Type 3654 is a two-microphone probe kit for measuring sound intensity.
Designed for use with Hand-held Sound Intensity System Type 2270, the probe kit includes the ½” Sound Intensity Microphone Pair Type 4197 for 1/3-octave centre frequency measurements between 20 Hz and 6.3 kHz. Extending the upper 1/3-octave centre frequency to 10 kHz can be achieved using pressure correction.
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Used with ½” Microphone pair Type 4197, the probe complies with IEC 1043 Class 1. These ½” microphones feature patented phase-corrector units making precision low-frequency phase matching practical, leading to increased measurement range and accuracy.
Uses
- Sound intensity measurements using two-microphone technique in accordance with IEC 1043 Class 1
- Sound power measurements in accordance with ISO 9614 – 1, ISO 9614 – 2, ECMA 160 and ANSI S 12 – 12
Features
- Microphone pair matched for phase and amplitude response
- Individual calibration data
- 1/3-octave centre frequency ranges: – 20 Hz to 10 kHz with corrections – 50 Hz to 6.3 kHz according to IEC1043 Class I
- Minimal shadow and diffraction effects
- Well-defined acoustical microphone separation
Specially designed for use with Hand-held Analyser Type 2270.
It strong but lightweight and is connected to Type 2270 directly via a cable, or via an extension rod and handle with a cable. The probe kit includes an ellipsoidal windscreen.
Sound Intensity Microphone Pair Type 4197
Phase matching of the ½” microphone pair Type 4197 is better than 0.05 degrees between 20 Hz and 250Hz, and is better than f/5000 degrees at higher frequencies, where f is the frequency. Such phase matching is the result of the integral microphone phase-corrector units (patented) which are fitted to the Type 4197 microphones. The normalised microphone frequency responses differ by less than 0.2 dB up to 1 kHz and by less than 0.4 dB up to 7.1 kHz. Type 4197 is supplied with 8.5, 12 and 50 mm spacers. Calibration data provided (Fig. 4) include phase matching up to a 1/3-octave centre frequency of 6.3 kHz, microphone sensitivities at 250Hz, actuator responses and individual free-field frequency responses valid for the microphones mounted on a ¼” preamplifier. The microphones operate on a polarization voltage of 200V.
Specifications – Sound Intensity Probe Kit Type 3654
Matched Sound Intensity Microphone Pairs:
Sound intensity free-field frequency ranges (centre frequency – 1/3-octave) with 1/2" microphones Type 4197 connected to Dual Preamplifier Type 2683 (IEC 1043 Class 1):
8.5 mm spacer: 250 Hz to 6.3 kHz ( pI0 >15.3 dB)*
12 mm spacer: 250 Hz to 5.0 kHz ( pI0 >16.8 dB)
50 mm spacer: 20 Hz to 1.25 kHz ( pI0 >23 dB above 250 Hz)
Sound intensity free-field frequency ranges with 1/4" microphones Type
4178 (optional accessory):
6 mm spacer: max. 10.0 kHz
12 mm spacer: max. 5.0 kHz
* Pressure-Residual Intensity Index
DIMENSIONS:
Length of Extension Stem: 42 cm (16.5 in)
Width: 43 mm (1.7 in)
WEIGHT:
Incl. handle: 0.35 kg (0.77 lb)
In case: 6.50 kg (14.3 lb)
Specifications – Sound Intensity Microphone Pair Type 4178
Sensitivity: 4mV/Pa
Frequency: 4Hz–100 kHz
Dynamic Range: 28–164 dB
Temperature: –40 to +150°C (–40 to +302°F)
Polarization: 200 V External
MICROPHONE MATCHING SPECIFICATIONS TYPE 4178
Phase Response Difference (1/3-octave centre frequencies):
100Hz–200 Hz: ±20 deg/f [Hz]
200Hz–1 kHz: ±0.1 deg
1 kHz–20 kHz: ±0.1 deg × f [kHz]
Amplitude Response Difference (normalised at 200 Hz):
<0.3 dB: 100Hz to 10 kHz
<0.5 dB: 100Hz to 20 kHz
