High frequency noise

The emergency declaration was lifted all over Japan, and social activities are beginning to resume.

I was annoying the noise came in the back alley about 30 m away, it seemed the asphalt cutter that the pavement was being peeled off.

I moved to the window and measured it using the high frequency noise detection app, " Mosquitone Detector ".


In detection mode, the maximum noise level was 61.4 dB at 8-16 kHz, which was not so big level.


The noise level was even lower at 16-23kHz. This was because the amount of attenuation due to distance was more larger in the high frequency range.


In search mode, it was simply showing the direction of the window.

The construction work seemed to be completed in 20-30 minutes. The noise was annoying sound, so I was relieved to stop it in a short time.
posted by toons at 10:28 | Environmental noise


COVID-19 activity restriction stress and noise problems.

With the COVID-19 pandemic, we spend a lot of time at home.
At the same time, it seems that noise troubles are occurring frequently. In Tokyo, the number of cases of noise disputes in March and April increased by nearly 30% compared to last year.

There is annoying noise around my house now. The renovation work in the neighborhood has resumed, and the noise is becoming extremely loud.


I felt noises as a fairly low frequency, so I investigated what kind of noise is present there by using " Low Frequency Detector " app.

As a result, many low frequency noises were clearly detected in the frequency range of 20Hz to 110Hz.

I will keep this noise data as evidence to prepare for future problems.
posted by toons at 12:33 | Environmental noise


COVID-19 vs. Noises in living environment

The declaration of emergency due to COVID-19 has been extended until the end of May.

Feel like the tunnel with no visible exit, or rather, it may be lost the way myself in a deep forest with no map and no compass.

Currently, our fight against the new coronavirus is left to the actions of the individual.

However, due to self-restraint in social activities, the time spent at home is greatly increased, and our various stresses tend to accumulate.

Now the problem of noises in the living environment may become apparent.

The sensitivity of noise varies greatly from person to person, so we have no choice but to find the source of the noise and find a solution.

Knowing the noise situation in yourself and at home will help you to deal with outside noises as well.

So introduce our app that supports such living environment sound problems. There are also free editions, so please feel free to try them.

icon-sla_v300.png "Sound Level Analyzer"

"Sound Level Analyzer" is a standard sound level measurement app with sound frequency analysis tools.
It can display automatically the instantaneous sound level such as environmental noise, specific sound sources, live sounds in real-time.
In addition, the high-end app "Sound Level Analyzer PRO" has more powerful noise analysis function. " Sound Level Analyzer Lite " is also provided free of charge !

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icon-lfd_v100.png Low Frequency Detector

"Low Frequency Detector" is a new acoustic measurement tool for detecting low frequency noises that is hard to hear in the normal situation. It supports very lower frequency range less than 100Hz.

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icon-mtd_v100.png Mosquitone Detector

Mosquitone Detector" is a sound measurement app that detects high-frequency noises and ultrasonic sounds hard to hear for human ears. It may have been exposed to artificial high-frequency noise while you do not notice. It can detect and visualize such high-frequency noises.

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icon-vs_v300.png Vibroscope

"Vibroscope" is a new analysis tool for analyzing vibration by using the iPhone's acceleration sensor in real-time. It allows you to monitor by visualizing the low-frequency vibration, such as inaudible by ear. "Vibroscope Lite" is also provided free of charge !

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posted by toons at 03:05 | Environmental noise


Got FoodSaver FM2000! - its noise level?


As a new kitchen tool, I got the vacuum packer “FoodSaver FM2000”.

I've wanted this tool since purchasing the low temperature cooker “Boniq”.

There are various manufacturers of vacuum packers, and their performance and price are very different. In the past, I used a semiconductor vacuum device, so I know how it works. But the consumer products is proved to be incomparable to expensive professional products with vacuum chambers. For the time being, I decided to choose a product that seems to be reasonably durable next to performance.

I finally selected FoodSaver's “FM2000”. FoodSaver has the US No.1 share, but it seems that the cost performance is not so good because a special pack is required.


This product has a lot of accessories such as handy sealer, vacuum fresh box, special pack roll, bottle stopper, etc., so it is quite profitable.

“FM2000” is designed to perform vacuuming and sealing automatically, so it may be packed with air remaining due to malfunction of the pressure sensor.

In fact, I think that the manual method that can perform vacuuming and sealing by separate operations is more certain.

Ay first, I tried to make rice into a vacuum pack to check the packingoperation of FM2000.


The important point of FoodSaver products is to set the rough side inside the original pack roll to the lower side. On the other hand, it seems that vacuuming process tends to fail.



The rice vacuum packed in a tick has been successfully completed.

There are rumors that the vacuum packer is quite annoying and cannot be used at night, so I tried to measure the noise level during vacuuming.

I use the sound level meter app " Sound Level Analyzer PRO" that was measured at a distance of 30cm from "FM2000".

foodsaver-MF2000-sla.jpg foodsaver-MF2000-sla-tc.jpg

According to this measurement result, the maximum noise level during vacuuming with FM2000 was 68.7dBA, and the average of 10 seconds at the last vacuuming was 65.4dBA.

As the degree of vacuum increases during the vacuuming process, the noise level gradually increases. But it turned out to be much quieter than I had imagined in advance.

Looking at the results of statistical analysis, the noise level with higher occurrence is 62 dB, which can be said to be steady noise during vacuuming.


Furthermore, looking at the frequency analysis results when the noise level is maximum, it seems that the main component of the noise is around 500-1000Hz.

Since there is no peak at a specific frequency, there is no harshness in the sense of hearing. Unless midnight, FM2000 seems to be usable normally.


I would like to use it for frozen storage of food, but the special pack is quite expensive, so I need to search a cheap alternative. Well, FoodSaver products are major, so the SNS reviews will be very helpful.
posted by toons at 17:50 | Environmental noise


Uncovering the fact of "Mouse Repeller" with the high-frequency noise detection app "Mosquitone Detector"!


"Mouse Repeller" - a dubious electronic device that is generated an ultrasonic disliked by the mouse.

I found this device installed in my friend's house!
Even though he has no effect at all, he seems to have continued using it for a long time.
In addition to ultrasonic, both electromagnetic waves and ions are also generated, so it was advertised that would repel the mouse.
In fact, it is generally evaluated as a fake product with no scientific basis.

Therefore, I examined what type of ultrasonic which this device is emitting with our high-frequency noise detection app, "Mosquitone Detector".


This device was output at a high-frequency noise of 22.1 kHz and very large volume of 94.1 dB.
Although the audible range of a general person is exceeded, it may be heard as a very unpleasant noise to a person with high hearing ability and an infant.
As expected, it may cause hearing impairment when listening closely to this high-frequency noise.


I asked him to remove this device immediately and never use it again.

There are a lot of such scientifically unfounded goods in the world. We should be careful not to use these fake products that appeal pseudoscience because we may pay wasteful money and create secondary damage.

posted by toons at 01:43 | Environmental noise


About environmental noise level and unit.

The sound transmitted through the air is a minute pressure fluctuation centered on the atmospheric pressure. The effective value of the variation component is called sound pressure, and the unit is Pascal (Pa).

The range of sound intensity that human beings can feel is very large, and it has a large fluctuation width of 100,000 times from 20 uPa to 20 Pa. Therefore, in order to quantify the physical size of the sound, the ratio to the minimum reference sound pressure (static pressure) is taken and its common logarithm is displayed as the sound pressure level (dB: decibel).

In the noise measurement field, the level (A characteristic sound pressure level) corrected by the frequency weight characteristic determined based on human auditory characteristics is mainly used as the noise level. Because this A characteristic matches audibility sensitivity, low frequency below 200 Hz is hardly reflected in sound pressure level.

Examples of environmental noise and the level of noise level are shown below.

130dB : Engine sound of Airplane
110dB : Horn of Car
100dB : Noise of passing train
90dB : In loud factory
80dB : In the train, Vacuum cleaner
70dB : Noisy office, Noisy street
60dB : Quiet Car, Normal conversation
50dB : Quiet office
40dB : In the library, Quiet residential area
30dB : Outskirts of midnight, Whisper
20dB : Sounds of rubbing leaves

The above can be measured as A characteristic noise level (dBA) by our application "Sound Level Analyzer PRO". However, please note that the explosion sound like aircraft jet engine sound is beyond the limit of built-in microphone measurement.

posted by toons at 18:11 | Environmental noise


Example of FFT measurement for low frequency noise using "Low Frequency Detector" app.

Example of FFT measurement for low frequency noise using "Low Frequency Detector" app. It jumps to the app support page by clicking the below image.


posted by toons at 19:53 | Environmental noise

Example 1 of "Low Frequency Detector" measurement.

Example of 1/3 octave-band measurement for low frequency noise using "Low Frequency Detector" app. It jumps to the app support page by clicking the below image.


posted by toons at 19:44 | Environmental noise