The physics and understanding of low frequencies - Page 4 - AVS Forum
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Old 02-21-2011, 11:50 PM
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Originally Posted by ymalmsteen887 View Post

I am not saying they sound the same but the differences aren't the same as drinking a coke than trying a pepsi. Maybe you can help me out go on itunes and mess with the presets and listen to the changes in the music thats the same thing I hear when I listen to differnt speakers so if you just messed with an equilzer you could make one speaker sound like another. I am not saying thats true just seems to be the case.

I've listened to cheap headphones or a cars stock speakers of my favorite kind of music and get still get all emotion filled.

So if you could prove me wrong that there are some speakers out there that will blow me away that would be awesome?


I am not the smartest or most experienced on this subject, but it seems that with the bold part of your quote, you have already admitted that different speakers sound differently. Maybe I'm wrong, but isn't the whole point of equalization to cater the sound towards a certain goal? If all speakers sounded the same and were perfectly accurate, we wouldn't need it.

Bottom line is, you seem to simply be disregarding all sorts of obvious facts. Different drivers use different materials, and those materials will affect their output in various ways thus creating different sounds. That's way before you even put any of the other variables into account.

Don't take any of this the wrong way, if I'm wrong, I am more than open to correction. After all, this is a great place to learn.
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Old 02-22-2011, 03:50 AM
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Heres some physics for you that may explain how speakers sound different:

An object in motion tends to want to stay in motion. Otherwise known as inertia.

Now, let's take a tweeter made from aluminum, and a tweeter made from titanium, which is heavier than aluminum.

Now, we excite this tweeter with a frequency of some sort. What happens when the sine wave reaches it's first peak? The cones on both tweeters will want to continue moving in that direction at the same speed. What happens when the sine wave passes the peak? The decreasing voltage is telling the tweeter to start moving in an opposite motion.

Now, the lighter tweeter will respond faster than the heavier one. Reason being, it takes more energy to reverse a greater mass than a lighter one. So ultimately, the two tweeters will have a slightly different sound.

So why not make all tweeters aluminum? Maybe because Titanium holds it's form better, and is less likely to flex at the highest frequencies. So there is a trade-off.

Now, extend this to midranges and woofers. They can be made from paper, aluminum, kevlar, ceremetallic, coated paper, plastic, any number of materials. Each of these materials is going to weigh differently. So their inertia can make them sound different.

So why aren't all speakers made out of the same material? Cost. Paper is cheap. But play at too high a volume, and the paper can literally catch on fire. Aluminum is more expensive to work with, but it can act as a heat sink, so you ca play at louder volumes. But the speaker will cost more. Or maybe another manufacturer uses an expensive alloy because it's light, but holds its shape under high stress, and dissapates heat well.

The sound of a speaker can vary because of many factors. Heavier or lighter drivers have more or less inertia. Different materials can flex differently under stress.
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Old 02-22-2011, 04:18 AM - Thread Starter
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Originally Posted by Gater96 View Post

I am not the smartest or most experienced on this subject, but it seems that with the bold part of your quote, you have already admitted that different speakers sound differently. Maybe I'm wrong, but isn't the whole point of equalization to cater the sound towards a certain goal? If all speakers sounded the same and were perfectly accurate, we wouldn't need it.

Bottom line is, you seem to simply be disregarding all sorts of obvious facts. Different drivers use different materials, and those materials will affect their output in various ways thus creating different sounds. That's way before you even put any of the other variables into account.

Don't take any of this the wrong way, if I'm wrong, I am more than open to correction. After all, this is a great place to learn.

So youre saying im right and that speakers are just like different presets then that means what im saying about speakers is accurate. The idea of speakers good for rock , jazz, classical etc is just asanine. If were to listen to an orchestra or a guitar and they had there playing down they would have great dynamics and really get you into the song like this http://www.youtube.com/watch?v=wvXgu5HgGwQ or this
http://www.youtube.com/watch?v=K4xRCCz5ZWM

Notice how some parts are quiter than others without this the emotion wouldnt be there like at 4:20 into the second link and then after awhile it gets quiter like someone is walking away or finally at peace or however you want to interprete it. So to say speakers are dynamic is weird becuase they get louder or softer depind on the signal otherwise I coulndt claim that these songs have dynamics cause i can listen to them on my cheap computer speakers and still hear the emotion put into the song.

If you can show me otherwise that would be great, if there are speakers out there taht can play those songs and make it like im hearing it for the first time that would be awesome
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Old 02-22-2011, 04:29 AM - Thread Starter
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Originally Posted by DanLW View Post

Heres some physics for you that may explain how speakers sound different:

An object in motion tends to want to stay in motion. Otherwise known as inertia.

Now, let's take a tweeter made from aluminum, and a tweeter made from titanium, which is heavier than aluminum.

Now, we excite this tweeter with a frequency of some sort. What happens when the sine wave reaches it's first peak? The cones on both tweeters will want to continue moving in that direction at the same speed. What happens when the sine wave passes the peak? The decreasing voltage is telling the tweeter to start moving in an opposite motion.

Now, the lighter tweeter will respond faster than the heavier one. Reason being, it takes more energy to reverse a greater mass than a lighter one. So ultimately, the two tweeters will have a slightly different sound.

So why not make all tweeters aluminum? Maybe because Titanium holds it's form better, and is less likely to flex at the highest frequencies. So there is a trade-off.

Now, extend this to midranges and woofers. They can be made from paper, aluminum, kevlar, ceremetallic, coated paper, plastic, any number of materials. Each of these materials is going to weigh differently. So their inertia can make them sound different.

So why aren't all speakers made out of the same material? Cost. Paper is cheap. But play at too high a volume, and the paper can literally catch on fire. Aluminum is more expensive to work with, but it can act as a heat sink, so you ca play at louder volumes. But the speaker will cost more. Or maybe another manufacturer uses an expensive alloy because it's light, but holds its shape under high stress, and dissapates heat well.

The sound of a speaker can vary because of many factors. Heavier or lighter drivers have more or less inertia. Different materials can flex differently under stress.

based on what youre saying about the aluminum versus titanium if the speaker cant respond fast enough to come back then it cant produce that particular frequency period the air wouldnt vibrate at that frequency thats the only way the ear responds is changes in air pressure so if it cant do it, it cant do it.

About the speakers materials 20hz is 20hz if the air isnt vibrating at regular 20 cycles a second the ear wont register anything. If youre saying they make their own sounds thats different like when you have really loud bass and youre car or home has vibraitons happen from windows and such that would be an unwanted sound like when youre guitar has fret buzz or a flute has a material lose and the air is causing it to make a sound these are thingsyou want to fix.. Listen Ill use 50 hz as an example since i probably cant hear down to 20 if you had a 100 differnt woofers of different companies, boxes, materails,sizes whaterver and feed them a 50hz sound wave they would all the sound the same 50hz will always sound like 50hz now if the enclosers there in or the materials of the diamphram are making there own sounds from the movement pressure waves on the box that would be an undesirable trait that needs to be fixed.
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Old 02-22-2011, 04:32 AM
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Let's try this way, when the speaker is good it is more accurate, so an orchestra should sound like an actual orchestra and you should be able to hear not only the overall music, but the part of each instrument, as well as being able to locate that instrument spatially.

If the speaker is not good enough you can still hear the overall music, but the location get fuzzy, and instruments seem to blend together.

This is not something you get from an equalizer as you said, the distortion due to the speaker can vary if the signal is simple or have a lot of harmonics.
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Old 02-22-2011, 04:34 AM
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Originally Posted by ymalmsteen887 View Post

based on what youre saying about the aluminum versus titanium if the speaker cant respond fast enough to come back then it cant produce that particular frequency period the air wouldnt vibrate at that frequency thats the only way the ear responds is changes in air pressure so if it cant do it, it cant do it.

No it still produce a sound but not a perfect sine wave.
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Old 02-22-2011, 05:09 AM - Thread Starter
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Originally Posted by jwickers View Post

Let's try this way, when the speaker is good it is more accurate, so an orchestra should sound like an actual orchestra and you should be able to hear not only the overall music, but the part of each instrument, as well as being able to locate that instrument spatially.

If the speaker is not good enough you can still hear the overall music, but the location get fuzzy, and instruments seem to blend together.

This is not something you get from an equalizer as you said, the distortion due to the speaker can vary if the signal is simple or have a lot of harmonics.

Thats one thing that hasnt been mentioned yet is spatial location.
I dont know how speakers could put a sound in any other place but its location I mean yeah there is a sound coming from the center of two because you ear is recieving the same amount of sound from both sides just like if there was a sound directly in front of you and if one speaker plays the sound slightly louder the sound will move more towards that speaker. So if you recorded with 2 micorphones you would automaticlaly get this location your talking about with any two speakers.

About the complexty of mulitole instruments youre not understanding that youre making it more comlicated than you realize the speaker or electrical signal doesnt know that there are mulitple instruments thats exclusive to us all its doing is reacating to changes in voltage just like the microphone reacts to changes in pressure. Hearing each instrument is up to the persons own ability to isolate musical passages and harmonies this has nothing to do with speakers
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Old 02-22-2011, 05:26 AM
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Originally Posted by ymalmsteen887 View Post

About the complexty of mulitole instruments youre not understanding that youre making it more comlicated than you realize the speaker or electrical signal doesnt know that there are mulitple instruments thats exclusive to us all its doing is reacating to changes in voltage just like the microphone reacts to changes in pressure. Hearing each instrument is up to the persons own ability to isolate musical passages and harmonies this has nothing to do with speakers

Yes but the signal is more complex, so if you lose some of the details you tend to lose more in that case.

Think of a picture, if it is very simple like 4 square of different colors, even if you add noise and distortion you can still perceive the original picture very clearly.

If the picture is complex, like for example a high res satellite picture, the smallest amount of noise or distortion will mean you wont be able to figure out the details. For example you can still see there are roads and cars, but you cannot distinguish the pedestrians, or the car models on the road.
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Old 02-22-2011, 06:09 AM
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Originally Posted by ymalmsteen887 View Post

based on what youre saying about the aluminum versus titanium if the speaker cant respond fast enough to come back then it cant produce that particular frequency period the air wouldnt vibrate at that frequency thats the only way the ear responds is changes in air pressure so if it cant do it, it cant do it.

Both tweeters can vibrate at that frequency. But how well they reproduce the input signal is the difference. If you were to look at the tweeter's actual waveform on an oscilloscope and compare it with the input waveform, there will be differences.

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50hz will always sound like 50hz now if the enclosers there in or the materials of the diamphram are making there own sounds from the movement pressure waves on the box that would be an undesirable trait that needs to be fixed.

EXACTLY! Therein lies the issue. The enclosures, material, and diaphram of any speaker do make their own sound. If you want to build a cheap speaker, you don't worry about that. But if you want to build a speaker that is as true as possible to that 50Hz tone, then you need to spend extra time and $$$ into researching how to best reduce and eliminate these undesirable traits. And so a manufacturer will spend more money on better enclosures, better engineers, better driver materials. That added cost gets passed on to us, the consumers, in the form of more expensive (and better sounding) speakers.

You mentioned enclosures making their own sound. That is a perfect example. Lets say you put a 12" driver into a 1/2" thick plywood box and play 50Hz. What is that thin plywood going to do? It is going to vibrate at 50Hz as the driver pressurizes and depressurizes the box. That will create an undesireable noise which was not in the original 50Hz sine wave you fed it.

Now, let's say you use 1" thick plywood, and install internal bracing. That box is now going to vibrate a lot less, and as a result, it will not add as much of it's own undesireable sound. So now you have a speaker which plays a better sounding 50Hz tone. And you've spent more money doing it, so you need to charge your customer more.

Now let's say your customer doesn't like the look of raw plywood. So you put a polished wood grain veneer on the cabinet to make it look pretty. Now you need to charge your customer even more because it cost you time and money to make a pretty box.

Now let's say your customer has issues with room modes. So you build a parametric equalizer into the subwoofer box. Now you need to charge even more!

That's why there is such a huge variety of speakers. Maybe I'm a struggling college student, and all I can afford is the 1/2" plywood box. I might want the sub with the PEQ, pretty veneer, and thick box, but I can't afford it. So I get the cheap one. On the other hand, maybe I'm a Sheik from Saudi Arabia. I don't want the cheap box that sounds bad. I want the thick pretty box with PEQ. And I want it diamond encrusted. And I want the driver to look pretty, so I want you to make it gold plated.
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Old 02-22-2011, 07:14 AM - Thread Starter
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Both tweeters can vibrate at that frequency. But how well they reproduce the input signal is the difference. If you were to look at the tweeter's actual waveform on an oscilloscope and compare it with the input waveform, there will be differences.



EXACTLY! Therein lies the issue. The enclosures, material, and diaphram of any speaker do make their own sound. If you want to build a cheap speaker, you don't worry about that. But if you want to build a speaker that is as true as possible to that 50Hz tone, then you need to spend extra time and $$$ into researching how to best reduce and eliminate these undesirable traits. And so a manufacturer will spend more money on better enclosures, better engineers, better driver materials. That added cost gets passed on to us, the consumers, in the form of more expensive (and better sounding) speakers.

You mentioned enclosures making their own sound. That is a perfect example. Lets say you put a 12" driver into a 1/2" thick plywood box and play 50Hz. What is that thin plywood going to do? It is going to vibrate at 50Hz as the driver pressurizes and depressurizes the box. That will create an undesireable noise which was not in the original 50Hz sine wave you fed it.

Now, let's say you use 1" thick plywood, and install internal bracing. That box is now going to vibrate a lot less, and as a result, it will not add as much of it's own undesireable sound. So now you have a speaker which plays a better sounding 50Hz tone. And you've spent more money doing it, so you need to charge your customer more.

Now let's say your customer doesn't like the look of raw plywood. So you put a polished wood grain veneer on the cabinet to make it look pretty. Now you need to charge your customer even more because it cost you time and money to make a pretty box.

Now let's say your customer has issues with room modes. So you build a parametric equalizer into the subwoofer box. Now you need to charge even more!

That's why there is such a huge variety of speakers. Maybe I'm a struggling college student, and all I can afford is the 1/2" plywood box. I might want the sub with the PEQ, pretty veneer, and thick box, but I can't afford it. So I get the cheap one. On the other hand, maybe I'm a Sheik from Saudi Arabia. I don't want the cheap box that sounds bad. I want the thick pretty box with PEQ. And I want it diamond encrusted. And I want the driver to look pretty, so I want you to make it gold plated.

The second thing you said contradicts the first if you understand that the other sounds are unwanted then what do you mean the tweeter cant respond fast enough this would mean it cant do a certain frequecny past a certain point.

Also another question why is it that you feel bass in your chest and why cant you feel higher frequencies and what would a 0.5hz frequency feel like if it was loud enough?
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Old 02-22-2011, 08:15 AM
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I think the big picture thing that's being danced around a bit here is distortion. It sounds like your main premise is that if speakers were EQ'd to have the same FR they'd then all sound the same which is intuitive for most I'd think. The problem is speaker drivers cannot 100% accurately reproduce the input signal they're asked to and the enclosures they're placed in have a large effect on the speakers' acoustic frequency response. If you ask a speaker to play 50hz they will play 50hz but they'll also be playing a lot of other notes that they weren't asked to because of the inaccuracies (distortion - harmonic and non-linear). That alone can cause two speakers with the same measured FR to sound differently but we can extend that even further. Now imagine you have two speakers. One has a naturally flat FR curve, the other has a large 10dB bump in the FR at 200Hz caused by the enclosure. You EQ the 2nd one to be flat by bringing down the bump at 200Hz though and expect them to sound the same. Now you play a loud 100hz note on the first speaker then the 2nd speaker and they sound very very different. Why would this be??? Even though you've electronically "fixed" the 200hz bump of the 2nd speaker the harmonic distortion produced by the 100hz note (at 200hz) is still being boosted significantly by the enclosure.

Another example that's not too complicated is off-axis frequency response. Due to speaker baffle size, driver layout, crossover, and even whether the edges of the baffle are rounded over, chamferred, etc the FR of different speaker designs will be significantly different then each other as you move off axis vertically and horizontally. Since the majority of what we hear when we play a speaker is reflected sound rather than direct these differences have a significant effect on how a speaker sounds. Another oversimplified example. Say we have two speakers again, both with flat on-axis FR. Speaker one rolls off very smoothly both vertically and horizontally - say it's -3dB at 15 degrees off axis at all frequencies and -6dB at 30 degrees off axis at all frequencies (NO speaker would be this "nice"...). Speaker two has a narrower vertical window around the crossover frequency - say 2kHz. In most of the FR it matches speaker one but at 2kHz it is -6dB at 15 degrees off axis vertically and -12dB at 30 degrees. Now, even though on-axis they measure the same FR = flat, they will sound significantly different at 2kHz when placed in a room as speaker #2 is contributing less energy toward the ceiling and floor to be redirected to the listener. For more details on directivity see the polar maps near the end of this paper posted by Earl Geddes (the paper is actually sales literature... I didn't read the entire thing but the polar maps are very interesting): http://www.gedlee.com/downloads/directivity.pdf

These are just two simple examples of why speakers with the same measured FR would sound different. There are lots and lots and lots of things that affect the sound of a speaker that cannot be seen by a simple FR measurement (and cannot be fixed by EQ alone...).
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Old 02-22-2011, 08:23 AM
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Originally Posted by ymalmsteen887 View Post

Listen Ill use 50 hz as an example since i probably cant hear down to 20 if you had a 100 differnt woofers of different companies, boxes, materails,sizes whaterver and feed them a 50hz sound wave they would all the sound the same 50hz will always sound like 50hz now if the enclosers there in or the materials of the diamphram are making there own sounds from the movement pressure waves on the box that would be an undesirable trait that needs to be fixed.

Assuming each was equally able to exactly replicate the signal (shape, amplitude, etc - far more things than the frequency affect the sound) this is correct.

This is NOT the way things actually work however. If you measure the waveform generated by each speaker it will not perfectly match the input signal. Some may be closer than others. In general, the more expensive speakers will be closer than the cheaper speakers. This is an inherent of mechanical systems.

Many of your questions seem to ignore this fundamental issue with speakers and sound replication. Two main things:
  1. There are more elements to a sound wave than frequency (such as amplitude, shape, etc)
  2. No mechanical device can 100% replicate an input signal (speakers are mechanical devices)

Does both of these statements make sense?


Quote:


The second thing you said contradicts the first if you understand that the other sounds are unwanted then what do you mean the tweeter cant respond fast enough this would mean it cant do a certain frequecny past a certain point.

There are two types of "fast." One is "can the tweeter vibrate at a certain frequency indefinitely." The second, which is the important one in understanding speaker differences (assuming the speaker isn't so bad of quality it cannot even do the first) is "how quickly can the tweeter change to vibrate at the given frequency."

ie

You go from 0 to 15 kHz. The tweeter will not go from 0 to 15 kHz immediately. It will likely take a short amount of time to go from 0 to 1kHz to 2kHz, etc, all the way to 15 kHz. This happens so fast we barely notice it. Factors like this contribute to speaker differences.

The graph I showed previously really illustrates this.

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. I really want to understand how waves, light water, sound etc. I bought a book called physics of waves by william C. Elmore and Mark A. Heald and cant even get past the first page where it talks about transverse waves, so I was hoping to get some help with my questions. What math do I need to know to understand fluid dynamics,pressure, attenuation etc.

----
What kind of math do you have to know to understand this.

http://en.wikipedia.org/wiki/Wave_equation

Without knowing your background, it is difficult to say. My background contains a lot of math and science. I will say though that understanding those equations is something I do not necessarily think is required to having a pretty good understanding of why speakers sound different. Perhaps this would benefit you in understanding more mathematically why you feel bass instead of hearing it.

(disclaimer: the following is just my thoughts on the matter, and while there is a scientific background here, everything I am saying are conclusions I draw from that )

My assumption would be as the wavelength of the sound increases (with decreasing frequency, a 20 Hz soundwave has a wavelength significantly longer than a 1000 Hz soundwave) it eventually hits a point where your ear can no longer determine its characteristics and therefore you do not "hear" it. This is the same as if you tap someone on the shoulder, and increase the speed at which you do it - eventually you will be tapping them fast enough they cannot tell individual taps apart. Well if you are able to move your hand fast enough I guess. Probably would require a non-human 'tap' to move quickly enough to have this be possible.

Waves also transmit energy. For a simple wave, as the wavelength increases, the distance between a peak/trough (hi/low amplitudes) also increases. Eventually this becomes enough to remove a "constant" pressure. As this distance decreases we perceive the relative differences less and less. For lower notes (lower frequencies) these differences might be enough where you can "feel" the energy from the wave. Instead of a constant pressure, there is a perceptible oscillating pressure wave (very roughly at 20 times a second for a 20 Hz wave; wavelength of roughly 17m and a speed of 343m/s means you get about 20 waveforms per second).

*shrug* Not sure on the math of that or even if what I said above is right.
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Old 02-22-2011, 09:08 AM
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Originally Posted by ymalmsteen887 View Post
So youre saying im right and that speakers are just like different presets then that means what im saying about speakers is accurate. The idea of speakers good for rock , jazz, classical etc is just asanine. If were to listen to an orchestra or a guitar and they had there playing down they would have great dynamics and really get you into the song like this http://www.youtube.com/watch?v=wvXgu5HgGwQ or this
http://www.youtube.com/watch?v=K4xRCCz5ZWM

Notice how some parts are quiter than others without this the emotion wouldnt be there like at 4:20 into the second link and then after awhile it gets quiter like someone is walking away or finally at peace or however you want to interprete it. So to say speakers are dynamic is weird becuase they get louder or softer depind on the signal otherwise I coulndt claim that these songs have dynamics cause i can listen to them on my cheap computer speakers and still hear the emotion put into the song.

If you can show me otherwise that would be great, if there are speakers out there that can play those songs and make it like im hearing it for the first time that would be awesome
No. The fact that equalization exists proves that speakers sound different and are inaccurate.

The only real asanine statement here is to say that computer speakers sound the same as a set high end floor standers. Not being mean, it just is.

The dynamics of a speaker is how well it responds to those changes in signal input and its ability to remain accurate over a given volume range. Saying that two speakers using completely different drivers, crossovers, cabinets and materials will produce the same results is just silly.

It also seems a bit odd to ask me to watch a youtube video as an example of dynamics when you yourself said you cant get a fair listen over the internet.

Once again, not being combative, these are good discussions to have.
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Old 02-22-2011, 10:33 AM
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The second thing you said contradicts the first if you understand that the other sounds are unwanted then what do you mean the tweeter cant respond fast enough this would mean it cant do a certain frequecny past a certain point.
It is true that some tweeters go higher than others. Some tweeters don't make it all the way to 20KHz. Some go further. For example, the Axiom M80 speakers have tweeters that go to 20KHz. But the Klipsch RF-7 speakers have tweeters that go to 24KHz.

My main point about tweeters is that while it can vibrate 15,000 times a second, how cleanly is it vibrating? Does it's waveform look like a sine wave, or does it look more like a sawtooth?

Quote:
Also another question why is it that you feel bass in your chest and why cant you feel higher frequencies and what would a 0.5hz frequency feel like if it was loud enough?
Bass has more energy than midranges. That's why it takes more wattage and bigger woofers to recreate bass. More energy moves more air. Less energy moves less air.

What would .5Hz feel like? Ask Adam Savage from Mythbusters. I think they subjected him to .5Hz during the "brown note" myth.
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Old 02-22-2011, 11:41 AM
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Originally Posted by ymalmsteen887 View Post

Also another question why is it that you feel bass in your chest and why cant you feel higher frequencies and what would a 0.5hz frequency feel like if it was loud enough?

this question really points out that you don't understand the fundamental aspect of "sound"...

you need to buy "the master handbook of acoustics"...

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Old 02-22-2011, 11:45 AM
 
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Originally Posted by sage View Post

It's actually TWO sentances. I thought of Papa.

That's a riot,

Too bad most here won't get it.
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Old 02-22-2011, 12:36 PM
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Originally Posted by ResIpsa View Post

That's a riot,

Too bad most here won't get it.

That's okay. I've long since made peace with the fact that almost nobody gets my humor.
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Old 02-22-2011, 06:15 PM - Thread Starter
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Originally Posted by ccotenj View Post

this question really points out that you don't understand the fundamental aspect of "sound"...

you need to buy "the master handbook of acoustics"...

Actually I have an idea. I'm thinking its because when there is an increase in pressure if it lasts long enough your body will react to the changes in heat like when you touch a hot stove and move your hand away in time. So if the changes in pressure are to quick then you want notice the change in heat.
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Old 02-22-2011, 06:16 PM - Thread Starter
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Originally Posted by DanLW View Post

It is true that some tweeters go higher than others. Some tweeters don't make it all the way to 20KHz. Some go further. For example, the Axiom M80 speakers have tweeters that go to 20KHz. But the Klipsch RF-7 speakers have tweeters that go to 24KHz.

My main point about tweeters is that while it can vibrate 15,000 times a second, how cleanly is it vibrating? Does it's waveform look like a sine wave, or does it look more like a sawtooth?



Bass has more energy than midranges. That's why it takes more wattage and bigger woofers to recreate bass. More energy moves more air. Less energy moves less air.

What would .5Hz feel like? Ask Adam Savage from Mythbusters. I think they subjected him to .5Hz during the "brown note" myth.

No that was 5hz they did on mythbusters not 0.5hz
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Old 02-22-2011, 06:25 PM - Thread Starter
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Originally Posted by Gater96 View Post

No. The fact that equalization exists proves that speakers sound different and are inaccurate.

The only real asanine statement here is to say that computer speakers sound the same as a set high end floor standers. Not being mean, it just is.

The dynamics of a speaker is how well it responds to those changes in signal input and its ability to remain accurate over a given volume range. Saying that two speakers using completely different drivers, crossovers, cabinets and materials will produce the same results is just silly.

It also seems a bit odd to ask me to watch a youtube video as an example of dynamics when you yourself said you cant get a fair listen over the internet.

Once again, not being combative, these are good discussions to have.

Wow I cant believe this youre asking me to listen to differnt speakers that are recorded for playback on my speakers if they have qualities that other speakers cant reproduce then how could I hear them. Why dont I just go over to a friends house who has a 10000$ set of speakers and record them playing my favorite songs and then go back to my house and play it back on my 100$ speakers and I can have the same expierence.

So what I said about dynamics is still true im asking you to listen to the music regardless of speakers.

I know guitar players have different sounding tones I would say the guitar itself, the pickups and the enhancement stuff they buy plays the biggest role.
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Old 02-22-2011, 06:34 PM - Thread Starter
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Lennon and enderland are the only one who has actually touched ground on what I am talking about.

regardless of what youre saying a sinewave is always present in any sound. If you have changes in pressure at 20 cycles a second you will hear 20hz if cycles occasianlly speed up they will sound louder if they often more or less often you would get a higher or lower frequency and if it wasnt consistent you would get a vibrato or tremolo when you say the wave is not perfectly smooth youre saying there are other frequincies present if you saw a frequency represented by voltage you would see it go up and down at different amplitudes and cycles its always going to be smooth.
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Old 02-22-2011, 08:22 PM
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I have no problem continuing this discussion, but if I am going to continue it you have to adress this. Because otherwise all my efforts here are a waste of time --

  1. There are more elements to a sound wave than frequency (such as amplitude, shape, etc)
  2. No mechanical device can 100% replicate an input signal (speakers are mechanical devices)

Does both of these statements make sense?
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Old 02-22-2011, 10:55 PM
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Originally Posted by ymalmsteen887 View Post

Wow I cant believe this youre asking me to listen to differnt speakers that are recorded for playback on my speakers if they have qualities that other speakers cant reproduce then how could I hear them. Why dont I just go over to a friends house who has a 10000$ set of speakers and record them playing my favorite songs and then go back to my house and play it back on my 100$ speakers and I can have the same expierence.

Actually, that's a great idea. Take the recording while you listen in person, then play it back at your house and note the differences. I can promise you there will be some.

So what I said about dynamics is still true im asking you to listen to the music regardless of speakers.

I understand, but that's putting an awful lot of trust in the compression and quality of the internet video as well the connection between my computer and my amp. Just too many variables there.


I know guitar players have different sounding tones I would say the guitar itself, the pickups and the enhancement stuff they buy plays the biggest role.

So you agree that different guitars can have different sounds but not speakers? I'm curious about this.
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Old 02-23-2011, 01:27 AM - Thread Starter
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Originally Posted by enderland View Post

I have no problem continuing this discussion, but if I am going to continue it you have to adress this. Because otherwise all my efforts here are a waste of time --

  1. There are more elements to a sound wave than frequency (such as amplitude, shape, etc)
  2. No mechanical device can 100% replicate an input signal (speakers are mechanical devices)

Does both of these statements make sense?

Amplitude is the displacement of the medium the wave is traveling through, right? Is shape if you were to add another frequency to the wave, if so thats still frequency.

I still dont understand the second statement, to me it seems it is reproducing the signal but there are other factors adding to the signal.
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Old 02-23-2011, 01:42 AM - Thread Starter
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Originally Posted by Gater96 View Post

So you agree that different guitars can have different sounds but not speakers? I'm curious about this.

Well Im not saying a less compressed sound file want sound better. If certain values are eliminated from the music than you are missing out on the full sound but the volume isnt affected, if it is could you explain how compression makes a file smaller and as such the music is compomised in dynamics?

I guess the way I look at it is like the guitars are depending on a natural phenomena to determine the sound so just slight adjustments to the shape and size will affect the sound. Where as speakers are being told what to do the guitar has different strings, tensions, and length to determine the note. Basically the speaker doesnt change size or loosing up to play a different note it just vibrates mechanically faster or slower.
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Old 02-23-2011, 02:45 AM
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Originally Posted by ymalmsteen887 View Post

regardless of what youre saying a sinewave is always present in any sound. If you have changes in pressure at 20 cycles a second you will hear 20hz if cycles occasianlly speed up they will sound louder if they often more or less often you would get a higher or lower frequency and if it wasnt consistent you would get a vibrato or tremolo when you say the wave is not perfectly smooth youre saying there are other frequincies present if you saw a frequency represented by voltage you would see it go up and down at different amplitudes and cycles its always going to be smooth.

Here is what the waveform of a violin looks like...


Image from: http://musikality.net/general/audio-...riertransform/

That is not a pure sine wave. There are waves there, but it is not a sine wave. However, that signal is what your speaker will see. And that is how your speaker will have to vibrate to reproduce that sound.

As explained on the site I sourced the image from, the sound of a violin is made up of several frequencies. The fundamental, and all the harmonics of that frequency. Now, let's examine this waveform.

Right near the zero crossing line, there are little ripples in the waveform. Very small, but there nontheless. A cheap speaker may not be able to recreate those ripples accurately. Perhaps it's mass overshoots, and exaggerates the ripple. Perhaps it's not sensitive enough to react to such a minute change.

Sensitivity is an important spec in any speaker. Lets say that speaker A will generate 85db when fed a 1KHz tone at 1 watt. Lets say that speaker B will generate 101db when fed a 1KHz tone at 1 watt. Which speaker is going to be better at reproducing that slight ripple in the violin's waveform? Speaker B, because it's much more sensitive to variations in sound.

An interesting thing to note is that while in the above example speaker B is the better of the two, there are cases where it will sound worse. If you feed speaker B a well recorded signal, you will get great sound out of it. But let's say you play a vinyl record on speaker B. You'll hear the music, and you'll also hear every scratch, pop, and other imperfection in that record wonderfully reproduced on the highly sensitive speaker. Garbage in, garbage out. But the less sensitive speaker A, will still reproduce some of the imperfections, but they won't be as easy to notice.


Okay, let's try another exercise. Total Harmonic Distortion, or THD. THD is how much distortion is introduced to a sound. In another thread I started, I did a hearing test where I asked people to listen to a 10Hz - 19Hz tone to see if they could hear it. Here is a spectogram of the source file:


The sound file starts at the bottom of the picture, and slowly works its way up to the top, from 10hz to 19Hz. Notice how there is one single vertical line per tone. This is the sine wave. The second and third harmonics of 12Hz would be 24Hz and 36Hz. Looking over at the 24Hz and 36Hz portions of the graph, we see only inky blackness. So our source signal has no harmonic distortion. Just a clean 12Hz sine wave, and nothing else.

Now, this was recorded from my headphone output:


Now look at the 12Hz fundamental (3rd orange line from the bottom) Look to the right. There is another line at 24Hz, and a third line at 36Hz! That audio was NOT in the source file. But the speakers in my headphones produced it nontheless! This is distortion. This is the speakers in my headphones not reproducing the 12Hz (or any other frequency on this chart) accurately.

Let's look at a different chart. This is my headphones producing 10Hz.



Recall that the original source file had zero distortion. However, on this graph, note the areas marked 2 and 3. These are the 2nd and 3rd harmonics of 10Hz (20hz and 30Hz) Those little spikes there standing above all the others are distortion. They were NOT in the source signal. But they are there now.

Now, let's look at a slightly more expensive sound system built by notnyt:



My headphones produce about 5.7% THD at that frequency. But notnyt's system produces 3.8% THD at that frequency. (and notice his level is over 30db louder than mine).

There they are. Objective measurements from two sets of speakers being fed the exact same 10Hz tone. Yet one is clearly doing a better job than the other. If a speaker is a speaker is a speaker, and they all sound the same, then both I and notnyt should have the same results. But we don't. Why? Because different speakers do sound different.
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Old 02-23-2011, 03:03 AM - Thread Starter
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Originally Posted by DanLW View Post


the other. If a speaker is a speaker is a speaker, and they all sound the same, then both I and notnyt should have the same results. But we don't. Why? Because different speakers do sound different.

Thanks for giong to such lenghts to help me understand but thats exactly what I was talking about notice in the vioin wave that when it repeats that whole pattern that is the fundemental you are adding multiplae sinwaves at deifferent frequencies. You make it sound more complicated when you say minute changes its not that its having to react like a person having to hit their breaks because a car pulled out in front of them. look at the violin wave again put a dot at any loctation of the wave that would be the excursion the speaker would be at at that moment, its like raise the signal by+8 then subtract+4 then add+2 then add+4 then +subtract+2 then subtract +8 etc.
I hope youre understanding what I mean it played any of these fluctuations at different times wouldnt make since.

I know if you have multiple drivers then phase of waves could be off by some because they have different locations but the ear just mixes sine waves together thats why the sounds are still recognizable. Kinda like if two violins are tuned the same but the players dont play the note at the same time so they are slightly off(is their a name for this?) but the difference hear is that they all have their own harmonics where as the speaker is seperating the range.

But yeah the THD stuff I get.
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Old 02-23-2011, 05:05 AM
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Quote:
Originally Posted by ymalmsteen887 View Post

look at the violin wave again put a dot at any loctation of the wave that would be the excursion the speaker would be at at that moment, its like raise the signal by+8 then subtract+4 then add+2 then add+4 then +subtract+2 then subtract +8 etc.

If a speaker could play with 0.00% THD, then that would be correct. But speakers can't do that. Some speakers get closer to 0 THD than others. So while the input might be +8 -4 +2 +4 -2 +8, what the speaker actually does might be more like +8.22 -3.91 +1.86 +4.13 -1.95 +8.13. That is exactly what distortion is - a speaker not playing a signal accurately.

Check out the "Servo Subwoofer" section of this wikipedia article: http://en.wikipedia.org/wiki/Subwoofer#Servo_subwoofers

The point of a servo subwoofer is the engineers who made it know that the cone is not going to replicate the input signal exactly. And so they put a sensor on the cone which measures actual cone movement. A microprocessor compares the input signal to actual cone excursion, and adjusts the output in an effort to get the cone to more precisely reflect the actual input signal. If all speakers truly replicated the input signal exactly with no distortion, there would be no need for a servo subwoofer.
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Old 02-23-2011, 08:00 PM
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I think there is a very serious language barrier here.

By the way, I asked how old you were to determine your age, period, don't worry about what I was assuming, I was just asking.

You seem to be a person whose natural first language is not English. If that is true, I think that is contributing to some of the confusion.

The other possibility is, well unkind and I won't say it. Good luck.

deeper than the deepest ocean
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Old 02-24-2011, 09:10 AM
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Quote:
Originally Posted by ymalmsteen887 View Post

Well Im not saying a less compressed sound file want sound better. If certain values are eliminated from the music than you are missing out on the full sound but the volume isnt affected, if it is could you explain how compression makes a file smaller and as such the music is compomised in dynamics?

I guess the way I look at it is like the guitars are depending on a natural phenomena to determine the sound so just slight adjustments to the shape and size will affect the sound. Where as speakers are being told what to do the guitar has different strings, tensions, and length to determine the note. Basically the speaker doesnt change size or loosing up to play a different note it just vibrates mechanically faster or slower.

Guitar speakers have VERY different sounds. That's why, for example, for at least much of his carreer Malmsteen has used a Celestion speaker that is not "native" to the cabinets he is using. I can't imagine switching all four speakers in 28 separate cabinets to a speaker that many, especially vintage buffs, think is "inferior" (but it's really all about horses for courses) because it doesn't make any difference(!).

Your desire to rest on your untutored assumptions is wrecking any capacity to learn the answers to the questions you are asking.

While the differences may be subtle in some cases, and utterly irrelevant to you in all cases (i mean if you can't hear the difference between speakers, be happy and buy cheap) you can come very close to turning a Marshall into a fender just by switching to Jensen-style speakers, and LOTS of people get somewhere in the Vox/Marshall sound world with Fender Blues Jrs simply by putting a celestion Blue (or alternative aftermarket speaker like a Weber equivalent). It makes what to me, and to folks who heard me audition celestion-based amps with a Weber Jensen-style speaker. Changes the character of the sound a lot. Easy as pie for anybody who would bother to look at the speaker websites that I have twice suggested you visit to see the beginnings of the reason why: their FRs are significantly different at low power. But even more differences come as you pour on the power - - how each speaker's FR changes, the way they compress (or don't) and how the cones break up really makes a difference.
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