User manual

304
Appendix
General Information
Reference Sound Pressure Level
The reference sound pressure level is 114 dBSPL relative to
20 mPa.
Reference Level Range
The reference level range is MID, 20 - 120 dBSPL
Reference Orientation
The microphone reference point is located in the middle of the
microphone membrane. The 0° reference orientation and the
orientation of the membrane’s surface normal is identical.
Verified Frequency Range
20 Hz to 20 kHz
Greatest Peak-To-Peak Voltage at the Electric Input
(Refer IEC61672-1 paragraphs 5.1.16, 9.3.i)
The highest sound pressure level at the M2230 microphone
with a sensitivity of S = 42 mV/Pa is 143.5 dB.
Initial Time Interval after Power On (IEC61672-1, 5.1.18)
The XL2-TA Sound Level Meter and M2230 microphone meet
the given specifications for the electro-acoustical response af-
ter an initial time interval of no more than one minute following
switching on the power. This assumes that the devices have
been allowed to reach equilibrium with the prevailing ambient
environment before switching on the power.
Insertion of Electrical Signals
(Refer IEC61672-1 paragraphs 5.1.15, 9.3g)
The capsule replacement NTI-K65-15 can be used to insert
electrical signals to the preamplifier MA220. The device pro-
vides at one side a contact that corresponds to the center con-
tact of the replaced microphone capsule, at the other side a
BNC-plug for the electrical signals. The impedance at the out-
put of the device is 15 pF with a maximum deviation of ±
1 pF.
The electrical noise floor is measured by shorting the con-
tacts of the BNC plug. Before the NTI-K65-15 can be mount-
ed to the preamplifier MA220, the microphone capsule must
first be detached. The nominal sensitivity S of the capsule is
S = 42 mV/Pa. Measurements with the NTI-K65-15 therefore
require that the sensitivity in the calibration menu is manually
adjusted to S = 42 mV/Pa.
The maximum electrical input voltage is 36 Vpp. The attenu-
ation between the device and the XLR input of the XL2-TA is
0.78 dB at a reference frequency of 1 kHz. A 1 kHz signal with
459 mVrms level is required at the input of the device, to sub-
stitute the signal of a microphone capsule with the sensitivity
42 mV/Pa at a reference level of 114 dBSPL.