pump-noise apartment.wav

A sound-study.

A new central (industrial) heating installation has been installed in the apartment complex in which I live. a friend of mine lives diagonally under the boiler room. He complained to me that he could not sleep because of the noise at night.

0-5 seconds Bedroom friend
5-10 seconds Bedroom me
10-15 seconds Living room friend
15-20 seconds Living room me

I live 100 meters away in the complex.
I have taken measurements.

In this file of 20 seconds you can hear and see the results.

Because noise is a subjective experience, we have opted for a difference / reference measurement. You hear and see the difference in noise from both houses. We look for the striking differences in Level and Frequency values.
As a sound example, an audio file has been created with intervals of 5 seconds. Alternately friend and me.
The level settings of the equipment and the location and height of the microphones are exactly the same in both cases.
There is a difference of both rooms measured because that can say something about the experience of sound.

Experience sound

note: (The loudness perceived by the human ear does not go the same with the exact size as the sound level.) Thus, a subjective doubling of the loudness appears to correspond with an increase of the sound level by 3 dB, so by a factor of 3 for the intensity. See a graph for db (A): https://nl.wikipedia.org/wiki/DB(A) )

The pump makes a noise at about 870 Hz. with my friend I measure a level of -21 dB. for me that is -38 dB.
The low-frequency noise (<200Hz) is -16 dB for my boyfriend and -23 dB for me.
In dB (A) weight, low-frequency noise is approximately 10 dB less annoying than the pump noise.

After correction the pump noise is -11 dB compared to the low-frequency noise of -16 dB.

My friend experiences the pump noise about 3 times harder than the low-frequency noise.

Conclusion; No wonder he is not sleeping well after installing the new heating system.

Used equipment;
Sennheiser MKH30 and MKH50 in MS Mid-side setting.
Sound Devices 302 pro field mixer
Tascam dr-100 Mk2 recorder (set: 48 kHz / 24 bit)
Sennheiser HD 25 - 70 Ohm headphones.
All equipment has a flat frequency characteristic.
Recording decoded in Audacity from Mid-side to STEREO to get a good impression of the sound experience.

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