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I have been doing some work with cheap headphone earbuds for quite a while now. I was wondering, when buying earbuds in bulk, if there was any way to tell what the sound quality would be before purchasing. Obviously one would expect more expensive earbuds to be of higher quality, but there is always the chance that they are just a scam.

I've noticed there is an Ohm value for each headphone and some other metrics like speaker size that are listed within each earbud spec sheet, but I dont know which of these are more important for sound quality. Also, I've taken apart some more expensive earbuds and found that they have fluffy yellow stuff (magnetic shielding?) lining the wires that probably helps drown out noise. Lastly, I'm wondering if gold-tipped TRS/TRRS plugs would make a difference over silver or aluminum ones.

Really, I'm just looking to determine the general sound quality of bulk headphones before purchasing them so that I can make an educated compromise before purchasing them.

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  • \$\begingroup\$ build quality? somewhat. Sound quality? not at all really. THD isn't that important to "perceived" quality, while max DB (sadly) is. If you can see flat response curves, you can more easily customize the presentation to your ear's prefs, but "better sounding" is such a loaded term it's meaningless and varies by age, gender, music type, hearing abilities, mood, humidity (yes, really), time of day, etc... \$\endgroup\$ – dandavis Jul 24 '17 at 3:47
  • \$\begingroup\$ While "good" quality is hard to define, what I really want to know is, how can I tell the headphones aren't "shit". I.e., I just want something that isnt shitty, which most bulk headphones i seem to buy are. You can definitely tell a difference between passable and shit -- there's like no base in shitty ones, it's almost like half the sound is missing. \$\endgroup\$ – nick carraway Jul 24 '17 at 4:36
  • \$\begingroup\$ generally, flatter curves, higher sensitivity (aka efficiency), lower THD, more weight, thicker cords, and wider freq resp indicate higher quality drivers. that's only generally though and vendors can lie anyway. the best is to hear first: sample wide and strike fast upon satisfaction; hoping you catch the same lightning bolt. \$\endgroup\$ – dandavis Jul 24 '17 at 4:44
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    \$\begingroup\$ I've always intended to connect my two ear buds together with shortest possible length of tygon or similar silicon tubing, use one as a source, the other as a mike, and sweep the response using audacity as a source/sensor and look for flatness, but have never got around to it. I would expect by reciprocity the mike sensitivity to track source, assuming they're both electrodynamic, so transfer response of one should be sqrt(total response). Expect a Helmholz resonance at the top end, otherwise, I would expect the flatter the better. \$\endgroup\$ – Neil_UK Jul 24 '17 at 5:50
  • \$\begingroup\$ Would these stats indicate a high-quality sound? "Impedance: 32 OHM Maximum Power Input: 5 mW Sensitivity: 115db (front), 102db (back) Frequency Response: 20 Hz to 20KHz Connector: 3.5mm diameter stereo plug." I mean, I would expect my headphones to have a 20Hz to 20kHz frequency response as thats the range of human hearing, but the other metrics I'm not as familiar with... wouldn't a graph be much more informative than this text I just posted? \$\endgroup\$ – nick carraway Jul 25 '17 at 16:55
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You can take a look at frequency response curves for a general sense of how neutral a pair of headphones is. If you're trying to do analytical work, you really don't want a heavily biased pair of headphone (very bass heavy or very poor bass response), however this still won't capture how much detail it is able to create in terms of maintaining accuracy of quiet bits while reproducing a louder portion.

The best bet is to try a pair. If you can't try a pair, reviews by people doing analytical tasks with them is your next best bet. Beyond that, it's a guessing game/deciding if you know the manufacturer well enough to trust how they are marketing it.

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The best test is your ears and inspection of wire strength as strain relief is usually done by nylon or some plastic fibers that coat the wire need to stretch less than copper to protect the copper from becoming brittle.

Strain relief at both ends is critical for reliability. Compare Apple earbuds with cheap earbuds. "Smokin Buds" brand tend to be good value but not necessary highest quality.

Quality tends on diaphram size, material neodinium magnet size, gap control of moving coil, 60 Ohm range is nominal good value for low but adequate power.

I recall 55 yrs ago as a kid a crystal earbud tightly sealed near eardrum had better bass response with a large crystal wafer than modern earbuds.

You can create your own test patterns for frequency response with Audacity and listen for poor resonant vs flat response and use mixed sweeping sinusoids and listen for aliasing harmonics +/- differences of the order of 10% vs earphones <1% due to the nonlinear response of small rare earth magnets with cone deflection.

One could get more technical and model the ear canal and couple the earbud o a high quality magnetic microphone to capture the frequency response and harmonic distortion in Audacity.

But having done many component qualifications, I could give more detail to define the tests I would do to verify cord reliability with yank tests to failure and sound quality tests, but your eyes and ears ought to be good enough to compare each brand samples with cost.

Gold plating is always used for all relay contacts < 2A to avoid the oxidation that occurs . But nickel plating is pretty common (shiny metal) and often adequate and sometimes not. The gold would likely be flash plating 1~2u" may be a nice to have but wire strength, vs flexibility and sound quality with cost I think are the 3 top variables.

p.s. I just remembered that silicone size adapters were a great feature of Smokin Buds that help with air sealing and ear retention with 2 or 3 sizes included for different ear canal sizes. The hard plastic are easier to keep clean but easier to fall out and harder to fit a wide range of ear sizes. The best ear buds for comfort are almost invisible and create no high pressure feeling yet stick to the ear canal with the rubber like silicone adapter and dont have to be expensive but well designed.

A collar clip is also handy to drop ear buds momentarily without actually rolling them up. Also package container for storage and reuse is an important factor. THe round windup spools are better for protecting the fragile stranded AWG 48~50 wires.

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  • \$\begingroup\$ One can also scan frequency response with small ohm current sensor for some clues \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jul 24 '17 at 21:12

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