[junebug654]

Whenever I look on the box of headphones, or even here on head-fi I see people compare headphone specs, and I don't know a thing about any of them.  For example, freq. response, sound pressure level, THD, normal impedence, etc
 
What do all of those mean and what exactly says what is bad or good in these specs?  Is there a bad freq. response, pressure level, thd, or low impedence?  Is there a threshold when it becomes hi-fi?
 
Also what confuses me the most is about freq. response.  I've seen headphones that are like 20-39500 in the response, but I thought the human ear can only indentify between the spectrum of 20-20k?

 

[mralexosborn]

I am no expert, but let me try here.
 
Anything with the audible range of 20-20k Hz is fine. If you can't hear it, why would it matter?
Impedance doesn't make too much of difference in SQ. The lower impedance (8,16,32 ohms) the easier it is to drive.
 
To be blunt, most specs mean nothing for headphones. Sometimes they are indicators, but not really of SQ. Read reviews not spec sheets. 

 

[Eric_C]

junebug654: I think you mean "nominal" impedance, not "normal".
Anyway if there are 2 specs to look out for, it would be impedance and sensitivity. These help give an idea of how loud a pair of headphones can get, and what kind of amp might be suitable for them.
 
Impedance: Low impedance (usually 12-32 ohms) means it needs more current, less voltage. High impedance (250ohms and up) means more voltage, less current. For this reason, tube amps--which can supply a lot of voltage--are often recommended for Beyerdynamic headphones--of which the 250 and 600 ohm models are frequently praised.
 
Sensitivity: Far less debate on this issue than impedance, it basically means how loud the headphones will get for a given amount of watts. Anything below 100 dB is difficult to get loud, and the highest that you will see on most headphones is 120 dB. The difference between a 110 dB headphone and 120 dB headphone is quite large, so do be aware of this.
 
Finally, one spec that you can ignore on most "consumer" brands (e.g.: Skullcandy) or entry-level headphones is frequency.
The human ear can only hear between 20Hz to 20,000Hz. 
Almost all cheap headphones in a Walmart or Best Buy or what-have-you claim to have a frequency response of 20Hz to 20,000Hz. Yet when you try them, you will easily notice that some obviously lack bass, some are obviously lack highs. How can they all have the same frequency response?
Therefore ignore this spec. If you want to know what frequencies a headphone can handle, bring your own test tracks of tones at specific frequencies, and just play them.
 
But as mralexosborn said, don't get too caught up in the specs. They will fail to paint a picture of how the headphones really sound.

 

[junebug654]

Quote:

Impedance: Low impedance (usually 12-32 ohms) means it needs more current, less voltage. High impedance (250ohms and up) means more voltage, less current. For this reason, tube amps--which can supply a lot of voltage--are often recommended for Beyerdynamic headphones--of which the 250 and 600 ohm models are frequently praised.

 
I've heard a lot about impedence also, but it still is such a complex idea to get around.  To me it sounds like cheap headphones have a smaller ammount of ohms, but are easy to use, as where the hi-fi phones have a lot higher impedence making them harder to amp, but when fully amp sound a lot better than the phones with lower impedence.  Is that correct or am I still missing something regarding that point?

 

[mralexosborn]

Quote:

Quote:

Impedance: Low impedance (usually 12-32 ohms) means it needs more current, less voltage. High impedance (250ohms and up) means more voltage, less current. For this reason, tube amps--which can supply a lot of voltage--are often recommended for Beyerdynamic headphones--of which the 250 and 600 ohm models are frequently praised.

 
I've heard a lot about impedence also, but it still is such a complex idea to get around.  To me it sounds like cheap headphones have a smaller ammount of ohms, but are easy to use, as where the hi-fi phones have a lot higher impedence making them harder to amp, but when fully amp sound a lot better than the phones with lower impedence.  Is that correct or am I still missing something regarding that point?

No, not necessarily. All of Grado's lineup is 32 ohms and can go toe to toe with most any other HiFi gear. Also IEM's can have low impedance and best most full sized (i.e. JH16). I guess I would say some headphones are designed to be higher impedance therefore sound better when amped while others are low impedance but sound great without lots of power (i.e. SM3).

 

[Eric_C]

+1 to what mralexosborn said on low vs high impedance headphones.
 
junebug654, bear in mind that many cheap headphones are going to be used by people straight out of the iPods or computers. The companies that make these headphones know this. Therefore, the headphones must work well with these devices, and without an external amp, so it would never make sense for them to have high impedances.
 
There are 2 groups of people likely to have an external, dedicated amp for use with high impedance headphones: people who use headphones for work (e.g.: music industry), and audiophiles. So the headphones that are made for such people can have high impedance, but will also be better than cheap, throwaway headphones anyway. It's not the impedance that makes it good or bad--it's who the companies are trying to sell the product to.

 

[RexAeterna]

not true in most cases. the reason behind high impedance is it allows more movement of the voice coil from a more powerful magnet. it's the density of the magnet that needs more voltage or current to operate the voice coil in a way. more movement of the voice coil means more precise flow of frequencies  i'm not 100% right or claim to be an expert. i just use my common sense and read a lot with an open mind.

now other thing to take in mind of impedance. it dips and spikes. it doesn't stay flat dead at 55ohms or whatever. a headphone with good built drivers(magnets) even claiming to be low impedance will have a spike or dip at a certain frequency range which will require either more voltage swing or current swing depending on the shift of impedance. that's why you hear people insist akg,grados or other good makes are hard to drive even due to low impedance on the spec sheet. same thing with speaker drivers.

but overall impedance doesn't mean anything regarding the headphones capabilities of sound reproduction. it's the individual ears to determine  if it sounds good or not. 
Quote:

I've heard a lot about impedence also, but it still is such a complex idea to get around.  To me it sounds like cheap headphones have a smaller ammount of ohms, but are easy to use, as where the hi-fi phones have a lot higher impedence making them harder to amp, but when fully amp sound a lot better than the phones with lower impedence.  Is that correct or am I still missing something regarding that point?

 

[DapperDan]

I hate to see such lack of attention to the Frequency Response.
Yes, on most cheap headphones, these numbers are typically skewed, with some even claiming to have the standard 20-20k Hz when they don't.
However, people often say "You can't hear it, so why would you care about the frequency above or below anyways?"
 
And that is a wonderful question!
 
There are two wonderful reasons that I find to be true (not everyone agrees on this, so I want you to keep in mind that this is my opinion/ self-research):
 
1.) You may not be able to hear these higher frequencies, but you CAN feel them.
 
Sure, your ear is incapable of converting anything below 20 hz or anything above 20k Hz to audible sound. But that doesn't mean your eardrum itself doesn't vibrate. Especially with the low bass sounds, you can FEEL the vibrations of the cans. And this helps improve the experience. Because there is literally something vibrating, the feeling of a lower end sound begins to exist. You can literally feel that bass shaking in your head. A similar thing happens with the higher frequencies as well! Your ear may not HEAR the frequency, but it vibrates. And you can feel the sound resonating through the cans and your head as well. It allows your highs to become even more piercing and sound more clear.
 
2.) By having a larger range, they work less hard to produce the same sound.
 
The best way to imagine this is like a Mustang Shelby GT (Fast Muscle Car). This vehicle is capable of speeds around 200 mph. But most people NEVER reach speeds like that, especially not the average consumer. Sure, you can get a car that's top speed is 75 mph; but because that is the FASTEST it can go, it will struggle more and more to get to that point the longer you use it. By having a vehicle that can go above and beyond the necessity, you can more easily obtain 75 mph and you can do it for much longer.
Basically: Because the system's range is higher, making it more capable, it doesn't struggle nearly as hard to reproduce sounds.
Like a marathon runner who is just walking, he won't get tired NEARLY as fast if he isn't running his top speed.
 
Again, this is just what I find to be true through my experience and testing. Frequency DEFINITELY isn't everything. But it is something that is good to look for when buying higher-end headphones.

 

[jerg]

Quote:

I hate to see such lack of attention to the Frequency Response.
Yes, on most cheap headphones, these numbers are typically skewed, with some even claiming to have the standard 20-20k Hz when they don't.
However, people often say "You can't hear it, so why would you care about the frequency above or below anyways?"
 
And that is a wonderful question!
 
There are two wonderful reasons that I find to be true (not everyone agrees on this, so I want you to keep in mind that this is my opinion/ self-research):
 
1.) You may not be able to hear these higher frequencies, but you CAN feel them.
 
Sure, your ear is incapable of converting anything below 20 hz or anything above 20k Hz to audible sound. But that doesn't mean your eardrum itself doesn't vibrate. Especially with the low bass sounds, you can FEEL the vibrations of the cans. And this helps improve the experience. Because there is literally something vibrating, the feeling of a lower end sound begins to exist. You can literally feel that bass shaking in your head. A similar thing happens with the higher frequencies as well! Your ear may not HEAR the frequency, but it vibrates. And you can feel the sound resonating through the cans and your head as well. It allows your highs to become even more piercing and sound more clear.
 
2.) By having a larger range, they work less hard to produce the same sound.
 
The best way to imagine this is like a Mustang Shelby GT (Fast Muscle Car). This vehicle is capable of speeds around 200 mph. But most people NEVER reach speeds like that, especially not the average consumer. Sure, you can get a car that's top speed is 75 mph; but because that is the FASTEST it can go, it will struggle more and more to get to that point the longer you use it. By having a vehicle that can go above and beyond the necessity, you can more easily obtain 75 mph and you can do it for much longer.
Basically: Because the system's range is higher, making it more capable, it doesn't struggle nearly as hard to reproduce sounds.
Like a marathon runner who is just walking, he won't get tired NEARLY as fast if he isn't running his top speed.
 
Again, this is just what I find to be true through my experience and testing. Frequency DEFINITELY isn't everything. But it is something that is good to look for when buying higher-end headphones.

Usable frequency response data:

 
 
 
 
Not usable frequency response data:
"herp derp 5 Hz - 50 kHz"
 
 
 
 
Just because something theoretically plays a super/subsonic tone at 40 dB below the average response level in sonic range, often with massive harmonic distortions (especially for sub-sonic response), doesn't mean it extends that far in practice. Want to show people the frequency extension? Show us a frequency response measurement with proper measurement equipment, smoothing, and compensations done.

 

[DapperDan]

Quote:

Usable frequency response data:

 
 
 
 
Not usable frequency response data:
"herp derp 5 Hz - 50 kHz"
 
 
 
 
Just because something theoretically plays a super/subsonic tone at 40 dB below the average response level in sonic range, often with massive harmonic distortions (especially for sub-sonic response), doesn't mean it extends that far in practice. Want to show people the frequency extension? Show us a frequency response measurement with proper measurement equipment, smoothing, and compensations done.

Very True sir ^^
And I would hope that whoever is specifically looking for headphones would do their research such as this!
I don't think you should take ANY company selling a product for their "word".
But I do stand by my statements. Again, just being an audiophile/ voice actor, these are the things I have found in my own use of the products and the like.
I am no expert by any means (Yet!).

 

[alivallo]

Here is the crux of confusion;  its in the naming of the performance:  
 
ohms does not equal or describe Lower Bass;  
Hertz does not equal or describe better sound range;
sensitivity does not equal or describe better durability;  
driver size does not always equate to better sound; 
 
No one in this group mentions DRIVER Size;   in "in ear Headphones"  15mm driver size is good;  more hardware better sound;   9mm is lightweight; possibly good for running but will not produce Better sound;   I have "over ear" phones with Driver sizes 32mm drivers that sound like garbage compared to 42mm drivers;  and "in ear" phones that are 12mm that outperform some sony "overear" 50mm brands.  
 
Also many manufactures don't advertise certain features like "Pressure" sometimes its a gimmick but in cases like the Senheizer 300 this is a real quality indicator of base.  
 
Also I have looked at design;  many manufactures use the same suppliers;  SL99 are by far the best headphones I've owned at $99;  the company sold SOUL brand and is now 'Republic who sells the same product Even Improved  SH9bk for $25; and the Sentey amptitude x360 Looks exactly like the same product designed SL99 for $20; (not sure about the hardware but I bet Sentey would sound comparable) ... getting last years model saves you money too unless there is an obvious flaw noted in the reviews.  
 
Check out ebay's headphone Buyers Guide;  its by FAR the most meaningful explanation I've read online.  Here are the tips:  
If the earphones your going with have a lower sensitivity rating you would want the power handling to be less.
32 ohm earphone - 100mW peak, 
16 ohm Earphone - 200mW peak, 
 
A 95 to 102 dB (decibel) driver only efficiently uses about 4-10% of the power received, the remaining power is wasted by turning into heat.
Although sensitivity is rated in decibels (dB), ***the sensitivity rating has nothing to do with the units peak volume or sound quality. ***
 
Higher Sensitivity = better sound = pop easier = require less power.  92dB, 105dB, 110dB, 120dB are typical sensitivities;   Big driver, higher sensitivity, better overall.  
 
Frequency Response = Look At Design;  a 3 piece speaker has the same FR response as a 1-Piece;  but having 3 pieces dedicated to each range will sound better.  Same with Headphones;  you will see upper end headphone drivers with more housing space and better sound wall design.  
 
 1) Simple Frequency Response numbers to give us the range.  2).  +/-3dB single line graph showing us the driver response curves, not to sharp or to lose, ideally flat would be king. 3)  A MLLSA graph, which is basically a 3D sound graphic showing us the drivers drop-offs. If a sound is supposed to start instantly and come to a sharp end, this shows how well the drivers kept up. The 4th, Environment, the actual listening of the device in play. some drivers just don't response well to certain types of music and/or environments, also taking into account that we just might not like that certain earphones overall sound experience. 

 

[l337h4xx0r]

Driver diameter is a pretty pretty big thing, quite often it's the wider drivers capable of producing a much richer sound with bass that you can feel more easily.

One of the things I often look for (But is rarely listed) is the type of the magnet, drivers that use neodymium magnets can produce a better sound with a lower driver size than a ferrite magnet (And often these headphones can have a cleaner sound due to the magnet being a lot stronger, so better bass response, etc).
 
Another thing that hasn't been mentioned yet is THD (Total Harmonic Distortion). Most THD levels on headphones tend to be <5% THD, some are <1% and very occasionally even less than that (but only on really expensive headphones). The lower the distortion, the better the sound quality, obviously, which indicates better quality headphones.