Will Greenies Kill Bass

by Bite on Wed Apr 28, 2010 9:14 pm

I extracted this from the Harbeth site. Some interesting reading. A PROTON speaker for the tropics?

All loudspeakers from all manufacturers are designed at and with a target operational temperature in mind. By convention, this is 20 degrees C, which is universally deemed to be the ideal temperature for human comfort: neither too cold nor too hot: just right. So what? Well, 30 degrees C is a +50% rise on the target operating temperature (which would be, say 18-20 degrees = 20 degrees +/- 10%) and this has a dramatic effect on the molecules within the drive units - specifically in the plastic cones and the rubber surround. It does not effect the steel magnet parts.

Rubber is an extremely temperature sensitive material. You know that from playing with BlueTak or chewing gum or a squash ball. When it heats up it become much more elastic and that increase in elasticity even over the 20>30 degree range has a marked effect on the bass unit's rubber surround. Its throw increases, control, damping and Q all degrade. So all the Thiele-Small parameters that have been carefully calculated to give a nice smooth, tight bass at 20 degrees C are completely screwed by the temperature rise. So, when the temperature is elevated as high as 30 degrees, the bass will be softer, flabby and there will be a lot more of it.

Strange things happen to the molecules inside the cone too at elevated temperatures. When plastic materials are formulated the chemists have in mind a target operating temperature, somewhere between the plastics' hard and rubbery phases. For all typical bass/mid plastic cone materials (including RADIAL) if the temperature is substantially elevated above target, the acoustic damping characteristics of the cone change - the 'air' dries out around instruments, and the sparkle is lost as the clarity in the presence band diminishes. In short, the excess heat makes the plastic material of the cones behave in a more rubbery way, and as we know, rubber has good damping properties. So that over-damps the transient detail in the sound.

I would add, that this temperature sensitivity makes it virtually impossible to undertake highly critical design loudspeakers in the UK during the winter when the ambient temperature is around 5 degrees C. At these low temperatures, the bass unit's rubber surround tightens up and it is easy to underestimate the bass output of the system. Very dangerous if the customer's listening temperature is much higher.

Rubber and plastics have completely reversible temperature characteristics, so once the temperature is returned to 20 degrees C, all will be well again.

Conclusion:

So taken together, the significantly elevated room temperature will .....

A. Give much more bass, less controlled and slower bass ...
B. Reduce clarity and detail in the presence band.

For critical listening, listen within a range of about 18-22 degrees and note that hifi demo rooms are normally set at this cool, shirt-sleeve temperature.

by **drife** on Wed Apr 28, 2010 9:21 pm

ok. i might just A/B one hot afternoon. this might further increase aircon sales. especially the high current low noise ones : )

by **drife** on Wed Apr 28, 2010 9:23 pm

i bet we've seen some warped tannoy driver surrounds online : )

by hughesths on Wed Apr 28, 2010 9:32 pm

I experienced this room temperature which affects sound quality 10 + years ago :

When I listened to my hifi system without switching on the air-con, the overall sound was warmer, less controlled and muddier bass, imaging and pin point were not that good, and background was noisier.
With air-con temp set at 25-26 degree, overall sound was more controlled, better imaging, bass was tighter, and background was quieter.

I thought it was due to the density of the air caused by difference in ambient temperature. Colder the ambient, higher the air density thus sounds more controlled and vice versa. It's like the car engine performance.

by Bite on Wed Apr 28, 2010 9:34 pm

The preamble to the article was....a woman wasnt happy with bass from her system. Temperature in her room was 30 degrees C. The a/c noise interfered with her listening.

Will have to fit an a/c before I can verify, so drife, let us know of your findings.

by Bite on Wed Apr 28, 2010 9:40 pm

I didnt know either but read somewhere moisture in the air improves sound quality. Supposed to sound better after a heavy shower. It went on to say some go to the extent of spraying water in the room before listening. Hate to think of the condition of the equipment.

by **drife** on Wed Apr 28, 2010 9:43 pm

no harm getting an A/C. it sounds better when we're comfortable and relaxed. can't really enjoy the details when we're perspiring.

warm, the system should be, not the listener. haha.

by **drife** on Wed Apr 28, 2010 9:55 pm

during the hot weather streaks after CNY, my friend's in-house thermometer shot up to about 36-37 degrees celsius. and this was a 24X80 (i think) terrace hse in K.Kemuning.

bad for PC and electronics. the humans get temperament too : )

the effect of hifi4sale? too many orders for tank-like mono blocks?

maybe just too many tubes running

by mugenfoo on Wed Apr 28, 2010 11:16 pm

Bite wrote:I didnt know either but read somewhere moisture in the air improves sound quality. Supposed to sound better after a heavy shower. It went on to say some go to the extent of spraying water in the room before listening. Hate to think of the condition of the equipment.

Can you quote the source of this opinion ?
Maybe from some other website or link ?

by mugenfoo on Wed Apr 28, 2010 11:45 pm

hughesths wrote:I experienced this room temperature which affects sound quality 10 + years ago :

When I listened to my hifi system without switching on the air-con, the overall sound was warmer, less controlled and muddier bass, imaging and pin point were not that good, and background was noisier.
With air-con temp set at 25-26 degree, overall sound was more controlled, better imaging, bass was tighter, and background was quieter.

I thought it was due to the density of the air caused by difference in ambient temperature. Colder the ambient, higher the air density thus sounds more controlled and vice versa. It's like the car engine performance.

The analogy with car engine performance is totally not applicable here.

Whilst changes in density of air changes the speed of sound, but this change can be for the better or for worse depending on room factors.So when the ambient temp changes, this means the room's freq nodes will also shift accordingly and therefore different sonic signature.

Internal Combustion engines benefit from higher air density
(and lower temps means denser air) because the oxygen content of denser air is also naturally higher. And
more oxygen (and provided there's also more fuel with the optimum
mixture ratio) in the incoming air charge therefore means more explosive power.

In a nutshell, engines will almost always benefit from denser (colder) air.

But a room's acoustics may not necessarily benefit from denser (colder) air every time depending on the room's dimensions, speaker/wall boundaries, etc etc. If the colder ambient temp is going to shift the room nodal freqs onto some of the musical freqs, the room would be horrible sounding or might have a nasty boom instead (from the cooler ambient temp).

by **drife** on Thu Apr 29, 2010 12:07 am

would the hardcore tweakers here go to the extend of temp-sound tweaking? just a curious question

we already know that there are hardcore cord/cable tweakers. keep the spirit... and please share with us the results. everyone will benefit.

by **drife** on Thu Apr 29, 2010 12:12 am

hey, hugh's actually correct. lower temps = better engine performance.

by mugenfoo on Thu Apr 29, 2010 12:16 am

drife wrote:hey, hugh's actually correct. lower temps = better engine performance.

correct for the engine part, but not for the hifi part, and also not for the same reasons.

by hughesths on Thu Apr 29, 2010 12:18 am

What i was talking about was listening to the same hifi system in the same dedicated hifi room with the only "changes made" was only the room ambient temperature. You'll experience sound quality changed from less controlled, noisier background..the above mentioned sound to a more controlled, tighter bass, quieter background sound just after few minutes - after you get the air-con switched on! The colder you set the temp, the more controlled the overall sound.
Bear in mind that sound needs air particles to transmit, so like the car engine, the density of air would probably affect sound quality too.
Try listen to your hifi system yourself without ,and then with air-con switched on, of any differences made to the overall sound quality. You'll hear the difference.

by mugenfoo on Thu Apr 29, 2010 12:24 am

I've already explained why car engines will almost always benefit from cold air.

Spoiler:: (there are also situations where cold air can really screw up an engine's performance but this would be seriously off topic, nanti kena deleted by the admin like that Type-R thread elsewhere earlier)

However, the cold air "benefit" is not always the case for sound in a listening room, specifically because how the change in air temp changes the speed of sound. And this change in speed of sound can be either more beneficial or more detrimental to the sonic qualities of the listening room. In your case, hughests, it benefited your room. But it cannot be universally applied across board generically.

Hence there is no similarity here in the comparison of sound benefit to engine benefit.

Yes, air density DOES affect sound quality. But not always in a POSITIVE manner. It can also be in a NEGATIVE manner.

by hughesths on Thu Apr 29, 2010 12:31 am

I also don't believe air density affects the sound quality, but previous experiences told me otherwise.
Just a few minutes...after the air-con is switched on, the room "air "( not the room matters and equipments temperature ) temperature drops to just few degree, you instantly hear the difference. The room furnitures, acoustics treatments, floors, walls, ceilings, etc have not yet cooled down by the temp you set ( only the air temperature drops ), but you'll hear the difference already.

by hughesths on Thu Apr 29, 2010 12:37 am

Maybe all of you can experiment this using your own hifi system to see how the ambient air temperature (density )affects the overall sound quality whether in a positive or negative way, then share with us here. Regards.

by **drife** on Thu Apr 29, 2010 12:41 am

interesting. i'll fiddle with the remote control tmrw night. play hifi now have to play with remote pulak. stress.

thanks H

by CT-Boy on Thu Apr 29, 2010 12:47 am

Air density, temperature, humidity, affect sound somewhat.
Whether you can hear it affecting your system is another story...

by **drife** on Thu Apr 29, 2010 12:50 am

then those in the recording studio might notice this too. if the sound engineer was mastering things on a hot summer day with temp-sensitive monitors plus a broken air-con then Muddy Waters will get more muddy, or too clean. haha. just joking...

by mugenfoo on Thu Apr 29, 2010 1:00 am

hughesths wrote:I also don't believe air density affects the sound
quality, but previous experiences told me otherwise.
Just a few
minutes...after the air-con is switched on, the room "air "( not the
room matters and equipments temperature ) temperature drops to just few
degree, you instantly hear the difference. The room furnitures,
acoustics treatments, floors, walls, ceilings, etc have not yet cooled
down by the temp you set ( only the air temperature drops ), but you'll
hear the difference already.

Yes. No one is disagreeing on this. What you experienced is perfectly fine & rational. But just remember that while u experienced a positive effect, it doesn't mean that other scenarios will also always benefit positively from lower ambient temps. This is the point I'm making here.

hughesths wrote:Maybe all of you can experiment this using your own hifi system to see how the ambient air temperature (density )affects the overall sound quality whether in a positive or negative way, then share with us here. Regards.

Now u get the point...

CT-Boy wrote:Air density, temperature, humidity, affect sound
somewhat.
Whether you can hear it affecting your system is another
story...

Great if u can back this statement up with facts ? Pls do share...

by Bite on Thu Apr 29, 2010 9:24 am

Mugen Foo, afraid I cant help you there. Something I came across while researching room acoustics. It wasnt supported or qualified in anyway. Did put it down to change in density but no inclination to verify.

The article posted relates to the effect of temperature on speaker woofers constructed of certain material. Based upon perception alone, for the temperature range mentioned , I am more inclined to think there would be an audible difference from the equipment and less room.

At 30 degrees I wouldnt be able to appreciate the proceedings for long anyway.

by hughesths on Thu Apr 29, 2010 10:07 am

mugenfoo wrote:
Bite wrote:I didnt know either but read somewhere moisture in the air improves sound quality. Supposed to sound better after a heavy shower. It went on to say some go to the extent of spraying water in the room before listening. Hate to think of the condition of the equipment.

Can you quote the source of this opinion ?
Maybe from some other website or link ?

Sound better after a heavy shower.....it is probably something to do with the better grounding condition of the household earthing after such heavy rain....

by hughesths on Thu Apr 29, 2010 10:27 am

mugenfoo wrote:I've already explained why car engines will almost always benefit from cold air.
Spoiler:

(there are also situations where cold air can really screw up an engine's performance but this would be seriously off topic, nanti kena deleted by the admin like that Type-R thread elsewhere earlier)

However, the cold air "benefit" is not always the case for sound in a listening room, specifically because how the change in air temp changes the speed of sound. And this change in speed of sound can be either more beneficial or more detrimental to the sonic qualities of the listening room. In your case, hughests, it benefited your room. But it cannot be universally applied across board generically.

Hence there is no similarity here in the comparison of sound benefit to engine benefit.

Yes, air density DOES affect sound quality. But not always in a POSITIVE manner. It can also be in a NEGATIVE manner.

Although car engine performance benefits always from colder air...there must be a limit of how low the air intake temperature would benefit the car engine performance, there is an optimum air temperature for the best benefit. Temperature below the optimum would also negatively affect the engine performance. Therefore, everything has positive and negative sides, it's relative and all depends on how one looks at it.

Whether the colder air positively or negatively affects the sound quality is all depends on the taste of the listeners, some listeners prefer warm and less controlled bass, so it's considered positive for them and vice versa...

by hughesths on Thu Apr 29, 2010 10:37 am

If it is proven that lower ambient air temperature ( denser air )"positively" affects sound quality, please avoid torturing ( chilling ) yourself by setting the air-con temperature way too low while "enjoying" music.

by mugenfoo on Thu Apr 29, 2010 11:48 am

hughesths wrote:
Although car engine performance benefits always from colder air...there must be a limit of how low the air intake temperature would benefit the car engine performance, there is an optimum air temperature for the best benefit. Temperature below the optimum would also negatively affect the engine performance. Therefore, everything has positive and negative sides, it's relative and all depends on how one looks at it.

Whether the colder air positively or negatively affects the sound quality is all depends on the taste of the listeners, some listeners prefer warm and less controlled bass, so it's considered positive for them and vice versa...

... presuming that do know how an internal engine operates and are familiar with its principles right ... ?

Same goes for acoustics and its relation with air temps also right ?

by hughesths on Thu Apr 29, 2010 12:00 pm

It's the way it should be, i guess. Everything has its limit and optimum condition to perform its best....optimum state that more positive than negative.

by cmboy on Thu Apr 29, 2010 12:22 pm

AFAIK, room air conditioning does reduce humidity to somewhere at 50 to 70% level. Different places here will have different humidity levels amongst other factors that determine one's hifi sound.
Long ago, I experienced a hugely different and satisfying experience when my hifi was somewhere in the highlands at 5000ft above sea level. Brought it back down to KL and it sounded like shyte (simply said). I would want to experiment that again sometime in the near future. Besides, in the highlands, its dead quiet at night, unlike here in urban area.

by hughesths on Thu Apr 29, 2010 12:32 pm

cmboy wrote:AFAIK, room air conditioning does reduce humidity to somewhere at 50 to 70% level. Different places here will have different humidity levels amongst other factors that determine one's hifi sound.
Long ago, I experienced a hugely different and satisfying experience when my hifi was somewhere in the highlands at 5000ft above sea level. Brought it back down to KL and it sounded like shyte (simply said). I would want to experiment that again sometime in the near future. Besides, in the highlands, its dead quiet at night, unlike here in urban area.

There are many variables in your case, the better sound might probably due to better ac quality in the mentioned highlands area where less users compared to KL.

by cmboy on Thu Apr 29, 2010 12:36 pm

hughesths wrote:
There are many variables in your case, the better sound might probably due to better ac quality in the mentioned highlands area where less users compared to KL.

No lah.. I don't think its only that. Its the air and less dense and different atmospheric pressure due to greater heights above sea level thats likely most significant in the role. Perhaps you may like to experiment this in future...why not? lug your hifi for a holiday too.

by hughesths on Thu Apr 29, 2010 12:49 pm

Unless you do the experiment with the same hifi system, same hifi room, same ac quality, same mood...but different ambient air density, temp, pressure or humidity level, then it'll only be considered accurate.

by cmboy on Thu Apr 29, 2010 12:57 pm

You can't possibly have the same room, but same hifi system.
Anyway, whatever I experiment in this direction isn't for research purposes or prove to anyone else I'm right. If the change of air makes my system sing much better or beyond own expectations, I'll feel elated that I've proved myself right and thats what matters most. Cheers!

by zul on Thu Apr 29, 2010 12:59 pm

I am not a rocket scientist but hear my two sen out. Sound travels through air. I can still remember doing an experiment eons ago to prove this. We had an apparatus to create a vacuum and a tuning fork was used. As air is suck out to create a vacuum the sound became softer till nothing was heard as the apparatus created zero air vacuum. To date I am a staunch believer that air density affects sound frequencies.
On another note...take helium gas. it is much lighter than air. If you inhale the gas (don't do this as it can be fatal! but it's fun to do) and start talking, your voice will change. It will effeminate a baritone voice (say Darth Vader). You'll sound like a shrieking young girl. The reason...helium's resonant frequency in your vocal tract changes from the norm. Speed of sound in gases vary. This is a fact and I am not promoting PMC.

Coming back to Earth, there should be some minute effect on sound from your gear as sound emanates from your speaker in a dense humid room as compared to a clean detoxed room. Food for thought for the super tweakers. but at my age hearing above 18 khz is already a problem. Anyway most speaker manufacturers designed their speakers on Earth and not on a planet with 98% helium. LOL! Just my two sen.

by shah zain on Thu Apr 29, 2010 2:19 pm

So is the conclusion we have to listen to hifi in a freezer cold room for better sound, or perhaps on top of Mt Everest?

The things people think about

by Bite on Thu Apr 29, 2010 3:23 pm

Listening on top Mt. Everest, could cause some serious damage to your equipment if you're still alive to bother.

Like Zul cant remember much of my physics. Lets leave aside the original topic of the effects on speakers and resultant sound which is of more interest to me as my speakers have a fair amount of rubber etc. Think the vacumn test affects the sound as the medium of transfer is being removed. May be wrong.

From what I remember temperature and density affects sound. Higher temperature faster sound. Higher density faster sound. If correct then in theory, in hot room sound should travel faster as well as on moist/humid days. Therefore in theory acoustics will be affected, whether perceptible or not I dont know. I seem to think not within our listening room.

Question arising from above. When sound travels slower or faster is there a change in the original frequency assuming same distance and medium? By that I mean do we hear the same sound and then in correct phasing/timing? Hmmm......what distance?

Mugen Foo maybe you can shed some light on the matter in a nice way please.

by teleman51 on Thu Apr 29, 2010 4:08 pm

Yah,

this temperature issue in respect to speakers is spot on.

Malaysian temperatures caused the poly cones on my Rogers
speakers to warp and I had to retire them, as there were
no more replacements available.

No more poly cone speakers for me duh!!!

cheers & shalom
teleman51

by tycham on Thu Apr 29, 2010 4:35 pm

Bite wrote:

Question arising from above. When sound travels slower or faster is there a change in the original frequency assuming same distance and medium? By that I mean do we hear the same sound and then in correct phasing/timing? Hmmm......what distance?

Mugen Foo maybe you can shed some light on the matter in a nice way please.

Yes, you would hear a change in the frequency from the original frequency when sound reaches you faster or slower due to the Doppler's effect. Frequency is wavelength per time.

by cmboy on Thu Apr 29, 2010 4:38 pm

Sad case, which I happen to come across many Rogers speakers (only of a particular model with whitish translucent cones) that seem to exhibit the same complaint. If its happens..might as well shop for another pair of speakers. This kind of phenomenon shouldn't happen, save the rubber surround breaking up too.

by teleman51 on Thu Apr 29, 2010 6:55 pm

Yeah cmboy,

tese were the Rogers LS4/2a.
Saw several units around KL being sold 2nd hand, all
exhibiting the same problem.
They even landed up in cash converters.

Sad ending to a good speaker.

cheers & shalom.
teleman51

by THT89 on Thu Apr 29, 2010 8:07 pm

http://www.jblpro.com/catalog/support/getfile.aspx?docid=275&doctype=3

This is what i read before, tried to understand PA.. Anyway, can see page 1-6 & 1-7...

2 cent from JBL....

by THT89 on Thu Apr 29, 2010 8:32 pm

The Doppler's Effect analogy is not quite correct isn't it? I thought it's like when an ambulance pass by, the sound will shift to the lower frequency, due to the moving vehicle, not due to the speed of the sound.

Sound still travels in 341 m/s (lazy to check, hope it's correct), but the oscillating source changes its position, coz it's moving.

Just like the red shift of stars' spectrum, coz they are moving out from us.. speed of light is still constant (but this constant is not applicable to sound wave, Einstein said only light could, i guess, LOL!).

But i'm not quite sure about effect of change in speed of sound wave.. I only know that sound travel faster in high density material, like what we learned in primary school, when we did experiment of sound on wood + ticking clock...

What is it like when sound wave travels faster?? what do we hear?

by mugenfoo on Thu Apr 29, 2010 10:21 pm

OK, for all of you who have forgotten your college physics (or did not learn them at all coz you did economics, or finance etc etc, which are all also very important and useful subjects)...

Doppler Effect only arises when the source AND the observer are either constantly moving towards or away from each other. Which is the case of the Ambulance going "PEEEPOOOPEEEEPOOOOPEEEEEPOOOOOOPEEEEEEEEEPOOOOOOOOO...."

Totally NOT applicable in a hifi enviro, because the speakers are stationary. The woofers vibrating around its constant axis do not count. The listener is also stationary in your most comfortable listening chair in the sweet spot.

Simple proof, play a 1KHz tone using a test CD or similar. No matter where u are seated around the room, near or far.. the "pitch" of the 1KHz tone doesn't change. Unlike the ambulance what passes u by and u can hear that the pitch of the siren will drop lower when the ambulance is speeding away from you.
(But if u are like Bimmerman who like to drive "cucuk" style and u cucuk the ambulance all the way , ie maintaining the relative same distance throughout the whole journey, the siren's pitch would also stay constant and u wont be hearing any pitch-change coz there's no Doppler effect at work here).

However, on that same experiment, you would hear loud and quiet spots of that 1KHz tone around the room as u move your head position to various spots of the room. And when the ambient temp changes, the location of these "loud" and "soft" spots will also vary around the room. Hence this effect which is due to the speed of sound that has changed with ambient temperature.

I won't go into the math behind it for these reasons:
1) its really hard to type equations with a standard keyboard,
2) Most people might just end up getting more confused, mis-informed and mis-lead. (a little bit of knowledge is a dangerous thing).

For those who truly want to seek to truth (like a famous TV character also said: "The truth is out there"), please go visit MPH, Times or Kinokuniya and pick up a good Acoustics for Dummies or Physics for Dummies series kind of book.

As to the question "What is it like when sound wave travels faster,
what do we hear? "
Answer is : If it was open space and sound reflections are not a factor .. you'll hear ABSOLUTELY NO DIFFERENCE because the pitch of the tone is still the same. A 1KHz tone at 15C ambient temp and a 1KHz tone at 35C ambient temp would still SOUND the SAME to the human ear. The Frequency of that sound DID Not Change.

In the case of an enclosed room with acoustic reflections & reverbs etc etc, the TONE would still sound the SAME, but you'll just hear some weird loud and soft spots around the room due to standing waves and other reflected interferences (what some would call "comb effects" ). But the "PITCH" of that 1KHz would still remain the SAME. Always, Amen.

Spoiler:: For the more physics-inclined, Red-shifting (E = h x f , where E = energy,
f = frequency, h = Planck's constant) in all practical intents and
purposes really DO NOT APPLY to the audible spectrum of sound waves,.
This is more for astronomy and interstellar phsyics in which then its
effects are of any concern. Really. Trust me on this one ok? No mortal
on this planet in the real of audio engineering has ever had to consider
or even had to ever know how Planck's Constant might be of any
relevance because safe to say, the physics of audio engineering and
sound reproduction doesn't even begin to scratch into the realm of
quantum physics... at least for the next foreseeable 100 years or so.
(like said before, a little bit of knowledge is a dangerous thing)

by tycham on Thu Apr 29, 2010 10:55 pm

THT89 wrote:
The Doppler's Effect analogy is not quite correct isn't it? I thought it's like when an ambulance pass by, the sound will shift to the lower frequency, due to the moving vehicle, not due to the speed of the sound.

Sound still travels in 341 m/s (lazy to check, hope it's correct), but the oscillating source changes its position, coz it's moving.

Just like the red shift of stars' spectrum, coz they are moving out from us.. speed of light is still constant (but this constant is not applicable to sound wave, Einstein said only light could, i guess, LOL!).

But i'm not quite sure about effect of change in speed of sound wave.. I only know that sound travel faster in high density material, like what we learned in primary school, when we did experiment of sound on wood + ticking clock...

What is it like when sound wave travels faster?? what do we hear?

It's not the Doppler's effect? Then my bad for misleading the forum. 341m/s is thereabout for the speed of sound.

Maybe a wash-out sound if sound wave travels faster, but like you, I really have no idea.

by mugenfoo on Thu Apr 29, 2010 10:58 pm

tycham wrote:
Yes, you would hear a change in the frequency from the original frequency when sound reaches you faster or slower due to the Doppler's effect. Frequency is wavelength per time.

Wrong.

Frequency is "Cycles (or waves) per time". Not Wavelength. BIG difference here.

Wavelength is the distance taken to complete "one cycle" of the wave or oscillation. hence the term "wave - length"

Wave equation: V = F x L
V = SPEED of the traveling Wave (in a particular medium and its physical conditions)
F = frequency of the wave
L = the physical length of the wave

tycham wrote:
341m/s is thereabout for the speed of sound.

Consider these ambient temps:
at 15 Celcius, speed of sound = 340 metres/sec,
at 25 Celcius, speed of sound = 346 metres/sec,
at 33 Celcius, speed of sound = 351 metres/sec,
at 60 Celcius, you'd probably have other things to worry about than the speed of sound already. But its 366m/s in case you're curious.

Massive differences here.

THT89 wrote:
Just like the red shift of stars' spectrum, coz
they are moving out from us.. speed of light is still constant (but this
constant is not applicable to sound wave, Einstein said only light
could, i guess, LOL!).

What Einstein said of the speed of light being a constant is only within the vacuum of space. Only.

Did u know what the speed of light in the Earth's atmosphere, even more so when passing thru denser mediums like water or even when passing thru that Acrylic platter of that classy and expensive looking Clearaudio turntable is much slower than when Light is zipping all around in the vacuum of space ? Well... now you do !

by sflam on Fri Apr 30, 2010 12:08 am

i am not sure of the effect of the aircon cooling the listening room thus improving the sound.

what i do know is that malaysia's hot and humid climate will result in:

1) foam surrounds rotting away very quickly

2) foam pads in headphones (like my sennheiser 600) 'vanishing' or 'melting' into a sticky mess.

3) the conductors peeling off magneplanars.

4) fungus growing on cds.

5) rust in metal parts like screws, chassis, etc.

by Bite on Fri Apr 30, 2010 9:12 am

Thank you Mugen Foo. That was informative. So is it fair to conclude:

1. regardless density of air, the sound will still sound the same.
2. a 30hz and a 18khz signal would arrive at the same time regardless air density.
2. in higher density sound would not travel as far (if no boundaries).
3. in our rooms there would be no audible difference rain or shine.

Yes sflam, buyers of equipment in international markets take that into consideration i.e equipment from the tropics.

by mugenfoo on Fri Apr 30, 2010 10:07 am

Bite wrote:Thank you Mugen Foo. That was informative. So is it fair to conclude:

1. regardless density of air, the sound will still sound the same.
2. a 30hz and a 18khz signal would arrive at the same time regardless air density.
2. in higher density sound would not travel as far (if no boundaries).
3. in our rooms there would be no audible difference rain or shine.

Yes sflam, buyers of equipment in international markets take that into consideration i.e equipment from the tropics.

1. Depends...
2. yes.
3. Depends...
4. No.

Not so straightforward eh? Wink

by Bite on Fri Apr 30, 2010 10:20 am

Just on the first point. If I read your reply correctly, sound which travels faster or slower sounds the same then it should not make a difference. What other factors could affect the sound? density, pressure, temperature all within the same medium. If we go to extremes of any, would it then affect sound?

by THT89 on Fri Apr 30, 2010 10:23 am

mugenfoo wrote:
As to the question "What is it like when sound wave travels faster,
what do we hear? "
Answer is : If it was open space and sound reflections are not a factor .. you'll hear ABSOLUTELY NO DIFFERENCE because the pitch of the tone is still the same. A 1KHz tone at 15C ambient temp and a 1KHz tone at 35C ambient temp would still SOUND the SAME to the human ear. The Frequency of that sound DID Not Change.

For the more physics-inclined, Red-shifting (E = h x f , where E = energy,
f = frequency, h = Planck's constant) in all practical intents and
purposes really DO NOT APPLY to the audible spectrum of sound waves,.
This is more for astronomy and interstellar phsyics in which then its
effects are of any concern. Really. Trust me on this one ok? No mortal
on this planet in the real of audio engineering has ever had to consider
or even had to ever know how Planck's Constant might be of any
relevance because safe to say, the physics of audio engineering and
sound reproduction doesn't even begin to scratch into the realm of
quantum physics... at least for the next foreseeable 100 years or so.
(like said before, a little bit of knowledge is a dangerous thing)

Sorry, just to explain the doppler, light doesn't need any medium (different), and not intended to explain those crazy stuff, which i don't know.. And, ya, only in vacuum. (Eh, you know damn a lot lar, stretch to modern physics edy, crazy!!)

But the main thing i'm confused is.. If light is to be deflected, will sound be as well? It's not flat in freq response throughout the 360 degree of space right? Then have effect is it?

Then, in different fluid, sound diff as in water.. But it sound clear if via wood? Change in the characteristic of fluid really no effect? Maybe high frequency will damp faster, maybe they loss energy faster due to heavier medium?? moving faster is more energy loss?? But at least the sound will not be damped till have any audible loss/shift in freq response when it reaches our ears, which are quite near? I suddenly confused what's the factor of giving this effect. Sigh...

Ai yah, just use your original room temperature, change the sound characteristic with your gadgets la, it's like sweating while listening or wearing those fluffy shirts, what for...?

How to enjoy?? LOL...

by mugenfoo on Fri Apr 30, 2010 11:51 am

Sound waves are mechanical in nature.
Light waves are electromagnetic in nature.

'Nuff said.