Period: 175 s
Output Connector: Auxiliary 1 output
Control: See Measurement Control

External Generator

Selectable as alternative to Internal Generator
For controlling external noise generator
Levels: 0 V (Generator off), 4.5 V (Generator on)
Rise-time and Fall-time: 10 µs
Control: See Measurement Control.


Instantaneous: For display, no storage 'Live' spectrum - Leq with a short averaging time
Range: Follows setting in Levels and Reverberation Time
Generator: Turned on and off manually
Levels: For Display and Storage
Leq: (L1, L2, B2) in octave or 1/3-octave bands
L1 and L2 simultaneously or as single channels
Averaging time: 1s to 59 min. 59 s
Range: Manual range or Auto range
Generator: Controlled automatically
Averaging: Up to 25 measurements may be averaged
Status indications: Overload, under range, start time
Reverberation Time: T20 and T30 in octave or 1/3-octave bands Decays are measured and stored, using averaging times between 8 and 96 ms, depending on bandwidth and decay time

Manual entry

After measurement, the value in each band, for each position, may be changed by user entry

Broadband average

The arithmetic average of the Reverberation Time for selected bands is calculated and displayed (not stored)

Impulse excitation

When level (say from starter pistol) exceeds user selected trigger level, the decay is recorded and backwards integration performed ( Schroeder Method). The decay curves can be exported to a spreadsheet for detailed analysis


Controlled automatically


Decays can be repeated automatically up to 99 times (ensemble averaging)


up to 25 T20 and T30 measurements can be averaged (arithmetic averaging)

T20 and T30 calculation

From slope in evaluation range
Slope estimation: Least squares approximation
Status indications: Overload, under range, start time, T20 - T30
Correlation Coefficient; extensive list of Status codes

RT range

Max. 30.00 s, min. 0.1 - 0.7 s, depending on bandwidth


External (acoustic): Using the Sound Level Calibrator Type 4231 Internal (electrical): Uses internally generated electrical signal combined with keyed-in value of microphone sensitivity Initial calibration stored for comparison with later calibrations Initial factory calibration traceable in conjunction with ISO 9001 certification

Measurement Control

Manual or semi-automatic. Measurements are started manually and can be automatically stored on completion of measurement. The noise generator is turned on and off automatically With Inst. spectrum on display, the generator can be turned on and off manually for checking Selected frequency bands can be measured serially, i.e., one by one in automatic sequence. This feature works for the functions L1, L2 and T2 and for single as well as 2 channels

Measurement Displays

L1: Shows the spectrum of the level measured in the source room
L2: Shows the spectrum of the level measured in the receiving room. A dimmed curve shows background noise
L1 and L2: 2-channel measurements, L1 and L2 are displayed simultaneously
B2: Shows the spectrum of the background level measured in the receiving room. A dimmed curve shows the L2 level
T2: Shows the spectrum of reverberation times (T20 or T30) measured in the receiving room. Also, decay curve can be shown for each centre frequency
Spectrum: Octave or 1/3-octave band spectrum. Y-axis can be zoomed
dB(A): Instantaneous level is shown as a column next to the spectrum, with cursor readout. Single-channel only The graphical displays have cursor read-out facilities

Display Resolution

Levels: 0.1 dB
Reverberation Time: 0.01 s

Result Display

Shows the sound reduction index (spectrum and weighted) according to the selected standard, along with the reference curve (if any)

Storage System

Internal disk for storing application software, user-defined setups and measurement data. Setups and data can be recalled for further analysis
Capacity (32MB disk): The supplied application software requires approximately 2 MB
Measurement data space requirements: 65 kB for typical Job (one partition)
Application Card: For installation of application software
External Memory Card: For Store/Recall of measurement data and transfer of data to and from a PC (SRAM or ATA flash cards)
MS-DOS: Compatible file system (from Ver. 3.3)

Serial Printer/Output

Setups and measurement data can be printed on an IBM Proprinter (or compatible) or a Portable Printer Type 2322. The formats can be screen dumps or tables
Measurement data can be output in spreadsheet format for post processing on a PC


Transfer of measurement data in binary form to a PC for use with Bruel & Kjaer Type 7830 application software
Transfer time to 7830: 30 s for typical Job.
Baud Rates: 1200, 2400, 4800, 9600, 19200, 38400 and 115200


Concise context-sensitive help for keys and menus


All software available in English, German, French, Italian, Spanish and Czech


Update Rate: Instantaneous - typically 5 times per second

Auxiliary Outputs

Aux. 1: noise generator output
Aux. 2: 'Input' signal monitor output can be set to either monitor 'Input' signal with variable attenuation from 0 to -80 dB in 1 dB steps, or can be switched Off to reduce power consumption

AC Inputs/Outputs

Signal Output: Buffered, unweighted microphone signal
Signal Input: From an external source such as a tape recorder
See also specifications in platform manual

Settling Time

From Power On: Approx. 25 s

Effect Of Vibration

Less than 72 dB for a 50 Hz vibration at a level of 1 m/s2

Effect Of Temperature

Operation: <0.5 dB from -10 °C to +50 °C (+14 °F to +122 °F)
Storage (without batteries): -20 °C to +70 °C (4 °F to +158 °F)

Effect Of Magnetic Fields

80 A/m (1 Orsted) at 50 Hz causing a reading of: 63 Hz Octave-band filter: <30 dB

Effect Of Humidity

Operation: <0.5 dB for 30% < RH < 90% (at 4 °C and 1 kHz)
Storage: Cool, dry environment recommended to avoid formation of mould etc.


Type: 6 x Lr14/C-size 1.5 V alkaline, QB 0009 Lifetime (at 20 °C): 8 hours of typical use (decreases significantly at low temperatures)

External DC Power Supply

Voltage: Regulated or smoothed 10 to 14 V, maximum ripple 100 mV
Power: 3.5 W, current: 300 mA, Inrush current: 1000 mA
Socket: Ø5.5 mm with Ø2 mm pin (positive)


1.2 kg including batteries, Input Stage ZC 0026 and pre-polarized free-field 1/2" Microphone type 4189


375 x 120 x 52 mm including Input Stage ZC 0026 and pre-polarized free-field 1/2" Microphone type 4189
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E&OE - specifications subject to change without notice.