[spott]

what is the point of making extreemly high impedence headphones (such as the hd600's) from what i have heard, there is no difference, the ER4p and ER4s are the same headphone except the 4p's have less impedence, this doesn't make sense to me, please explain.


thanks

 

[blessingx]

I'm still confused, but this is related.

 

[LTUCCI1924]

HI: This bothers me too. I think that the high ohmage cans need a lot of power and sound very full sounding with the power but my AT A1000 that are only 40 ohms sound great with a little or a lot of power. I stopped buying high ohmage cans.

 

[JaZZ]

Brave assertion: There's no special relation between impedance and sound (quality).

But there are special relations between amps and impedances. Some amps handle high impedances better (e.g. tubes), some prefer low impedances, such as portables with their not so strong built-in amps (caution: some of them suffer from a bass roll-off with low impedances)..., and to complicate the whole thing: depending on the headphone or its specific sound (!), resp. (synergy!) But I'm sure: there's no such thing as an «impedance sound».

 

[DanT]

What I'm wondering is what happen with the ety P -> S converter. Same phone different impedance. Why do people think S amp sound better then a P amp (otherwise why do people pay 50$ for a converter if there is no difference ,ok there the no official converter that cheaper but)

There is a difference in their respond curve If we look at the graph ety provide. Better match with the amp or maybe better match with the driver?

 

[JaZZ]

The adapter («converter») switches an additional serial resistance of ~80 ohm into the signal path (the «P» has already 22 ohm in series) which interacts with the driver's impedance curve, thus creating a different frequency response. Note that the driver itself has only 5 ohm nominally.

Amps with high output impedances have a similar influence on headphones' frequency responses, although gradually different: e.g. 120 ohm in series to a 300 ohm headphone have a minor impact than in series to a 32 ohm headphone. But it's also clear that the headphones' impedance curves play an important role: the flatter, the minor the sonic impact of serial resistances.

 

[gerG]

I am not sure, but I will conjecture for the sake of argument.

There is a significant difference between a high impedance driver, and a low impedance driver with a resistor in series.

A high impedance driver has, I think, more windings in the coil. This will result in a motor system with much higher force for a given current. This should yield a "stiff" system. That is, the normal inconsistencies and nonlinearities are a small percentage of the primary signal. I believe that it also creates a higher back emf, which results in better electrical damping and driver control.

Low impedance coils rely on fewer windings, and lower force for a given current. The advantage is lower mass, and higher force at a given voltage due to the higher current allowed by the low impedance. Disadvantage is difficulty of controling driver motion, and nonlinearities become a large factor.

This is just based on a conceptual anderstanding of the components. I anxiously await an informed EE to straighten me out, and to please explain what the hell I am talking about, because I really want to know!


gerG

 

[Mike Scarpitti]

Quote:

Originally posted by gerG I am not sure, but I will conjecture for the sake of argument. There is a significant difference between a high impedance driver, and a low impedance driver with a resistor in series.

Aren't some phones available in two different impedence versions, depending on what kind of amp they are to be used with?

 

[spott]

okay, now to futher the question:

the whole theory of impedance is that you want a large output impedance, and a small input impedance so that most of the signal is dropped across the speakers. however, with large impedance headphones this seems counter productive, you don't get as much of the signal, so therefore they theoretically can't give off as much detail in music as a low impedance driver.

this probably just confuses things, but do try to explain

 

[JaZZ]

Quote:

Originally posted by gerG There is a significant difference between a high impedance driver, and a low impedance driver with a resistor in series.

That's for sure. But the Etys are a great exception in this regard. Normally the only serial resistance on the headphones' side is the cord - and this is negligeable.

Quote:

A high impedance driver has, I think, more windings in the coil. This will result in a motor system with much higher force for a given current. This should yield a "stiff" system. That is, the normal inconsistencies and nonlinearities are a small percentage of the primary signal. I believe that it also creates a higher back emf, which results in better electrical damping and driver control.

Actually (from what I know) the back EMF is the only factor worth considering when it comes to «control» - and it's limited to the bass resonance. In the remaining frequency range there's virtually no control of the voice coil's vibration, be it with high or low driving force. This has been measured BTW on loudspeakers with very different magnetic field forces, but otherwise the same components.

Quote:

Low impedance coils rely on fewer windings, and lower force for a given current. The advantage is lower mass, and higher force at a given voltage due to the higher current allowed by the low impedance. Disadvantage is difficulty of controling driver motion, and nonlinearities become a large factor.

I doubt the last part, according to what's mentioned above. As to the moving mass: low-impedance voice coils are not necessarily associated with low mass; they may just as well have a larger wire diameter (and they probably have indeed) - for higher efficiency and higher load capacity.

 

[wallijonn]

rather than re-iterate my position on impedance, as I put forth my position in http://www4.head-fi.org/forums/showt...threadid=34127, the shockwave program in http://users.erols.com/renau/impedance.html is enlightening as one can see what happens to phase shift as a function of resonance shift when capaitance and resistance is changed within a circuit with a constant inductance. The problem with the program is that low enough values can not be inserted, which headphones operate in. Note where it says "This graph also displays Xl and Xc and illustrates the fact that at frequencies much lower than the resonant frequency the circuit is mostly capacitive (Z is close to Xc, a hyperbolic function of f), that at frequencies much higher than the resonant frequency the circuit is mostly inductive (Z is close to Xl, proportional to f), and that at resonance Xl = Xc."

I have stated before that a high impedance headphone sounds better because it tends to go into distortion (by virtue of the fact that it can handle more power before it distorts) at a more gradual rate than a lower impedance headphone which could be limited by the amplifier's voltage and current due to its difference in inductance. (The question then is, what is the inductance of a driver in a high impedance headphone, and what is the nominal average of inductance in low impedance drivers?) Such distortion inducement is directly correlated to the fact that the amp can only supply a finite amount of current or voltage, by virue of its being limited by its bias voltage and the amount of current that the transistors (and therefore, also, ICs) can safely pass through to the output circuit.

Since the ETYs are supposedly rated at 5 ohms, has anyone connected them directly to the output leads of a home speaker amplifier? (sure, you can blow them up by feeding more than one watt, I just hope that the amp has a logrithmic volume potentiometer than a linear one, so that the power can be turned up gradulally.) But it does tell me that a 1 watt @ 8 ohm amplifier should be able to drive it safely to the same sonic levels as a headphone amplifier which is rated at 1 watt at 120 ohms (the SAC for one).

or do low impedance headphones sound best when driven by transistors and high impedance headphones sound best when driven by tubes? The Sony CD3000 can not be molded to fit these hypossesies.

 

[cscott23]

Quote:

Originally posted by gerG I am not sure, but I will conjecture for the sake of argument. There is a significant difference between a high impedance driver, and a low impedance driver with a resistor in series. gerG

That's correct for two reasons:

A resistor's impedance is not frequency dependent--whereas, a driver's impedance is.

A resistor in series with the driver "steals" some of the voltage from the driver. In the case of the ety's, this turn out to be quite a bit (and ever more power).

Good post.

 

[cscott23]

Quote:

Originally posted by spott the whole theory of impedance is that you want a large output impedance, and a small input impedance so that most of the signal is dropped across the speakers. however, with large impedance headphones this seems counter productive, you don't get as much of the signal, so therefore they theoretically can't give off as much detail in music as a low impedance driver.

Other way around. You got it backwards.

amp output=small

driver=big

 

[cscott23]

Quote:

Originally posted by wallijonn (The question then is, what is the inductance of a driver in a high impedance headphone, and what is the nominal average of inductance in low impedance drivers?) .

Inductance is constant. Impedance varies proportionally (if memory serves) to the inductance.

 

[wallijonn]

Scott,

what I am asking is if low impedance drivers have a low inductance, say 100 mH, versus a high impedance driver which may have, say, 500 mH, or if they are all in the same range.

inductance will vary slightly as current flows through it. infinitesimally, perhaps, but heat should affect it.