Headphone impedances

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ed
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Headphone impedances

Post by ed » Sat Mar 03, 2012 4:05 pm

Can anybody explain the relative pros and cons of headphones that offer different impedances.

I know next to nothing about open backed headphones and I was looking at a pair for mix monitoring/hifi use - akg k701. Then somebody put me on to beyerdynamic dt880 which offer loads of different impedances....one very confused bear!

I currently use an aura 40 for monitoring but I don't know what the headphone output is all about because it's never been an issue with recording monitoring and closed back headphones.

The other headphone output I sometimes use is from the layla 3g audio interface, but that simply says 'headphone output x 1' in the spec....no indication of what type of headphones to use.
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Post by Laurence » Tue Mar 06, 2012 2:52 pm

The higher impedance is an easier match so generally aim for higher impedance.

The classic studio monitor the Sennheiser HD414 open back headphones were adopted wholesale when they came out because of their higher impedance in their day. They are close field monitors for the ears. Absolutely flat response.

But if you try them having just had "hifi" headphones on they will sound flat and not seem to have enough sparkle or enough bass. But if you want something which tells the truth these are the phones.

The other reason they were so popular was comfort and strength. But the leed is not hifi it is strongly made for the studio. A rewire is recommended.

Don't buy any of the mutations they were not as good you want the originals.

they come up once in a blue moon on ebay for £50 to £100.

Remember they are not kind to the music, they tell the truth.

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Post by JamesD » Fri Mar 09, 2012 5:01 pm

Oh dear I hate doing this...

Sennheisser HD414 do not have an absolutely flat response. Many experienced and qualified listeners and similarly qualified measurements on the HD414 have all shown that they are not flat and have more than one peak and trough in their response...

Don't take my word for it - here are some references...

1) The one and only Linkwitz http://www.linkwitzlab.com/reference_earphones.htm

2) Bob Carlyon, Cambride University. http://www.auditory.org/mhonarc/1996/msg00012.html

3) http://www.borrill.org.uk/stephen/thesis/toc_/Pt09.html

there are more but these all confirm Sennheissiers own notes on the HD414 which state " Rolls off @6dB/octave below 50Hz; flat from there to ~1.5kHz, whereupon response rises rapidly and peaks at +4dB @2kHz; thereafter it rolls off at about 3dB/octave with a slight dip at 5kHz and a faster rolloff above 12kHz." Note: Sennheissers notes do not agree with other measurements either but make it clear that they were engineered to not have an absolutely flat response - quite the opposite...

But that is not to say that they aren't good or useful, they are rather good as monitoring headphones but they aren't flat - no headphones are from 20 to 20KHz and they aren't reference quality headphones - although I do like them.

James

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Post by JamesD » Fri Mar 09, 2012 5:41 pm

I ought to say something abouts Ed's question as well.

Ken rockwell does a reasonable job of explaining this http://kenrockwell.com/audio/beyer/dt-880.htm - Yes its a photgraphy site :D

Basically 32ohms is for iphones and such - 32 ohms to minimise voltage swing (and maximise current swing... and good for being driven by a normal power amplifier output.

600ohms maximises voltage swing and minimises current swing so good for lightly loading high quality headphone amps like valve ones. And also traditionally professional audio was distributed at 600R so these can be plugged straight into a patch field. Not so relevant now-a-days...

250ohms a compromise for general use.

DO they all sound different - yes! but not least because they all load the driving amplifier differently and that subtly changes the sound. Basically they sound the same given proper driving... :D

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Post by ed » Fri Mar 09, 2012 8:06 pm

Thanks James

I think that was exactly the information I wanted, and the link was good as well. I'm making the transition from closed back to open back, and all the open backed models I've tried so far have left me speechless...they are all so spacious that I'm still reeling, can't see the wood for the trees.

I think I'll go with the 600ohm version....

fwiw I have to use the closed backs for tracking(for obvious reasons), but we'll see if the dt880s can compare with the nearfields for mixing.....

onward
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Post by Laurence » Sat Mar 10, 2012 11:55 am

JamesD wrote:Oh dear I hate doing this...

James
That's fine James, you obviously have a lot more experience of these things, I was only saying what I had picked up. I am still learning many things, and just gave what I had, even if it was found wanting.

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