When buying headphones, it seems only professionals are privy to the impedance specifications. However, professional or not, I think it helps to know a little bit more about this story.
Whether you’re buying headphones simply to get a phenomenal sound quality when listening to your music player or you’re using them in a professional setting, you should consider the impedance and its effect on your life.
It’s not that the gates below will open up if you select the wrong one, but you want to get your money’s worth and match your headphones to your best usage.
When it comes to low-impedance headphones, rated under 50 ohm, it’s fine for use at home with a receiver or even hooked up to your smartphones.
Most people buying those over-the-ear headphones for jamming out to their favorite tunes while hopping subway cars on the way to work or making the workday pass by more pleasurably are buying those.
High-impedance models though are better to use at home or in your studio where you can truly feel and be one with the music. The higher that impedance, the better sound quality you’re going to get. It gives more turns of wire from the driver’s voice coil.
I’d like to dig a little deeper into the meaning of impedance in headphones and how that impacts you so you can make a wise buying decision for your needs. Keep reading and you’ll see what I mean!
The Difference of Impedance in Headphones
So, you’re shopping for headphones and you see “ohms” and you’re new to all this. I’m going to break it all down, so it’s easy. When you’re looking at each set of headphones, the ones you find with an impedance greater than 100 ohms fall into one of two categories:
1) They’re professional-grade studio designs
Or…
2) They were made before the 1990s
What does the 90s have to do with this? Receivers and professional audio equipment from back then usually incorporated resistors that attenuated the speaker wattage.
This was a simple way to make a cheap headphones circuit. Headphone circuits then often worked most efficiently with those high impedance headphones.
There were even some that were designed to link multiple pairs in tandem during professional studio sessions.
There’s a bunch of math involved in that, so I’ll spare the details, but essentially, that high impedance load saves the source output voltage so it can drive several pairs of headphones simultaneously.
It might sound strange, but this was the standard even in 1996, which doesn’t seem that long ago, but it was. Back in 1996, the standard output resistance for that application was at 120 ohms.
But we’re in modern times now and the headphones today are crafted to appeal to a broader market set.
That means they must play nicely with your mobile devices. It only makes sense since everyone has some form of battery-operated musical device from iPods to smartphones, even tablets that they tote along religiously. Most of the headphones you see available today are around 32 ohms, or lower impedance.
How Many Ohms Are Considered High and Low Impedance?
In determining what you need for your headphones, you’ll want to look more into high and low impedance and the standard ratings. Therefore, it begs the question, how many ohms are considered high, and how many are low impedance?
High impedance is best for longer runs of cable and more speakers to each line. You’ll see it denoted as 25V, 70V, or even 100V.
This high impedance allows you to keep speakers at lower power via adjustable taps and gives output with fewer amplifiers.
On the opposite end of things, low impedance runs from about 2 to 16 Ω, making it best for high performance with high-powered speakers and shorter runs of cable.
Now that you know what you’re looking at when you’re reading the packaging on a set of headphones, you’re probably thinking high impedance headphones are better. You’d be right, though it all really depends, so keep reading.
Why Are High Impedance Headphones Better?
Do you love music? High impedance headphones give you a clearer and more defined sound, particularly with bass. Classic Metallica back in the days of legendary Cliff Burton sounds majestic via this avenue.
Headphone impedance is mostly determined by the voice coil of the driver. Take Beyerdynamic’s high impedance models.
The voice coil wire is so thin, merely half the thickness of one of the hairs on your head! According to the senior product manager for Beyerdynamic, Gunter Weidemann, the process of manufacturing those voice coils is so complicated, it is done in Germany.
These impeccably thin wires have more layers on the voice coil than their low impedance counterparts, even in the same brand umbrella of Beyerdynamic.
Those low impedance versions feature thicker, heavier voice coils, which are much easier to produce. Because that thin wire has a lower mass, it lends a better sound quality to those high impedance headphones.
The voice coil wires fit tighter, which means less air gets between the windings, creating a stronger electromagnetic field. Distortion is reduced incredibly when compared to low impedance styles.
High Impedance Headphones Require Higher Voltage Sources
Ah, but wait! Before you choose those high impedance headphones, you need an amplifier that can handle the voltage and drive the impedance spikes at the proper frequencies. So, if your amplifier can’t hang with it and keep up the spike frequency, guess what you get? Distortion or roll-offs of frequency.
Those inconsistencies can be quite noticeable and rather unpleasant, something you’d most certainly want to avoid.
Let’s take the case of Sennheiser’s headphones. Many of them replicate an exaggerated frequency spike when it gets to 100Hz.
With the Sennheiser HD 600 open-back headphones (Amazon link), you need a high voltage, which makes it a poor match for most mobile devices.
However, it’s excellent with a proper tube amplifier that can handle 120 ohm output impedance.
To break it down another way, high impedance headphones need sources of higher voltage, while low impedance headphones need higher sources of currents. Got it?
In case you need another example, if you have a source with a 50 ohm output impedance and you stick it with headphones that run in the realm of 16 to 32 ohm, it’s going to have a hard time.
But it’s not an open and shut case, for if only high impedance headphones worked at all, then there wouldn’t be low impedance versions. Low impedance headphones require something more to help them along. Find out what below!
Low Impedance Headphones Need an Amplifier
When it comes to low impedance headphones, you need an amp. That pushes the large currents they require.
Spending a large sum of money on your headphones might mean you should consider buying an amp for your headphones.
Even a simple one like the Fiio Amp (Amazon link) can make all the difference in amplifying your headphones properly. It takes the music appreciation experience up more than just a notch.
It’s all linked though and you’ve got to go down that food chain, so to speak to find out what is lacking.
You can have a pristine copy of music, amazing headphones, and then a limited-power amp in your laptop, smartphone, or tablet.
What’s that going to do? It’s going to butcher your music and make you think your headphones you just shelled out a chunk of change for are junk.
But the problem can easily be rectified with an amp connected to the player and your headphones. You’ll get clarity. You’ll get detail. You’ll get dynamics. You’ll get lost in the music. Oh yeah!
It’s not that high impedance headphones don’t need amps. They can solidly benefit from one, especially when united with portable players on limited voltage via those puny batteries. But with low impedance headphones, when you lower the damping factor with your amp and headphones, you need more current.
So they’re loud enough, yes, but that sound quality isn’t all there and you can get it to really sing, pardon the pun just by pairing it with a headphone amp.
Depending on the dimensions and size of your headphones is whether you may want to consider an amp add-on. With earbuds and those in-ear headphones, they’re less likely to really require it. But when you have an over-the-ear model, the sound becomes clearer and more precise with an amp.
Some models may even need an amp so you can listen to the music at a volume you can hear when you put them with your portable device.
Should you be using a laptop, computer, or even a tablet, you might want a headphone amp that has an internal digital to analog converter like the FiiO E10K (Amazon link).
This really boosts your listening. Choose a line output version for portable devices if you can but if you don’t have the option for that, take the headphone jack and use it to put the signal to your headphone amp.
Headphone Models with Multiple Impedances
Most of the time, certain headphone models are only produced in one impedance. With Beyerdynamic, it creates quite a few versions of each model that are only different when you look at the impedance.
For example, beyerdynamic’s DT880 (Amazon link) and DT990 offer 32, 250, or 600 ohm versions. Whereas the DT770 models (Amazon link) are available in 32, 80, or 250 ohms.
According to cnet’s own Steve Guttenburg, the voice coils in the high impedance models of Beyerdynamic’s headphones is 0.018mm. So, the thinner that wiring there, the better the sound quality. Of course, you need to have it properly paired up with the right devices to truly appreciate it.
What Beyerdynamic does though, is offer models in those versions that make it easier for the discerning listener to pair up with their needs.
Essentially, it all goes back to what I said earlier on. High impedance headphones need higher voltage sources. Low impedance headphones need higher current sources. By working within that realm, you will find your desired sound quality.
Amps make it easy to find a happy medium if you’ve only bought low impedance headphones. If you’re still deciding, you may find it’s worth it to invest in high impedance.
Those coils are tighter from the thinner wires giving you the privilege to hear sound like you never dreamed. Your own immaculate concert right in your ears, like a world all your own!
Lower moving mass from the 250 and 600 ohm headphones have voice coils that are lighter than those 32 ohm versions, which makes high impedance headphones just sound so much better than those basic versions.
Even if you have very little idea about the inner workings of headphones, you can basically reason that a lower quality set is going to make anything sound like pure garbage. What you need is to step up your listening game with a quality set of headphones.
Of course, if you can’t rationalize the purchase of high impedance headphones, if you choose low impedance, you should at least budget in a decent amp to help propel that sweet music to your ears.
Conclusion
Listening to music should be a joy, but often, we’re disappointed when we pair our listening devices to our headphones.
Even when we invest in good quality, we wonder where we went wrong. If that’s the case, get out your packaging and check the ohms. You can always fix the sound to your liking through adding a proper amp to balance it out.
If you’re shopping around for new headphones, it may be worth your while to go for the gold standard and choose high impedance for your best sound quality.
No matter the style of music that you love to listen to, or even if you have a broad range of tastes, it deserves to be heard in its purest form, something high impedance headphones can deliver with perfect panache.