Headphones question/recommendations

[Alistair S]

My old Sennheiser HD280s have given up the ghost and need replacing.

I need some new ones. They need to be closed with decent isolation for tracking. I will mostly use them for a quick reference and for detail.

I could get more of the same type but wondered about other recommendations before I buy.

What about impedance? I'm pretty ignorant about that. I use a FF400 and I believe the headphone output is around 30 ohms. The nominal impedance on the Sennheisers is 64 ohms. What do I need to look out for? I notice that some headphones come in varieties of impedance (Beyer Dynamics DT770s are available at 30 ohm but are also available at 80 ohm and 250 ohm, for example). Educate me, please?

Also, are there any good choices that are wireless? Wireless would be nice but not if I need to sacrifice anything else.

Hopefully that all makes sense. What would you look at?

I'm currently thinking Audio-Technica ATH-M50x. Good choice? Bad choice?

[Softsynth]

Higher impedance is generally better. The diaphragms are better controlled, notably in the bass. Also they give the amplifier an easier time, as a highly resistive load.

The trade off is efficiency. Therefore headphones designed for portable devices are low impedance, trading performance for high loudness capability with better battery life.

I suggest you look at the higher impedance models 80+ ohms.

Alternatively with a dedicated headphone amplifier or a soundcard or device designed to drive higher impedance headphones (in the hundreds of ohms) you can get better performance with more serious cans.

[Alistair S]

Thanks! I've gone for the 80 ohm DT770s. Hopefully, they will be fine

[DVDdoug]

Under normal conditions the impedance itself isn't an issue.


Hang on... This is going to get a little "technical".


The main issue with impedance is related to frequency response.


The impedance of a headphone (or speaker) isn't constant over the frequency range. Headphones are tested with a low-impedance (constant voltage) source. That is, the voltage out of the headphone amplifier doesn't change when the load impedance changes.


A good headphone amplifier will behave the same way and impedance doesn't have any effect and the frequency response will be "as specified".


If the headphone amplifier source impedance isn't low relative to the headphone impedance you have a voltage divider where the "top" resistor is the source-resistance the headphone amp and the "bottom" resistor is the headphone impedance.


If these were both pure resistors the only consequence would be a signal loss. If the resistors are equal you'd get a 6dB drop. (Higher headphone impedance or lower amplifier impedance means less voltage drop.)


If the headphone amp has an output capacitor, the voltage divider becomes a high-pass filter. If the capacitor value is too low, or if the headphone impedance is too low, you'll get a loss of bass.


As the headphone impedance varies over the frequency range, the output varies (if the source impedance is not low relative to the headphone impedance).


An impedance-rise in the mid-bass (which is somewhat common) will create a boost in the mid-bass frequency response.


A higher impedance headphone (and/or a low impedance headphone amplifier) minimizes both of these effects.


Unfortunately, amplifier output-impedance is rarely published. They usually just publish the recommended load impedance. It's the same with power amplifiers... The source impedance of a power amplifier (designed to drive 4 or 8 Ohm loads) is usually far-less than 1 Ohm, but that's not published in the specs. (Sometimes they publish the damping factor which is the ratio of the load impedance to the source impedance.)


Impedance is also related to power (milliwatts in the case of headphones). With a given voltage, half the impedance gives you double the power. If you have a low-voltage headphone amplifier (like what's built-into a cell phone) you may not get enough volume. The volume from laptops or other devices may be limited too.


But although volume/loudness is related to power, some headphones are more efficient than others. Lower impedance headphones tend to be louder, but that's not always the case.

[Softsynth]

Originally Posted by Alistair S

Thanks! I've gone for the 80 ohm DT770s. Hopefully, they will be fine

Best to not to get too bogged down with impedance matching, it should be a non issue for you here anyway.
80 ohm is a very safe average impedance which should work well with Hi-Fi grade headphones amplifiers and much of the time with weedy amplifiers in portable devices alike, even those better matched with say 32ohm cans on paper (for reasons explained before).

The 770s seem popular and Beyer is a reliable brand- shame you cannot try before you buy - cheap enough to try though.
Beyer typically make comfortable cans too, which is possibly the most important factor, over a given reasonable quality standard.

[Softsynth]

If you want to see an article explaining the technical ins and outs a little more (as per DVDdoug's post):


http://nwavguy.blogspot.com/2011/02/...impedance.html

[Dannii]

I'm in full agreement with DVDdoug and Softsynth here.
Regarding your choice of the Beyer DT770s, I reckon you'll be more than happy with them. A year or so ago, I purchased a pair of DT1990 Pros and am absolutely delighted with them! They are extremely revealing in a good way and very accurate, especially coupled with Sonarworks Reference 4.
Most of my use for them is recording and mixing but I also work as a mastering engineer for some clients and the Beyers are terrific for that task.

[Alistair S]

Thanks guys. They arrive today so I can hear for myself. I'm pretty sure they will be more than adequate for the job.

Edit (to avoid bumping). They came. I'm very pleased. Thanks again.