I would like to start a discussion involving how sound works.

[ymalmsteen887]

Actually, the notes in an orchestra have to be tuned pretty well. If they are off then the orchestra produces beats when it plays a sustained note. Case in point:

http://upload.wikimedia.org/wikipedia/commons/6/6f/Terzosuono.ogg

As the two frequencies just start to diverge we can hear the rumble from the beating that occurs. This starts to happen in the first two seconds of the clip.



Yes, and it does. But the transient time here is too minimal for you to notice. Like I said, 343 m/s is very fast and so the first set of reflections comes in milliseconds. This is too fast for us to really consciously appreciate it though our body does make use of this slight delay for things like positional information.

As for going outside, you most definitely should notice a difference. Try talking in a closed room and then go out to an open field. The difference in terms of echos should be night and day.

there's definitley a difference in the way it sounds but no real difference in volume.

I still don't get the whole waves adding up wouldn't my body feel the first wave of pressure and then get more intense as the waves build up this would make the sound really bad.

 

[JaredJames]

Im not saying its it exactly the same but a small high school gym full of people clapping won't sound any louder or quiter than a basketball stadium because its all relative to your position.

Not true. It's all about acoustics. One person clapping in a gym sounds different to one person clapping in a stadium.

Read here: http://en.wikipedia.org/wiki/Acoustics

Basically if that logic was true than all the sounds happening anywhere would add together , after a certain distance the waves don't seem to matter anymore

I gave you the links to intensity and energy. You need to read them and ensure you understand them. They explain why waves only travel so far before they "don't matter".

actually just one person clapping is preety much how loud it gets the combination of people clapping just gives a more lively sound.

More people clapping gives the perception of more loudness. Again, acoustics.

This is like saying 5 speakers give the same volume as 1 speaker. Although the sound system may show them giving the same output, the actual perceived volume will be louder. (Think of the difference between 2.1 and 5.1 surround sound systems.)

The same reason why there are mulitple violins in an orchestra to give that unison sound because the notes arent tuned perfectly the same.

As above, more violins will give you more volume - but it's not a case of doubling the volume as you double the number of violins.

 

[ymalmsteen887]

Not true. It's all about acoustics. One person clapping in a gym sounds different to one person clapping in a stadium.

Read here: http://en.wikipedia.org/wiki/Acoustics


I gave you the links to intensity and energy. You need to read them and ensure you understand them. They explain why waves only travel so far before they "don't matter".


More people clapping gives the perception of more loudness. Again, acoustics.

This is like saying 5 speakers give the same volume as 1 speaker. Although the sound system may show them giving the same output, the actual perceived volume will be louder. (Think of the difference between 2.1 and 5.1 surround sound systems.)


As above, more violins will give you more volume - but it's not a case of doubling the volume as you double the number of violins.

Wait a minute you just said that waves travel so far before they don't matter so you understand what I mean by the extra people want make it louder, the people 500 feet away in the stadium arent going to contribute to the overall volume of the people near you. I know that it will sound different if you cahnge the size of the room.

If the violins are louder because there is more than one what about when they have a violin soloists and you can hear the violin independent of the others which are playing in unison?

 

[Born2bwire]

there's definitley a difference in the way it sounds but no real difference in volume.

I still don't get the whole waves adding up wouldn't my body feel the first wave of pressure and then get more intense as the waves build up this would make the sound really bad.

Like I said in the post, the time delay between the reflections and the source is so small you cannot perceive the difference in most situations. When you hear a noise in a standard room you are generally hearing it with all of the echoes and interferences already contained. The reflections do not have to travel very far and so the the echo is not heard distinctively. Compare this to an echo point in an outdoor setting where the sound takes a second or two to return. Yet this single reflection can disperse over a large distance (which takes away a lot of the energy. The space loss factor as it is called causes the power to drop off over the distance squared.) and still be perfectly audible when it arrives back at your ear.

 

[JaredJames]

Wait a minute you just said that waves travel so far before they don't matter so you understand what I mean by the extra people want make it louder, the people 500 feet away in the stadium arent going to contribute to the overall volume of the people near you.

You are confusing things here. If loud enough, people 500ft away certainly can affect the volume of people near you. This is where your intensity et al (that I've been trying to get you to read) comes in.

Have you ever been in a stadium? If I'm stood next to you (and it's only me and you in there) it's quite easy to hear me. Now put a few thousand people around us all talking at the same time and it's significantly more difficult to hear you - to the point you have to shout.

Of course, there will be a distance at which it makes no difference - but this is where acoustics come in and specifically constructive interference - concert halls and theatres are designed with this in mind.

If the violins are louder because there is more than one what about when they have a violin soloists and you can hear the violin independent of the others which are playing in unison?

You do realize instruments don't have set volumes don't you. You can play pianissimo (quietly) or fortissimo (loudly) - those are just two, but by utilising the various playing techniques you can achieve quite a lot. Including hearing a soloist over the backing.

 

[ymalmsteen887]

You are confusing things here. If loud enough, people 500ft away certainly can affect the volume of people near you. This is where your intensity et al (that I've been trying to get you to read) comes in.

Have you ever been in a stadium? If I'm stood next to you (and it's only me and you in there) it's quite easy to hear me. Now put a few thousand people around us all talking at the same time and it's significantly more difficult to hear you - to the point you have to shout.

Of course, there will be a distance at which it makes no difference - but this is where acoustics come in and specifically constructive interference - concert halls and theatres are designed with this in mind.


You do realize instruments don't have set volumes don't you. You can play pianissimo (quietly) or fortissimo (loudly) - those are just two, but by utilising the various playing techniques you can achieve quite a lot. Including hearing a soloist over the backing.

Off topic for a second but is this orchestra playing unamplified?

http://www.youtube.com/watch?v=dYecLvwOiVA&playnext=1&list=PL88DE08D9FEF14799

 

[JaredJames]

Off topic for a second but is this orchestra playing unamplified?

http://www.youtube.com/watch?v=dYecLvwOiVA&playnext=1&list=PL88DE08D9FEF14799

I want to say yes (notice the design of the stage - that's not just for looks).

But there are noticeable microphones around, so I'm not perfectly sure. However, I'd say those mics are purely for recording it not for amplification.

 

[ymalmsteen887]

I want to say yes (notice the design of the stage - that's not just for looks).

But there are noticeable microphones around, so I'm not perfectly sure. However, I'd say those mics are purely for recording it not for amplification.

I think the microphones are for recording in 2ch audio for later viewing. Why would an orchestra use amplification wouldn't audiophiles complain about that?

 

[JaredJames]

I think the microphones are for recording in 2ch audio for later viewing.

Sounds about right.

Why would an orchestra use amplification wouldn't audiophiles complain about that?

Sometimes the instruments alone just aren't powerful enough to do the job. Although these situations aren't particularly common for your usual orchestra performances.

 

[ymalmsteen887]

something I don't understand about harmonics. If all musical notes are made up interger frequencies then how come different instruments sound different not to mention the different kinds of flutes gutiars drums etc, can sound different. Same with the human voice like people singing the same vowels yet sound different and even males are distinguisable from females and yet individual males and females can be told apart. How is this explained.

 

[Pythagorean]

something I don't understand about harmonics. If all musical notes are made up interger frequencies then how come different instruments sound different not to mention the different kinds of flutes gutiars drums etc, can sound different. Same with the human voice like people singing the same vowels yet sound different and even males are distinguisable from females and yet individual males and females can be told apart. How is this explained.

The harmonic profile is distorted by reality. That is, real strings aren't massless, don't have perfect tension, there's nonlinear effects (aeolian harp effect, possibly)

So each set of strings is going to have their own specifications based on these "flaws".

Also, there's the sounding technique. If you strum a guitar and wait a couple milliseconds, the higher harmonics die out quickly, leaving a more mellow, pure tone. But with a violin, you're always scratching the string with the bow, so you're not letting the harmonics dies out; you continuously agitate the string, so violins have richer harmonics.

look up "timbre"

 

[ymalmsteen887]

The harmonic profile is distorted by reality. That is, real strings aren't massless, don't have perfect tension, there's nonlinear effects (aeolian harp effect, possibly)

So each set of strings is going to have their own specifications based on these "flaws".

Also, there's the sounding technique. If you strum a guitar and wait a couple milliseconds, the higher harmonics die out quickly, leaving a more mellow, pure tone. But with a violin, you're always scratching the string with the bow, so you're not letting the harmonics dies out; you continuously agitate the string, so violins have richer harmonics.

look up "timbre"

I have looked up timbre. So are you saying that there is more then just the integers. Why doesn't the voilin bowed sound like a guitar being picked continuously. That only tells me why the sound changes on the guitar and not the violin.You said nonlinear effects if you take the fundamental note of a 82hz guitar note and a 82hz cello note that would just be a sine wave so how is it that instruments ,voices sound different?

 

[Pythagorean]

I have looked up timbre. So are you saying that there is more then just the integers. Why doesn't the voilin bowed sound like a guitar being picked continuously. That only tells me why the sound changes on the guitar and not the violin.You said nonlinear effects if you take the fundamental note of a 82hz guitar note and a 82hz cello note that would just be a sine wave so how is it that instruments ,voices sound different?

No, it's still the harmonic series. The point is that you have a different ratio of amplitudes across the spectrum for different timbre. So different harmonics will be more pronounced for different instruments (all harmonics are still there in all cases, just to varying degree) .

And no, it's not true that a real note from an instrument produces a sine wave. Sine waves are an ideal. Like I said earlier, their is really a distribution of frequencies, which doesn't look anything like a sine wave. Even before you consider harmonics, you can't really just strike one exact note, there will be a small distribution around that note. Then a bunch of harmonics, depending on the physical properties of the resonating body (String, drum membrane, flute cavity, whatever...)

Why doesn't the voilin bowed sound like a guitar being picked continuously

picking delivers an impulsive force (very fine point in time and space) followed by letting it ring... even when you're doing tremolo, the small space between picks is sufficient and still doesn't compete with the constant agitation of the bow. Bowing imparts a friction force (spread across time and space). The friction between the bow and the string causes little super-tiny impulses to be delivered smoothly. Even between impulses of some particular chunk of surface contact, there's always another area of contact causing another impulse, so you get a sustain.

So basically one big, slow pick vs. thousands of rapid, tiny picks. Much different emergent result.

 

[ymalmsteen887]

No, it's still the harmonic series. The point is that you have a different ratio of amplitudes across the spectrum for different timbre. So different harmonics will be more pronounced for different instruments (all harmonics are still there in all cases, just to varying degree) .

And no, it's not true that a real note from an instrument produces a sine wave. Sine waves are an ideal. Like I said earlier, their is really a distribution of frequencies, which doesn't look anything like a sine wave. Even before you consider harmonics, you can't really just strike one exact note, there will be a small distribution around that note. Then a bunch of harmonics, depending on the physical properties of the resonating body (String, drum membrane, flute cavity, whatever...)


picking delivers an impulsive force (very fine point in time and space) followed by letting it ring... even when you're doing tremolo, the small space between picks is sufficient and still doesn't compete with the constant agitation of the bow. Bowing imparts a friction force (spread across time and space). The friction between the bow and the string causes little super-tiny impulses to be delivered smoothly. Even between impulses of some particular chunk of surface contact, there's always another area of contact causing another impulse, so you get a sustain.

So basically one big, slow pick vs. thousands of rapid, tiny picks. Much different emergent result.

About the violin thing that's not what I meant I am saying they sound different regardless how you play them say you played a violin with a pick and did some rapid picking and then a guitar and then a bango they all sound different. You said because of the different levels in the harmonics then how come when I change the equilizer for my on my guitar amp I can never make it sound like another instrument see this is what i am asking?

 

[Pythagorean]

About the violin thing that's not what I meant I am saying they sound different regardless how you play them say you played a violin with a pick and did some rapid picking and then a guitar and then a bango they all sound different.

Ah, ok. But I already told you the different physical characteristics of the instrument alter the harmonic landscape of any given note.

violins have f-holes and hourglass shape bodies

guitars have round holes and a pear shape

The geometry of the resonance chamber thus has an effect on the sound too. Violins also have shorter length strings at different tensions. There's a variety of different strings you can use for both: nylon and steel are the popular contemporary materials. They all have different resistances to motion as the waves try to bend the strings under tension.

You said because of the different levels in the harmonics then how come when I change the equilizer for my on my guitar amp I can never make it sound like another instrument see this is what i am asking?

Because we're talking about a spectrum a lot more complex than a couple of knobs at discrete locations in the spectrum; there's a time-scale associated with the events, so you'd have to have thousands of equilizers that change with time (to account for attack, decay, and vibrato). You would need a high quality synthesizer to even come close. But even synthesizers can't do the real thing.

Remember that a note is not really just one event. It's a complex architecture of millions of events over different spatiotemporal scales. Your equalizer naively filters the waveform every x milliseconds to eliminate each frequency. There are several micro sound events happening within each note, so you have to consider the function of time.

If you're interested in the math/engineering aspects, here's an example of an attempt to model attack and decay:

http://www.rs-met.com/documents/notes/AttackDecayEnvelope.pdf

 

[ymalmsteen887]

Ah, ok. But I already told you the different physical characteristics of the instrument alter the harmonic landscape of any given note.

violins have f-holes and hourglass shape bodies

guitars have round holes and a pear shape

The geometry of the resonance chamber thus has an effect on the sound too. Violins also have shorter length strings at different tensions. There's a variety of different strings you can use for both: nylon and steel are the popular contemporary materials. They all have different resistances to motion as the waves try to bend the strings under tension.



Because we're talking about a spectrum a lot more complex than a couple of knobs at discrete locations in the spectrum; there's a time-scale associated with the events, so you'd have to have thousands of equilizers that change with time (to account for attack, decay, and vibrato). You would need a high quality synthesizer to even come close. But even synthesizers can't do the real thing.

Remember that a note is not really just one event. It's a complex architecture of millions of events over different spatiotemporal scales. Your equalizer naively filters the waveform every x milliseconds to eliminate each frequency. There are several micro sound events happening within each note, so you have to consider the function of time.

Ok so a bass guitar would have its own unique qualities separate form a double bass but what about drums how come you don't have to tune a drum when a song changes key. I heard it doesn't have a tonal quality so is it not made up of integers if not then what. Also what about earthquakes are they the same as white or pink noise?

 

[Pythagorean]

Ok so a bass guitar would have its own unique qualities separate form a double bass but what about drums how come you don't have to tune a drum when a song changes key. I heard it doesn't have a tonal quality so is it not made up of integers if not then what. Also what about earthquakes are they the same as white or pink noise?

I'm not completely sure about less ideal resonators. I play stringed instruments, so I think about the physics a lot more with strings. Having tonal quality means you can associate a particular frequency with it. Noise is an example of a sound that doesn't have tonal quality (so maybe the harmonics from the drum are approximately as loud as the fundamental).

I don't know about earthquakes.

 

[ymalmsteen887]

Does anybody else know about the harmonics of a drum and why they are not tonal?

 

[nasu]

Does anybody else know about the harmonics of a drum and why they are not tonal?

Technically, the drums don't have harmonics and some authors would say that they don't have a pitch. What they mean is that the frequencies of the "harmonic" components are not multiple of the fundamental. So when you hit the drum you produce a sound that is a combination of various components but those components are not in harmonic ratio.

 

[ymalmsteen887]

This is what I was asking at the begging if you have a sound source approaching you at 80 miles per hour and you hear 40hz, what would the frequency be if moitionlesss and when leaving you?

Also say you decide what the pressure is motionless what changes the attenuattion when leaving and coming towards you?

 

[JaredJames]

This is what I was asking at the begging if you have a sound source approaching you at 80 miles per hour and you hear 40hz, what would the frequency be if moitionlesss and when leaving you?

Also say you decide what the pressure is motionless what changes the attenuattion when leaving and coming towards you?

What you are talking about now is the doppler effect and you certainly haven't asked this before.

 

[ymalmsteen887]

What you are talking about now is the doppler effect and you certainly haven't asked this before.

I know its called the doppler effect and its relevant to my question about why certain frequencies travel farther than others like if the source is moving away its still producing the samw amount of energy though, right so the lower frequency should travel just as far but not farther, am I wrong?

 

[JaredJames]

Once again, higher frequencies experience more attenuation than lower ones and so don't travel as far.

I have already been through this with you, multiple times. Now you're asking the same thing all over again.

 

[ymalmsteen887]

Not true. It's all about acoustics. One person clapping in a gym sounds different to one person clapping in a stadium.

Read here: http://en.wikipedia.org/wiki/Acoustics


I gave you the links to intensity and energy. You need to read them and ensure you understand them. They explain why waves only travel so far before they "don't matter".


More people clapping gives the perception of more loudness. Again, acoustics.

This is like saying 5 speakers give the same volume as 1 speaker. Although the sound system may show them giving the same output, the actual perceived volume will be louder. (Think of the difference between 2.1 and 5.1 surround sound systems.)


As above, more violins will give you more volume - but it's not a case of doubling the volume as you double the number of violins.

About the violins I meant to say that even if they are tuned perfectly no one person is starting at the exact same time and so the waves are not perfectly in phase and gives an orchestra its characteristic sound.

I read somewhere that all the violins don't contribute much to volume because even if you put two subwoofers in an enclosure the boost is like 3db and that's with bass this becomes less significant the higher in frequency you go.

 

[JaredJames]

I read somewhere that all the violins don't contribute much to volume because even if you put two subwoofers in an enclosure the boost is like 3db and that's with bass this becomes less significant the higher in frequency you go.

Correct, as I said, it isn't a case of double the speakers = double the volume.

 

[ymalmsteen887]

Once again, higher frequencies experience more attenuation than lower ones and so don't travel as far.

I have already been through this with you, multiple times. Now you're asking the same thing all over again.

Well I don't understand yet so I am trying to make this easier for me to understand.

i guess what I am saying it isn't really a lower of higher frequency.

If each frequency has the same amplitude means it has the same pressure that would mean that the lower the frequency the more pressure to have the same perceived volume as a higher frequency cause a tweeter can be ear piercing loud and you won't see it move but a woofer can be playing a 30hz frequency and be moving a lot and not be loud.

 

[JaredJames]

Do you understand the concept of attenuation and how (as I've linked to and explained previously) high frequency experiences more of it over a set distance than a low frequency does?

You keep jumping around different issues. One minute we're on the doppler effect, next your talking about frequencies and how far they travel and now you're on pressure levels.

Pick one, learn it and then move on. Learn the difference in terms (as I've kept telling you to and linking you to).

I'm sorry, but we're on page 3 soon to be 4 and it seems as if you haven't bothered to read anything anyone has written or linked to. We can't carry on like this. I have constantly asked you to check your understanding of the various terms and how they relate (I even pointed you to some specifics) but you haven't bothered. We need to focus on one aspect, get it clear and then move on to the next item. In your last three posts we've jumped around to three different areas (as above) and if this is how it is going to continue I feel I'm wasting my time, so I will respectfully remove myself from here.

 

[Born2bwire]

About the violins I meant to say that even if they are tuned perfectly no one person is starting at the exact same time and so the waves are not perfectly in phase and gives an orchestra its characteristic sound.

I read somewhere that all the violins don't contribute much to volume because even if you put two subwoofers in an enclosure the boost is like 3db and that's with bass this becomes less significant the higher in frequency you go.

That doesn't have anything to do with the relative phases. Doubling the amplitude only gives you an increase of 3dB.

 

[ymalmsteen887]

Do you understand the concept of attenuation and how (as I've linked to and explained previously) high frequency experiences more of it over a set distance than a low frequency does?

You keep jumping around different issues. One minute we're on the doppler effect, next your talking about frequencies and how far they travel and now you're on pressure levels.

Pick one, learn it and then move on. Learn the difference in terms (as I've kept telling you to and linking you to).

I'm sorry, but we're on page 3 soon to be 4 and it seems as if you haven't bothered to read anything anyone has written or linked to. We can't carry on like this. I have constantly asked you to check your understanding of the various terms and how they relate (I even pointed you to some specifics) but you haven't bothered. We need to focus on one aspect, get it clear and then move on to the next item. In your last three posts we've jumped around to three different areas (as above) and if this is how it is going to continue I feel I'm wasting my time, so I will respectfully remove myself from here.

Ok no I don't understand this stuff and how is pressure not related to how far something travels. Whats wrong with answering my other question.

I don't learn well from reading stuff I need back and forth dialoge and it sounds like your expecting me to have a certain understanding already. I am not well versed in this stuff I need very laymans terms of understanding this stuff. I just want to understand it for my own personal purposes, if this is a problem Ill leave. If I understood this stuff I would be jumping at the chance to teach someone else who wanted to learn. Also you may have to recommend what maths I need to know to understand what youre saying, attenuation was foreign to me before you brought it up and I still don't get it seems like it means loses energy over time.

 

[ymalmsteen887]

That doesn't have anything to do with the relative phases. Doubling the amplitude only gives you an increase of 3dB.

The Thing about phases has nothig to do with what I said about the increrase in volume.