[nahog99]

So I have had a pair of Sennheiser HD600's for quite some time now but have never really taken advantage of them. I knew when I bought them that they required a lot of power and that something like an ipod or in my my case an iphone 4 wouldnt power them well. Well today after not really using them for years and years I plugged them into my iphone and they didnt sound too bad but I know they can sound Much better.
 
So I have been looking all over the internet for explanations about the power requirements of headphones and to be honest i am just getting very confused. I know with Enough reading i could probably figure it out but i realized id have a much better chance if i could ask questions, so here they are and if anyone understands this very well please help me out.
 
First and really most important question is how much power is required for my HD600's. They have 300 ohms resistance which i know is more than portable audio components can really power. Can someone explain to me in numbers why an ipod does not have enough power. I understand sensitivity for the most part.. It takes a certain number of watts to reach a certain SPL and that sensitivity changes for different speakers. I cannot for the life of me figure out where the OHMS factor in.. I just read somewhere that the 4th gen ipod puts out 50-60 mw of power. I know that the sensitivity of the hd600's is 97 dB according to this page    http://gilmore2.chem.northwestern.edu/tech/dbohn1_table.htm
So that should mean that 1 mW of power should produce an SPL of 97 dB right? If that is the case then why does EVERYONE say the hd600's need a headphone amp? How many mW's is a headphone amp going to put out. and after looking at all the other headphones on that graph they all have similar sensitivities yet drasitcally different impedance so how in the hell does the impedance affect the sound level? I'm having a hard time right now even forming good questions because my mind is so jumbled right now sorry for that.
 
Second question is this: my headphones were loud enough when i had my phone turned all the way up but shouldnt the sound quality be worse with a low power source such as the iphone? I always felt like having a headset properly powered will make them sound better at ANY volume am i wrong in thinking this? With that said, what is properly powered? I read that too powerful of an amp can hurt the headset. How do i figure out what is the correct power of amp to use?
 
I think the reason ive had such a hard time figuring out how the ohms factor in is that all the equations ive found involving ohms mention nothing of watts, only volts and amps. Why are amps measured in watts and not volts if the impedance relies on how many volts are passing through.
 
I know reading through this was probably painful and i apologize but please if anyone can explain to me how an amp, or more powerful source benefits me in my specific situation and then relate that to a situation involving LOW impedance headsets that would be great. Thanks in advance.
 
 
Summary: How much power do sennheiser hd600's with 300 ohm impedance require to maximize potential? Why? How does the impedance affect the power requirements?

 

[tme110]

Sorry, I really couldn't tell at what level you were asking this so if I answer the wrong question I didn't mean too.  But if you're post is summarized by the last sentence then - that's just the way the world works and you can't get around it - it really isn't a headphone thing.
 
Taking it to the simplest level and ignoring things like resistance/impedance etc a power equation is:
 
Power = (current squared) x (resistance)
 
So in order to maintain a certain a mount a current required to drive the phones, as you increase your resistance then you must increase power (to maintain the desired current).  If you don't increase power then current must go down and you no longer have enough to drive the phones.
 
There are 100's of headphones out there suitable and made for ipods.  Though they all have certain trade offs in order to make that happen and most people don't care.  You have a very nice set of phones that are made to sound better than portable ipod phones.  I don't think this is the best solution but you can get a FIIO E5 amp for only $20 and you'd barely notice it if you walked around with it. But since the hd600's really aren't all that portable themselves I'd at least go with the e9 (or upcoming e11) though again there are dozens of portable amps which are made to mate up with ipods - I'm just mentioning popular, inexpensive ones that are on amazon.  So the amp does not have to be expensive or intrusive and I think you will be surprised at the difference it makes.  Either that or I'd trade your headphones for ones that weren't designed to be amped.

 

[Durberg3]

I would be interested as well.