This small article can be useful for those of you, who want to invest some money into more expensive, hi-end headphone system. Following is a small adventure, that with my friend - I experienced several months ago.
I think, the cheap headphone system (excluding "multimedia" headphones designed for computers, which are usually more expensive and sound worse than typical musical headphones, like a "dummy box" I would place somewhere between USD 5 and USD 35, average between USD 40 to USD 100, expensive somewhere between USD 150 to USD 400, and all over USD 500 (can even cost USD 1500) would be "for special uses". "Special uses" is "selfclaimed audiophile" section perhaps, because I saw people who spent so much money to buy such system (which responds to wide frequency range like above 90kHz) to listen... MP3s (which are flat and distorted in nature, frequency range rather below 20kHz).
Cheap headphones can be great, trust me. I personally own 3 pairs of USD 10 panasonic neodymium clip-ons, which I use since about 10 years, and I would not change them into "legendary" koss (they are 2-3x cheaper than koss, but although lower dynamics and loudness, they have wider range of sonic details and sound somewhat warmer, speaker-like for me). But there are a lot of in-ear cheap headphones which are also great; I just prefer clip-ons, because they are so comfortable to sensitive ears.
Anyway. Sometimes, when you buy a great headphones, one of your first experiences you encounter is... certain discomfort. Sure, the sound is great (loud, dynamic, detailed), but sometimes seems to be "dirty", somewhat out of tune or just unbalanced in some way, impossible to regulate with left/right balance wheel. So you begin to look around, what is wrong. Is something with the headphones? Or your soundcard (or mp3 player) died somewhat? Or perhaps there is something with your hearing not right?
Let say that you have purchased expensive headphones, for example audio-technica ATH-M50. Why not sennheiser? Well; these are a "monitor headphones", designed for sound production (have rather analytic characteristics than overcoloured soprano details and/or overboosted lows). One thing you will notice - the space (in terms of sound localization) in such headphones - is much accurate and wider. Therefore - if you deal with badly made production - you will notice all positioning errors. If there is too much on the left or right - then it can be painfully too much... such things are not noticable in cheap systems. Another thing is the clarity of sound - "out of tune" and dirtiness artifacts. Yep, this is how it really sounds, when it is recorded with very sensitive and expensive microphones. A friend of mine said once, that "if you decide to buy a good and expensive headphones, either you learn to get used to average quality of most sonic productions (and learn to ignore errors you hear), or you begin to really hate your so much loved music". And he was unfortunately right.
Among all these things mentioned above, from time to time - it can happen, that there is also objectively something WRONG with the sound. The better headphones you have, the better they must be paired in terms of frequency response (left = right). If the inserts are not paired correctly, then sound will wander left or right, but not entire sound - only vital parts of frequency range. That why the balance wheel will not help here. But if you deal with such wide and detailed and dynamic sound, how can you measure, what is wrong?
We developed a simple procedure in order to know whether the headphones must be send back or not.
In a few days, I add a link to a simple "test signal", that you can use for your measurements.
The "test signal" is a mono recording, which means, that if everything is OK - you will hear it always in the center, and it will not wanter left or right. It is a monophonic signal, it has no separate "left" or "right" channel. The "test signal" is a sinus, which means that this is a pure tone, with no harmonics. You will hear only one, smooth frequency. The pitch of this "test signal" moves from low frequency to high, so at first you will hear bruming sound (frequencies below 40-50Hz), then regular raising tone-to-whistle, than hissing end (perception above 10-12kHz). Although the "test signal" has a constant amplitude, due to so called "hearing curve" (see wikipedia for details), perceivable loudness will change, depending on frequency. So you can hear it louder, then quieter, then louder again, then quieter again, and so on. This is normal. Also it is normal, that depending on general loudness - these differences will be smaller or greater.
So, you have your test signal, and you must decide what is wrong. Headphones? Sonic output? Your hearing? Probably many of you will be surprised to notice, that the sound wanders left or right at certain points. If this is due your hearing - it may have to do with damages, but also it can be related with how well your ears are naturally wasted or trained due to exposition or perceptual habits (like left-right handers).
Anyway. If you connect your headphones to your playback device (soundcard, mp3 player, mobile; whatever, but turn off all DSP processors, EQs and special effects), and you will hear that the sound is not always in the center - notice how the sound wanders and where. If you connect the same headphones to different playback device, and the wandering will be similar - then you can exclude your playback devices from the list. If you have expensive soundcard, you can breath with relief.
If the problem is with headphones, then even if you have damaged hearing, you will notice the symmetry of wandering sequence if you switch your headphones (letf to right) on your head.
If you swich your headphones, and you hear constant (unchanged direction to left or right) shift points (for example, you can hear that the hissing goes always left, no matter how you wear the headphones) - then this is the part of your hearing perception.
Having done these simple tests - you will know what the problem is. If you have any complaint/return problems and your seller claims that with your equipment is everything OK (although you should have no such problems with professionals, like folks from audio-technica service) - this is your unbiased and empiric argumentation to enforce your customer rights.
* * *
It looks, that Freesound has a little bit crazy filtering system. I could not post the article with multiple "dollar" signs, so I changed it into "USD"
As promised - here is the test signal for checking your output-headphones-hearing profile:
If I have a little bit more time, I add TTS/spoken indicators of frequency/note positions, so you can know where you are during listening. But perhaps some of you - would like to do it?
This was super extra useful, thank you!