Massdrop Plus

Foreword: The Plus is Massdrop's first fully in-house developed IEM, sporting three BA drivers. This sample was kindly provided by @CEE TEE.

Frequency Response

Rescaled


Impulse


CSD


THD


Impedance response

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Analysis

• The 8k resonant peak on the Plus is highly affected by insert depth. It essentially flattens out the closer it is to the reference plane (for reference, most IEMs with the same peak simply have the peak shifted down rather than flattening out). It can be inferred that a deeper insert is optimal for the Plus. (The same characteristics can be seen in Etymotic IEMs)
• Channel matching is good. No qualms.
• The Plus follows Etymotic's Diffuse Field tuning but with a 5dBish boost in the bass. In theory, this should make for a more "musical" signature.
• Being a full BA setup, D3 distortion is expectedly high. In this case, it is slightly higher than the other BA IEMs that I've measured (UERM, Atlantis etc.). D2 distortion is also comparatively higher.
• Extremely reactive with impedance. Source rolling and matching highly recommended.
• Incredibly textured and clear notes, too much for my tastes. I'd prefer to smooth it out slightly with higher OI devices, but your mileage may vary.
• I follow @Hands' opinion of the Plus' timbre; a little thin and almost "crinkly" sounding. Timbre is much better with a better fit, but still leaning more towards thinness in terms of note weight. Great for picking out details, but admittedly not as good for a more "natural" sound a la Andromeda or UE18+.
• Overall the MD+ is a very technically proficient IEM and works well for reference and critical listening, easily on the level of the ER4 veterans, perhaps higher depending on your uses. A great take on the "slightly fun reference" signature whilst sacrificing none of the performance.

 

Man, that 8k peak looks very different on this measurement than on measurements I've seen elsewhere. Do you notice the peak when listening to the IEM, or is it a measurement artifact?

 

I wouldn't really call it an artifact but it's very specific to insert depth. To me, the MD+ is certainly bright and my optimal setup is foam tips + probably a higher Zout (tried it with the 20ohm resistor, it was definitely too much but definitely in the right direction.

I'll just steal Speakerphone's analysis of the effects of insert depth on Etymotics as a primer

See that the peak doesn't shift, but rather flattens out. I observed about the same characteristic with the MD+. I'll throw up some measurements on the reference plane later today when I'm free.

 

Insert depth variation test results:



Unfortunately the IEC microphone does not let me go beyond the reference plane, so for the next few tests I will be using the trusty IMM-6 with a compensation file.



Red line represents the deepest insert out of the three.

 

Went through the bag of tips provided with the sample and decided to settle on the black medium silicone tips. Seems like the combination of the stiff hybrid Symbio tips and the large bore of the eartip resulted in quite a bit of pneumatic pressure buildup within my ear canals, which somehow aggravated the "crispy" nature of the timbre as well as accentuating the treble. Opening my jaw, inserting the IEMs then closing seems to work, reducing the sharpness of the sound quite significantly. Not sure what phenomena is going on here; if any audiologists can chime in for a knowledge bomb (or harsh chastising for misinformation) please do.

Anyway, new impressions are much better. Will edit the first post accordingly.