[size=small]  I bought some earbuds I was very happy with it until I decided to listen to some reggae.[/size]
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[size=small] Reggae songs normally have a bass guitar on the background. At low volumes I can hear the bass guitar well, but If I put average to high listening volume, I don't hear the smooth bass from bass guitar, but a very noisy distortion. Is my set damaged/defective or is it the earphones that are so low quality that can't play that low frequency? I don't believe it is normal because the earphones gives me great music other than that.[/size]
[size=small] If I turn the volume to low levels the distortion disappears. Note that It starts distorting at listening levels, not only at very high volume.[/size]
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[size=small] In the beginning I thought it was the music but I tried all my other headphones, but none gave me the distortion I hear from earbuds.[/size]
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[size=small] I am not saying which earbud it is because it may be a defective set, so before hearing from the seller, I won't name it.[/size]
[size=small] I can say they are supposed to be high quality earbuds, near the top of its class...[/size]

Why not simply name what make the earbuds are of?
 
I was going to write a review for a pair of Yuin OK1 but found issues similar to what you are describing...In my case, the small amp supplied (with zero cost) is making that impossible however. Left/Right output is not balanced and I hear crackling noises when playing low sine-tones on very high levels, this varies depending on battery power available in the tiny amp...
 
Switching to another source, without an amp, I can not hear the same problems but on the other hand I can hear typical problems from a small amplifier taking on too much of a workload, distorsion and with that a bad dynamical range as perceived..
 
Conclusion is that it is really hard to troubleshoot hi-fi products without a lot of equipment available, and then, said equipment must have been proven to be neutral, capable to drive workloads within certain parameters, with no defects, etc. That is tough work to accomplish, dare I say only a few esoteric groups of people have this worked out...
 
Generally I have found that the best products, engineered with care, performs more or less the same under all typical circumstances. They do not put uncalled for requirements on other equipments, such as amplifiers. That would simply not be a good engineering practice - a clear sign of missing understanding, in need of correction.
 
But of course, I do believe there are exceptional speakers, and perhaps also earbuds, that require a good match to perform as intended, doing so producing very nice results.
 
Sure, this is not good engineering practice, but on the other hand, no can master all accounts related to hi-fi?
Perhaps one is good at physics but ignore how one perceive sounds, or perhaps one is good at engineering but not physics.... There are many ways to reach likeable solution and likewise there many ways to get problems.
 
For me, I realize that I only have one real option, which is: I need to get a really capable amplifier and then settle on a conclusion...or give up...
 
I will go for the first option but I can not know if it's a waste of money.

I didn't put the name because I am working with the manufacturer to solve this. If in the end of the day it keeps working like this or if there is no solution, I will tell everyone so they can know before waisting their money.
The thing is that this particular song seems to be too demanding for low frequency response.
I tested it with my desktop amp and my dap, but I keep getting distortion.
Well the first thing I thought after finding this problem was to look for sennheiser mx980. why? because I tested the same song with my sennheiser omx 95 vc II, and didn't have any sort of distortion.
 
I am starting to think that some manufacturers tune very well their drivers and housing, but the drivers components/technicality is not on par with traditional manufacturers like sennheiser or AKG.
 
The funny thing is one IEM which gives me the same distortion at high volume too. This IEM is one of the most popular IEMs here.
May be it is the track that is low quality.