INTRODUCTION

    Audiophiles looking for the best in terms of audio reproduction will always put wired connectivity above wireless and yes, I also feel the same way. Of course there's no denying that wireless connectivity is far more versatile since such models ditch cables entirely and offer certain features not found with wired ones (like ANC) but when it comes to audio quality wired connectivity will probably always be in the lead (alas not by much eventually). Fosi Audio is an audio manufacturer I never had the opportunity of cooperating within the past so when they recently reached out asking whether or not I'd like to test their latest i5 Planar Magnetostatic Headphones I was very intrigued.

    Fosi Audio, established in 2017, is dedicated to the development, manufacturing, and global distribution of high-quality HiFi audio products. Our extensive range includes home audio amplifiers, preamps, DACs, headphone amplifiers, speakers, portable DAC amps, and more. Fosi Audio has rapidly emerged as a prominent player in the HiFi audio sector, earning accolades from audiophiles worldwide. With a distribution network spanning over 100 countries, we have sold an impressive 20 million audio products to date. Guided by our mission statement, "Redefining HiFi with Unmatched Value," Fosi Audio is committed to advancing the HiFi industry. We continuously enhance our R&D efforts and collaborate with users to co-create innovative HiFi equipment. Our pledge is to offer exceptional HiFi gear that combines high value for the price, innovative design, cutting edge technology, and premium quality. All our products are backed by a 24-month warranty, ensuring customer satisfaction for audiophiles worldwide.

    The i5 is an full size open back wired model based on two 97mm sized planar magnetic drivers that sport a grand total of 44 high-strength (N50) neodymium magnets (arranged symmetrically - 11 on either side of the diaphragms) together with 2nm ultra-thin diaphragms, 1.3nm thin silver-etched voice coils and acoustic damping rear chambers. This configuration requires a power input of over 100mW (250mW recommended) and allows the i5 to produce a very wide frequency response of 10Hz-50kHz with 28Ohm impedance, 98dB sensitivity and a maximum SPL of 120dB. Fosi Audio has also equipped the i5 with a memory (silicon adjustment slider system) metal headband, dual axis earcups made of CNC machined aluminum and walnut wood, left/right 3.5mm audio ports, and easy to remove Velcro earpads. So, time to see what the brand new i5 Planar Magnetostatic Headphones by Fosi Audio are all about.

SPECIFICATIONS AND FEATURES

PACKAGING AND CONTENTS

The i5 arrived inside a large black box that has a product image at the front, company logo and the model name.

Contact information and things like the warranty period, return period and lifetime product support are printed at the rear.

Fosi Audio has placed the i5 inside a thick formed piece of foam.

Along with the i5 inside the box you'll also find a balanced 4.4mm cable and a single-ended 3.5mm cable (both in soft pouches), 6.3mm gold-plated jack adapter and a user manual.

THE I5

The 550g heavy i5 are made of CNC machined aluminum, walnut wood, faux leather, plastic and suede leather (among others).

Just like with most if not all planar magnetic headphones the i5 are large (perhaps even XL) in size.

The exterior of both earcups is perforated and has the company logo on it.

Left and right markings are printed on both ends of the headband.

The silicon adjustment slider system actually works well and almost like a suspension system.

At the base of the earcups we find the 3.5mm audio ports.

Both earcups can swivel 180 degrees (and more) so they should fit well.

The large earpads are dressed in faux leather on the outside and soft fabric on the inside.

Early samples of the i5 produced less than impressive bass levels but this has since been resolved with the addition of a rubber sound-isolating ring (as seen above).

The head strap is made of suede leather, so it looks great if you ask me.

All jacks are gold plated and it's also worth pointing out that the i5 are currently available with a balanced 4.4mm cable and a single-ended 3.5mm version or with just one of these cables (both cables feature 1120-strand 5N OFC silver-plated wires).

Since both the FiiO R9 and M15 are my favorite music players to date these were primarily used for this review.

Here you can all see an exposed view of one of the earcups (marketing material).

CONCLUSION

    2 things you’ll immediately notice once you put the i5 on your head for the very first time, how exceptional/immersive they sound and just how heavy/large they are. Planar magnetic headphones offer superior audio reproduction over regular dynamic models and the i5 don't disappoint. Overall sound signature is very clear with crisp, detailed, and vibrant highs. Mids are clean and accurate and even though the i5 do tend to emphasize highs a bit more than mids, they don’t produce distortion even at high volume levels. Bass is ample and warm but since I never tested the i5 without the rubber isolating ring I can't comment on how they used to sound (keep in mind that some people call this revision 2). Finally, as for soundstage the i5 are clearly among the top headphones I’ve ever tested in that regard. It’s not only wider than expected but it also offers good transparency, sufficient spacing and accurate instrument separation. The sole thing I didn't quite like about the i5 by Fosi Audio is comfort levels. The silicon adjustment slider system works well but having a pair of very large headphones that weigh over half a kilo on your head is not something I’m used to (could be both because I haven’t used that many planar magnetic headphones and because I don’t use headphones as much as many of my colleagues out there). This of course is not an issue just with the i5's by Fosi Audio, all planar headphones are considerably heavier compared to regular dynamic models but at 550g the i5 sit right in the middle of similar models in terms of weight.

    The Fosi Audio i5 Planar Magnetostatic Headphones were released officially today so you can currently grab your very own for USD544 directly from Fosi Audio (using code FAI5MKT15 at checkout) or for USD559.99 inside the USA (Amazon.com) and for 625.20Euros inside the EU (Amazon.de – code FOSII515 at checkout). Worth pointing out is that this price is somewhat higher than expected based on what Fosi Audio had said during their Kickstarter event but it’s still good for what you’re getting in return. Cost aside the i5 Planar Magnetostatic Headphones do what they were created to do, and they do it extremely well, so the Golden Award is in order.

PROS

- Good Build Quality
- Audio Signature (Across The Board)
- Wide & Accurate Soundstage
- Slider Adjustment System (Comfortable)
- Earcups Can Swivel (180-360 Degrees)
- Balanced 4.4mm & Single Ended 3.5mm Cables

CONS

- Size & Weight
- Final Retail Price