https://www.enjoythemusic.com/magazine/equipment/0424/FiiO_M17_Portable_Desktop_Class_Player_Review.htm

If I were reviewing the M17 as a full-sized component in my main audio system, I’d describe its sound quality using the cliché “an iron fist in a velvet glove.” With size comes power, and this idiom was especially true when using the M17 when plugged into the wall outlet using its AC to DC power supply. When using its battery, its output power lowered, but sonically, there was such a slight difference in sound quality it wasn’t audible unless I squinted my ears.

Regardless of genre, source, or a file’s resolution, what I heard from my headphones was the epitome of “audiophile sound quality.” Yes, that description has become a bit of a cliché ever since “audiophile sound quality” has been appropriated by the mass-market audio industry. But I’d be wasting the reader’s time going through each recording and attempting to elaborate on what I heard, such as its slamming, deep bass, transparent midrange, and sparkling treble. This is because the recording determined the M17’s sound quality and which headphones I was using much more than the sound quality provided by the M17. In other words, the M17 sounds exceptionally transparent. I can think of no greater praise for an audio component.

The first-ever flagship DAP from HiBy was the R8. Although it was a fine unit, it didn’t quite have the pure sound performance to shape up with the best in the market. The RS8 that came afterwards has been a well-received flagship unit and it’s still considered one of the best. Now HiBy released the successor of the original R8, with dramatic design changes and much better figures/specs on paper. The company calls the R8 II a ”portable concert hall”.

The following is a description of the SR35’s sound in quad-DAC mode. We will briefly go over the changes in sound quality when switching to dual-DAC at the end of this section.

The SR35 can be described as a smooth yet engaging sounding DAP. Especially vocals have some warmth around them, that fills the body and give a rounder presentation. But in some cases that warmth has made the vocals sound too soft for me, where I was missing some bite and raw energy.

Looking at the bass section of the SR35 it sounds rounded and soft to me. Music does not deliver the same punch and force that I am used to sometimes. But that’s mostly the case for hard-rock and grunge styled music. Listening to the new Chemical Brothers album I feel the bass has good body, speed and energy.

https://www.enjoythemusic.com/magazine/equipment/0823/FiiO_M15S_Desktop_Portable_Hi_Res_Audio_Lossless_Music_Player_Review.htm

Performance was so good with the expanse that I had no qualms stepping over to the HiFiMAN HE6se which is my hardest-to-drive headphone. Queuing up Speakers Corner Quartet’s “Further Out Than The Edge” (24-bit/44.1kHz – Qobuz), again I was able to get excellent dynamics out of lower than expected gain settings, this time “medium gain”, but I quickly moved up to “ultra high gain” which put loud at about 107 out of 120 with this electronica / jazz / hip-hop quartet, easily scaling the amp’ed up bass and percussion. Once again the result was wonderfully musical despite the HE6se’s heavy lean into the top end. Even with the USB power disconnected, I was able to get acceptable power levels out of the M15S though it did indeed perform better plugged in.