TRN ST5 Review

TRN (Zuodu Acoustic Technology Co., Ltd) has been a prominent name in the earphone market for some time. The ST5 is the latest model in a recent batch of releases from the company, including the TA-1 Max and the flagship BAX both of which have been praised for their tuning. It is a five-driver hybrid (1DD + 4BA) and is their first model in this configuration since the popular V90. 


The Packaging

The ST5 comes attractively packaged in a white box with a slip cover bearing a full colour image of the IEMs on the front. Removing the cover reveals the IEMs displayed in a foam cut-out below which is a card box with the accessories. In all the box contains:

  • ST5 IEMs
  • 2-pin 8 core OFC modular silver plated cable
  • 3.5mm single ended adaptor
  • 2.5mm balanced adaptor
  • 4.4mm balanced adaptor
  • 3 pairs white silicone tips
  • 3 pairs black silicone tips
  • 1 pair grey foam tips
  • Documentation

It is a generous bundle but there is no carrying case (the cheaper TA2 includes one). 

Build and Design

The ST5 has a CNC formed magnesium alloy housing and is very solidly built. The faceplate features the TRN logo and a pattern of black swirling lines and the metal nozzle is coloured gold with a silver grille and a prominent lip to secure the tip. There is a pinhole vent on the underside and three horizontal vents on the back of the earpiece. The raised 2-pin sockets accept a QDC type connector. 

Internally, there are five drive units per channel with a three-way crossover network. Bass duties are handled by a 10mm dynamic driver with dual magnets and a beryllium plated diaphragm. This is the same driver as in the TA-1 Max. Two 50060 balanced armatures cover the midrange and a pair of 30095 BAs are employed for the high frequencies. This is a similar driver set-up to the popular CCA C10 and KZ ZS10 Pro models. 

The cable is an 8-core OFC silver plated type with a fairly loose braid. The 2-pin QDC type connectors are clear plastic with a metal ring and channel identification is provided by embossed L and R markings. These are hard to read and colour coding here would have been preferable.

The cable is modular and is terminated in a black knurled socket which accepts the three provided plugs, a 3.5mm single ended plus 4.4mm and 2.5mm balanced. The plugs are in the same black knurled finish and the correct polarity is indicated by a white arrow which aligns with a white dot on the cable. The Y-split is a black cylinder with TRN branding and a clear plastic bead serves as a chin slider.

Fit and Isolation 

The ST5 was very comfortable in use. The smoothly contoured earpieces provided a good fit with above average isolation. I did find that I had to use a smaller tip than usual and selected the medium size of the black silicone tips. All the sound impressions were obtained using the 3.5mm single ended plug. See note below for results with the 2.5mm balanced version. 

Sound Impressions 

The ST5 was principally auditioned with a Hidizs AP80 Pro X DAP. A CD player and a smartphone were also used. It was easily driven with adequate volume obtained from all sources and with no need for additional amplification. The IEMs underwent a 100 hour burn in process before evaluation. 


The ST5 impressed straight out of the box. The overall profile was a gentle, well-balanced W shape. There was a deep, tight and well-textured bass with good weight, a forward midrange with excellent clarity and a bright, detailed and extended treble. The soundstage was expansive in all three dimensions. There was some initial sharpness in the high frequencies but this was much reduced after burning in. 


The ST5’s bass was fast, clean and well-extended with a high level of detail and fine resolution. It was slightly above neutral in level and very well balanced with the rest of the frequency range. Sub bass showed good depth and timbre and never dominated but could have benefited from a little more weight and impact. The mid bass was dialled back, transitioning into the midrange with little evidence of bass bleed.

Transients were handled very well with sharp attack and quick decay, giving an impression reminiscent of a BA rather than a dynamic driver which is likely to be the result of the use of Beryllium in the diaphragm. Orchestral basses and percussion displayed good timbre and separation and bass guitars possessed an authentic “growl”. The reproduction of ambience in the low frequencies was notable, being unusually clear and airy. 


The midrange was forward and extremely clear with a high level of detail. The tonality was a touch cooler than neutral and became a little brighter with frequency. Like the bass, the transient response was fast and incisive, with leading edges well defined.

The timbre of various instruments, especially woodwind, was well differentiated and the fine detail allowed counterpoint and musical strands to be followed with ease. Male vocals were characterful with excellent diction but lacked a little weight, whereas female vocals were clear and airy. Sibilance was well controlled, only occurring when present in the recording. The brighter upper region joined the treble very smoothly. 


The treble continued where the midrange left off with a wealth of detail and very good extension. The lower treble was emphasised, occasionally displaying a sharp timbre but the rest of the range was clean and airy in nature and there was a good balance between the technical and the musical.

The reproduction of fine detail was excellent with subtle elements such as the decay of pianos and the harmonics defining timbre clearly evident, especially in the high register of violins and woodwind. Although the high frequency BAs are placed in the nozzle, the treble was approximately at the same level as the upper midrange and with a similar clean, bright tonality. It shared the same speed and immediacy seen in the bass and midrange, the result of good coherence between the drive units.

Soundstage and Imaging

The soundstage was very expansive due to the vented earpieces and the width extended well beyond the ears. Despite the forward nature of the midrange, there was a good impression of depth and height was also well rendered. Imaging was of a high standard, allowing a believable picture of the layout of an orchestra or the positions of the members of a band to be produced.

Layering and separation were of a similar quality and enabled the listener to appreciate the interplay of instruments and the relationship between them, which created a more authentic depiction of the piece. Movement was also well reproduced with stereo effects clearly portrayed, especially in electronic music. 

Balanced Operation (2.5mm)

The modular cable made it simple to switch from single ended to balanced mode. There was an immediate increase in volume and the staging expanded in all three dimensions. The tonality became a touch warmer with the treble appearing smoother and the bass gained in both depth and weight. The midrange was largely unchanged except for an improvement in separation which allowed the elements in complex tracks to be easily followed. This mode elevated the ST5 to a higher tier and its use is highly recommended if you have this facility. 


Fiio JH3 (£50)

The JH3 is a hybrid design, employing a large 13.6mm dynamic driver for the low frequencies and two custom balanced armature drivers for the midrange and treble. It has a lively, dynamic sound. The overall profile is V shaped, just on the bright side of neutral, with a powerful and well-textured bass, a slightly recessed but clear midrange and a clean, crisp treble.  The soundstage is extensive and imaging fairly precise, with separation very evident.

The ST5 has a much flatter profile and does not suffer from recession in the midrange. It does not have the elevated mid bass of the JH3 and consequently does not exhibit bass bleed, rather concentrating on the sub bass. The JH3 has a much warmer tonality and the ST5’s treble is brighter and more detailed but perhaps not as smooth as the JH3, displaying a “warts and all” approach whereas the JH3 is more forgiving. The build quality and cable are superior although the JH3’s bundle is generous. 

TRN TA2 (£40)

The TA2 is a hybrid design with three drivers. The dynamic driver, covering the bass frequencies, is an 8mm dual magnetic unit with a CNT (Carbon Nanotube) diaphragm. It has a 2-pin connection and a vented enclosure. Two Knowles 33518 balanced armatures,  placed within the nozzle, handle the midrange and high frequencies. 

The TA2 displays a largely neutral/bright mild “W” profile which is well balanced across the whole spectrum. Bass is sub-bass focused with a neutral mid bass, transitioning into the mids without bleed. Midrange is open, slightly forward and very detailed.

This excellent detail is retained in the treble which is clean, extended and airy with very good resolution. The soundstage is expansive, extending well beyond the ears with good depth and height. Layering and separation are of the same high standard. 

Once more, the ST5 is more detailed than the TA2, has a more neutral profile and has a more restrained bass region. The midrange is generally clearer and more precise but the TA2’s Knowles drivers are more refined and smoother. Treble extension honours go to the ST5, but the TA2 is no slouch here either. Build on the TA2 is very good but not as solid as the ST5. 

CVJ CSN (£50)

The CSN IEM is the second release from the CVJ company. It is a more ambitious design than the earlier dual hybrid CSA, and features six drivers per channel (1DD + 5BA). Housed in a full alloy shell, the driver complement comprises one 10mm dynamic driver for the bass region, featuring a double magnetic design using N52 neodymium; two 50060 balanced armatures cover the midrange and three 30095 BA units are employed for the high frequencies. The connection is 2-pin. 

The CSN has a neutral character with a touch of extra brightness. Detail retrieval is excellent and transient response snappy and immediate. The bass region is somewhat sub-bass focused with a neutral mid-bass, the midrange is a little forward and the treble clean and well-extended. In addition, the CSN possesses excellent coherence with the transition between the various drivers seamless.

Of the three comparison models here, the CSN is closest in tuning to the ST5, unsurprisingly since the drive units are very similar with the CSN having one extra 30095 HF unit. Both display a similar neutral/bright shaping.

The ST5 displays a sub bass emphasis, moderate mid bass, an absence of bass bleed, clear and open midrange and bright extended high frequencies. The tonality of the CSN is a little cooler than the ST5, but there is a little more “BA timbre” in the CSN’s reproduction resulting in some sharpness and somewhat unnatural tone of instruments, which the ST5 exhibits only very occasionally. They are both very well made with full alloy earpieces but the ST5 has the modular cable which is a definite plus point. 


TRN have produced a very accomplished model in the ST5. It leans more towards the analytical with good technicalities rather than a “fun” V tuning. Its profile does conform to my preferences so not everyone will agree with my findings but I consider it one of the best hybrids I have heard. It is tuned very well with a superb clear and detailed midrange and I have only minor criticisms of the bass and treble. With a little more weight in the sub bass and a slightly smoother top end, it would be perfect, but these issues are partly resolved in balanced mode. 

The build quality is excellent, the accessories are generous (minus a case!) and the high quality modular cable is a bonus. The ST5 is representative of the general improvements in tuning we have been seeing in IEMs recently and it has to be right at the top of recommendations in its price range.  


  • Drive units: 1DD + 4BA
  • Frequency response 20Hz-20kHz
  • Connector type: 2 Pin
  • Impedance: 22Ω @1kHz
  • Sensitivity: 120dB

About Post Author

Author: Lynn Gray

Lynn has been interested in audio since the 70s when his brother brought him his first ever Hi-Fi system. Since then, he has developed an interest in portable audio when the first Walkman came out. He has been testing products for a number of years and enjoys experiencing new technology.

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