LA-3260/LA-3560/LA-3570Noise meter/Sound level meter

Guangzhou Chengmin Electronic Technology Co., Ltd. specializes in supplying the full range of noise meters/sound level meters from Ono ONOSOKKI in Japan

LA-3260、LA-3560、LA-3570、LA-1410、LA-1440、LA-4440

Product features:

3.5-inch large display screen indicates easy observation
Easy to operate with multiple function keys
110 dB wide dynamic range measurement does not require range adjustment
Can simultaneously represent measurement and calculation data of 4 different characteristics
You can use headphones to monitor object noise while recording
By using various optional functions, the sound level meter can evolve into an acoustic analyzer, recorder, sound level comparator, and one unit can complete sound level measurement,
Recording, analysis, and comparative judgment significantly improve testing efficiency
Compliant with the Japanese Metrology Law, JIC C 1509, IEC 61672-1

Product selection table:

The extension distance of the microphone recorded on the specification sheet is the data when using our company's designated special cable.
The usage time may vary depending on the operating mode, storage mode, backlight usage, and other conditions.
In principle, our company conducts self inspection before leaving the factory, and then stamps it with a "conformity standard seal". For the inspection of products after leaving the factory, it is generally carried out by our company
After the adjustment, the Japanese Quality Assurance Agency (JQA) was commissioned to conduct the inspection. In addition, for users who require our company's untested products to be used as standards,
And if products with verification (with standard seals) need to be inspected by government agencies after leaving the factory, please specifically mention it when placing an order for our company to dispose of

Noise meter/sound level meter function options:

LA-0351 1/1 real-time octave band analysis function
LA-0352 1/3 real-time octave band analysis function

1/1 octave filter mode, 1/3 octave filter mode
Using headphones to monitor abnormal sounds for sound source detection

By using the octave band filter mode, it is possible to evaluate the sound pressure level of a specified single frequency band. If a certain frequency band containing abnormal sound components is measured, sound source detection can be achieved. At the same time, it can also monitor the sound of a designated single frequency band, and its sound level and trend can be represented.

1/1 real-time octave band analysis mode, 1/3 real-time octave band analysis mode
If abnormal sounds occur, the octave band analysis function is an effective tool for conducting abnormal sound analysis

The sound is divided into several frequency bands based on the pitch (frequency), and the characteristics of each frequency band are analyzed and compared to understand and grasp the state and characteristics of the sound.

LA-0353 Spectrum analysis function

By using the trigger function, the resonance frequency can be easily measured

The FFT spectral analysis function can perform high-precision spectral analysis of sound in a narrow band domain. Through the averaging function, averaging processing can stabilize the spectral waveform. In addition, through the triggering function, not only can the steady-state sound source be captured, but even single shot noise phenomena can be analyzed. When using the trigger function, the window function will automatically be set to a rectangular window, and testers do not need to worry about the convenience and reliability of setting the window function. A sampling frequency of 64 kHz can meet the analysis frequency range of 25 kHz. By pressing the DISP button, the peak data table can also be displayed.

LA-0354 recording function

Sound level meter evolves into recorder

The abnormal sound phenomenon generated by the tested object can be recorded and saved in WAVE file format at any time on the testing site. The recorded data can be replayed by a sound level meter, which can immediately confirm the recording results with peace of mind and reliability. At the same time, considering the efficiency of playback confirmation of long-term recorded data, time trend data will also be recorded and saved simultaneously. When replaying, the position with high noise can be quickly identified by observing the time trend data before confirming the replay. The recorded data can be analyzed and processed using OS-2000 series time series data analysis software.

SC-3120 Precision Sound Level Calibrator
SC-2120A Simple Sound Level Calibrator

Sound level calibrators are essential for acoustics and noise measurement. Compliant with JIS C1515:2004, IEC 60942： 2003 and other standards.
SC-3120 is a piston type precision sound level calibrator. Compliant with Class 1/C. Generate a sound pressure signal of 250 Hz and 114 dB. Please use SC-3120 precision sound level calibrator for the calibration of LA-3000 series sound level meter. SC-2120A uses a speaker as the sound pressure source and belongs to Class 2 sound level calibrator. Generate a sound pressure signal of 1000 Hz and 94 dB.

AG-3400 series microphone extension cable

AG-3401 microphone extension cable (5m)
AG-3402 microphone extension cable (10 m)
AG-3403 microphone extension cable (20 m)
AG-3404 microphone extension cable (30 m)

AX-501 signal cable

LA-0203C three legged voice meter

PB-7090 AC power adapter

DPU-414 Thermal Printer (for RS-232C)

OS-2000 series time series data analysis software

DS-3000 series data analysis system

Recommended SD/SDHC memory card

Working principle of noise meter/sound level meter:
The sound is converted into an electrical signal by a microphone, and then the impedance is transformed by a preamplifier to match the microphone with an attenuator. The amplifier adds the output signal to the weighting network, performs frequency weighting on the signal (or an external filter), and then amplifies the signal to a certain amplitude through an attenuator and amplifier, and sends it to the effective value detector (or an external level recorder). The noise level value is displayed on the indicator head.
1) A microphone is a device that converts sound pressure signals into voltage signals, also known as a microphone. It is the sensor of a sound level meter. There are several common types of microphones, including crystal type, electret type, moving coil type, and capacitive type.
1.1 A dynamic coil microphone consists of a vibrating diaphragm, a movable coil, a magnet, and a transformer. After being subjected to acoustic pressure, the vibrating diaphragm begins to vibrate and drives the movable coil installed with it to vibrate in the magnetic field to generate induced current. The current varies according to the magnitude of the acoustic pressure applied to the vibrating diaphragm. The higher the sound pressure, the greater the generated current, and the lower the sound pressure, the smaller the generated current.
1.2 Capacitive microphone is mainly composed of a metal diaphragm and a metal electrode located very close to it, essentially a flat capacitor. The metal film and metal electrode form the two plates of a flat capacitor. When the film is subjected to sound pressure, it deforms, causing a change in the distance between the two plates and thus altering the capacitance. The voltage in the position measurement circuit also changes, achieving the function of converting sound pressure signals into voltage signals. Capacitive microphones are ideal microphones in acoustic measurements, with advantages such as large dynamic range, flat frequency response, high sensitivity, and good stability in general measurement environments, making them widely used. Due to the high output impedance of the condenser microphone, impedance transformation is required through a preamplifier, which is installed inside the sound level meter near the location where the condenser microphone is installed.
2) Amplifier
Generally, two-stage amplifiers are used, namely input amplifiers and output amplifiers, which amplify weak electrical signals. The input attenuator and output attenuator are used to change the attenuation of the input signal and the attenuation of the output signal, so as to make the meter pointer point at the appropriate position. The adjustment range of the attenuator used in the input amplifier is for measuring the low end, and the adjustment range of the attenuator used in the output amplifier is for measuring the high end. Many sound level meters have a high and low end limit of 70dB.
3) Weighted network
In order to simulate the different sensitivities of human auditory perception at different frequencies, a network is installed in the sound level meter that can simulate the auditory characteristics of the human ear and correct the electrical signal to approximate the auditory perception. This network is called a weighted network. The sound pressure level measured through a weighted network is no longer an objective physical quantity of sound pressure level (called linear sound pressure level), but a sound pressure level corrected for auditory perception, called weighted sound level or noise level.
Weighted parameters, also known as weighted parameters, are parameters measured after weighting the frequency response curve to distinguish them from unweighted parameters in a flat frequency response state. For example, signal-to-noise ratio. According to the definition, we measure the noise level (which can be power, voltage, or current) at the rated signal level. The ratio of the rated level to the noise level is the signal-to-noise ratio. If it is a decibel value, we calculate the difference between the two. This is an unweighted signal-to-noise ratio. However, due to the varying perceptual abilities of the human ear towards noise in different frequency bands, it is most sensitive to intermediate frequencies around 3kHz and slightly less sensitive to low and high frequencies. Therefore, disregarding the weighted signal-to-noise ratio may not necessarily match the subjective perception of noise levels by the human ear.
How to unify the measured values with subjective auditory perception? So there was the balanced network, or weighted network, which moderately attenuates both low and high frequencies, making the middle frequency more prominent. By connecting this weighted network between the tested equipment and the measuring instrument, the influence of intermediate frequency noise in the equipment will be "amplified" by the network. In other words, the intermediate frequency noise that has the greatest impact on listening sensation will be given higher weight. The measured signal-to-noise ratio at this time is called weighted signal-to-noise ratio, which can more accurately reflect the subjective listening sensation of humans.
Depending on the weighting network used, they are referred to as A-level B-level and C-level, expressed in units of dB (A), dB (B), and dB (C). A-weighted sound level simulates the frequency characteristics of the human ear to low-intensity noise below 55dB, The B-weighted sound level simulates the frequency characteristics of moderate intensity noise ranging from 55dB to 85dB, The C-weighted sound level simulates the frequency characteristics of high-intensity noise. The main difference among the three is the degree of attenuation of low-frequency components of noise, A attenuates the most, Next to B, C is the least. A-weighted sound level is currently the most widely used type of noise measurement in the world due to its characteristic curve being close to the auditory characteristics of the human ear. Many national regulations related to noise use A-weighted sound level as an indicator. However, due to significant changes in the light curve on which A-weighted sound is based after multiple revisions, the status of A-weighted sound level is gradually declining. Currently, popular weighting standards include NR and NC light standards.
4) Detector and indicator head
The function of a detector is to convert rapidly changing voltage signals into slower changing DC voltage signals. The magnitude of this DC voltage should be proportional to the magnitude of the input signal. According to the measurement requirements, detectors can be divided into peak detectors, average detectors, and root mean square detectors. The peak detector can provide the maximum value within a certain time interval, while the average detector can measure its absolute average value within a certain time interval. Pulse sound requires measurement of its peak value, and in most noise measurements, a root mean square detector is used.
The root mean square detector can square, average, and square root of the AC signal to obtain the root mean square value of the voltage, and then transmit the root mean square voltage signal to the indicator head. At present, the sound level meter used for measuring noise can be divided into four types of meter responses based on sensitivity:
(1) Slow. The header time constant is 1000 ms, usually used to measure steady-state noise, and the measured value is the effective value.
(2) Hurry up. The time constant of the meter head is 125ms, which is generally used to measure unstable noise and transportation noise with large fluctuations. Fast gear approaches the human ear's response to sound.
(3) Pulse or pulse hold. The needle rise time is 35ms and is used to measure pulse noise with longer duration, such as punch presses, hammers, etc. The measured value is the maximum effective value.
(4) Peak holding. The rising time of the meter needle is less than 20ms. It is used to measure pulse sounds with short duration, such as gun, cannon, and explosion sounds. The measured value is the peak value, which is the highest value. LA-3260/LA-3560/LA-3570 noise meter/sound level meter

LA-3260/LA-3560/LA-3570 noise meter/sound level meter