TFZ started out in 2015 with a debut line up that consists of TFZ Series 1,3 and 5. Since then, they have come up with new products in Exclusive 1,3,5, King and Series 4. In this review, I will be reviewing the Series 4. I would like to thank Penon Audio and TFZ for this review unit. You can purchase the Series 4 from Penon.



The Series 4 comes in a rectangular black box with a silver TFZ logo at the top and words “SERIES 4 IN-EAR-MONITOR” in silver colour at the centre. At the back of the box, you get the information of TFZ in different languages and a sticker showing the colour of the iem. The Series 4 that I will he reviewing is grey in colour. After removing the lid, you will see a thin sheet of semi-hard paper sporting the words “TFZ MAKE EVERY SONG AMBILIGHT BEAUTIFUL LIKE THE STARS” in silver colour and with a cushion at the back to protect the iem. You will be greeted with the iem after removing the paper and there is an accessories box.



In the accessories box, you will get an instruction manual, warranty card, 1 pack of eartips and a soft carrying pouch.


IEM Build & Design

The Series 4 has a glossy grey faceplate with the model name “TFZ Hi-Fi Series MONITOR SERIES 4” printed on it. The shell is black in colour. There is a vent near the edge of the iem and on the inside too. I find the build quality solid. You can notice the dynamic driver in the iem as it is slightly translucent. It utilises 2-pin 0.78mm flushed socket for the detachable cables. The shape is quite good for my ears as the iem sits in my ears rather comfortably. The nozzle is slightly angled and it prevents earwax from going in with a metal mesh. Overall, the build quality is good and it is constructed well.


Cable Build & Design

The cable is 4 core braided. On each of the 2 pin connectors, there is a L & R marking on the inside of the left and right respectively. There is a memory wire area and the cable is enclosed in a transparent heat-shrink tube which is very flexible. Moving on to the y-splitter, it is circular and matte black with the TFZ logo on it. Lastly, the jack is 3.5mm gold plated with strain relief. On the housing of the jack, there are 2 small rectangular metal plates with one sporting the words “” and another one sporting just “TFZ”. There is a smooth surface to the jack housing. Overall, the cable is flexible with minimal microphonics.


Sound Analysis


The sub-bass of Series 4 is extended well. There is a good rumble with it which helps to accentuate the overall sub-bass presentation. I find it rather punchy and it is tight. The mid-bass is controlled and slightly authoritative. The bass operates in a rather clinical approach since the decay is fast with details. The quantity of the bass is quite sufficient and with a linear presentation to it, there is maturity shown. The bass texture is rendered smoothly and it is very soothing to listen to. In addition, the bass transits beautifully to the lower mids but I feel there should be more quantity to the lows so the lower mids will not sound lacking in body. Overall, the linear presentation of the bass and its extension makes it a smooth listen.


The Series 4 midrange is spectacular especially the upper mids. The lower mids has a decent amount of body. I feel there should be more quantity to avoid hollowness in the male vocals. The upper mids has a good emphasis and female vocals sound particularly sweet and intimate. The midrange is very smooth but there is a slight nasal feeling in the lower mids department. The details retrieval is excellent and there is a good layering. Next, I personally do not find the upper mids shouty and there is a tight control on it. There is a good balance of musicality and technicality here. Overall, with a good resolution and boosted upper mids, female vocals shine here.


The treble is extended decently but the extension does not hinder the vocals performance. There is still energy and sparkle should have more quantity to it. There is no sibilance and harshness as the treble is rather controlled. The amount of air is decent and it certainly helps to improve the imaging. The clarity is not expressed technically due to the rather laid back details. There is a slight definition with not much of a crisp. Overall, the treble is smooth in a laid back manner and it can be improved with more air, sparkle and extension to give a more complete performance.


The Series 4 has a good soundstage for both the width and depth. I find the expansion to be fairly alright to avoid congestion. It helps to aid the overall positioning of vocals and instruments. The stage is just what you would expect from an iem at this price point.



TFZ Series 4 vs TFZ Exclusive King

The Series 4 has less sub-bass quantity and extension than the King. The King is more authoritative. Its sub-bass performance is more clinical and impactful, leading to a more engaging listen. The King is tighter with faster decay. Rumble on the King has more speed and demonstrates it technical performance to be more superior than the Series 4. The mid-bass on the Series 4 is more laid back while on the King, it packs a punch and results in more dynamics. Due to the more exciting bass nature, the King appears lively. The lower mids on the Series 4 has more body than the King. The quantity is more so male vocals would not sound hollow and it has a more organic feel to it. The upper mids on the King is more forward and there is a better mastery on it so female vocals sound more intimate and engaging. I feel the midrange is less congested than the King. In the treble section, the King has more extension and details. The King is more prone to sibilance and harshness than the Series 4. The air presented from the King is more than the Series 4. The treble on the King is extended better with more articulation. There is just more clarity on the King. The Series 4 has a slightly wider soundstage while the King has the better depth. The resolution of King is better as the sound has more definition to it. Overall, it really depends if you like more emphasis on sub-bass and upper mids (King) or a smooth and controlled sound (Series 4).

TFZ Series 4 vs Kinera H3

The Series 4 has similar sub-bass quantity but it is less extended than the Kinera H3. The bass on the H3 is more crisp and tight. It is better emphasised on the H3 with a quicker decay. There is a quicker rumble on the H3. H3 presents the bass more cleanly and there is a better bass definition. The mid-bass quantity on both is around the same. The way how Series 4 tackles the mid-bass is more laid back. In the H3, there is more weight to it and enhance the overall dynamics. The lower mids on the H3 sound more dry. The upper mids on the H3 is more forward and there is more crisp to it. This results in a more organic performance. In the treble section, the H3 has better extension with clarity to it. There is slightly more air and sparkle on the H3. With more definition, the H3 definitely outshines Series 4 in this aspect. Lastly, the Series 4 has more soundstage width than the H3. There is better depth on the H3. I feel the instruments and vocals positioning is more accurate on the Series 4. The resolution of both is very similar. I find the Series 4 to be more mature in vocals presentation although it has less dynamics than the H3. The H3 is more v-shaped sounding.

TFZ Series 4 vs Westone UM Pro 10

The Series 4 has better sub-bass quantity than the UM Pro 10 and it is better extended. The bass of the Series 4 is presented with more control and tightness. Furthermore, the bass texture is being rendered smoothly. The overall bass just digs deeper than the UM Pro 10. Moving on to the mid-bass, both are equally laid-back. The definition on the Series 4 is slightly better. There is an equal amount of rumble on both. The lower mids on the Series 4 has slightly more body than the UM Pro 10. I feel Series 4 does male vocals more justice than the UM Pro 10. The upper mids on both are very similar. In the treble section, both are extended to a similar extent. There is slightly more air on the UM Pro 10. The sparke on both is lacking. Moving on to the soundstage, there is better depth for the Series 4. UM Pro 10 width enhances the imaging and it is portrayed better than the Series 4. The resolution of UM Pro 10 has an edge over the Series 4.


The Series 4 is an excellent iem that has a linear bass presentation and a smooth midrange with boosted upper mids. The build quality is quite solid. The accessories are quite sufficient and the cable provided is of good quality. Overall, the TFZ Series 4 is another winner by TFZ for its impeccable smooth midrange.