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Topic: Audible differences between neutral speakers (Read 16265 times) previous topic - next topic
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Re: Audible differences between neutral speakers

Reply #25
Consider an example:  the cone is hooked up to a resistor, and then placed near a second speaker producing an output sound. 
As mentioned earlier, you seem to be disagreeing with work = force * distance moved in the direction of the force plus Newton's third law. In addition you include electricity and/or resistors when they would seem to have nothing directly to do with what is being discussed. I am wondering if you might have been mislead by the word impedance. In this case it refers to mechanical impedance (force/velocity) or acoustical impedance (pressure/velocity) and not electrical impedance.

Re: Audible differences between neutral speakers

Reply #26
Define 'neutral' in an objective way.

A sine sweep from the speaker reads flat on a perfect sound level meter in a perfect anechoic chamber. These are theoretical conditions; in reality measurement flaws exist, but "neutral" seems to mean this when used by people who publish measurements. In this context, I use neutral to refer to a flat signature, as opposed to a V, or something else.

There is no such thing, without a lot of DSP.  Some of the best speakers in the world might have +/-2dB, which is more than enough to be audible.  There's also decay time and lots of room interactions, as others have pointed out.

Re: Audible differences between neutral speakers

Reply #27
Consider an example:  the cone is hooked up to a resistor, and then placed near a second speaker producing an output sound.
As mentioned earlier, you seem to be disagreeing with work = force * distance moved in the direction of the force plus Newton's third law.

No I'm disagreeing with your (mistaken) claim that the "rate of work done by the cone on the air is the product of the cone velocity and the air pressure". You used that statement to disagree with me that a cone could do negative work while moving through air, but actually, your revised statement above shows that it can if the air is pushing the cone.  Now consider what happens if you are not in freespace, which means the cone is being pushed by the air... 

I am wondering if you might have been mislead by the word impedance.

Why would you wonder that?  I made no mention of impedance at all.  Its definition has no bearing on anything I said and you are completely missing the point.  Stop assuming you understand this as well as you think you do, and if you won't consider the implications of my example, at least read xnor's (which you seem to have ignored entirely). 

Re: Audible differences between neutral speakers

Reply #28
As mentioned earlier, you seem to be disagreeing with work = force * distance moved in the direction of the force plus Newton's third law.
No I'm disagreeing with your (mistaken) claim that the "rate of work done by the cone on the air is the product of the cone velocity and the air pressure".
Now we seem to be making some progress. Why don't you think force (pressure*area) * velocity (rate of distance moved in the direction of the force) is not the rate of work done (well flux)? If this is not how mechanical energy is transferred between the cone and the air how is it transferred?

You used that statement to disagree with me that a cone could do negative work while moving through air, but actually, your revised statement above shows that it can if the air is pushing the cone.
I did not intend to disagree with you about anything because I could not make sense of what you were saying. But if you look back to post #13 I said "Given a reasonable cabinet there will be negligible short circuiting of sound in the near field and so the sound from the monopole source will end up in the far field." Would you agree that this statement would seem to rely on an understanding that a vibrating body can both generate and absorb sound?

Now consider what happens if you are not in freespace, which means the cone is being pushed by the air... 
I cannot see why the one follows from the other.

I am wondering if you might have been mislead by the word impedance.
Why would you wonder that? 
Because you were talking about resistors and electricity which had nothing directly to do with sound and cones. I was trying to work out why and your assuming impedance had something to do electricity was a possible explanation.

I made no mention of impedance at all.  Its definition has no bearing on anything I said and you are completely missing the point.
Well at least we are agreed that I have been missing your point. I still am by the way.

Stop assuming you understand this as well as you think you do, and if you won't consider the implications of my example, at least read xnor's (which you seem to have ignored entirely).
I have been asking you questions to try to find out what you are gong on about. Is that the actions of someone that is not interested? I read xnor's post and it didn't seem relevant. If he wants to expand on why it is relevant I expect he will chip in.


Re: Audible differences between neutral speakers

Reply #29
There is no such thing, without a lot of DSP.  Some of the best speakers in the world might have +/-2dB, which is more than enough to be audible.  There's also decay time and lots of room interactions, as others have pointed out.

Sure  but the +/-2 dB of a single free field frequency response measurement is not the only reason why two such speakers would sound different.
"I hear it when I see it."

Re: Audible differences between neutral speakers

Reply #30
You used that statement to disagree with me that a cone could do negative work while moving through air, but actually, your revised statement above shows that it can if the air is pushing the cone.

I did not intend to disagree with you about anything because I could not make sense of what you were saying.

I don't think that solves the problem.  Yes, putting it close means that you measure a larger signal leaving the speaker, but the amount of energy coupled from the speaker into the room depends on the boundary conditions imposed on the room.  If a given room couples less energy, than you will measure a lower amplitude no matter how close you get to the driver. 

What would be required to directly change the measurement significantly is to change the impedance of the air. That is the force experienced by the cone pushing on the air. What is going on at the room boundary is an indirect influence.

You are absolutely disagreeing with my assertion that the amount of energy coupled into the room depends on boundary conditions.  You believe it depends only on impedance.  Let me try to make this clear:  impedance is irrelevant here and you should not even be mentioning it.  The same argument applies to ultrasound in seawater as well as to speakers in air.  What is relevant is how much of the electrical energy introduced into a transducer is coupled into a propagating mode of the medium.  Do you understand, as xnor and I have pointed out, that this depends critically on boundary conditions?  The same electrical excitation could result in positive, negative or even no energy being coupled into the modes of your environment? 

I was trying to work out why and your assuming impedance had something to do electricity was a possible explanation.

Quote me saying anything at all about impedance, let alone making assumptions about it. 

I have been asking you questions to try to find out what you are gong on about. Is that the actions of someone that is not interested?  I read xnor's post and it didn't seem relevant. If he wants to expand on why it is relevant I expect he will chip in.

You are just asking questions . . . except about the things you don't understand.  I think you are interested merely in arguing. 

Re: Audible differences between neutral speakers

Reply #31
Why don't you think force (pressure*area) * velocity (rate of distance moved in the direction of the force) is not the rate of work done (well flux)?
The cone has two sides, so the velocity is positive on one side and negative on the other. Does this mean that the code does positive work on one side and negative work on the other?

Re: Audible differences between neutral speakers

Reply #32
You are absolutely disagreeing with my assertion that the amount of energy coupled into the room depends on boundary conditions.
I am saying it is an indirect influence not that it is wrong whereas the mechanical energy being transferred from the cone to the air is the direct measure (product of the pressure and velocity at the cone surface). So why complicate things unnecessarily by introducing a range of indirect factors?

You believe it depends only on impedance.  Let me try to make this clear:  impedance is irrelevant here and you should not even be mentioning it.
I am afraid that impedance (force/velocity) is the jargon engineers and scientists use to express how well energy transfers across an interface. It is simply the ratio of the two quantities involved. When you didn't seem to understand I changed to force * distance moved in the direction of the force which is broadly school level physics talk for the same thing.

What is relevant is how much of the electrical energy introduced into a transducer is coupled into a propagating mode of the medium. 
Why do you think what is going on inside the speaker is relevant? The transfer of mechanical energy happens at the surface of the cone and that would seem to be all that needs to be considered.

Do you understand, as xnor and I have pointed out, that this depends critically on boundary conditions? 
I understand reasonably well how a moving cone produces sound. I am aware but have omitted qualifications about the proportion of mechanical energy transferred to sound rather than other forms of air motion and other forms of energy that may be involved.

The same electrical excitation could result in positive, negative or even no energy being coupled into the modes of your environment? 
But will it do so without changing the impedance? And so might it be simpler just to consider that?

You are just asking questions . . . except about the things you don't understand. 
I have been asking about what you are going on about and I didn't understand that.

I think you are interested merely in arguing. 
Since your tone degenerated I must confess to a small degree of teasing but this wasn't present earlier when chatting about what it would take for low frequency near field measurements in rooms to become significantly inaccurate.


Re: Audible differences between neutral speakers

Reply #33
The same electrical excitation could result in positive, negative or even no energy being coupled into the modes of your environment? 
But will it do so without changing the impedance?

Of the medium?  Absolutely, xnor gave you an example of that.

I'm not going to address the rest of your argument until you at least understand that. 

Re: Audible differences between neutral speakers

Reply #34
Why don't you think force (pressure*area) * velocity (rate of distance moved in the direction of the force) is not the rate of work done (well flux)?
The cone has two sides, so the velocity is positive on one side and negative on the other. Does this mean that the code does positive work on one side and negative work on the other?
Not really. The pressure and velocity is changing with time. If for simplicity it is varying sinusoidally then if the peaks of pressure and velocity are misaligned then pressure*velocity will be positive for some of the time and negative for some of the time over a period. Depending on the alignment the sum can be positive, zero or negative. It is the same mechanism for pushing (force) someone on a moving (velocity) swing. Depending on the timing of the pushing energy can be put into the motion or taken out of it.

So for a given cone motion different air pressures at the cone surface can put energy into the sound or take energy out of the sound. So you could have positive or negative work on both sides of the cone but normally on average energy is transferred from the cone to the sound waves in the air which then clear off and get dissipated elsewhere with only a small proportion coming back and changing the pressure around the cone.

Re: Audible differences between neutral speakers

Reply #35
Frequency alone is not sufficient  to describe neutrality or overall sound. A violin and a trumpet may hit the same primary frequency but the timbre will be completely different. How the headphones handle the added complexities of real music cannot be determined by a frequency sweep.. 02$

Re: Audible differences between neutral speakers

Reply #36
What is timbre other than multiple frequencies at once? 

What are multiple frequencies at once other than a single frequency which is their sum? 
Creature of habit.

Re: Audible differences between neutral speakers

Reply #37
Frequency alone is not sufficient  to describe neutrality or overall sound.
Yeah, I hate when strawguy insists that it is.

A violin and a trumpet..
...are not electro-acoustic transducers. Like HS8 and Neumann KH 120.

How the headphones(?) handle the added complexities of real music cannot be determined by a frequency sweep.. 02$
Please do tell us what can.
Loudspeaker manufacturer

Re: Audible differences between neutral speakers

Reply #38
Frequency alone is not sufficient  to describe neutrality or overall sound.
Yeah, I hate when strawguy insists that it is.

A violin and a trumpet..
...are not electro-acoustic transducers. Like HS8 and Neumann KH 120.

How the headphones(?) handle the added complexities of real music cannot be determined by a frequency sweep.. 02$
Please do tell us what can.

Well no, the transducers are not instruments but they are required to reproduce these timbres, subtle differences etc and some do a different job than others,perhaps appearing harsh to some or others smooth.

Good transducers would come close to accurately reproducing these timbres than others. The only thing I can think of that would guaranteed be accurate to the listener would be their ears and brain to differentiate these complexities with maximal accuracy. The transducers job is to mimic the source as accurately as possible.

Re: Audible differences between neutral speakers

Reply #39
Well no, the transducers are not instruments
Right, not the transducers were are referencing.

but they are required to reproduce these timbres, subtle differences etc and some do a different job than others,perhaps appearing harsh to some or others smooth.
Right, so what outside FR and cumulatives like sound power accounts for this timbral harshness, according to you?

Good transducers would come close to accurately reproducing these timbres than others.
Via??

The transducers job is to mimic the source as accurately as possible.
The transducers "source" is an electrical signal. Of unknown providence. I assume you understand what "transduce" means?

Loudspeaker manufacturer

Re: Audible differences between neutral speakers

Reply #40
If we take for a thought experiment a loudspeaker that has a "perfect" response (you define "perfect" however you like) and place it in one spot in any room that is not a perfect anechoic chamber and measure it, move it a few inches and measure it again, I believe there will in fact be easily measurable differences in the two positions.  And they will likely be audible differences, too.

I have never actually tested this myself, though.
Ed Seedhouse
VA7SDH

Re: Audible differences between neutral speakers

Reply #41
Yes you can easily find difference between different type of speakers. I even found the same in earbuds that I use, the one that I received with my headphone tend to be making a lot of echoing noises while the other that I purchased over Amazon had pleasant sound and works well for me.

Besides they both were used on the same platform and with metrics. Also it depends on the user who is hearing the sound from them as we all have different types of hearing ability.

Re: Audible differences between neutral speakers

Reply #42
@maverick1245 What do you mean by "same platform and with metric"? Hopefully not the same "20-20k Hz" FR and "16 ohm" impedance numbers on the spec sheet. Those are almost completely useless. :s

Two completely different sounding headphones can have the same specs... that's not what we're talking about here.

There's a similar problem with headphones as with speakers. Different ears, ear canals, even head shapes of the users and placement will change the sound.
"I hear it when I see it."

Re: Audible differences between neutral speakers

Reply #43
I stumbled across this research the other day:

http://www.gedlee.com/distortion_perception.htm

From one of the letters, "The bottom line here is that we know so little about how humans perceive the sound quality of an audio system, and in particular the loudspeaker, that one should question almost everything that we think we know about measuring it.  From what we have found most of what is being done in this regard is naive.  Things like distortion measurements that don’t consider masking, or axial frequency response that does not consider the reverberant field or arrival time issues of group delay."

Re: Audible differences between neutral speakers

Reply #44
---written in 2005. 




Re: Audible differences between neutral speakers

Reply #45
Has there been progress since then?

Re: Audible differences between neutral speakers

Reply #46
From Earl Geddes's POV?  Hard to say.  He already seemed to dismiss the body of work existing up to 2005.  I can't say what he'd make of the body of work since then. So ask him.  Then, for other perspectives, maybe ask Floyd Toole, Sean Olive, and Siegfried Linkwitz.

Re: Audible differences between neutral speakers

Reply #47
From one of the letters, "The bottom line here is that we know so little about how humans perceive the sound quality of an audio system, and in particular the loudspeaker, that one should question almost everything that we think we know about measuring it.  From what we have found most of what is being done in this regard is naive.  Things like distortion measurements that don’t consider masking, or axial frequency response that does not consider the reverberant field or arrival time issues of group delay."
Jut a word of warning: From your way of posting and quoting, I infer that you are leaning towards quote mining. Stop it. It won't work.

Re: Audible differences between neutral speakers

Reply #48
What is quote mining?

Re: Audible differences between neutral speakers

Reply #49
From Earl Geddes's POV?  Hard to say.  He already seemed to dismiss the body of work existing up to 2005.  I can't say what he'd make of the body of work since then. So ask him.  Then, for other perspectives, maybe ask Floyd Toole, Sean Olive, and Siegfried Linkwitz.

Well, the JBL's I'm enjoying right now seem to do a good job handling off-axis FR.  I don't know how to measure their group delay, etc.