It's becoming quite the hard sell getting people to spend ridiculous amounts of money on flagship IEMs when they can get Hi-Fi sound at much lower price. Take for instance the Fiio FD1, a pair of IEMs which integrate beryllium, aluminum brass nozzles and a see-through body shell design that lets you see the inner workings.
The transparent clear plastic on the front shell has a magnifying-like construction that makes the celluloid faceplate have a cool bubble-like effect. Side by side, the FD1 look virtually identical to the Fiio FH1S but, beneath the outer shell the Fiio FD1 has a entire different driver setup.
While the Fiio FH1S integrate two drivers (1 balanced armature + 1 dynamic driver) per earphone, the Fiio FD1 has one single 10mm dynamic driver per earphone. The Fiio FD1 dynamic drivers integrate Beryllium-plated diaphragms and NdFeB N50 magnets. The Fiio FD1 dynamic driver is smaller than the 13.6mm dynamic driver in the FH1S but the FD1 driver has slightly higher impedance (32 ohms) and sensitivity (109dB).
If you plan to use the Fiio FD1 for commuting to work and/or for drowning outside noise, the FD1 won't disappoint. They have exceptional audio dynamics similar to the Fiio FH1S, although the sound signature couldn't be more opposing!
This is not surprising though, since the Fiio FD1 single dynamic driver has to deliver all the frequencies, making the treble, midrange and bass have a natural dynamic emphasizes, which is perfect for lively and energetic music genres. There is clear instrument separation, punchy deep bass, pronounced vocal mid-range and clean treble.
The Fiio FD1 can be driven comfortably from a smartphone but, like with all earphones with high sensitivity, you can get better performance (i.e. wider soundstage) by using a bluetooth headphone amplifier such the BTR3K, which works with phones and computers and supports LDAC, aptX HD, aptX LL, aptX, SBC and AAC.
You will also be able to hook the Fiio FD1 to most external sound cards and powered amplifiers, thanks to the FD1's high input power rating (100mW). For monitoring or mixing music though, you should consider getting the Fiio FH1S dual driver in-ears. If you aren't looking to use an external amp dac, the included Comply foam tips should help out maximize the sound quality. The foam eartips also work great as earplugs when you need to block background noise like building work across the road!
FiiO branding can be found embedded in the internal celluloid faceplate, as well as inline the cabling on a small housing unit, which looks like an inline remote/microphone but, it is in fact a Y-splitter. All wired in-ear earphones have a Y-splitter, which is usually hard plastic and designed to split the audio wiring into Left and Right audio channels. The Y-splitter on the Fiio FD1 is made of metal and integrates a cable cinch to tighten the Y sections of the cabling.
The Fiio FD1 earphone cable terminates into a 3.5mm right angled jack at one end and, 2-pin connectors at the other. The 2-pin male plugs and 3.5mm male jack are made of hard plastic, while the 2-pin female ports on the FD1 earphones extend outwards within reinforced tiny clear plastic retainers. The pins and contacts are all gold plated.
The 2-pin connector plugs have red and blue markers (red for Right and blue for Left). The red/blue markers are integrated on the underside of the 2-pin plug but not on the earbuds themselves, which is odd since the user guide shows them to be color coded. This, of course, doesn't affect performance although, having red/blue markers would make it more convenient to quickly tell which side is left and which side is right.
Visible blue/red markers would have probably cheapen the premium-look design of the Fiio FD1, which is probably the reason why the Fiio designers did not implement it. Aside from the blue/red markers, there are also R and L lettering on the outside of the 2-pin connector plugs.
The 2 pin connectors easily slide in and out, although you have to be mindful when removing them because there is no polarity marking (positive/negative), which would help prevent inserting the 2-pin male connector plugs the wrong way, causing the drivers to be out of phase. While this won't necessarily damage the drivers, it distorts the stereo imaging and even reduce bass response. You will know you have inserted the pins the right way when the R/L markers on the plugs face down towards the ear tips.
Having detachable cables on earphones is a really neat feature that you typically find with headphones. Most wired earphones don't have detachable cables and those that do have a 2-pin plug or MMCX type connectors. The 2-pin plug style is probably more popular because it is cheaper but both types can be easily converted to wireless via a 2-pin bluetooth module (not included) like the Fiio UTWS1.
Just like most 2 pin bluetooth adapters, the Fiio UTWS1 bluetooth module will work with any compatible 2 pin connector earphones that use a 0.78mm 2-pin connector plug. When buying replacement cables or a bluetooth adapter for the Fiio FD1, you want to keep in mind the size of the plug because there is also 0.75mm 2-pin type connectors, which wouldn't be compatible with the Fiio FD1.
Aside from Comply foam tips, the Fiio FD1 include different size silicone eartips (three red ones and three black ones). The silicone eartips have a standard bowl shape but the red pair of eartips have a slightly larger inner hole diameter.
As far as fit, the Fiio FD1 have a comfortable secure fit, thanks to the cabling terminating in ear-hooks that wrap behind the ear. The Fiio FD1 has the same 1.2 meter long Litz wire cable found on the Fiio FH1S. The cable has multiple strands of braided, steampunk-colored copper wires that can be seen through the transparent cable sleeve.
A lot of wired earphones are worn straight-down, although with weightier earphones like the Fiio FD1 the "around the ear" design makes more sense. The Fiio FD1 have a total weight of 24 grams. The cable itself weighs 14 grams, while each earphone weighs 5 grams.
The weight of the Fiio FD1 won't really a deal breaker though since these IEMs aren't intended for fitness/sports but for stay-at-home listening, replacing bulkier headphones. That said, you can easily and securely transport the Fiio FD1, thanks to the included FiiO FD1 which is a hard-shell waterproof protective case. You can buy the Fiio FD1 earphones from Fiio and amazon.