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The AKG K7XX Massdrop First Edition Thread
Dec 26, 2014 at 4:26 AM Post #947 of 4,580
Ohms have nothing to do with power. You can have a 40ohm headphone that can handle watts, and a 600ohm that can get louder than the AKGs by quite a bit off lesser power. The 700 series of AKG is known to demand a bit more than typical headphones.
 
Dec 26, 2014 at 9:55 AM Post #949 of 4,580
mad lust envy said:
Ohms have nothing to do with power. You can have a 40ohm headphone that can handle watts, and a 600ohm that can get louder than the AKGs by quite a bit off lesser power. The 700 series of AKG is known to demand a bit more than typical headphones.
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ohms have everything to do with power. electrical power is calculated P=VI which using substitution and ohms law is P=I^2*R. A lower resistance or load is going to produce a much larger current than a high impedance load which means they will take more power at the same voltage, using a different substitution you can calculate it as P=V^2/R which is maybe a little easier to understand why a higher impedance headphone will produce lower power at the same voltage. With a low impedance headphone you can produce quite the power with a turn of the knob.
 
http://en.wikipedia.org/wiki/Electric_power
 
btw turning the knob of your amp does not vary the power, it varies the output voltage.
 
just giving a heads up, take it or leave it, up to you. All I'm saying is turn the knob until you have exceeded volumes you would use the headphone at and no further - there is no point, all headphones will rattle and or blow out at some volume.
 
Dec 26, 2014 at 1:07 PM Post #952 of 4,580
redbull said:
Don't forget also efficiency which has something to do with current.
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Not really forgetting it...it wan't a part of the discussion. A headphones efficiency is a spec listed by manufacturers that links either power or voltage (depending on manufacturer) to the loudness produced by a headphone. 
 
I guess while we are at it we can just calculate the maximum voltage these headphones handle according to specs. They handle 200mW, which is 0.2W. Using the power equation in the form of P=V^2/R with P = 0.2 and R=62 we get V = 3.5V. So if your amp is outputting 3.5V into these cans, they receive 56.4mA of current and it should be considered unsafe at that point. 
 
If we use the sensitivity of the phones to calculate the SPL we get 105+20*log_10(3.5) = 115.9 dB
 
So if this 200mW max power rating is given with a low factor of safety, 116dB spl loudness is a possible volume to blow these out.
 
Here is a good resource with a calculator.
http://www.apexhifi.com/specs.html
 
Dec 26, 2014 at 1:53 PM Post #953 of 4,580
Figured someone would take my post completely out of proportion. What i mean is that if youre only looking at ohms as the gauge to see how much a headphone canbhandle, well, youre doing it wrong. Like i said, there can be incredibly insensitive low ohm headphones, and there can be very sensitive high ohm headphones. Ohms do not determine how much a headphone can take.
 
Dec 26, 2014 at 2:57 PM Post #956 of 4,580
trae said:
  They do VERY well with tight, deep, realistic bass at lower volumes compared to other, more capable headphones. Because of the open nature of the K/Q7XX headphones, you get very little bass feedback, and because of that, some people are inclined to turn the volume up the hear the bass better. The downside is that these headphones perform poorly when reproducing bass at loud volumes (relatively speaking for these drivers. It's loud for these headphones, but quiet for something like the Beyer COPs). Therefore, for the people who turn up the bass too loud, it will distort earlier compared to other headphones, especially those with some reinforcement on the diaphragme membrane.
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I couldn't agree more. The bass is kind of weird for me on these. The louder I turn up the music the more the bass loses resolution and separation. It's like the notes start to blend together. Combined with this it seems like the bass doesn't decay that fast. So it sounds like a blob of bass or something. They are nothing like a pair of planars, where you hear every bass note crisply and distinctly.
 
Dec 26, 2014 at 3:05 PM Post #957 of 4,580
mullet said:
  I couldn't agree more. The bass is kind of weird for me on these. The louder I turn up the music the more the bass loses resolution and separation. It's like the notes start to blend together. Combined with this it seems like the bass doesn't decay that fast. So it sounds like a blob of bass or something. They are nothing like a pair of planars, where you hear every bass note crisply and distinctly.
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I think I'm glad I went with the the Phillips X2 and the Hifiman 400i if the bass is "weird". I haven't heard them so I suppose I shouldn't judge. It's just good to read all the discussions here and make the best informed decision on any purchase.
 
Dec 26, 2014 at 3:09 PM Post #958 of 4,580
Let's not forget impedance matching, as long as we are taking ohms as a critical specification  
rolleyes.gif
 

And clipping, from pushing an inadequate amplifier beyond it's capabilities.  This is more often the cause of damage to headphones/speakers than over "powering" them is, especially if you have them on your head.
 
Dec 26, 2014 at 4:06 PM Post #960 of 4,580
Just doing some comparison with SR-009...pretty interesting 
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Where SR-009 acts like a electron tunneling microscope, making everything amazingly clear, dynamic, clean, separated and extended, K7XX has a kind of veiled, crunchy and messy sound which is curiously pleasant with some dirty pop / rock tracks. Comfort and soundstage of the fourteen-times-cheaper-AKG are not to be ashamed of, too.
 
Ali
 
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