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Why is noise louder at night?

abdo123

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I remember setting my amplifier's gain to 75 dBSPL @ -30 dBFS during the day and there was no sign of hiss at the listening position.

few days later at night the hiss was so glaringly obvious I was completely bamboozled.

is it biological or is it the ambient noise of room going down at night?
 
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tomtoo

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Usually ambient noise gets down at night.

And then the ear is like a hunter. Once sniffed the pray, all attention goes to it.

So i would gues, both effects are true.
Maybe you can test it? Maybe you can even hear now the hiss at daytime?
 

ZolaIII

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If it's there it's there, environmental noise will differ but still shouldn't be to the huge difference. On the other hand given your listening habit regarding listening (quiter) preference difference can really be a night and day when you gain 15 dB range or such (on 35~40 to 50).
 
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abdo123

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If it's there it's there, environmental noise will differ but still shouldn't be to the huge difference. On the other hand given your listening habit regarding listening (quiter) preference difference can really be a night and day when you gain 15 dB range or such (on 35~40 to 50).

my volume control is digital so like you said 'If it's there it's there', noise doesn't change with my listening habits.

So you haven't really answered my question to be honest.
 

ZolaIII

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my volume control is digital so like you said 'If it's there it's there', noise doesn't change with my listening habits.

So you haven't really answered my question to be honest.
You listen on rather moderate quieter levels two steps above usual conversation lv (60 to 75 dB or again 15 dB). Get something to measure environmental noise and difference and answer it yourself even smartphone will do (tho not much of them with even half deacent mics), otherwise I can guess only. 15 dB is a lot especially on lo base.
 

restorer-john

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Night time listening for me is where it is at. We have no noise, at all, where we are at night. Virtually no cars, trucks, neighbours, dogs barking, just nothing. The house is silent and if there is no wind, your ears just "rush" like an automatic gain control on a recorder.

Hiss will leap out at you from across the room. Channel balance issues stand out like the proverbial dog's b#lls. During the day, not so much. The overall base level of "life" masks it.

Ask @amirm about masking thresholds and urban/domestic noise- I bet he has some really useful knowledge/expertise in that area.
 
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abdo123

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Night time listening for me is where it is at. We have no noise, at all, where we are at night. Virtually no cars, trucks, neighbours, dogs barking, just nothing.

Hiss will leap out at you from across the room. Channel balance issues stand out like the proverbial dog's b#lls. During the day, not so much. The overall base level of "life" masks it.

Ask @amirm about masking thresholds and urban/domestic noise- I bet he has some really useful knowledge/expertise in that area.

it was insane, even with all the windows closed during the day the hiss was inaudible 1 meter away from the speakers. At night 4 meters away from the speakers and it was hissing like small powered computer speakers from the 90s.
 

Frank Dernie

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I remember setting my amplifier's gain to 75 dB @ -30 dBFS during the day and there was no sign of hiss at the listening position.

few days later at night the hiss was so glaringly obvious I was completely bamboozled.

is it biological or is it the ambient noise of room going down at night?
Back in the early 1970s when I was doing noise and vibration research and both instrumentation and the knowledge of how to use it was very rare I was asked to measure the noise level in the bedroom of a couple who were complaining about the level of noise being created by the night shift of an engineering unit on a nearby small industrial estate (which ironically they owned!).
I took all my kit and set it up in the bedroom and whilst I could agree it was an irritating noise it really wasn't loud at all, at the limit of my B&K meter.
The reality there was the background noise was very low at night and the irritating noise was the single tone of a lathe cutting hard steel. It was around 600Hz iirc and I wouldn't have liked to try to sleep through it but the actual level was so low there was nothing effective that could be done about it.
 

Propheticus

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Back in the early 1970s when I was doing noise and vibration research and both instrumentation and the knowledge of how to use it was very rare I was asked to measure the noise level in the bedroom of a couple who were complaining about the level of noise being created by the night shift of an engineering unit on a nearby small industrial estate (which ironically they owned!).
I took all my kit and set it up in the bedroom and whilst I could agree it was an irritating noise it really wasn't loud at all, at the limit of my B&K meter.
The reality there was the background noise was very low at night and the irritating noise was the single tone of a lathe cutting hard steel. It was around 600Hz iirc and I wouldn't have liked to try to sleep through it but the actual level was so low there was nothing effective that could be done about it.

In offices they sometimes install white/grey noise generators. These literally raise the noise level to mask other annoying sounds like AC.
 

Thomas_A

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-Why is noise louder at night?

-Because noise is lower at night.

(Sorry couldn't resist. :))
 

Koeitje

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Ambient for sure, but there also might be some biological effect at play.
 

milotrain

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This is not what's going on but I always noticed that distant traffic was louder at night and pre dawn. Then I realized it was much louder right before a rain. Humid air carries sound further.
 

Propheticus

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Related: https://www.sweetwater.com/insync/effects-of-temperature-humidity-live-sound/

But as Wikipedia would say "citation needed".
From the psychics I remember the statements about refraction and air density make sense.

Found a calculator on sengpielaudio.com/calculator-airpressure.htm
Which does reference sources. It also has a graph showing levels of attenuation for different frequencies at different relative humidity%. Indeed higher humidity attenuates less, with the most significant differences at higher frequencies.

Edit
Found a citation: figure 5 in "Environmental Effects on the Speed of Sound", Dennis A. Bohn, published 1988, Journal of The Audio Engineering Society corpus.id: 18639998

Edit 2:
ISO standard 9613-1 "Acoustics - Attenuation of sound during propagation outdoors - part 1: Calculation of the absorption of sound by the atmosphere" (1993, reviewed and confirmed 2021)
The standard costs more than €100 but is referenced in several articles of which the figures can be easily found.
 
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egellings

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Ambient noise is likely lower at night, so a noise source will stick out like a sore thumb more under those conditions.
 

Marmus

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Several years ago I did some testing over a three year period of electrical noise in an urban environment. Used both a magnetometer that could resolve 10microT and an antenna system I could pick up light switching g in nearby homes. Purpose was to discriminate meteor plasma trail reflections of FM signals but I had to first identify the signals I was receiving on a log periodic antenna pair tuned to about 93kHz.
All noise clearly subsided in the late evening and picked up again about 5am. Every day. Same with the magnetometer but only as applied to the magnetic field. Also noted that audio sounds ready ed dramatically at night but was not measuring thAt. That was meteor tracking but I also found I enjoyed music much more after 12 too. Just some thoughts on ambient noise levels at night.
 

Marmus

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Several years ago I did some testing over a three year period of electrical noise in an urban environment. Used both a magnetometer that could resolve 10microT and an antenna system I could pick up light switching g in nearby homes. Purpose was to discriminate meteor plasma trail reflections of FM signals but I had to first identify the signals I was receiving on a log periodic antenna pair tuned to about 93kHz.
All noise clearly subsided in the late evening and picked up again about 5am. Every day. Same with the magnetometer but only as applied to the magnetic field. Also noted that audio sounds ready ed dramatically at night but was not measuring thAt. That was meteor tracking but I also found I enjoyed music much more after 12 too. Just some thoughts on ambient noise levels at night.
That was tuned to 93MHZ and resolving audio level noise.
 

Andretti60

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This is not what's going on but I always noticed that distant traffic was louder at night and pre dawn. Then I realized it was much louder right before a rain. Humid air carries sound further.
It depends also on the direction of the wind, that changes during the day especially if you live close the ocean. I live close to a highway bridge with a high volume of traffic, that I can clearly hear it is in the morning, but not in the evening.

 
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