Thieaudio Legacy 4 IEM Review






Thieaudio Legacy 4 IEM Review




Thieaudio was launched in 2019 as a creative endeavor of Linsoul Audio. It offers portable audio products such like planar magnetic headphones like the Phantom as well as the Voyager, Legacy and Signature series In-Ear Monitors (IEM’s).

The Legacy 4 is a Hybrid Driver IEM that utilizes a new in-house developed 8mm diameter poly-membrane dynamic driver + 3 Knowles Balanced Armature drivers with an intuitive low-mid passive crossover design. These drivers are integrated in to beautiful looking hand made resin shell that comes with two sound tuning switches.



The Thieaudio Leagcy 4 IEM was provided to me by Linsoul Audio for review purposes. I am not affiliated with Thieaudio or Linsoul Audio beyond this review and these words reflect my true and unaltered opinions about the product.




The MSRP price of the Thieaudio Legacy 4 IEM is actually around $195,00USD. More information’s can be found under the link below;




Package and Accessories:

The Legacy 4 comes in a pretty large box that is in black color. On the top of the box is the Thieaudio branding, while the some technical specifications and a frequency table is available at the bottom of those box.


This box is including the following contents/accessories; 

  • 1 x pair of Thieaudio Legacy 4 In-Ear Monitors
  • 1 x Detachable Cable with 2-Pin Connectors
  • 6 x pairs of Black Silicone Ear Tips
  • 1 x Big Storage Case
  • 1 x Zipper Case
  • 1 x Switch adjusting tool
  • 1 x Some Print Material


 The Legacy 4 came inside a large zipper storage case with a fabric surface in grey color that has the Thieaudio brand logo on the top. All accessories and the Monitors where nicely organized inside this case.

Inside the storage case are 6 pairs of silicone ear tips that are placed on to a stylish metal organizer with an engraved Thieaudio logo on the top. The Legacy 4 came also with a smaller zipper case with the same fabric material surface that sports the Thieaudio brand logo on the top.

Thieaudio has put a tool for the adjustable sound tuning switches, which is a nice addition.





Design and Build Quality:

The Thieaudio Legacy 4 a pretty nice looking IEM with a Semi-Custom like monitor shape that fits very comfortable to my medium sized ears. The hand crafted housing is made of medical-grade German resin.

The faceplate has a beautiful pattern that reminds me to the planet Jupiter with the colorful waves and swirls. The right faceplate sports the Thieaudio logo in silver color that looks eye-catching.

On the top of the monitor shells are the 0.78mm diameter 2-Pin female connectors that do show a tight and secure connection.

Near the 2-Pin female connector is a pressure vent for the dynamic driver.

The inners surface has an ergonomic shape that fits prefect to my medium sized ears. Here is also the Legacy 4 branding and serial number of the monitor that was printed in white color.

On the top of the sound nozzle are three (3) small openings for the 3-Way Crossover Network.

The sound nozzle is a bit short, which could be a limitation for the use with several ear tips.

At the rear side of the monitor shell are two sound tuning switches that are quite small, which makes the tool that came inside the box very helpful for the adjustment.

The Legacy 4 comes with a 4core 7N purity OCC wire cable that has a nice braided design. The cable utilizes pretty soft transparent plastic isolation with very low amount of microphonic effect.

The detachable cable of then Legacy 4 features 0.78mm diameter 2-Pin female connectors that are protected with a metal housing in silver color. Each connector sports Left (transparent) & Right (red) indicators and blue dots for the right (+/-) insertion).

The cable of the Legacy 4 has a metal Y splitter and a transparent plastic chin slider.

The cable comes with a 3.5mm headphone jack that has a straight profiled metal housing in silver color. The housing features a plastic strain relief for extra durability. The build quality and design of both the cable and the monitor shells is on a high level!




Fit, Comfort & Isolation:

The Thieaudio Legacy 4 has a very ergonomic IEM thanks to its relative small semi-custom like shape and didn’t hurt my average sized ear concha even after long listening periods.

The passive noise isolation of the Legacy 4 is about 24dB, which makes it quite sufficient for the use in public transport like metro, bus or train.



Technical Specifications: 
  • Driver Configuration   : 3x Knowles (ED29689) BA Driver + 1x 8mm Diameter Dynamic Driver
  • Frequency Response : 20Hz ~ 20 kHz
  • Sensitivity                   : 108±0.5db
  • Impedance                  : 9.4 Ω
  • Noise Isolation            : 26dB
  • Cable Material            : 4core OCC Wire
  • Connector Type         : 0.78mm Diameter 2-Pin Connector
  • Plug                            : 3.5mm Single Ended (TRS)
  • Cable Length              : about 120cm




The very low impedance of only 9.8Ω and a sensitivity of 108dB makes the Thieaudio Legacy 4 to a very easy to driver In-Ear Monitor that is highly compatible with relative weak sources like Smartphone’s, Tablet’s and MP3 players.



Equipment’s used for this review:
  • IEM’s              : Thieaudio Legacy 4, Tansio Mirai TSMR-3 Pro, Mee Audio MX4 Pro
  • DAP&DAC’s   : iBasso DX220 MAX, FiiO M11 Pro, iPad Air2




Albums & Tracks used for this review:
  • Sting – Englishman in New York – (Flac 24bit/48kHz)
  • Casey Abrams – Robot Lovers (Spotify)
  • Barry White – Just The Way You Are (Flac 24bit/48kHz)
  • Isaac Hayes – Walk On By (Flac 16bit/44.1kHz)
  • Sting – Englishman in New York – (Flac 24bit/48kHz)
  • Elton John – Rocket Man (Flac 24bit/96kHz)
  • Eric Clapton – Wonderful Tonight (Flac 24bit/96kHz)
  • Chopin – Nocturn No. 20 In C-Sharp Minor (Flac 16bit/44.1kHz)
  • Sonya Yoncheva – (Giuseppe Verdi) II Trovatore, ActI (Flac 24bit/44kHz)
  • Edith Piaf – Non Je Ne Regrette Rien (Flac 24bit/48kHz)
  • Diana Krall – So Wonderful (DSF)
  • Aretha Franklin – I Say a Little Prayer (Flac 24bit/96kHz)
  • Fazıl Say – Nazım Oratoryosu (Live) (Flac 16bit/44.1kHz)
  • Vivaldi – Le QuarttroStagioni “The Four Season” (Tidal Hi-Fi)
  • Otto Liebert& Luna Negra – The River (Spotify)
  • Gogo Penguin – Raven (Flac 16bit/44.1kHz)
  • Armin Van Buuren – Vini Vici (Flac 16bit/44.1kHz)
  • Lorde – Royal (Flac 24bit/48kHz)
  • Massive Attack – Angel (Flac 24bit/192kHz)
  • Twerl – Lishu (Spotify)
  • U2 – Sunday Bloody Sunday (Flac 16bit/44.1kHz)
  • Photek – The Hidden Camera (MP3 320kpbs)
  • Metallica – Sad but True (Flac 24bit/96kHz)
  • Megadeth – Sweating Bullets (Tidal Hi-Fi)
  • Rush’s – Leave That Thing Alone (Flac 16bit/44.1kHz)
  • Slayer – Angel of Death (Spotify)
  • Tom Player – Resonace Theory “Album” (Tidal Hi-Fi)
  • Liquid Tension Experiment 2 – Acid Rain (Spotify)




The Sound:

This review is written after a burn-in period of 50 Hours. I have used the stock OCC cable and the black silicone ear tips that are included to the package.


Switch Configurations:

The Thieaudio Legacy 4 has 2 build-in sound tuning switches to change the bass and midrange response of the IEM.

The switch with marking 1 (1-0) is dedicated for the bass response, which offers a slightly audible enhancement / increase of the sub- and midbass intensity of the Legacy 4.

The switch with the marking 2 (0-2) changes the midrange character. Noticeable changes are the more forward midrange character and slightly more neutral tuning that is especially audible in the low frequency region.

The switch is at default mode when you set both the switch 1 and switch 2 to the position 0 (0-0).

My sound impressions below are mainly based to the default switch tuning, which are set to 0-0.



The low frequency region of the Thieaudio Legacy 4 shows a fairly linear response with focal point that is concentrated in the subbass region. The most remarkable feature of the bass response is the general speed, control and decay that are quite impressive for an IEM that is producing this range with a dynamic driver.

The subbass shows a moderate depth and sufficient level of extension. The intensity and rumble that is produced by the 8mm diameter Dynamic Driver is not overwhelming even if you set  the switch to 1, which is especially noticeable while listen to bass heavy genres like EDM or Electronic music. However, the speed and control of the subbass that is produced by the Dynamic Driver is quite impressive.

The midbass region on the other hand shows slightly less intensity compared to the subbass area, which offers an sufficient level of impact and slam effect. The overall intensity and the level of extension are quite good while listen to instruments like an acoustic guitar or organ, which are represented with a good sense of fullness and body.

The overall clarity, resolution, control and speed of the bass that has been produced by the Legacy 4 is was quite impressive. However, the bass maybe won’t scale the expectations of bassheads in terms of quantity and intensity.



The Thieaudio Legacy 4 has a slightly warmer than neutral tonality and shows a good level of clarity and airiness while listen to both vocals and instruments. Here is a low amount of coloration that comes from the upper midrange and lower midrange regions, which does avoid a dry or too dull presentation and adds the Legacy 4 a nice sense of musicality.

The lower midrange of the Legacy 4 is less highlighted compared to the Upper midrange and shows an average level of intensity and body while listen to male vocals or instruments like hi-hats and acoustic guitars.

The upper midrange of the Legacy 4 is quite highlighted and has an audible peak around the 3 kHz region female vocals and instruments like pianos and electric guitars vibrant, clear and detailed.

The Thieaudio Legacy 4 shows an above average midrange performance that is beyond is price level, thanks to its well pronounced upper midrange tuning that offers a nice sense clarity and detail reproduction.



The Thieaudio Legacy 4 offers a smooth but fairly detailed treble presentation that is less pronounced compared to the upper midrange region. The transitions from the upper midrange towards the lower treble region are pretty controlled, without to show any remarkable negative situations like sibilance or sharpness.

The lower treble region of the Thieaudio Legacy 4 is more highlighted and detailed compared to the upper treble region. The lower treble region has an audible peak around the 5 kHz region that was also visible in some measurements about the Legacy 4. This area is able to produce a good sense of clarity without to sound harsh or cause irritation while listen to soprano vocals or instruments such like snare drums or pianos. The extension in this area is on a pretty sufficient level

The upper treble shows an audible and controlled roll-off and a shorted extension compared to the lower treble area, and is concentrated around the 8 kHz area. This frequency range shows an average intensity and extension, while the airiness and sparkle that has been produced was on a sufficient level when I do listen to strings and cymbals.

The treble range of the Thieaudio Legacy 4 sounds in general smooth and controlled that makes it to a fatigue free IEM for longer listening periods.


Soundstage & Imaging:

The Thieaudio Legacy 4 offers a soundstage with a good level of separation and positioning of both vocals and instruments. The soundstage of the Legacy 4 has a moderate depth and above average wideness. The neutral air between the instruments makes the overall soundstage presentation fairly airy.




Some Comparisons:


Thieaudio Legacy 4 (0-0 default) versus Tansio Mirai TSMR-3 Pro (0-2-0 Balanced):

The Tansio Mirai TSMR-3 Pro has a V shaped sound signature with a laidback presentation. The bass is strong and shows good depth, the midrange is smooth and pretty musical, while the upper midrange and treble is controlled, warmish and well pronounced.

The subbass region of the Thieaudio Legacy 4 shows a slightly better sense of depth and intensity compared to the Tansio Mirai TSMR-3 Pro. The midbass region on the other hand is more pronounced and impactful with the TSMR-3 Pro, while the Legacy 4 offers a more linear character.

The lower midrange of the TSMR-3 Pro has more depth and intensity, which is an advantage for male vocals and instruments like acoustic guitars and trumpets, while the Legacy 4 is more noticeably more successful with female voices and instruments like violins and pianos thanks to the more pronounced and detailed upper midrange character.

The treble range of both IEM’s shows many similarities and has in general a smooth and relaxed/controlled nature. The lower treble region of both the Legacy 4 and TSMR-3 Pro is more pronounced and detailed compared to the upper treble area, while the Legacy 4 has the slightly edge in terms of overall extension and detail retrieval.

The Thieaudio Legacy 4 offers a slightly more airy and spacious soundstage atmosphere. The soundstage of the Legacy 4 has a slightly better sense of wideness, while the depth is nearly identical to those of the TSMR-3 Pro.



Thieaudio Legacy 4 (0-0) versus MEE Audio MX4 Pro:

The MEE Audio MX4 Pro is an IEM with a slightly warmer than neutral tonality. The main focus of the MX4 Pro is especially the midrange and treble region.

The focal point in the lows of both the Thieaudio Legacy 4 and MEE audio MX4 Pro is the subbass region that shows more intensity and depth compared to the midbass area. The subbass presentation of the Legacy 4 is slightly tighter and faster compared to those of the MX4 Pro. The midbass region of the MX4 Pro is a tad more impactful/punchier compared to the Legacy 4 which has the slightly edge in terms of decay.

The midrange of the MEE audio MX4 Pro is slightly more forward in its presentation with a tad of additional warmth that comes from the lower midrange. The Legacy for offers a better sense of clarity and airiness especially when I did listen to female vocals and instruments like a violin or flute.

The treble range of the MEE Audio MX4 Pro is slightly more pronounced compared to those of the Thieaudio Legacy 4, especially in the upper treble area. The treble character of the MX4 Pro is a bit more energetic, while the Legacy 4 offers a better sense of controlled.

The soundstage of the both the Thieaudio Legacy 4 and MEE Audio MX4 Pro do show a pretty similar performance in terms of wideness, while the Legacy 4 has the slightly edge in terms of soundstage depth.




Thieaudio is a relative young company in the portable audio scene but has grown very fast in the last two years thanks to some popular products like the Monarch, the Clairvoyance and several members of the Legacy series. The Legacy 4 seems to continue the success of the company against numerous competitors in this price range, thanks to its excellent resolution and detail retrieval with respect of its price over the whole sound spectrum and with the amazing hand crafted monitor shell.



Pros & Cons:
  • + Overall Resolution
  • + Bass Speed & Control
  • + Midrange Clarity & Detail Retrieval
  • + Beautiful Hand Crafted Monitor Shell
  • + Ergonomic Monitor Shape
  • – Upper Treble Roll-Off
  • – Lower Midrange Depth
  • – Relative Short Sound Nozzle


Thank you for the Read!







You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *