December 6th, 2017

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.

If any of these sounds have been of help, and you are feeling charitable, please do consider donating to Freesound to help keep the site running (a link is also on the home page). Any donations are greatly appreciated!

YOU ALWAYS HAVE TO CREDIT/ATTRIBUTE me (klankbeeld) and freesound.org in your work if you use this sound.
Please do it like this if possible: https://freesound.org/people/klankbeeld/
Thank you.
This sound may NOT be used in (royalty free) stock material. Don't put my raw sounds/files on youtube or anywhere else. You can use them in creative way as a part of art-form, but not "re-distribute" as (royalty free) stock material. Thank you.


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    gis_sweden 4 days, 9 hours ago


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