Frequency Response –
Testing Methodology: RMAA via Startech External Sound Card
As expected, the BTR5 offers a linear frequency response through the audible spectrum with no roll off, an ideal result. This suggests that it adds no intentional coloration to the sound. Due to the quality of my sound card, I am unable to reliably test other measures such as distortion and crosstalk so they will be used as a personal reference only. Qualities here can impact the sound in subjective listening.
Output Impedance & Hiss –
Fiio’s transparency about their device specifications to buyers is surely a great thing so I went in expecting good things here. And indeed, this was the case; the BTR5 has a very low output impedance ideal for low-impedance multi-driver IEMs and sports a dead silent noise floor (to my ears) that further reinforces this impression. Employing my usual test with the Campfire Audio Ara (8.5 ohms, 94dB), I experienced no hiss nor sounds signature deviation relative to my desktop stack with THX789 (1-ohm output impedance). This is an excellent result.
While some sources do offer sub 1-ohm output impedance, this is a quality that audibly affects only a very small number of earphones like the Ara with its mechanical crossover. In addition, even for very low volume listeners, the BTR5 offers a clean sound with zero noise even on my most sensitive gear. It does so without elevating the OI impedance with a 1-ohm rating through the single-ended output providing great versatility. Please note that the balanced output is rated at 2-ohms, so for low-impedance gear under 10-ohms or so, I would recommend using the single-ended output.
Driving Power –
Most Bluetooth receivers are quite paltry when it comes to output power and I found this to affect the listening experience. However, the BTR5 reads significantly higher on paper than most, to the extent that it even rivals some entry-level DAPs. And in listening, I found this to provide a world of difference. Of course, power output is just a snapshot, and it doesn’t speak for the capacitance of the power supply or the dynamics it is capable of. Still, the BTR5 is a good performer here, it has strong maximum volume and was even able to drive my full-size headphones well past my comfortable listening volumes. I found my IEM collection to be driven well by the BTR5 with only minor deficiency in dynamics compared to my larger DAPs. Stepping up to larger headphones, even ones that were easier to drive like the Audeze LCD-X (20 ohms, 103dB) and it was clear the BTR5 was reaching its limitations.
Bass didn’t hit with the same authority nor was it as dynamic as my larger DAPs such as the iBasso DX200 yet alone my desktop amp stack. However, this is not to say the sound was lacking as it remained balanced and clean, which means the hit to dynamics and extension wasn’t nearly as apparent in isolation. It was subjectively an enjoyable experience with a nice punchiness and a linear signature. Contrast this to the BTR3 which experienced a more substantial low-end roll off that thinned out the LCD’s sound and it becomes clear that the BTR5 does not intend to replace a wired dedicated source. Rather, it seeks to bridge the gap between these two product types without exorbitant cost or unwieldly form.
Testing Methodology: SPL volume matched AB with LCD-X connected to in-line splitter between THX 789 and SH-9 both connected to SMSL SU-9 with RCA splitters.
Though not intended to drive full-size headphones, the LCD-X is a reasonable load and more discerning of changes between sources than most IEMs. And, where I felt before that the BTR1 and BTR3 came with some compromise to sound quality relative to a wired source, the Q5 and BTR5 demonstrate that Bluetooth is not quite as limiting as once thought. This is a commendable performance for a wireless source and one that you can happily listen to on the go without feeling like anything is inherently missing. It will not replace a high-end DAP or a desktop stack of course, simply, the sound is balanced and resolving enough to appease the critical portable listener. Take note that the brick wall filter, SE output and high gain was used for this review.
The BTR5 has only subtle colourations like any good source should. Starting from the bottom, the BTR5 offers a slightly fuller and punchier low-end than neutral. It isn’t overt, but in direct AB comparison to my THX789 reference, a slight increase in sub-bass body was evident. Otherwise, bass sounds linear with minimal tonal colouration. There is no drop off in extension with an authoritarian slam and defined rumble. Note size is slightly enlarged though timbre is accurate otherwise. To counterbalance this, the BTR5 has notably quick decay which enhances separation and retains a well-defined image. Compared to the THX amp, there was clearly less control; the mid-bass wasn’t as defined, the low-end on a whole simply not as composed, especially on complex tracks. Timing wasn’t as accurate nor was the bass as dynamic. This is to be expected and, compared to lower-end BT sources, the BTR5’s tonality and extension make it stand out. Meanwhile, the quick decay aids a slightly aggressive albeit defined and engaging presentation without overly skewing timbre.
The midrange tells a similar story with some colouration but nothing that would affect synergy or an enjoyable listen. Vocals are slightly forward with less depth than the desktop reference, and they have bolstered size and body with an uptick of warmth. In turn, the BTR5 upholds strong coherence and has a powerful and rich voicing. This is likely in good taste for a portable source where ambient noise can thin out the sound. Similarly, wireless is often associated with a loss of low-end frequencies so some compensation here of that is not necessarily a bad thing. Otherwise, the midrange enjoys a natural voicing and good linearity. Clarity is upheld as is upper-midrange extension. The treble sits in a good position enabling an articulate but never sharp or sibilant presentation.
I also was quite enamoured by the top-end performance of the BTR5. The foreground is impressively detailed and about on par with a good lower-midrange wired source. The timbre is also impressively accurate, there isn’t too much colouration at play which is not so easy to come by from BT sources. There is a hint of grain in the lower-treble, body is just a touch diminished and attack slightly aggressive relative to my desktop source. This makes for a slightly tizzier sound with a bit less texture. Still, detail retrieval is focused and instruments retain a natural presentation overall. And above, the BTR5 showcases more than sound headroom and extension. Of course, we can observe some limitations of Bluetooth here, even over LDAC, but altogether, some sparkle and micro-detail is present which is more than good enough for portable listening.
The soundstage is where things are less spectacular. The BTR5 has a relatively intimate presentation with decent width that can stretch outside the head but diminished depth relative to similarly priced wired sources. This means that though it offers a detailed and well-bodied sound, it isn’t the most immersive and involving. Still, imaging is a good performer, there’s a nice sense of layering enabled by the stronger than average extension and detail retrieval in addition to accurate positioning on behalf of its mostly linear sound. Vocals do sit somewhat upfront but maintain a strong centre image and this also aids separation to some degree. The BTR5 doesn’t excel with separation, but is about average due to its fullness that is offset, in part, by slightly shorter note decay.