Lapas RX400 – Review

Lapas RX400

Lapas RX400

| 6 mm MicroDriver |


? This time we are reviewing the Lapas RX400, probably not a brand that is heard very often but design, looks and a microdriver convinced us to give them a try and see how they perform during our tests. The Lapas RX400 is an interesting earphone with a design that looks like a nut (not the kind of nut that you eat but the nuts that screw through the threads of a bolt) and is also built like one with very sturdy and weighty metal construction. Despite the hefty construction they are as small as the KZ HDS3 and hold inside a tiny 6 mm microdriver. Details such as cable bifurcation and stereo plug are also made of metal and share the same colour as the housings. The cable is very attractive, transparent rubberized with a slight golden finish and has a inline microphone with a 1-button control. If you want to buy the Lapas RX400 you will have to be fast as they are quite difficult to find.

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Lapas RX400 - Review

Tests & Scores




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Accessories & Packaging

When you get the Lapas RX400 you will feel excited about the nice and big packaging that looks like they will hold inside a large array of accessories, unfortunately is quite the opposite as not even a single extra eartip is provided.



Bass & Sub Bass

The Lapas RX400 have a nicely achieved bass with good punch and enough depth which is not overdone nor boomy. Most music genres will find their bass requisites fulfilled by the RX400 without issues. An EQ makes them much punchier and depth got enhanced too. During our extreme bass tests the tiny 6 mm microdriver of the Lapas RX400 was able to handle 37% of a Fiio E12’s maximum power resulting in a great increment of mid-bass punch and deeper but distorted sub-bass. There was no basshead rumble or impact coming from the Lapas RX400.


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Mids & Vocals

Mids of the Lapas RX400 are generally somewhat recessed with a bigger roll off of lower mids frequencies than higher mids. Lower mids and lower vocals can feel a bit distant and lack some energy, higher mids are not harsh. With an EQ lower vocals sound certainly less laid back and higher mids still do not sound harsh.



Highs & Treble

Highs are able to resolve some detail and have some brightness but with a darkish tint. Piercing and sibilant highs are not an issue. An EQ makes them less darkish with some extra detail. Piercing highs still do not show up but sibilance starts to become noticeable.



Sound Leak

The sound leaking out of the Lapas RX400 is noticeably above an average earphone which will be perceivable by nearby people even on moderately noisy situations.



Sound Isolation

Sound isolation performance is above average offering sufficient isolation with normal listening volume levels but will not offer a total isolation unless a higher volume is applied.




The microdriver dynamic driver size usually allows the earphones to be tiny (other microdriver earphones would be the Remax RM-565i, UiiSii Hi-705, KZ HDS3) Thanks to their super small size and solid metal construction, the Lapas RX400 inspire trust and translate into comfort with no pain even on long listening sessions.


Response to Equalization

  The response to custom EQ of the Lapas RX400 was fair with noticeable improvement of mids and vocals frequencies, more energetic bass response and added brightness and detail of higher audio frequencies.


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Scores Scores

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Frequency Response (raw)

LAPAS RX400 Frequency Response

Lapas RX400 - Frequency Response
Lapas RX400 – Frequency Response



TypeMicro Dynamic Driver
Driver Unit6 mm
Sensitivity88 dB
Power Capacity10mW
Impedance32 0hms
Frequency Response18-23,000Hz
CordY-type, round cord
Cord Length1.2m
PlugStereo mini plug
Weight (Without Cord)Unknown
Supplied Accessories2x Eartips; cable clip

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We highly discourage anyone from trying to apply our testings to your own earphones, the risk of damaging or permanently breaking your iems is absolutely probable to happen. With our standardized equalization and amplification tests we push the limits of the earphones to the extreme. If anyway you decide to do so, we cannot be held responsible of the damage done to your equipment. Do it at your own risk.

Lapas RX400