The latest hi-res lossless music player on the market is the the FiiO M5 DAP, which is everything good the BTR3 portable bluetooth receiver amplifier is and more. Aside from the digital audio player (DAP) function, the M5 comes with the added bonus of being also a bluetooth transmitter with coaxial out (Spdif), allowing you to connect the FiiO M5 to an external DAC amplifier.
For times when you don't want to carry your phone on you (i.e. the gym) but want lossless playback, the FiiO M5 is a neat mini DAP solution. It only weighs 39 grams and measures 4.5cm long, 4.2cm wide and 1.4cm thick.
The FiiO M5 DAP is also a wearable so, you can sport it proudly on your wrist or, use it to drive a pair of high impedance headphones (up to 100 ohms). The FiiO M5 supports CTIA headsets and while the headset inline microphone gets disabled, the FiiO M5 integrates dual CvC microphones.
The FiiO M5 has a similar construction to the Apple Watch, featuring a CNC aluminum alloy body and 2.5D tempered glass on the back and front, giving the FiiO M5 a rounded-edge design.
Having screen protection already pre-applied to the screen of the FiiO M5 is handy to prevent scratches though tempered glass is thicker than gorilla glass so it's not as responsive.
If you have used a phone or tablet with a tempered glass protector, the FiiO M5 basically has the same screen responsiveness.
The 1.54-inch IPS LCD screen has a 240 × 240 resolution and supports single touch. The colors are really vivid and sharp, thanks to a high pixel density (220.4 PPI) and 262k colors.
The FiiO M5 battery performance is good. The built-in 3.7V Li-polymer battery has 550mAh capacity and integrates a power management chip (AXP192) that manages the on-screen time, helping to extend the M5 battery life during bluetooth playback (up to 13 hours via SBC) and sleep mode (150 hours or 3 weeks).
Battery life via the 3.5mm headphone jack should technically be longer but the FiiO M5 headphone jack has a balanced amplifier built-in, which drains more battery.
When using headphones with 30 ohms impedance or less, you can get up to 10 hours of playback time. While the FiiO M5 uses USB-C connectivity, there is no fast charge support so, recharging the FiiO M5 takes 2+ hours. You get a status bar on-screen to indicate charging status.
The FiiO M5 user interface (UI) is very responsive when swiping and tapping between menu screens but there is no quick way to return to the main menu because the menu screens don't feature any buttons.
You literary have to swipe back each menu screen to return to the main screen. That said, navigating between menus is relatively fast. The FiiO M5 has 64MB of RAM so, you can effortlessly scroll through hundreds songs stored in the micro SD card. The micro SD card slot supports up to 2TB, which is a massive 2,000 gigabytes! The FiiO M5 power management chip also prevents the internal battery from delivering too much voltage or current to the internal electronics.
While both the FiiO BTR3 and the FiiO M5 use the same CSR8675 bluetooth chip, the FiiO M5 has a higher quality 32-bit DAC chip - the AK4377 - whereas the FiiO BTR3 uses an AK4376a chip. With the AK4377 DAC chip, the FiiO M5 has a wider soundstage and approximately 24mw@32ohm analogue output power.
The FiiO M5 uses Qualcomm's CSR8675 chip with bluetooth 4.2 version though, this chip supports bluetooth 5.0. The M5 player can work as a bluetooth receiver and bluetooth transmitter, but in bluetooth transmitter mode, there is only support for SBC, aptX and aptX-HD. In bluetooth receiver mode, there is support for streaming music apps (i.e. Spotify,Tidal, Qobuz, etc), as well as wider support for bluetooth codecs, including SBC, AAC, aptX, aptX-HD, LDAC and LHDC (Low Latency High Def Codec)
Being a direct competition to Sony's LDAC, Huawei's LHDC is capable of 24 bit 96 Khz playback at 900 kbps flat. Of course, in order to benefit from these bluetooth audio codecs, headphones must support them. One of the first pairs to support the LHDC codec are the Sennheiser IE80S earphones. LDAC supporting headphones include the Sony MDR-XB80BS and 1000XM2 and the RBH Prostereo H2 earphones.

The FiiO M5 DAP player also benefits from noise reduction algorithms to minimize the noise floor when recording audio via the built-in microphone, which is clear enough for taking calls, as well as recording voice memos. Recorded files are written to the micro SD card, which offers a neat storage solution for offline music playback.
 The USB-C connection port on the FiiO M5 can be used as a USB digital out, as well as a asynchronous USB DAC when connected to a computer. Asynchronous USB DACs perform better than synchronous and adaptive USB DACs because asynchronous USB DACs handles the timing of the audio transfer; hence asynchronous USB DACs have lower clock jitter and digital distortion.
In USB DAC mode, the FiiO M5 can handle up to 24 bit/192kHz sample rate, which is nice but when the FiiO M5 is connected to an external DAC amplifier, bluetooth functionality gets disabled.
As a USB-C audio output, you can connect a USB C OTG cable and transfer files between your phone and the FiiO M5, as well as output DSD file formats via two modes D2P (DSD to PCM) and DoP (DSD over PCM) so, you can output an original PCM signal (up to DSD128 signal) as long as the connecting device also supports DSD.
There is no DAB Plus FM radio integration. In Bluetooth receiver mode, the FiiO M5 doesn't support album artist tagging, multi disc album tagging and podcast genre tagging to differentiate podcast files from music files.
The lack of audio information in bluetooth receiver mode might be a problem if you have large music collections. With that said, M3U playlist URL files can be read from the file browser.
The FiiO M5 will also remember natively the last audio track you were listening to after rebooting or shutting down. The M5 player lets you either resume playing the last song-played from the beginning of the track or continue the song progress where you left off.
The full screen clock on the FiiO M5 DAP player can be disabled and you get five face watches to choose from. There is no over-the-air (OTA) support so, firmware has to be upgraded by downloading a zip file to a micro SD card. You can change the screen display orientation (90-degrees, 180-degrees, 270-degrees and 360-degrees).
In bluetooth receiver mode, the equalizer gets disabled along with the coaxial/USB audio output. Multipoint isn't supported either; hence the FiiO M5 cannot connect to two bluetooth devices at the same time.
While there is OTG support, you cannot use the FiiO M5 as a USB DAC with an iPhone or Android phone nor can you connect a USB flash drive.
Dongles won't work either with the FiiO M5 so, you cannot use the Google USB-C to 3.5mm headphone jack adapter or the Anker USB C to Lighting adapter with the Audeze Cipher cable; hence you won't be able to use the FiiO M5 as a USB DAC amplifier with the Nintendo Switch.
Saying this, the Fiio M5 can connect via USB to Apple MFi certified DACs like the Q1MKII, and will work as a Bluetooth amplifier with mobile phones but there is no FiiO Link app support to remotely control the FiiO M5 DAP.
The addition of a companion mobile app like the FiiO Link could have made the FiiO M5 more convenient to control via a bigger external screen.
Accessories included with the FiiO M5 DAP player are a removable clear clip case with a strong spring, two screen protectors, a USB-C to USB-A cable, user guide and a FiiO-branded silicone watch strap. Buy it on Amazon. See the review of the FiiO M3 Pro DAP