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Sorry if this has been asked, but I am really confused and cannot come up with an answer on my own
I think of a musician creating a song
I think they use voice, guitars, bass, drums, etc...
I think these are all done at volumes to make the music well..., for lack o better english... good.
I think they record this for others.
Why don't headphones reproduce this?
If there are headphones that reproduce what was created, then all the headphone can do is volume.
If headphones cannot produce perfect images of what is created,.. first why? Second, if not, can it be done?
So, with all this rambling, why isn't there a headphone that creates the image of what the musician created?
And if there are, what are they, and why can't the same headphone do this on all sources (stereo, mp3 player, etc).
(for me, I use M50s and TF10s, I don't like TF10s for the fit and I don't like I have to use an amp for the M50s with my iPad) Money isn't an option for me on headphones, but I don't want something that creates something the artist didn't create in the first place.
I hope before there are any replies, you read into what I write and not take it word-for-word. I just want to know why headphones have to be rated for mids, bass, and highs instead of being a perfect copy of what the musician created.
Good question. Lets start by discussing the differences between headphones and speakers.
1. Sound stage.
Speakers in a room have lots of air between them and the listener. They can spread farther apart and this expands the sound stage so that there is a lot of subtelty between left, right, and center. The downside is rooms have walls and this causes standing waves, early reflections, late reflections, resonances, etc. Speakers get around these short comings by having users apply panels to a room, bass traps, to minimize these multiple paths and standing waves to make a flatter less resonant sound stage.
Headphones are only inches from your ear canal. Because of this proximity many headphones have a compressed soundstage. Sounds appear to either come full left, full right, or in the center of your head, without much subtle variation in between. But they don't have the pathing problems speakers have. They do still have resonances though because you still use air as a medium between driver and ear drum. However they send the information much more accurately than a given speaker because the path is direct. Headphones try to work around the soundstage limitations by angling the drivers so they aren't aimed straight in to your ear canal. The HD800's and T1's do this very well. Headphones also benefit in sound stage by having open driver designs to minimize internal reflections and resonances, and to allow more air into the sound path.
2. Detail
Speakers need to be physically larger so the drivers need to be larger. This introduces the problem of a large driver trying to create short wave forms (high frequencies) and visa versa. They get around this by splitting drivers up into tweaters, midrange, woofers, subwoofers. They usually do this with crossovers and the quality of the crossover and how it's tuned greatly affect the detail you hear and how balanced the sound is. Use a cheap crossover or have the crossover curves set wrong and you will get dips or peaks in sound and this colors the sound. However you are physically distant from the speaker and the room will color the sound. Also higher frequency sounds are much more directional so there is a sweet spot that you need to sit in. They get around this by using wave guides to spread the sound out more so the sweet spot is wider.
Headphones are very small so they only need a single driver to accurately reproduce a wide range of frequencies. Because there is a direct and short path between driver and ear canal they generally have much more detail than a speaker. This additional detail is also a result of the low power requirements of the driver which allows them to use a much thinner and lower mass driver and voice coil which lets it react to movement quicker creating a more detailed transient response. However due to the small size of their enclosures and proximity to your ear it is possible for the sound to develop resonances that will color the sound and this causes dips and peaks in the frequency response.
In general, you can get a quality sound with headphones for a few hundred dollars and if you wanted to get the same quality of sound with speakers it might run a few thousand dollars.
Most of what makes a given headphone 'good' or 'bad' is a mixture of personal preference, do you like bass, do certain frequencies annoy you like resonant treble, or sparkling highs. How much sound they let out and how much noise they let in also affect the experience.
The two biggest things that impact the sound of a headphone are the driver construction and the enclosure. Do you know what the difference is between a Sennheiser HD419, 429, etc? The enclosure. Many Sennheisers in the same model line use the exact same driver. The differences in sound are due to the enclosure. A good enclosure will be shaped and padded to minimize resonances, expand the sound field, and flatten the frequency response. Sennheiser recognizes that people have different preferences so they will have several models in a line up like the 400 series, 500 series, etc with the same driver but tuned differently, some for more bass, some for a flatter response.
Now with that out of the way lets talk about your question of musicians making a recording, and a headphone or speaker trying to reproduce that recording accurately.
1. Flat frequency response.
When you master a track there are many considerations a musician and engineer take into account. EQ, Dynamic compression (reduces differences between loud and soft sounds), effects like reverb etc, and the level or volume of each instrument in the mix. To do this accurately they need a common point of reference. The method used all over the world is using reference speakers. These are speakers that are made to be as flat in their frequency response as possible. Their job is to accurately produce the sound without coloring it.
Imagine that a producer used a speaker that was bass heavy. They would tend to mix down the bass in their song to make it sound right and it would sound fantastic on their studio speakers. They take it and give it to someone else who has a portable radio, and they won't hear any bass at all, because it was mixed out.
Or they have speakers with no bass so they crank the bass up in the mix to make it sound good, and then when somebody listens to that track with a subwoofer, it will shake their house off it's foundation. This is a huge problem.
So they use monitors with as flat a frequency response as possible. They often use more than one set of speakers to audition the track, playing it on car stereos, headphones, cheap portable radios, home stereos, until they are satisfied that their song will sound good on as many different equipment as possible.
2. Dynamics
Over the years, professional music has had more and more dynamic compression applied so that the average level of a song keeps getting louder and louder. This makes a song pop and sound in your face and catches your attention, but it doesn't sound terribly realistic. This is a very fine balancing act that a recording engineer must perform, between making a mix that sounds good on the radio, and without over compressing it so it's just a continual 0db droning.
Loudspeakers tend to handle dynamics very well because they have high power handling capabilities and the amplifiers tend to also produce a lot of power. You can turn them up to a comfortable level and they can shake your house when something explodes like 1812 overture with report, yet on quieter parts of the song you can hear everything.
Headphones have much lower power requirements and the phones themselves can't handle much power so in order to produce realistic dynamics you need a headphone that will not distort under high power, and you need a headphone amplifier that has headroom or power to spare if that piece of classical music you're listening to suddenly has a Tchaikovsky Canon blasting away in the back ground.
We call these things reference designs, reference levels, reference response curves etc. The idea being that you want to create a listening experience as close as possible to the conditions the studio mixed the song at. If you achieve this you will get a result on your sound system that is nearly ideal to the way it was intended to be heard.
In a headphone this means having a flat frequency response and good power handling characteristics, coupled with a headphone amplifier that does not color the sound and has power to spare.
However you will NEVER get a fully authentic listening experience on headphones because of the soundstage and something I haven't brought up before now, HRTF. HRTF is a fancy way of talking about the physical construction of your ear and the way that your brain interprets slight phasing, delays, and coloration of sound as it bounces around your pina, ear canal, etc. The very close proximity of driver to your ear canal causes very thin but very large resonance spikes, and dead spots in an audio signal. This has the perception of coloring the sound.
Many audiophile headphones do not have a flat frequency response above 1khz, yet they might sound better to you than a completely flat headphone. This is because those dips and peaks might help compensate for those resonances, but also for the way the ear is more sensitive to sounds in the 1-3khz range than to sounds in the 4-10khz range.
There are endless variations of physical headphone construction, driver construction, amplifier construction, that will greatly affect the sound of a recording. But the single greatest impact to whether something sounds good or not is the headphone or speaker.
A well designed headphone or speaker will sound very musical, dynamic, and while it may not be 100% faithful to the reference curve, it will sound good to most people.
Which brings us back to preferences. People who like Sennheisers might prefer a more laid back high frequency presentation, the so called 'veiled' sound. People that like midrange might ooh and ahh about the AKG 700 series. People who love soaring highs might swear by Beyerdynamics. People who love warm sounds might only use tube amplifiers.
In a nutshell, keep trying different headphones until you find one that you never want to take off. Don't worry about what sounds 'right' worry about what sounds 'good'.
