FiiO FD15 Review

FiiO FD15 Review

FiiO FD15 Review – Best Single DD IEM of the Year

FiiO FD15 Review

The brand-new FiiO FD15, succeeding the FiiO FD5, brings a top-notch driver design with a magnalium diaphragm DLC gasket driver. The FD15, an improved model, not only has better design and setup but is also much cheaper, almost half the cost of the previous version. This lower price is because of more efficient production methods that have cut down costs significantly in the four years since the FD5 came out.

FiiO FD15 Review

The FiiO FD15 stands out with its unique bass enhancement design inspired by the patented F.T.B.S. ‘Tesla Valve’. Through a precise powder metallurgy process, the earphone cavity is carefully crafted to create a fluid structure similar to a Tesla valve, resulting in a remarkable improvement in bass extension. Get ready for powerful and detailed bass like never before.

FiiO FD15 Review

The FD5 was the first FiiO product with a swappable plug design. Initially, this design was costly, but now it’s a standard feature in their mid-to-high-end products, thanks to development and production.

The FD5’s ear shells were made from stainless steel using CNC machining. Stainless steel is known for being difficult to work with, resulting in lengthy production times and expensive costs. FiiO has always prioritized being humble and honest, which is reflected in our pricing strategy. We don’t overprice our products solely based on sound quality, but instead consider the actual costs of production and research and development, while still maintaining reasonable profit margins. The savings from cost reductions are then passed on to our customers. As a result, the FD15 offers extensive improvements in design, craftsmanship, configuration, and sound quality compared to the FD5, all while being much more affordable.
FiiO FD15 Review

The FD5 brings a top-notch driver design, featuring a magnalium diaphragm DLC gasket driver. By cleverly blending these two materials, the FD15 not only provides an open and soothing natural sound, but it also reaches new levels in reproducing intricate musical details for a genuinely clear sound.

Magnalium diaphragm: a scientifically calculated blend of magnesium and aluminum that features high hardness and low distortion when moved for clear, detailed treble.
DLC gasket: DLC diamond-like carbon is known for being both rigid and flexible, which means less breakup during movement and ultimately higher-quality sound.
FiiO FD15 Review
The FD15 earphones confidently adopt advanced audio design principles with the innovative W-shaped gasket design. In comparison to regular diaphragms of similar dimensions, the FD15 showcases a remarkable 30% enhancement in the vibrating area. This larger effective diaphragm area and increased amplitude enable the core acoustic unit to hold more sound energy, resulting in a richer and more immersive listening experience.
FiiO FD15 Review
The FiiO FD15 is at the forefront with its F.T.B.S. ‘Tesla Valve’ bass enhancement acoustic design. By utilizing a high-precision powder metallurgy process, the FD15 is carefully crafted to optimize the length, angle, and number of channels in the earphone cavity. This results in a Tesla valve fluid structure that greatly improves the extension of bass.

FiiO FD15 Review

The FiiO FD15 is a unique blend of modern design and closed-back acoustics. Its carefully crafted surfaces create a beautiful interplay of light and shadow. The FD15 is built with 316L medical-grade stainless steel, ensuring durability. It undergoes precise hand-polishing and PVD electroplating for a luxurious mirror-like finish.
FiiO FD15 Review
The FD15 comes in obsidian black and racing silver, two chic colors to pick from. Furukawa monocrystalline silver + Furukawa monocrystalline silver-plated copper braided headphone cable. Skip the high prices and get your hands on affordable high-quality cables. Ever since the FT3, audiophiles worldwide have been seeking out cables made from Furukawa’s high-purity monocrystalline copper. The new FD15 also features these cables and includes a Furukawa monocrystalline silver + Furukawa monocrystalline silver-plated copper braided cable.
FiiO FD15 Review
The cable is composed of four big strands, with each strand containing 100 copper wires and 20 silver-plated wires, making a total of 480 wires. This number of wires is unmatched in its category. The cable has a cross-sectional area of 22AWG and has been subjected to high-temperature smelting at 1050°C. It is a high-quality cable available at a reasonable price. (This cable is identical to the LC-RC 2024 sold in stores for $65.99.)

Unboxing

Specs

FiiO FD15 Review

Price: $150

I want to thank FiiO for providing me with the review sample of the FD15.

Sound

FiiO FD15 Review FR Graph
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The FiiO FD15 provides likely the most ear-pleasing tuning of any single-DD earphone I’ve tested straight out of the box. The overall tonality is very pleasing. The bass is rich and powerful, but still well-managed and impactful, creating a solid base for a warm and inviting midrange sound.

The vocals have a relaxed vibe, yet they maintain clarity and a natural tone. At the same time, the high frequencies are sharp and full of energy. This makes it perfect for extended listening sessions. Overall, it’s a finely tuned sound that appeals to those who appreciate a balanced sound.

Lows

The FiiO FD15 offers a balanced low-end that is engaging without being overpowering. It caters to those seeking equilibrium in sound while also providing a bit of extra punch for those who enjoy it. The sub-bass extension is impressive, delivering a powerful impact with a clear definition even in the lower frequencies. This makes it a great choice for electronic music and drum enthusiasts.

FiiO FD15 Review

The mid-bass is prominent and slightly boosted. The bass is rich and has a warm sound. It transitions smoothly into a subdued lower midrange to prevent any coloration or excessive warmth. The notes are clear and detailed, thanks to the gradual tuning and minimal mid-bass boost, preventing any bloating or muddiness.

However, the FiiO FD15 excels in retrieving details. Its note presentation is precise and controlled, thanks to its rigid driver and powerful magnet structure. The decay and attack are both quick, which helps to balance out the enhanced richness. As a result, the dynamics are elevated, although a cleaner tuning would have further improved the subjective experience.

FiiO FD15 Review

The FiiO FD15 stands out with its strong impact on both the mid and sub-bass frequencies. Although it excels in retrieving details, its slightly reduced separation sets it apart from other earphones. What truly sets it apart is its remarkable depth, power, and texture, all of which contribute to a well-balanced sound experience.

Mids

The FiiO FD15 has a recessed lower midrange, which helps maintain a natural sound without too much tonal coloration. It still has a warm tone, but it balances it out with a slight reduction in the midrange note body.

In my opinion, this makes listening a bit easier because it’s not too intense. The earphones have a natural sound, with vocals placed slightly ahead of midrange instruments without being harsh or sharp.

FiiO FD15 Review

The FiiO FD15 never sounds too sharp to me, especially with its slightly laid-back midrange. The added warmth also makes it more enjoyable compared to your typical earphone. It’s forgiving, yet not overly colored to the point of sounding muffled or veiled; in fact, the FiiO FD15 enhances clarity with its articulate sound.

The FiiO FD15 is a pleasure to listen to and doesn’t have any major flaws. Some people who are sensitive to high-pitched sounds might find it a bit too bright and thin, but the lack of aggressiveness is done tastefully. As a result, the midrange sounds natural and clear, with a touch of warmth and improved note clarity, it’s very enjoyable.

FiiO FD15 Review

Treble

The FiiO FD15 offers great detail and a striking contrast against its clean, dark background. This highlights the lower treble, reducing harshness and ensuring a balanced brightness. Like other similar earphones, a slight boost in upper treble helps with depth and spaciousness.

The FiiO FD15 is clear, precise, and lively. It excels in capturing fine details, thanks to its quick response that enhances the separation of sounds. It delivers a satisfying level of energy and background intricacies. However, it may lack some sparkle and micro-detail at the highest frequencies, which more expensive models with a similar tuning style might offer.

FiiO FD15 Review

The FiiO FD15 offers a pleasant feeling of spaciousness without being too empty, and its layers are well-defined, including the smaller details in the background. It doesn’t overly emphasize details but still provides enough subtlety to create a satisfying sense of dimension and depth, which is quite impressive considering its affordable price.

Technicalities

The FiiO FD15 has an excellent treble extension, which enhances its overall presentation. It creates a spacious soundstage that extends beyond the head, providing a wide and immersive listening experience. While it doesn’t have exceptional depth, the oval presentation is still quite satisfying. Additionally, the imaging performance is highly impressive.

The FiiO FD15 offers excellent coherence and precise positioning from side to side. It provides clear directional cues and impressive layering with well-defined separation.

FiiO FD15 Review
Pairing FD15 with FiiO Q15 gives you a uniquely good sound

Sum-Up

The FiiO FD15 is a good-looking and well-constructed IEM that has a sound signature offering an impressively versatile tonality with a natural, inviting midrange and dynamic bass response. A general appeal that does well with almost any music genre. These IEMs sound as good as they look. FiiO FD15 delivers exactly what it promises, a true flagship dynamic driver IEM for a relatively good price. I think it’s the best single DD IEM of the year.