# Ohm - 32, 80, or 250 for an audio interface?



## sIR dORT (Apr 12, 2020)

Hey everyone,

I'm in the market for some headphones for mixing/mastering and was looking at the Beyerdynamic DT 770 Pro. I saw that they have it at three different levels of Ohm, and I'm trying to figure out what would work well with my MacBook Pro connected to my audio interface (UA Apollo Twin). I saw that you most likely want an amp if you're gonna go 250 Ohm, but would 80 be a good fit for an audio interface?

Also, I saw that the 770s are known for their flat frequency response, but was planning to get sonarworks reference. Do you guys think this is necessary with the 770s? Probably a question is probably meant more for any of you that actually have the headphones.

Thanks!


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## wst3 (Apr 13, 2020)

you are on the right track - you will get better results if you can match headphones to the source.

The Apollo Twin specifications are not complete (sad, but common). They claim a maximum output of 80 mW into a 600 ohm load. What the heck does that mean? Without a specification for source impedance it tells us very little. Pity!

TL;DR - there is no way to tell from the information available. The best test is to get both the 80 and 250 ohm models and audition them. Amazon, among others, will let you return the ones you don't like. Any reputable music store should do the same. I would avoid anything lower than about 50 ohms, and anything higher than probably 300-400 ohms, but that is a wild-assed guess.

The longer explanation - 

The rule of thumb is that a higher impedance headphone will be more difficult to drive (e.g. quieter) but that is not always going to be true. There are so many factors that come into play, the number of windings on the motor, the wire gauge, the construction of the magnet, and so on. And that's just on the headphone side of the equation<G>!

I designed a headphone amplifier for a personal mixer system years ago. It was one of the most challenging designs I've attempted, and it took a little over six months to complete. Compare that to the month, give or take, that it took to design the input stages, or the week it took to design the power supply.

My first instinct was to direct couple the output (no DC blocking capacitor to limit low frequency response), and to make the source impedance as close to zero as possible. That did not work well!

There are two ways to connect two devices. In the old days the objective was maximum power transfer. This was accomplished by matching the source impedance to the load impedance. This means you can never deliver more than half the available power, but, it gives you the best shot at minimal frequency response errors, and should create minimal distortion (huge generalizations!) And it is the maximum power you can transfer.

These days almost everything is designed for maximum voltage transfer. We don't worry about power, in fact we try to minimize current flow. To do this the source impedance needs to be very low, and the load impedance needs to be very high, the rule of thumb is 100:1 or sometimes 1000:1 (depending on who you ask.

The problem is circuit protection - a very low source impedance means it is really easy to damage the output stages, even by simply plugging the headphones in. This becomes even more of a problem if there are no blocking capacitors.

That isn't the tangent it may seem to be - I have no idea how the engineers at UA designed their output stage, so I have to guess that they went with a low, but not zero, source impedance, and they included blocking capacitors (making impedance frequency dependent.)

So I'd stay away from a 32 ohm load. They also have limited power available, so I'd probably avoid a 600 ohm load. Which leaves 80 ohms or 250 ohms. All other things being equal (which seldom happens<G>) the 80 ohm headphones will deliver more power to your ears.

We haven't even dipped our toes into the specifications for the headphones - sensitivity being the most important.

Sadly it is not easy to try both, if you can find a way that's what I would do. I'm still using headphones from AKG, Sennheiser, and Sony that I purchased decades ago, so I'm afraid I can't be more specific.


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## Instrugramm (Apr 19, 2020)

sIR dORT said:


> Hey everyone,
> 
> I'm in the market for some headphones for mixing/mastering and was looking at the Beyerdynamic DT 770 Pro. I saw that they have it at three different levels of Ohm, and I'm trying to figure out what would work well with my MacBook Pro connected to my audio interface (UA Apollo Twin). I saw that you most likely want an amp if you're gonna go 250 Ohm, but would 80 be a good fit for an audio interface?
> 
> ...


I would get something different than 770s, ideally you'd mix on open back headphones, if you get something like Sennheiser HD 600s you won't need Sonarworks, if you really need Beyer, either buy the 177x GOs (with perforated Brainwavz XL Pads) or a lot better, the 1990 PROs.

Audio Interfaces often have very weak/ bad amplifiers, get a decent headphone amp (Shiit Magni 3+ or Heresy for example) and ideally headphones with a high impedance, in some cases these yield better detail.

Take a look at some other headphone threads here on vi-control, I basically wrote a lot about this already, you can also check out some headphone reviews at www.facebook.com/sonostuff, I'll probably do some written and filmed reviews on my whole headphone collection, some of my amps, controllers and libraries etc. if I have the time.


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## vitocorleone123 (Apr 26, 2020)

I have the Scarlett 6i6v2 driving DT880 250ohm semi-open cans - it’s rated max ohm rating. I almost always use Sonarworks with it. Depending on DAW adjustments, sometimes it doesn’t have quite enough power. The v3 of the interface seems to have given up some headphone power for another pair of inputs.

More power isn’t always better sounding. I have a Schitt Magni v1 to sell some day because the 6i6v2 sounds so much better even though it has less power.

80ohm cans are a safe bet, and more easily used with other sources, should you want to.


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## TGV (Apr 26, 2020)

I've got an Audient i4 interface with a Beyer Dynamic 880 PRO with 250Ω impedance, and it delivers more than enough power to pay uncomfortably loud. I also use Sonarworks, and it suits me well: the difference isn't huge, but it does bring more clarity.


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## Loïc D (Apr 27, 2020)

TGV said:


> I've got an Audient i4 interface with a Beyer Dynamic 880 PRO with 250Ω impedance, and it delivers more than enough power to pay uncomfortably loud. I also use Sonarworks, and it suits me well: the difference isn't huge, but it does bring more clarity.


Interesting...
I’ve recently tried Sonarworks on DT 880 Pro and I find the sound very different. It tames the brightness but adds a ringing hi-mid.

It’s plugged on a Scarlett 2i2.

So either each can of DT sounds very different from each other (yikes!) or the interface doesn’t handle my cans so well. 
I’ll give a try on another interface...


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## TGV (Apr 27, 2020)

LowweeK said:


> It tames the brightness


It certainly does that, but it also clears up some sounds for me, e.g. snares. I can't hear the ring, though.

But headphones do have individual differences, so it seems. At least, that's one of the selling points of Sonarworks. But it would be strange they would differ that much.


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## sostenuto (Apr 27, 2020)

Various sources led to Beyer DT880 Pro 600-ohms for most home studio work. Using Focusrite Saffire Pro14(s) Audio I/F.
Waiting now for shipment of Beyers, Schiit Asgard 3 + Modi dac. Will be a bit deflating if seasoned ears don't hear much difference. Likely May 10.

( edit) (3) built-up Win10 Pro Desktop PC(s) and a bit frustrating that only one has S/PDIF optical from ASUS MB. Looking at eBay _ Asian source for rear-panel bracket/card with Optical out and wired connector to MB pins.









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