Samsung HS330

Originally designed by Young-Bo Electronics of South Korea as a stock IEM for Galaxy S 4, HS330 is Samsung's counter-blow to LG's hugely successful IEM, HSS-F450 aka Quadbeat, which is bundled with their Optimus G.

In order to overwhelm their competitor's sound quality, these South Koreans start to talk about boldness: They double the number of transducers, by coupling a ∅8 mm tweeter to a ∅10 mm woofer via a crossover network split at 4 kHz. Moreover, various acoustic tweaks have been utilized here in order to increase the overall fidelity.

First, a slit is created at the nozzle. This effectively relieves the air pressure built up in the ear canal, thus yielding airiness.

Second, two acoustic vents optimize the tonal balance of the IEM, by equalizing the air pressure deviation between the frontal cavity and the rear cavity.

And by further investigating into the document that the developer, Young-Bo Electronics, have provided, a deeper look into the double driver's working principle can be taken. Above diagram excerpted from the document suggests two drivers are acoustically well-insulated, removing the possibility of any ill effects caused by phase cancellation. However, as the rear driver is completely inverted, a good care must be taken during the manufacturing process in order to prevent polarity inversion of the entire frequency spectrum.

PRO: Bass quality is very open-air like.

CON: Short bandwidth. It seems the IEM is soldered inversely by default, to imbue an aligned phase characteristic to the woofer. However, measurement indicates the tweeter completely dominates the IEM instead.

ON SECOND THOUGHT #1: The deeper the insertion depth become, the better the treble extension with HS330.

ON SECOND THOUGHT #2: There's a slight treble attenuation, which is about  -3 dB @ 10 kHz at most, when the IEM is connected to a high source impedance.

ON SECOND THOUGHT #3: Interestingly, while attenuating the treble, an additional damping material inserted between the nozzle and the sleeve blocks the air flow of the sleeve slit, and boosts the bass accordingly. Thus, a foam plug seems to be a better option for taming the peaks.

ON SECOND THOUGHT #4: The sleeve slit on the nozzle does a great wonder in the low frequency range by mitigating the excessive air pressure in the ear canal. However, this only works when the sleeve can be loosely fit on the nozzle.

ON SECOND THOUGHT #5: This data may only concern to expert modders: Young-Bo Electronics' double driver is actually highly versatile in terms of tonal modifiability. The driver can be tuned from diffuse-field oriented, electrically flat, to completely bassless, depending on what modification scheme has been utilized by a modder.

ON SECOND THOUGHT #6: Here's my recommendation: First of all, fill up the nozzle with a small piece(2mm x 2mm x 2mm) of foam incised from Etymotic Rearch ER38-14F sleeve for increased acoustic damping- It shall be noted, however, that this will decrease the sensitivity of the driver by at least 9 dBSPL. Second, cut the IEM open, so that the frontal portion of the driver is exposed. Block the woofer output located at the bottom of the driver with a duct tape. Third, open up the rear housing, and get rid of the bi-layered rear driver mesh. Cover it with a duct tape, and create a pinhole(0.5 mm diameter) for better transient in the low frequency range. Fourth, invert the polarity of the IEM by soldering the positive(+ sign is indicated on the pcb board) to the ground, and vice versa for the negative. This will align the polarity of the tweeter, and invert the woofer. Lastly, equip a pair of Ultimate Ears stock sleeves for optimized bore resonance in the 3 kHz to 5 kHz range.

ON SECOND THOUGHT #7: The frequency response of Samsung HS330 is quite far from the Olive-Welti reference, unless it is extensively modified.

ON SECOND THOUGHT #8: Has the alliance between Samsung and Young-Bo Electronics beaten the collaboration of LG and iSound? I don't honestly think so. Although the dual driver is highly modifiable and can be tweaked to achieve better sound quality, in stock configuration, Quadbeat easily outperforms HS330, hands down.