Any reason to favor high-impedance headphones?

[Vincent3]

Is there anything about high-impedance headphones that is inherently better? I ask because I see lots of highly recommended headphones with low impedance (for example, Audio Technica ATH-M50, Sony MDR-V6, the entire Grado line) and wonder why I should get a higher impedance headphone that will necessitate a headphone amp.

 

If impedance is an issue, is there an impedance range that would work well on both a good moderate home system and a good portable mp3 player?

 

One point of reference is the Beyerdynamic DT 880 in 32, 250, and 600 ohms.

 

Thanks!

[anwaypasible]

well i'll tell you one thing, that much difference in impedance isn't going to add to a huge increase in performance.

it's not like using more metal means the voice coil is more sophisticated, especially at those amounts of increase.

the performance is more luck of the draw.

i had a pair of sony headphones that i calibrated using a microphone and the resulting sound was transparent (i could listen to myself talk into the microphone and i couldn't tell if i was listening to myself talk or if it was the headphones, other than the fact that i could feel the headphone pads on my head).

those headphones were 40 ohms.

i don't know if calibrating them caused them to break, or if i dropped them too many times, or if there was a piece of metal in the voice coil wrap that came loose or some material that dried up.

i kinda want to send them in and get them fixed though because even the headphone review website showed their waveform was damn near perfect.

even still, there's a lot that could be improved with those headphones.

for one, they had a habit of making a noise that tickled my ears out of the blue.

i know it sounds stupid to say considering the transparency of my vocals into the microphone, but i thought regular music sounded a little cold - though that might of been reduced dynamics (kinda sounded like there was a high resonant frequency that affected the midrange and grew worse with the treble, but overall i think it was a mixture of the two.)

i also thought the treble didn't have a whole lot of detail, but that could of been a lack of dynamics too (or a combination with distortion, i'm not sure).

 

 

remember, if the impedance is high, you'll need to turn the portable player up louder for the same volume and you'll drain your battery faster.

might come in handy if there's a change of plans that happens and you reach for the portable player but the batteries are already low.

[anwaypasible]

my headphones were hidden in a different category than studio quality headphones, perhaps that is why they sounded as good as they did.

their frequency response went down to 4hz with 104dB sensitivity (quite a sign of improved technology design).

plus fabric is probably the worst at attracting|holding bacteria.

some things to think about while looking.

 

i also thought the soundfield was way too compressed, i would of preferred sound that had space where one instrument could appear closer to my ear (or inside my head) than another instrument from the same speaker.

but for less than $100 that is asking for a lot.

 

if i had it my way, all that fixed for $150 - $179 and last for at least 1 - 3 years longer would already be on the market.

well i'd want all of it fixed for only 1 year longer lasting, but for 3 years the treble could be the same as long as it isn't worse.

any manufacturers browsing the forum? lol

[dalethorn]

Just be aware that some headphones, like the Beyer T1, have an impedance curve that gets to more than double the nominal impedance.

[anwaypasible]

okay, but does that translate to a severe drop in frequency amplitude for the more than double impedance area, or is the resonant frequency so bad that the amplitude drop is minimal?

i know house speakers usually have an impedance curve that rises up to more than double, but it is at their resonant frequency so the speaker wants to move at that frequency anyways thus the high impedance really keeps the frequency response from having a large peak.

 

i could see how a stubborn dip in frequency amplitude would make someone want to compensate more to boost the frequency back up, but i doubt there is such an equalizer on a portable mp3 player (not that i agree).

 

is it a sharp Q rise or more wide? because a sharp Q rise might be more trouble than it is worth if you can't use an equalizer band that is narrow enough to compensate, since adjusting a lot on each side of the impedance peak would prove to be more annoying than a good fit for the available equalizer (if any).

 

**edit**

 

eh, i looked and i seen that big peak at 10khz and thought what are the odds i try to bring that peak down and then the rest of the treble above that frequency falls and refuses to lift back up.

i had to live with a bit of a peak with my headphones, but it wasn't that high and it drove me nuts wondering what they would sound like with the peak & dip gone (if i remember correctly there was a dip at 3khz that didn't want to raise up).

 

i'm seriously starting to think headphones just aren't the go to hardware for high quality sound compared to house speakers.

i've heard about people saying they are a quick grab that guarantee good results because there aren't any room resonances to worry about, but i've had both and calibrated both and i think the imaging from the house speakers is a lot more fun than the imaging i got from the headphones.

there's just something about being able to not use a center channel with the audio splashing all over the screen that tickles me.

plus the panning from left, middle, right is more pleasant for me from the house speakers.

i don't really think it has to do with the sound being in my head as undesirable, i think it is because the overall imaging seems more full - but i might be somewhat confused because of the narrow sense of space the headphones gave.

the house speakers are very widely separated and they give me more peace as if there's room.

i really did get a sense of claustrophobia with those headphones, but i swear they were clean like freshly wiped lenses.

[AMR/iFi audio]

Is there anything about high-impedance headphones that is inherently better? I ask because I see lots of highly recommended headphones with low impedance (for example, Audio Technica ATH-M50, Sony MDR-V6, the entire Grado line) and wonder why I should get a higher impedance headphone that will necessitate a headphone amp.

 

If impedance is an issue, is there an impedance range that would work well on both a good moderate home system and a good portable mp3 player?

 

One point of reference is the Beyerdynamic DT 880 in 32, 250, and 600 ohms.

 

Thanks!

 

 

Hi,

 

Low impedance headphones are usually also high-sensitivity (e.g. IEM's, but also many recent On/Over-Ear-Headphones). They are intended to be driven from something like an iPhone to very high levels.

 

The low impedance does stress output stages more. At the same level a lower impedance will cause more distortion. But the high sensitivity usually means actual levels are quite low, so this often more or less nets out.

 

Some headphones are designed for 120 ohm source impedance and around 8V drive to get full output. Such headphones are often 'Pro' types that could be driven directly from Pro Audio gear and they are becoming more and more rare.

 

In the end it is down to matching the source well to the headphone. Get it wrong and the combo may not play loud enough or it may have too much noise.

[firedog]

my headphones were hidden in a different category than studio quality headphones, perhaps that is why they sounded as good as they did.

their frequency response went down to 4hz with 104dB sensitivity (quite a sign of improved technology design).

plus fabric is probably the worst at attracting|holding bacteria.

some things to think about while looking.

 

i also thought the soundfield was way too compressed, i would of preferred sound that had space where one instrument could appear closer to my ear (or inside my head) than another instrument from the same speaker.

but for less than $100 that is asking for a lot.

 

if i had it my way, all that fixed for $150 - $179 and last for at least 1 - 3 years longer would already be on the market.

well i'd want all of it fixed for only 1 year longer lasting, but for 3 years the treble could be the same as long as it isn't worse.

any manufacturers browsing the forum? lol

 

Ever heard of capitalization? There's actually a reason for it: it makes your text easier to read and understand. But, of course, if you only care about espousing your opinion and aren't really interested in dialogue, there's no reason for you to show any consideration for others....

[anwaypasible]

Hi,

 

Low impedance headphones are usually also high-sensitivity (e.g. IEM's, but also many recent On/Over-Ear-Headphones). They are intended to be driven from something like an iPhone to very high levels.

 

The low impedance does stress output stages more. At the same level a lower impedance will cause more distortion. But the high sensitivity usually means actual levels are quite low, so this often more or less nets out.

 

Some headphones are designed for 120 ohm source impedance and around 8V drive to get full output. Such headphones are often 'Pro' types that could be driven directly from Pro Audio gear and they are becoming more and more rare.

 

In the end it is down to matching the source well to the headphone. Get it wrong and the combo may not play loud enough or it may have too much noise.

 

the reason why high sensitivity amounts to actual lower levels is because a speaker with more dB per watt will play louder with that watt, and if you double the power you get +3dB and if you double the power again you get another +3dB

they say in order to get 10dB higher than the sensitivity you need 10x the power.

is that the limit of the speaker's loudness? i dunno.

but that is the math for house speakers and i don't see why it wouldn't apply to headphone speakers.

 

basically a higher sensitivity headphone will play louder with less power coming from the amplifier, could save you more battery life.

 

there's a good chance the above poster knows, but i wanted to clarify regardless because it wasn't said.

[anwaypasible]

Ever heard of capitalization?

 

i've heard of harassment, and you are not allowed to direct any towards me.

obviously you are too wound up in your childish games of jealousy to point out or support my facts and would rather instead insult me with personal attacks that don't outweigh the value of information (or time) given.

i plan on being productive, if you continue to get in my way - i dunno maybe i'll email the cops or something.

[AMR/iFi audio]

the reason why high sensitivity amounts to actual lower levels is because a speaker with more dB per watt will play louder with that watt, and if you double the power you get +3dB and if you double the power again you get another +3dB

they say in order to get 10dB higher than the sensitivity you need 10x the power.

is that the limit of the speaker's loudness? i dunno.

but that is the math for house speakers and i don't see why it wouldn't apply to headphone speakers.

 

basically a higher sensitivity headphone will play louder with less power coming from the amplifier, could save you more battery life.

 

there's a good chance the above poster knows, but i wanted to clarify regardless because it wasn't said.

 

Hi,

 

Speakers and Headphones mostly work the same way, excluding some exotic types (electrostatic).

 

The actual force on the diaphragm (and thus the sound produced) are proportionally direct, only and strictly to the current. As it is generally not a convenient way to drive speakers (or headphones) with current (plus it raises issues on the transducer side too) commonly both speakers and headphones are designed to be driven from a voltage source, that is a source of low impedance.

 

In this case, current though the transducer’s coil is determined by the impedance, which is often variable. This means the power consumed by the transducer depends not just on the voltage but also literally on the frequency content of the music and the headphone impedance.

 

Take a headphone with a nominal 50 Ohm impedance (@ 1kHz) which rises to around 220 Ohm at 100Hz and then falls again. If we apply 1V to this headphone (which incidentally produces 115dB at both 1kHz and 100Hz with minimal variation), the 1V/1kHz signal consumes

20mW, while the 1V/100Hz consumes 4.5mW. So operating with power in this context is misleading and unreliable.

 

For ease of use and comparison, we much prefer the rating of headphones as XXX dB/V (which parallels the way we rate speakers (as XX dB/2.83V).

 

In reality, the power levels in most headphones when listening are very low. In our earlier example we had 115dB/1V, if listening very loud with very dynamic music we may get those 115dB at peaks.

 

With this, one may expect an AVERAGE level that is at least 10 - 15dB lower, so for playing music with 115dB peaks and accounting for the headphone impedance, we may expect an average power of 1mW being drawn. With respect to battery life, even ten times as much is going to have minimal effect.

 

Where things matter more is if the source is able to produce enough voltage. Most mobile phones produce around 1V max, so we would probably like 110-115dB/V to run without additional amplification.

 

Very high impedance headphones

Very high impedance headphones usually have very low sensitivity, an old studio example with 600 Ohm rated impedance produces 91dB/V. So this headphone will need around 10V (+20dB) to reach the 110-115dB peak region. Definitely not a good match for a smartphone.

 

It will consume 170mW for a sustained 1kHz tone at 111dB, but with music, accounting for the impedance variation with frequency and music's amplitude statistics we will only see 28mW actual power draw.

 

Very high sensitivity IEM’s

Let’s consider the other extreme, an IEM rated 125dB/1V. To get this Headphone to 115dB we only need 0.3V. This may also considered excessive for smartphones.

 

At 115dB peaks we will have around 1mW power draw with music, much less than the first example, but in the overall scheme of things neither figure is going to do much to battery life.

 

But what is worse, if we have a nice Headphone Amplifier that outputs 10V (so is great for the earlier example 91dB/V 600 ohm headphone and has 120dB Signal/Noise ratio (which is very good and means zero audible noise with our 91dB/V 600 Ohm headphone) we can only use 0.3V of this 10V and thus lose 10/0.3V = 30dB of the available dynamic range and in fact, even though this amplifier is very quiet, there will significant audible background noise, never mind that the usable range of the volume control will be minimal.

 

So this 125dB/V IEM with our stellar 120dB SNR 10V output head-amp is a terrible match.

 

Note: power pretty much has no meaning in all of this, it is about matching sources and headphones in terms of sensitivity and output capabilities.

[anwaypasible]

the lower the impedance, the more the amplifier sees the connection as if simply touching the positive to the negative shorting the two together.

i dunno, maybe you are quite fond of your particular mp3 player and choose a pair of headphones with a slightly higher impedance in an attempt to make the player last longer.

(i've had attachments to material items before, i know what it's like to want them)

 

it was noted that 1mw - 10mw isn't enough of a power draw change to extend the life of the battery.

i wonder if this holds true for rechargeables and if it does, would it extend the number of recharges possible.

(not that i'm certain i would remember, or if i'd ever use the information again)

 

i got that it was said most players only output 1v so the only way to really see the sensitivity dB number is from a loud peak in the audio, did you?

but don't let that make you afraid, because 100+dB is very loud.

[AMR/iFi audio]

the lower the impedance, the more the amplifier sees the connection as if simply touching the positive to the negative shorting the two together.

i dunno, maybe you are quite fond of your particular mp3 player and choose a pair of headphones with a slightly higher impedance in an attempt to make the player last longer.

(i've had attachments to material items before, i know what it's like to want them)

 

it was noted that 1mw - 10mw isn't enough of a power draw change to extend the life of the battery.

i wonder if this holds true for rechargeables and if it does, would it extend the number of recharges possible.

(not that i'm certain i would remember, or if i'd ever use the information again)

 

i got that it was said most players only output 1v so the only way to really see the sensitivity dB number is from a loud peak in the audio, did you?

but don't let that make you afraid, because 100+dB is very loud.

 

 

Hi,

 

"it was noted that 1mw - 10mw isn't enough of a power draw change to extend the life of the battery. i wonder if this holds true for rechargeables and if it does, would it extend the number of recharges possible."

 

Well, with two channels at 10mW average (20mW) and a 3.7V LiPo Battery the current draw is 5mA... If your battery is 500mAH this means if ONLY the headphone power is needed the battery will last 100 Hours.

 

The problem is that all circuitry has what is called quiescent current. For a real-world example, in the iCAN nano we have a 1,200mAH battery and it lasts around 75 Hours with a fully-charged, fresh battery, playing music loud (Fostex T-50 which is fairly low impedance and not very efficient).

 

This suggest an average current draw of 16mA. The quiescent current (by design) is around 12-13mA. Meaning the headphone contribution is around 1/3rd of the basic no signal draw of the circuit.

 

Now in a portable player etc. you have a lot more bits that suck juice from the battery than just the headphone amp, so the headphone's contribution will be even less.

[Sam Lord]

anywaypasible: "Thank you AMR/iFi audio for your lucid explanations."

 

FIFY