[plonter]

I also didn't find anything wrong with the title.  as much as i will read and learn about impedance and sensetivity i will never figuere it out completely...I am just stupid i guess

at first i though that it is related only to impedance...the highest the harder to drive.  but than i read in head fi that also low impedance are hard to drive (i also saw the formula) usually the ones with the low sensetivity too.
most of the grado models have impedance value of 32ohm (pretty low) and sensetivity value of 98db which is also considered very low in the headphone world.   so what is the logic about them being very easy to drive?   they always say that low impedance are hard to drive and need a lot of power, now i guess that they usually means those with the rather low sensetivity as well.  98db is one of the lowest sensetivity rating i ever seen in headphones, so why are the grado easy to drive than...why more than the sennheisers?
this is probably for the sound science forum but if we are already discussing this i brought it up.

 

[oqvist]

Well the Ipod can´t supply sufficient amount of current for low impedance headphones either. Theory would be that it in comparison it has an easier time to supply more voltage that doesn´t eat battery life as much?

 

[TheWuss]

Quote:

^ exploding means, an explosion, not disassembly.
 
there is a difference.

Adj. 1. exploded - showing the parts of something separated but in positions that show their correct relation to one another; "the manufacturer provided an exploded view of the apparatus"

 

[Omega]

<Surprise> Stereophile sensationalizes a story, glossing over the well-known underlying physical phenomena.
 
In other news, the sky is blue.  I see no myths a'sploding--claiming that there was a myth in the first place is false.  They start titling things like "Sennheiser HD650 and Grado SR60i play at about the same volume from my IPhone," and nobody reads it, oh no.

 

[stokitw]

My question..
Should we expect the portable device output different level of current at a given setting of the volume control on the device??
 

 

[Ra97oR]

Totally agreed, however relatively speaking, most low impedance phones even if require huge current still is harder to produce bad sound.
 
You may not have driven it correctly/properly but it may just not sound as bad as an underamped high impedance phone. Well, all of that also really depends on the actual model of the headphones itself, there is not a single rule for all but most would agree that K701 unamped does sound rather poor.

 

[xnor]

Quote:

Well I do and any full sized can as well as even portable headphones or IEM's I've ever heard sounds better with a dedicated amp, usually much better. (No, not just louder!)
...
Not that hard to tell imo, in fact most of the time easy (because some--the receivers/integrated amp sound like crap, and others--the external amps do not) and no, I don't believe in "golden ears".

I shouldn't have mentioned that and don't want to turn this into some kind of debate. Actually it's not even on-topic.
But what you're saying sounds a bit like a Beyond Believe story, you might want to read up on some interesting topics in the sound science forum.
 
 
Quote:

OK, this is wrong. High impedance headphones need more voltage than an ipod can supply. Sure, an ipod can make the volume high enough. but volume is not equal to sound quality. If this was true, then everybody with an Omega 2 would be using a SRM-323A amplifier. It gets the volume high enough, why waste money on anything else...

1) For 90 dB the Sennheiser needs about 0.24 V and the Grado 0.07 V but the Grado also needs 2.73 times the power (about 2.2 mA).
2) Nobody said volume is equal to sound quality.
3) Why waste money on a Ferrari or ...
 
 
Quote:

I also didn't find anything wrong with the title.  as much as i will read and learn about impedance and sensetivity i will never figuere it out completely...I am just stupid i guess

at first i though that it is related only to impedance...the highest the harder to drive.  but than i read in head fi that also low impedance are hard to drive (i also saw the formula) usually the ones with the low sensetivity too.
most of the grado models have impedance value of 32ohm (pretty low) and sensetivity value of 98db which is also considered very low in the headphone world.   so what is the logic about them being very easy to drive?   they always say that low impedance are hard to drive and need a lot of power, now i guess that they usually means those with the rather low sensetivity as well.  98db is one of the lowest sensetivity rating i ever seen in headphones, so why are the grado easy to drive than...why more than the sennheisers?
this is probably for the sound science forum but if we are already discussing this i brought it up.

Impedance and sensitivity are two different things. High impedance does not mean low sensitivity.
Sensitivity tells you how efficient the headphone is at converting power (P=V*I or V²/R) into sound. Usually it's provided in dB at 1mW.
High impedance means you need higher output voltage and low impedance means you need higher output current. Every amp reaches limits at some point... be it V or I.
 
98 dB is not really low if you look at the high end AKGs with a sensitivity about 92 dB. 

And 32 Ohm is not very low either.
 
Oh and btw, the HD600's sensitivity is one dB lower.

 
Quote:

My question..
Should we expect the portable device output different level of current at a given setting of the volume control on the device??
 

See above please.

 
Quote:

Totally agreed, however relatively speaking, most low impedance phones even if require huge current still is harder to produce bad sound.
 
You may not have driven it correctly/properly but it may just not sound as bad as an underamped high impedance phone. Well, all of that also really depends on the actual model of the headphones itself, there is not a single rule for all but most would agree that K701 unamped does sound rather poor.

1) It's not the headphones producing bad sound but the amp facing it's limits. And many portable devices do have troubles with 16 Ohm 'phones.
2) That's a very interesting statement you've made there. I don't really know if an amp behaves better if it cannot provide enough voltage over current. Why are you so sure about this?
3) Every headphone sounds poor without amplification. 

 

 

[aimlink]

A corollary argument to this myth is the common advice that headphone X sounds great straight from an iPod since it's low impedance or headphone Z will need amping because of its high impedance.  This is such common advice around here that I have to agree with Subtle about the pervasiveness of the misconception.  Another piece of evidence is another commonly put forward piece of perplexity:  Why does the K702 require such strong amp'ing when it's a low impedance can?  This latter question is often put forward as a mindbender to explain. 

 

[TheWuss]

i think part of the problem with the k701/k702 may be the stock cabling design holding it back.  such that gobs of power have to be introduced for it to overcome imbalance / capacitance problems.
 
if i'm not mistaken, the signal travels over a nickel-plated piece of coat hanger wire to the right cup. 
so, is this one of the reasons it's such a finicky can in its stock condition?  i think maybe so. 
does anyone else agree w/ me on this?
 
as a rule, i don't necessarily believe in cable voodoo, but i pretty much believe that there was great room for improvement with the k701/k702.
 
while i  can't say if the SQ improved any with the black dragon split mod, i can say that it was louder and more forward sounding.  which tells me something.

 

[dcpoor]

akg has been doing the "coat hanger" headband thing for decades. that's not the problem.
 
the k701 stock cable is fine.
 
the k701 is low impedance AND low sensitivity.

 

[Raguvian]

Does this mean I don't need an amp when I get K702's? 

 

[Graphicism]

Quote:

<Surprise> Stereophile sensationalizes a story, glossing over the well-known underlying physical phenomena.
 

Sterophile is to audio what Best Buy is to electronics ~ if you're looking for advice or expertise look elsewhere!
 

 

[carledwards]

Quote:

Sterophile is to audio what Best Buy is to electronics ~ if you're looking for advice or expertise look elsewhere!
 

This is so true. I would characterize this "article" as basically worthless for anyone with even a passing knowledge of the subject.

 

[TheWuss]

i wonder what wearing hd800's backwards does????

 

[SillyHoney]

So low impedance headphones drain more battery life or high ones do?