proton007
Headphoneus Supremus
- Joined
- Feb 9, 2012
- Posts
- 3,518
- Likes
- 186
I've changed the 'required' to 'desired'. Makes more sense.
So the player's output impedance should be less than the earphone's impedance...is there an ideal ratio between the two?
Yeah but the power transfer theorem is about choosing a load resistance with a given (fixed) source resistance. In your lamp example you'd be best off not adding the resistor at all (assuming the lamp can handle that).
hi there i was just wondering if there is even a need to amp a low impedence headphone like the noontec zoros? if so how much of a difference does it make? i'm currently thinking about getting a fiio e 7 or 11 and maybe he fire eye mini
this is from innerfidelity
Impedance and phase plots show a 20 Ohm headphone with some modest resonances at 2kHz and 6kHz, likely originating from resonances behind the driver. With 16mVrms needed to achieve 90dB at the ear this is a very efficient headphone, and will easily be driven to loud levels from portable players. But the isolation plots shows that this headphone does not isolate well at all making this a headphone that can be used portably, but not for listening in loud environments. On the other hand, you will be able to remain aware of your surroundings, so using these cans portably in quite neighborhoods will work well.
Innerfidelity is pretty spot on with their analysis. From the data it seems it doesn't really require an amp.
thanks, for your reply, what would an amp even do anything? change in sq?
Louder (so you can go deaf faster). If your current "thing" is noisy or has massive channel imbalance (you'd know about both of these, no question about it) it might change that, depending on how you source the signal into it - but by and large: louder.
i always thought an amp would boost all the frequencies (bass,mids and treble)
why would anyone want headphones that have a high impedence even if its for home use ? if all it does it suck up more power? Hypothetically two headphones were identical in sound quality but the difference in impedence, logically the lower impedence is more economically friendly?
If it boosted all frequencies it would just increase the overall signal (= louder). But it will do *nothing* of the sort (at least not as you're proposing) - all an amplifier will (should) do is apply gain to the signal (that is, make the signal larger); it does not magically improve (or transfigure) the sound quality. Depending on the interaction with the load it is presented, and relatively speaking, it may act on the frequency domain to an extent, but an EQ is a better bet if you want "big, dramatic, night and day" changes, and if you're looking to change something on the time or radiative domain - look at the speakers/headphones.
Impedance is not a "quality" or "performance" spec, despite what a lot of marketing suggests. It's just a characteristic of a given driver - some will be high impedance by nature, some will be low impedance by nature, and there is no rule of thumb that one is better than another. Higher impedance doesn't actually even require more power (power requirement is determined by sensitivity and your target SPL (which should always be <85)), but it *may* require relatively proportionally more voltage (which is why some portable devices have problems with some high impedance headphones).
Generally with headphones sold for at-home use, the designer/manufacturer doesn't have to care either way, because the assumption is (or at least was, for many years) that you're plugging them into a stereo receiver or integrated amplifier which will drive its headphone jack with the "main" amplifier section built into it (with resistors in the way, to protect both ends). Usually these devices will put out a few watts per channel for headphones (which is more than any ten people should ever need; seriously). However that's changed in recent years, and people have started to want to take their headphones with them and plug them into things like CD players and iPods (which have inherently limited voltage swing, due to their battery power). So this is where low impedance headphones have an edge.
It's all relative, basically - if you're talking from the perspective of an AC powered integrated amplifier or CD player, it really truly doesn't matter what specifications your headphones have; if you're talking from the perspective of an iPod, it's better go with low impedance and high sensitivity, to get the best out of the device (and the less it has to put out, the longer the battery lasts); if you're talking from the perspective of a marketier - oh good lordy, your headphones better be at least one trillion ohms, and your amplifier's output better have negative impedance across it, so that you can show fantasy numbers with a ton of 0's and tell the customers about specifications (that have no actual bearing on their lives) and move more units.