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Topic: Why can bass be heard over a greater distance? (Read 13247 times) previous topic - next topic
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Why can bass be heard over a greater distance?

I dont know a good forum so i put this question here. Most of you have probabely noticed that bass can be heard far better in other rooms and at greater distances then higher frequencies. Can anybody give a scientific explanation for this phenomenon. 

This is especially noticable for my neighbours .

EDIT: i looked at google but i dont know where to look for . (crappy english)

Why can bass be heard over a greater distance?

Reply #2 –
Sound is damped by air, depending on its humidity, temperature, etc. This damping is higher for higher frequencies, low frequencies ( = bass ) have a lower absorption than higher frequencies.

Christian
matroska project admin
http://www.matroska.org

Why can bass be heard over a greater distance?

Reply #4 –
Quote
Does this have anything to do with the fact that the daytime sky scatters blue light (short wavelength, high frequency)?
[a href="index.php?act=findpost&pid=303645"][{POST_SNAPBACK}][/a]

Well, I don't think there's any relation because here we speak about physical wave (that needs air to be spread) whereas light is electromagnetical waves.

Why can bass be heard over a greater distance?

Reply #5 –
Quote
I dont know a good forum so i put this question here. Most of you have probabely noticed that bass can be heard far better in other rooms and at greater distances then higher frequencies. Can anybody give a scientific explanation for this phenomenon. 

This is especially noticable for my neighbours .

EDIT: i looked at google but i dont know where to look for . (crappy english)
[a href="index.php?act=findpost&pid=303215"][{POST_SNAPBACK}][/a]


In the case of sound (I'm probably wrong  ) The lower frequencies of sound refracts around objects like houses and resonates large surface areas like walls. This is why thunder can be herd from a long way off. I have read that the longer hairs in the inner ear are more durable then the short hair that pick up high sounds so the Bass sounds can be picked up through out peoples life more than high sounds. Also maybe our brains focus on low sounds are earthquakes, thunder, volcanoes, avalanches, land slides, Tsumamies as these are natural.


With Electromagnetic wave like radio waves...
LW radio 150Khz to 300Khz is not absorbed by the air much and refracts around objects that get in the way.

MW and SW ~500 Khz to 30Mhz is not absorbed by the air much and can bounce of the ionosphere.

FM (VHF) and  TV (UHF)  87.5Mhz to 108Mhz (I don't know the range for UHF) get reflected of objects containing metal. Only line of site reception is possible.

Microwaves 2450Mhz, This frequency gets absorbed by Water. (This is why food gets warm)

As the radio spectrum gets very high the air gets more opaque, more so if at is humid.


[span style='font-size:8pt;line-height:100%']Apologies for my spelling and grammer. [/span]
Death is the one thing we all face

Why can bass be heard over a greater distance?

Reply #6 –
Quote
I have read that the longer hairs in the inner ear are more durable then the short hair that pick up high sounds so the Bass sounds can be picked up through out peaples life more than high sounds. Also maybe our brains focus on low sounds are eathquakes, thunder, volcanos, averlanches, land slides, Tsumamies as thes are natural.
[a href="index.php?act=findpost&pid=303665"][{POST_SNAPBACK}][/a]

The human ear is much more sensitive to mid frequencies than low ones. While the shape of the curve changes as we age (to more comparitive sensitivity to lower frequencies) we are always more sensitive to midrange. I also think it is unlikely that better low frequency hearing would have an evolutionary advantage for the reasons you mentioned. Natural disasters are hardly a blip on the radar of dangers to humans.

Why can bass be heard over a greater distance?

Reply #7 –
Quote
Microwaves 2450Mhz, This frequency gets aborbed by Water. (This is why food gets warm)

This is actualy a popular misconception. Here's some crazy stuff about microwaves.

oops, yeah its not wrong what you said, but leads to the misunderstanding. Its a fun page anyway.. OT
no conscience > no custom

Why can bass be heard over a greater distance?

Reply #8 –
Quote
The human ear is much more sensitive to mid frequencies than low ones. While the shape of the curve changes as we age (to more comparitive sensitivity to lower frequencies) we are always more sensitive to midrange. I also think it is unlikely that better low frequency hearing would have an evolutionary advantage for the reasons you mentioned. Natural disasters are hardly a blip on the radar of dangers to humans.
[a href="index.php?act=findpost&pid=303666"][{POST_SNAPBACK}][/a]


I see, I dont think they are on a radar now but maybe 1000 or more years ago when we were not sheilded by technology. It seems that humans do not carry good natural sense as natural selection has been killed in the Human race by technology and now things like cloning.
Death is the one thing we all face

Why can bass be heard over a greater distance?

Reply #9 –
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Here's some crazy stuff about microwaves.
[a href="index.php?act=findpost&pid=303667"][{POST_SNAPBACK}][/a]


That was a good read , thank you. I have tried the arcs in my Microwave a few years ago. 

Johny5 Apologies for being alittle off topic.

Death is the one thing we all face

Why can bass be heard over a greater distance?

Reply #10 –
Heh,I havent tried myself -a bit wary of those 'plasmoids pervading the domain' and the huge voltages involved (not safe for my jackass attitude)

About the low sound frequencies travelling better, the article Sebastian quoted suggests low frequency waves travel through panels better because the arcs of the sound waves fronts dont interfer as much along the straight surface - but wheres the difference if the surface is arced to fit the sound waves, or is far enough away for the waves to be quite parallel?
I guess higher frequencies have to accelerate and deccelerate a bend or shift in physical barriers more powerfuly than low frequency waves of similar amplitude to carry themselves through, and that power is absorbed more readily by the less elastic material. But it is rather fuzzy in my head. As for the foghorn curving round the earth rather than floating off into the ionosphere Ive no clue at all.
no conscience > no custom

Why can bass be heard over a greater distance?

Reply #11 –
Quote
Its a fun page anyway.. OT


My question was actually kind off serious,  but with all the responce you wont hear me complain if it is going a little OT 

Why can bass be heard over a greater distance?

Reply #12 –
Low frequencies travel farther because absorption rate is proportional to frequency.  High frequency decays much quicker since the relationship is exponential. However, the loss of sound in free air is not the most significant effect.

Also there is a relationship between the wavelength and objects that can scatter the sound.  For example 50 Hz using 344 m/s as the velocity of sound is 7 meters.  So objects have to be on the order of 7 meters or more to really reflect these long wavelengths.  For the upper frequencies like 10 kHz the wavelength is 0.03 meters or 3 cm.  Things bigger than 3 cm will really scatter the 10kHz sound.  There are a lot more 3 cm objects between you and your neighbors than there are 7-meter objects.

Water gets hot from microwaves due to a resonance of the tumbling frequency of water molecules and the frequency of the microwaves.  There is no relationship with this and the question.

The sky is blue because the wavelength of blue light is less than nitrogen and oxygen molecules that make up the air.  Red light is about twice as long and is not scattered as efficiently.  This is similar to the effect I mention in paragraph 2.  So they are similar.

Light is a wave in the electromagnetic field and sound is a pressure wave in the air, but they are both wave phenomena.

Why can bass be heard over a greater distance?

Reply #13 –
Since I'm not the first to divurge from the topic, I'll point out that last week's MythBuster's show was exploring a rumour about the use of subsonic sounds as a weapon.

They had a bank of subwoofers and then had a guy stand in the middle with ear protection to protect his eardrums. They cranked up 130 db at the spot he stood and varied from 20 - 100 hz.

No, he didn't toss his cookies or go insane or anything. Of course, letting oneself be subjected to 130 db on purpose may have precluded him as a good test for sanity...

'reminded me of the time we got my subs tuned (with a sine wave generator) to the resonant freq of a wall in our dorm. The whole building was vibrating - we were on the third floor, and the walls in the lobby were shaking. And yes, pictures did fall off of my neighbor's walls (but he was in on it).

Subwoofers aren't *just* for walking dinosaurs in Jurassic Park.

Mark

Why can bass be heard over a greater distance?

Reply #14 –
Quote
Since I'm not the first to divurge from the topic, I'll point out that last week's MythBuster's show was exploring a rumour about the use of subsonic sounds as a weapon.
....

An ecowarrior friend of mine proudly recalled a story of a road protest camp he was at which was nearing eviction when the KLF turned up (the ancients of mu mu) with a truck carrying something described as a 'military sound weapon' which they said they got at an army surplus auction. There was apperently serious concern about the effect of the device within the containing authorities and the protesters were apprehensive about what to do with it. In the end they used it to blast the cops and balifs with Frank Sinatras Greatest Hits -but there were no casualties.

I think I read one of the early electrical pioneers - Telsa or Faraday or ? had a vibrating machine that was extremely pleasurable to stand on but could cause involuntary evacuation of the bowels.
no conscience > no custom

Why can bass be heard over a greater distance?

Reply #15 –
i thought it is also about the fact that we can 'hear' bass with the spline as well? (not that i can google out the support for that right now..)
PANIC: CPU 1: Cache Error (unrecoverable - dcache data) Eframe = 0x90000000208cf3b8
NOTICE - cpu 0 didn't dump TLB, may be hung

Why can bass be heard over a greater distance?

Reply #16 –
Quote
Low frequencies travel farther because absorption rate is proportional to frequency.  High frequency decays much quicker since the relationship is exponential.


Could you please give the formula for this, i am searching for this relationship but i cant find it on google.

Why can bass be heard over a greater distance?

Reply #17 –
Quote
Quote
Low frequencies travel farther because absorption rate is proportional to frequency.  High frequency decays much quicker since the relationship is exponential.


Could you please give the formula for this, i am searching for this relationship but i cant find it on google.
[{POST_SNAPBACK}][/a]

Perhaps the following link can help you further:
[a href="http://hyperphysics.phy-astr.gsu.edu/hbase/acoustic/revmod.html]Air absorption etc[/url]

Why can bass be heard over a greater distance?

Reply #19 –
Thank you all, i was really curious about this, and you really helped me out here

Why can bass be heard over a greater distance?

Reply #20 –
Quote
There was apperently serious concern about the effect of the device within the containing authorities and the protesters were apprehensive about what to do with it. In the end they used it to blast the cops and balifs with Frank Sinatras Greatest Hits -but there were no casualties.

There have been a few reports of lung collaps (Pneumothorax) after exposure to loud bass (disco, car, concert).
http://www.wired.com/news/medtech/0,1286,6...tw=wn_tophead_8
edit: another link: http://news.bbc.co.uk/2/hi/health/3614180.stm

Why can bass be heard over a greater distance?

Reply #21 –
I'll know to look out for that 

I havent noticed feeling sound in my spine - maybe an earthquake would do that, with rumbles coming up through the feet. I feel the whack of Drums and vibes of Bagpipes in my chest alright- feels great'
no conscience > no custom

Why can bass be heard over a greater distance?

Reply #23 –
Quote
All I know is that there is no way I'm letting my wife see those articles!

Mark

Why, are you one of those persons with a "BURP" button in the car?  Anyway, we are talking extreme exposure here and your wife doesn't fall into the "slender males < 40 years" risk group. Allthough I don't know how they came up with that since the data is extremely sparse (the article in "Thorax" discusses only 4 cases). Perhaps you don't see many slender > 40 year old males go clubbing these days so you get a skewed statistic.

Why can bass be heard over a greater distance?

Reply #24 –
Urban legends aside 

I found a good scientific discussion of sound attenuation

http://www.sfu.ca/sonic-studio/handbook/So...ropagation.html

The attenuation of sound in free air is not significant.

Perhaps most telling of all is the following table http://www.sfu.ca/sonic-studio/handbook/Ab...oefficient.html.  The absorption of sound on various surfaces is generally higher at higher frequencies.