What causes impedance?

[KingDaddyDaniel]

It's not that easy. Even if you have the best drivers and what not in a speaker, it'll sound like shit if the enclosure isn't a good design. It takes a lot of R&D to make a quality speaker.

I'm referring more towards the sales of speakers(drivers). Not speakers with enclosures. Stock enclosures are usually pretty shit, even with home theater systems.

[mr moose]

Yep, my bad. Confused 0 ohms with 1 ohm.

Also, if you pay attention to Newton's third law, then you'd know that it's impossible for a true superconductor to exist.

You'd have to reach absolute zero for a superconductor to actually exist (not possible on this planet)

 

When you increase the amps(I) and the voltage(V) remains the same, then resistance® decreases. R = V/I or 0.15Ohm = 12Volts/80Amps and if you increase the amps then the resistance will decrease 0.096Ohm = 12Volts/125Amps

 

No.  Resistance does not change and is dictated by the conductance of a material, it does not change when you change the voltage or the current.

 

Impedance on the other can increase and decrease because it is not resistance but the result of reactance in an inductor. 

[KingDaddyDaniel]

No.  Resistance does not change and is dictated by the conductance of a material, it does not change when you change the voltage or the current.

 

Impedance on the other can increase and decrease because it is not resistance but the result of reactance in an inductor. 

The definition of impedance is literally resistance.

[mr moose]

The definition of impedance is literally resistance.

no it's not.

 

 

In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current (AC) circuit. Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude. When a circuit is driven with direct current (DC), there is no distinction between impedance and resistance; the latter can be thought of as impedance with zero phase angle.

 

 

It is erroneous to refer to it as resistance because resistance is typically a DC characteristic,  AC has capacitance and inductance that also plays a role in the effects of impedance.

[KingDaddyDaniel]

no it's not.

 

 

 

It is erroneous to refer to it as resistance because resistance is typically a DC characteristic,  AC has capacitance and inductance that also plays a role in the effects of impedance.

Mkay, so I'd like to point out that being a troll is against CoC and with your high post count I'd advise against any further ignorance.

[mr moose]

Mkay, so I'd like to point out that being a troll is against CoC and with your high post count I'd advise against any further ignorance.

 

what?  Maybe you should do some research before accusing people of trolling when you clearly don't know what you are talking about.

[Lutkeveld]

Mister moose is right tho. Impedance with headphones is frequency dependant resistance

[DigitalHermit]

Most planar magnetic headphones range from 38-70 ohm, there is only 1 that I know off the top of my head that is above 100 ohm, and that is the Audeze LCD-3 Fazor(130ohm).

 

Thanks for clarifying my misconception...

 

Edit:

@KingDaddyDaniel,

@mr moose is correct in his explanation. We're talking AC here so capacitance and inductance play a role in impedance...

 

Here are some basic equations: http://en.wikipedia.org/wiki/Electrical_impedance#Device_examples

[KingDaddyDaniel]

Thanks for clarifying my misconception...

 

Edit:

@KingDaddyDaniel,

@mr moose is correct in his explanation. We're talking AC here so capacitance and inductance play a role in impedance...

 

Here are some basic equations: http://en.wikipedia.org/wiki/Electrical_impedance#Device_examples

Where do headphones use AC electricity? Where I live (United States) and with every speaker system I've ever tuned it's only ever been DC.

My bad. I didn't know there was a such thing as AC speakers

[Lutkeveld]

Seems likw you don't know what you're talking about. Every sound signal is AC

[mr moose]

Where do headphones use AC electricity? Where I live (United States) and with every speaker system I've ever tuned it's only ever been DC.

My bad. I didn't know there was a such thing as AC speakers

 

All sound signals are AC,  it is the frequency (number of times the signal alternates back and forth in one second) of this signal that gives sound the higher and lower pitches and the shape of the wave form that gives sound its character.  For example the sound of a violin would  look a bit like a sawtooth, while a clean note would be sinusoidal. The more times it alternated per second the higher the pitch. 

[DigitalHermit]

Where do headphones use AC electricity? Where I live (United States) and with every speaker system I've ever tuned it's only ever been DC.

My bad. I didn't know there was a such thing as AC speakers

 

The signal coming from the earphone jack is a varied-voltage (you can test it out with an oscilloscope)... It's not exactly a constant frequency AC (unless you're playing a clean, constant tone)....

 

The rapid changes in voltage causes the speaker to vibrate... It's the basic concept of speakers...

 

I can go a bit more in depth if you want...

 

Edit: ninja'd by @mr moose

[t0wer]

Where do headphones use AC electricity?

 

 

everywhere, because inductors pass DC and will just heat up destroying the driver.

 

inductors block AC through inductance and reactance, limiting the current.

[Lutkeveld]

I want to point out that speaker have a resistance, but it isn't as relevant as the impedance.

It's often called DCR or Re, the (dc) resistance of the voice coil.

It will be fairly stable but can be increased by some factors.

Impedance on the other hand is not stable at all and will vary depending on the frequency.

The impedance spike is at the resonance frequency (Fs) an Re is often 0.7*Znom

 

also: DC won't destroy a driver if it's within the limits of it's power handling. A lot of people test the polarity of a driver with a 9v battery for example.

[Whit3Rav3n]

Basically impedance comes from the inductance of the voice coil. When the voice coil moves through the magnetic field it actually induces a voltage that is opposite of the supply voltage. This causes additional resistance to the DC resistance of the coil. Also higher end headphones tend to be high impedance because you ideally want a high inductance and low weight coil. Inductance is defined by the number of winding of the coil (at given dimensions). To keep the weight low at a given inductance the wires need to be as thin as possible. This results in higher DC resistance and also higher overall impedance.

[ShearMe]

I'm not even sure which questions have been answered and which ones haven't so far...

[BoredErica]

Somebody on another forum wants to know "what causes impedance" in "high end headphones". Anybody care to explain thoroughly? The thread here (http://linustechtips.com/main/topic/243801-what-causes-impedance/ ) is probably full of BS answers and I want to know which answers are BS.

 

Two questions actually - what causes impedance, and Why do higher end headphones have higher impedance.

 

Impedance in headphones is caused by the combination of two electrical properties - reactance and resistance.  There are two kinds of reactance, capacitive and inductive.

 

Capacitive reactance is caused by two electrical conductors being separated by an insulating material called a dielectric.  Any insulator can be a dielectric. When you separate two conductors by a dielectric you create a capacitor which is an electrical device that stores energy in an electrostatic field whose intensity increases with the size of the voltage between the two conductors, the area of the two conductors that is exposed to each other, the absence of distance between the conductors, and also what is called the dielectric constant of the insulator.  A capacitor resists changes in the voltage that is dropped across it.

 

Inductive reactance is caused by current flowing through a conductor such as a copper wire. Winding wire in a spiral increases inductance. Putting magnetic materials inside the spiral increases inductance. Placing wires closer together increases inductance. A device that has inductance is called an inductor and it stores energy in the magnetic field that is always around it. The intensity of the energy stored in an inductor increases with the current flow. An inductor resists changes in the current flowing through it.

 

Resistance is a property of conductors that is neither capacitance nor inductance. It only dissipates energy and does not store it. Generally making conductors longer and thinner increases resistance.

 

Not surprisingly, a coil of wire has inductance and resistance. It may not be intuitive that a coil of wire also has capacitance, but it does.

 

The voice coils in earphones, therefore have some combination of reactance of both kinds, and also resistance. These, plus the mechanical connection between the diaphragm of the earphones and the mechanical properties of the diaphragm and the voice coil dictates the impedance curve of the earphones.

 

There is no necessary connection between the price of earphones and their impedance. If the voltage sensitivity of headphones can be kept high enough, a higher impedance makes them easier to drive.  Historically headphones have been driven from high impedance sources, and so there is a tradition of making headphones with high impedance.  Today, most headphones are driven by portable digital players which generally have limited voltage capabilities. This makes lower impedance headphones a more practical choice.

Arguing against Arnold typically results in him getting annoyed and the person arguing losing. 

[Jack H]

Impedance is the electrical resistance of your headphones/speakers. Factors affecting impedance include driver design, driver size (which impacts the length/dimensions of the voice coil for dynamic drivers for example). Usually, large drivers have higher electrical resistance.

 

As for 'causing' impedance...the electrical resistivity of the copper (or whatever) coil(s) used. Feel free to ask more specific questions

Awesome, thanks. Also, what component/mechanism common to high end headphones that is not commonplace in low end causes high impedance?

[steffen_anywhere]

Awesome, thanks. Also, what component/mechanism common to high end headphones that is not commonplace in low end causes high impedance?

 

This may give you some interesting information:

 

Dynamic drivers are the most common drivers present in headphones. This ranges from budget to high-end (e.g. Sennheiser HD800). As you get to the higher end, other driver designs such as planar magnetic drivers are used, which have higher impedance by design. Higher-end dynamic headphones can also have larger drivers that have a higher impedance. These two are usually the reasons.

 

As someone said before, high impedance does not mean 'high end' and vice versa. But mainstream headphones are designed to work with weaker amps (to work on iPods, phones, etc...), which means that they require lower impedance.

[BoredErica]

This may give you some interesting information:

 

Dynamic drivers are the most common drivers present in headphones. This ranges from budget to high-end (e.g. Sennheiser HD800). As you get to the higher end, other driver designs such as planar magnetic drivers are used, which have higher impedance by design. Higher-end dynamic headphones can also have larger drivers that have a higher impedance. These two are usually the reasons.

 

As someone said before, high impedance does not mean 'high end' and vice versa. But mainstream headphones are designed to work with weaker amps (to work on iPods, phones, etc...), which means that they require lower impedance.

I'm sorry, but almost all of us already know this. And planar magnetics tend to have lower impedances.

[steffen_anywhere]

I'm sorry, but almost all of us already know this. And planar magnetics tend to have lower impedances.

 

It was directed at the person that I quoted, i.e. the one who specifically asked that question. Sorry for trying to be helpful...

 

And sorry about the planar magnetic mistake, I got that mixed up then, I'm gonna rely on you saying that I'm incorrect as you have much more expertise here I assume...

[BoredErica]

It was directed at the person that I quoted, i.e. the one who specifically asked that question. Sorry for trying to be helpful...

 

And sorry about the planar magnetic mistake, I got that mixed up then, I'm gonna rely on you saying that I'm incorrect as you have much more expertise here I assume...

I know, what I was getting at is that your points have been repeated multiple times in this thread already. I know you're trying to be helpful, that's why I didn't flip out.

Anyways, planars like HE-6 have low impedance but very low sensitivity, making them it hardest to drive. HE-6 is going to require a motherload of current, whereas the DT990 600ohm is going to require a lot of voltage. HD800s are not that hard to drive (relatively). Although, I heard there is an Audeze prototype planar headphone that will have ludicrously high impedance, so we might see a very high impedance planar in the future.

[Huntsman]

more coils, connectors and higher amps would reduce impedance.

More coils allows power to flow easier(less resistance).

More connections to the coils increases power being shoved through total amount of wires and coils.

More amps causes more inefficient power usage, but also reduces impedance.

 

When you approach 1Ohm you would start to turn the wires into a super-conductor and (theoretically) reach 1Ohm. If we had a metal that could sustain enough amperage being flown through it to reach 1Ohm, then we would have the world's first superconductor.

 

eh... nope..

 

Yep, my bad. Confused 0 ohms with 1 ohm.

Also, if you pay attention to Newton's third law, then you'd know that it's impossible for a true superconductor to exist.

You'd have to reach absolute zero for a superconductor to actually exist (not possible on this planet)

 

When you increase the amps(I) and the voltage(V) remains the same, then resistance® decreases. R = V/I or 0.15Ohm = 12Volts/80Amps and if you increase the amps then the resistance will decrease 0.096Ohm = 12Volts/125Amps

 

Yes, there is no true superconductor. The so called superconductors nowadays are just conductors with small enough resistance for the resistance to be ignored. And resistance is usually fixed, unless changed by external factors such as temperature etc, NOT the voltage and current.

 

 

No.  Resistance does not change and is dictated by the conductance of a material, it does not change when you change the voltage or the current.

 

Impedance on the other can increase and decrease because it is not resistance but the result of reactance in an inductor. 

Right and wrong. Resistance is the inverse of conductance of any material. To put it in a simple way, the RESISTIVITY of any material is fixed, but the dimensions of the said material dictates the RESISTANCE of the product made from said material.

 

resistance = (resistivity x area) / length

 

Impedance is the result of BOTH the inherited capacitance and inductance of a component in AC environment. This is because capacitors and inductors both behave differently in high and low frequency. Thus giving a different impedance at different frequency. Usually in the audio domain, 1kHz is used as standard. So the impedance you see labeled is the impedance of the coils at 1kHz.

 

fyi, resistance is usually refering to conditions in DC.

 

The definition of impedance is literally resistance.

 

Again, right and wrong. Refer to my answer to mr.moose. Impedance at low enough frequency can be considered resistance, other than that, nope. Just abit of an extra info, 0Hz is DC since there are no oscillations. In the audio world, if you're getting DC into your headphones, you will burn your headphones. This is why some audiophiles are so nervous about DC offsets, it meant there are DC components going into their precious headphones and make bonfires out of the coils.

 

 

 

Finally, to answer OP's question about what causes impedance. Impedance in headphones is caused when you coil wires to form the driver. Coils of wire exhibits inductive properties in which resists the change of current flow(You might want to check out Lenz's Law for more info). This "resistive" properties are not the same when the rate of change of current differs thus giving different impedance at different frequencies. Since audio signals are a form of AC which changes the direction of current rapidly, the audio source (in this case your amplifier) experiences impedance as it tries to power the load(the coils of your headphones).

 

The higher the impedance, the harder the source has to drive the load since it needs to swing at larger magnitude to deliver the same amount of power.

This is why people suggest you get a proper amplifier when you have a high impedance headphones.

 

 

Source: About to finish my Degree in Electrical and Electronics Engineering

[mr moose]

eh... nope..

 

 

Yes, there is no true superconductor. The so called superconductors nowadays are just conductors with small enough resistance for the resistance to be ignored. And resistance is usually fixed, unless changed by external factors such as temperature etc, NOT the voltage and current.

 

 

Right and wrong. Resistance is the inverse of conductance of any material. To put it in a simple way, the RESISTIVITY of any material is fixed, but the dimensions of the said material dictates the RESISTANCE of the product made from said material.

 

resistance = (resistivity x area) / length

 

Impedance is the result of BOTH the inherited capacitance and inductance of a component in AC environment. This is because capacitors and inductors both behave differently in high and low frequency. Thus giving a different impedance at different frequency. Usually in the audio domain, 1kHz is used as standard. So the impedance you see labeled is the impedance of the coils at 1kHz.

 

fyi, resistance is usually refering to conditions in DC.

 

 

Again, right and wrong. Refer to my answer to mr.moose. Impedance at low enough frequency can be considered resistance, other than that, nope. Just abit of an extra info, 0Hz is DC since there are no oscillations. In the audio world, if you're getting DC into your headphones, you will burn your headphones. This is why some audiophiles are so nervous about DC offsets, it meant there are DC components going into their precious headphones and make bonfires out of the coils.

 

 

 

Finally, to answer OP's question about what causes impedance. Impedance in headphones is caused when you coil wires to form the driver. Coils of wire exhibits inductive properties in which resists the change of current flow(You might want to check out Lenz's Law for more info). This "resistive" properties are not the same when the rate of change of current differs thus giving different impedance at different frequencies. Since audio signals are a form of AC which changes the direction of current rapidly, the audio source (in this case your amplifier) experiences impedance as it tries to power the load(the coils of your headphones).

 

The higher the impedance, the harder the source has to drive the load since it needs to swing at larger magnitude to deliver the same amount of power.

This is why people suggest you get a proper amplifier when you have a high impedance headphones.

 

 

Source: About to finish my Degree in Electrical and Electronics Engineering

you say tomato and I'll say tomato.

[BoredErica]

you say tomato and I'll say tomato.