Headphone Impedance

[T on Y]

Off topic I know but you guys here have never failed me !!

Currently have focusrite 2i2 and wanted to get new headphones and was recommend the beyerdynamic DT 770 but they come in 30 80 250 ohm versions now the focusrite heaphone out is only 10 ohms so does than mean that if I went for the 250 ohm version I would need additional amplification or should I be getting the 30 ohm version if I'm never going to have  a outboard mixing console in my set up 

[razor7music]

I got the high ohm version, and man it's scary having to crank the volume up almost all the way (80%). I feel like if there's a system pop or something, they're gonna blow.

Also, be advised, they accentuate the low end. If you want accurate headphones for mixing, these might not be the ones for you. I use various references for mixing/mastering, so I know how to judge the bass--but wanted to point that out.

They are really good headphones. They are comfortable and have cloth instead of that flaky peely rubber stuff that gets all over your ears after a couple years.

Maybe you saw this, but here is how they recommend you decide.

[Tezza]

You could go for the 32 or 80 ohm version, with the 80 you get the same cups as the 250 but the lower ohmage, it's essentially the same as the 250 but only 80 ohms. The 32 ohm version is actually a different headphone, it has different cups (non velour) and there are also other differences I think. The cable or cable ends might be different It's worth checking this out. I used 60 ohm headphones with my 2i4, headphone volume was never a problem. It's not just about volume though, USB powered interfaces don't sound great if you have to really crank the volume. I definitely would not get the 250 unless you are going to have external amplification.

If the different cups on the 32 or any other differences are ok for you, then I would get those. If you prefer the velour cups and the differences of the 80 ohm then get those. I am looking at headphones at the moment, I have a number I am testing but none of the DT770, when I did research those, I came to the conclusion that I would get the 80 ohm version, can't remember exactly why but you do need to look a bit closer to the differences between the 32 and 80 ohm version of those headphones. Your needs may be different to mine.

Edited May 8, 2019 by Tezza

[DeeringAmps]

I went with the 80 ohm. 

I have a set of 990’s as well. 

T

[Bill Ruys]

Basically, the lower the voltage available to the internal amplifier, the lower impedance you need in the headphones to get reasonable power output (basic Ohms law).  The 2i2 is bus powered (5v), so using Ohm's law, the maximum theoretical power you would get from 250 Ohm headphones in this device is about 70mW RMS.  At 80 Ohms you have about 220mW and at 30 Ohms, you have about 590mW RMS maximum power.

So, for either bus powered or low voltage battery powered devices, I would go for the 30 Ohm set.  If you are likely to use them with some other devices too, like mixing desks, etc.  80 Ohm may be a better compromise.  The 250 Ohm set would be best suited for purpose-built headphone amplifiers or HiFi systems designed for high impedance cans.

In a nutshell, what it comes down to is that the lower the voltage of the amplifier design, the lower in impedance the headphones must be to get enough power for good volume levels (lower impedance means higher current, which means higher power).  Too high impedance headphones on a low voltage system results in low volume.

Edited May 8, 2019 by Bill Ruys
Wrong impedance value

[T on Y]

As expected, a comprehensive answer ……... Thanks to you all

Edited May 8, 2019 by T on Y

[sven450]

I have the 250 and they are wonderful.  I do not find that they hype the bass.  If anything, they have a bit of a bump around 6-7K.  Check out this graph

https://reference-audio-analyzer.pro/en/report/hp/beyerdynamic-dt-770-pro-80.php

I will say that now that I have these and have gotten used to them, I can no longer use my old Audio Technica m40s.  They are so bright it hurts!