What causes impedance?

[Jack H]

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.

Yeah, that helps a bit

[Valhallatier]

The material and the thickness state the impedance. 50mm driver doesn't always mean its hard to drive.
Though keep in mind most impedance rating are at 1khz impedance, not the whole thing. beyerdynamic T1 reaches up to 1400ohm btw ...

[frozeefrank]

impedence for hp or speaker is the same thing. The higher impedence, the more dc you need to make the driver(speaker)move. That means the amp/da needs to push more to produce less. It affects the accuracy at which the speaker can translate an electrical signal to a sound wave. The reason why "high-end hp" often have higher impedence is simply because the audio quality is noticably better with high impedence comapred to low impedence. And high end headphones are, most often than not, use in "professional"environment (recording/mixing studio) where the gear is able to push higher impedence.

[mr moose]

impedence for hp or speaker is the same thing. The higher impedence, the more dc you need to make the driver(speaker)move. That means the amp/da needs to push more to produce less. It affects the accuracy at which the speaker can translate an electrical signal to a sound wave. The reason why "high-end hp" often have higher impedence is simply because the audio quality is noticably better with high impedence comapred to low impedence. And high end headphones are, most often than not, use in "professional"environment (recording/mixing studio) where the gear is able to push higher impedence.

 

sorry, that's all wrong.

 

Read from post 29 on for a few explanations that are accurate.

[ManWithBeard1990]

It mostly depends on whether the coils in the drivers have many thin windings, or fewer thicker ones. More windings require more voltage (but less current) to drive at the same power level. This need for a stronger signal for the same volume helps with signal to noise ratio.

[Whit3Rav3n]

It mostly depends on whether the coils in the drivers have many thin windings, or fewer thicker ones. More windings require more voltage (but less current) to drive at the same power level. This need for a stronger signal for the same volume helps with signal to noise ratio.

Actually the trick is that you need the same amount of windings for a given inductance at given coil dimensions regardless of the coil wire thickness. Therefore the voice coils of low impedance headphones tend to be heavier.

[ManWithBeard1990]

Actually the trick is that you need the same amount of windings for a given inductance at given coil dimensions regardless of the coil wire thickness. Therefore the voice coils of low impedance headphones tend to be heavier.

That's not how it works at all. Yes you need the same amount of windings to get the same inductance, but you actually want a higher inductance for a higher impedance. That's the difference between impedance and resistance, you see. Impedance is like resistance to alternating current, and is composed of not only resistance but also, and more importantly, the inductance, which is the coil resisting not so much the current itself, but rather the rapid changes in current like you'd find in an audio signal.

[Whit3Rav3n]

That's not how it works at all. Yes you need the same amount of windings to get the same inductance, but you actually want a higher inductance for a higher impedance. That's the difference between impedance and resistance, you see. Impedance is like resistance to alternating current, and is composed of not only resistance but also, and more importantly, the inductance, which is the coil resisting not so much the current itself, but rather the rapid changes in current like you'd find in an audio signal.

That depends on the design, for example beyerdynamic has the same headphone in different impedance version. The only thing they changed is the wire thickness. So in that case the higher impedance versions have a lighter voice coil. I already know the definition of impedance.

[mr moose]

O.K, now all you smarty pants people out there, explain why it is a component of inductance and not simply  back EMF.

 

Here's a confusing statement to consider:

 

Given that you can use back emf to measure the rpm and position of a motor due to the back emf being proportional to armature speed (in the case of a driver the armature moves forward and back not around, so the speed would be measured in Hz), this would be how we can determine the freq being played by the impedance measured (or Voltage drop) without actually listening to or measuring the output.

[Whit3Rav3n]

O.K, now all you smarty pants people out there, explain why it is a component of inductance and not simply  back EMF.

 

Here's a confusing statement to consider:

 

Given that you can use back emf to measure the rpm and position of a motor due to the back emf being proportional to armature speed (in the case of a driver the armature moves forward and back not around, so the speed would be measured in Hz), this would be how we can determine the freq being played by the impedance measured (or Voltage drop) without actually listening to or measuring the output.

You can not really speak of back EMF in speakers. Back EMF is the induced current in a coil due to an externally changing magnetic field. This is for example the case in PMSM and BLDC motors where the rotor has permanent magnet pole pairs. When the rotor rotates the magnetic field changes in the coils due to the rotating magnets and this creates an induced current that is independent from supply current changes. In speakers the magnets are stationary and the coil ideally should not leave the homogeneous magnetic field of the permanent magnets. In this case there is only the effect of the inductance caused by the changing magnetic field induced by the coil itself due to the alternating supply current. So in short:

 

Back EMF: Current induced by a changing external magnetic field

 

Inductance: Current induced by the changing magnetic field that is induced by the coil itself due to changing supply current.

[mr moose]

You can not really speak of back EMF in speakers. Back EMF is the induced current in a coil due to an externally changing magnetic field. This is for example the case in PMSM and BLDC motors where the rotor has permanent magnet pole pairs. When the rotor rotates the magnetic field changes in the coils due to the rotating magnets and this creates an induced current that is independent from supply current changes. In speakers the magnets are stationary and the coil ideally should not leave the homogeneous magnetic field of the permanent magnets. In this case there is only the effect of the inductance caused by the changing magnetic field induced by the coil itself due to the alternating supply current. So in short:

 

Back EMF: Current induced by a changing external magnetic field

 

Inductance: Current induced by the changing magnetic field that is induced by the coil itself due to changing supply current.

 

now consider that the coil (armature) does not have to be static, so when the voice coil moves through the magnet field lines a counter force is generated, this is back emf.  Back emf only requires a coil (armature or VC) to travel across a magnet flux.

[Whit3Rav3n]

now consider that the coil (armature) does not have to be static, so when the voice coil moves through the magnet field lines a counter force is generated, this is back emf.  Back emf only requires a coil (armature or VC) to travel across a magnet flux.

No, back EMF needs a changing magnetic field. In the speaker the permanent magnetic field is ideally pretty much constant across the way of the coil so there is no back emf.

[mr moose]

No, back EMF needs a changing magnetic field. In the speaker the permanent magnetic field is ideally pretty much constant across the way so there is no back emf.

 

Back emf only needs the armature to move through a magnetic flux, it does not matter if it is the magnet that moves or the armature.  Most motors have static magnets and the coils rotate.  The only difference between a motor and a driver is the output force is rotation on one and linear on the other.

[Huntsman]

This topic has officially become a flame war spot for EE engineers...

[BoredErica]

I don't care really, HA > All other EEs.

[Lutkeveld]

HA?

[Lays]

HA?

 

http://www.hydrogenaud.io/forums/

 

it's some website wizzie nut-rides  (it's ok I ain't judgin, wizzie is my pal)

[creatip123]

http://www.hydrogenaud.io/forums/

 

it's some website wizzie nut-rides  (it's ok I ain't judgin, wizzie is my pal)

 

What does that forum gotta do with wizzie's nut(s)??

[ShearMe]

What does that forum gotta do with wizzie's nut(s)??

 

[mr moose]

This topic has officially become a flame war spot for EE engineers...

 

really, looks more like a conversation to me. 

 

So it appears someones nuts might be the cause of impedance,  makes sense though,  I would feel impeded too if it involved someone elses nuts.