Drivers, Mouthpieces and Other Back Caps

Ratings

Pros

• 12 different tunings possible, some of them very varied.
• Analytical and very detailed sound, but realistic and never unnatural.
• Great low end quality.
• Very good isolation and occlusion level, the sound does not leak out.
• Good cable.

Cons

• No choice of balanced cable.
• Lack of body in the low-mids of some tunings.

Purchase Link

https://penonaudio.com/lz-a4pro.html

Link to the Store

https://penonaudio.com/

Introduction

LZ HiFi Audio (Lao Zhong HiFi Audio) is introducing its new IEMS for 2021 and has recently released the LZ A2 Pro and the present LZ A4 Pro. One of the obvious changes is the change in shape and material. Previous LZ models used to have particular shapes and were made of metallic materials. Now, both models have been made of resin, with a semi-custom, more conventional shape. The outer face of the A4 Pro has been decorated with a beautiful flowing pattern in shades of blue, black and white. Internally, it features Knowles 3BA and a dual-cavity dynamic driver with a CNT nanotube diaphragm. It is clear that the DD is used for the low frequencies, while two BA are used for the mid frequencies and the third for the high frequencies. But one of the most relevant features of this new A4 Pro is the possibility to change its tuning by means of mouthpieces and rear caps. With the mouthpieces the mid/high frequencies can be adjusted, while with the back caps the low frequencies can be adjusted, thanks to their effect on the internal cavity. There are 4 different mouthpieces and 3 back caps, which results in 12 different tunings. But the good news doesn’t end there: LZ wanted to accompany this new sub-flagship model with a cable to match. This is a high-end standard 8-wire graphene alloy and silver cable, with a 2Pin 0.78mm connection, which matches the characteristics of the different tunings of the A4 Pro. Let’s see what the result of all these great qualities is in the following review.

Specifications

• Driver Type: 1 CNT dynamic driver (bass) + 2 BA Knowles (mid) + 1 BA Knowles (treble).
• Frequency Response: 20-20kHz
• Sensitivity: 112dB/mW, @1kHz
• Impedance: 26 Ω
• Channel error range: ±0.5dB
• THD: <1%
• Jack Connector: 3.5mm
• Capsule Connection Type: 2Pin 0.78mm
• Cable: Standard high-end 8-wire graphene alloy and silver.
• Cable length: 1.2m

Packaging

The LZ A4 Pro comes in a white, medium-sized box with dimensions 170x116x45mm. On the front side you can see a real photo of the capsules in the centre. In the top left corner is the brand logo. At the bottom is the name of the model, written in a holographic silver ink, in a bluish tone. Underneath is the product description, in Chinese and English. On the back side, the logo has been moved to the top right corner, while the rest of the side is completed with the product specifications in Chinese and English, as well as the brand’s contact details at the bottom. After removing the wrapping cardboard, a complete white box is revealed, with only the brand logo in the centre. After opening it, you can see a dark, round, rigid case with the brand name in white letters. It is protected by a dense black foam, as are the two capsules on top of it. On top of it is a warranty certificate card and a user’s manual. Underneath is a small plastic box with a variety of silicone tips. Inside the case is the cable and a black metal rod, which contains the filters screwed to it. The complete summary of all the contents is as follows:

• The two A4 Pro capsules.
• One 8-wire graphene-silver alloy cable with 2Pin 0.78mm connectors and 3.5mm plug.
• 3 pairs of grey silicone tips sizes SxMxL.
• 3 pairs of black silicone tips sizes SxMxL.
• 3 pairs of grey silicone tips and blue and large core, sizes SxMxL.
• A black metal rod to screw on the filters.
• 2 red nozzles.
• 2 champagne nozzles.
• 2 blue nozzles.
• 2 black nozzles.
• 2 black back caps.
• 2 red back caps.
• 2 blue back caps.
• 1 mini screwdriver.

The size of the packaging is medium and is appropriate for the amount of accessories that come with it. 3 sets of tips are fine, but I miss a set of foam tips. The cable is up to the quality of the capsules and except for the lack of a balanced plug, it would not be necessary to replace it with another one. I think that all brands should think about incorporating a balanced plug and some kind of SE adapter, due to the great demand of balanced sources that exist nowadays.
As for the number of mouthpieces, there are 4, which is quite a lot, plus 3 back caps that allow a lot of different tunings. Finally, the mini screwdriver is a flat screwdriver; a cross screwdriver would have been safer and more suitable for the rear plugs, as they also have cross slots.

Construction and Design

The A4 Pro capsules are 3D printed in pure resin. Their shape is semi-custom, medium to large in size. The outer face adopts a flowing pattern made up of various colours, such as blue, white, black and teal. There also appears to be some slight admixture of fine glitter. The shape of the face resembles the African continent, but more stylised. At the base of one side you can see the name of the brand, in silver lettering, set inside the flowing motif. Close to the mark, but turning the rim, on the side face, there is a small hole. On the opposite side face is the recessed, rectangular opening, which locates the 2Pin 0.78mm connection. On the adjacent side is the interchangeable rear plug.
The inner side is dark and semi-translucent. It is difficult to see the inside of the IEMS, some BA drivers and the dynamic driver. This side is very ergonomic and has a protrusion to anchor the IEM to the upper edge of the pinna.
The mouthpieces are metal and interchangeable. They are all the same size and shape, but the inside is what changes, apart from the colour. The height is 5mm, the maximum diameter is 5.5mm and the minimum is 4.7mm. There are 4 pairs in total and their colours are red, black, blue and champagne. There are three pairs of metal back caps, coloured red, black and blue. They have a diameter of 4.2mm, a hole in the centre and an inscribed cross for easy screwing with the mini screwdriver. Both nozzles and caps are screwed onto a black, rectangular metal bar. The mouthpieces are screwed on two opposite sides and the rear caps on the other two.
The entire capsule is soft and smooth, made of light, polished resin, which fits carefully to the ears.
Internally, each IEM has 1 CNT dynamic driver for bass, 2 Knowles BA for midrange and 1 Knowles BA for treble.
The cable is 8 wires of graphene alloy and silver, with 2Pin 0.78mm connectors and 3.5mm plug. Despite these 8 wires, it is quite manageable and does not take shape. The cap of the plug is straight, a black metal cylinder with a smaller diameter in the middle, the shape tapers down to that point. The marking is written lengthwise in white letters. The dividing piece has the same shape, colour and material, but is approximately half the length. This time it is the logo of the brand that is written on it. The pin is a transparent resin sphere with a through hole. The cable, close to the 2Pin 0.78mm connectors, has a semi-rigid transparent protection, shaped like an ear. The sleeve of the connectors is a smooth, metallic, black cylinder with the channel lettering written in white. The 2Pin connectors are mounted on a rectangular, transparent plastic base. Finally, it has a strip to collect the cable, made of grey Velcro, with the logo and the brand written in white along it.
I believe that the previous LZ models were not made of resin and their shapes were varied. Now, they have returned to a classic coherence, with the use of the semi-custom shape, built in resin. There is no doubt that metal is always appreciated, but a good resin construction is a bit warmer, more comfortable and not necessarily less resistant. Also worth mentioning are the cable, the nozzle bar and the construction of the nozzles and caps themselves, which, being made of metal, will last longer.
I will take advantage of this section to discuss the use and assembly of the nozzles and back caps. The nozzles are easy to assemble and do not require much skill. I would have liked to see more rubber washers, because it is an element susceptible to breakage. A bit more complicated is the disassembly/assembly of the back caps, because they are smaller parts to be handled with the fingers. It may require the use of tweezers and some patience, for those with large or thick fingers.

Adjustment and Ergonomics

The semi-custom shape fits my ears like a glove. The size and length of the nozzles allow a very secure insertion, which can range from shallow to medium, depending on the size of the tips. Once in, the sensation is light, the weight is not noticeable, although the friction is somewhat perceptible with the outer ear parts, due to the size of the capsules. I only found some discomfort after hours of use. The level of isolation is high, as is the occlusive capacity of the set.
All in all, very good fit, firm and durable, great insulation and only slight discomfort after several hours of use. However, you also get used to them and this discomfort tends to disappear.

Sound

Profile

With 4 nozzles and 3 back caps, 12 different tunings can be achieved. The black, champagne and blue nozzles tune the sound from 1kHz upwards, while the red nozzle modifies the sound from the sub-bass. The rear caps have their range of action from the sub-bass up to about 250Hz.
Starting from the default black cap/black nozzle profile, whose curve could be called a light V or W, the LZ A4 Pro, thanks to these nozzles and caps, can become a bass IEMS (red cap/red nozzle), going through a more pronounced V profile (red cap/blue nozzle), even reaching a more balanced and neutral, almost midcentric profile (blue cap/black nozzle). To my mind, the more extreme combinations such as those produced by the blue cap and the red nozzle are a bit out of my taste. Whereas I find the combinations between the red and black caps and the black, champagne and blue nozzles much more appealing and attractive. But there can always be an audience for all combinations.
All in all, the sound of the A4 Pro could be classified as technical/analytical IEMS, due to the precision of its BA drivers, without underestimating the ability of the dynamic carbon natotube driver.

Bass

As I mentioned, the bass can become anaemic with the blue cap, to become much more noticeable with the red cap. Somewhat beyond the middle is the black top. The bass range, as such, shines with the black and red caps. But they don’t turn the A4 Pro into an IEMS for bassheads, as long as they don’t join with the red nozzle. Beyond the different tunings is the profile of each cap. While the blue top provides a very light low end, with little noticeable sub-bass and a neutral energy punch, it still manages to provide a distinctive personality. This personality is enhanced by the black filter, which already provides a remarkable authority and shows off its virtues. These include speed and restraint. The decay is fast and the texture is quite good, despite the agility of the driver. In fact, the driver’s sonority matches quite well with the A4 Pro’s analytical skills. And the best thing is that these are not lost when you switch to the red top, but can even be enjoyed more, but with more energy. The sub-bass emphasis achieved with this tuning is moderately powerful. Thanks to its dryness, the punch is hard and controlled, with a remarkable level of authority, which does not lose resolution or analytical ability. In this way, the bass is drawn with very good depth, with a precious and detailed execution, which does not stray from naturalness, despite the technical level it possesses. The level of control, associated with the amount of energy it is able to emanate, is responsible for a timbre that could pass for that produced by an excellent BA driver, but with the power of a great dynamic, as is the case. Thus, the sonority is in that realistic/analytical range, which integrates seamlessly with the rest of the band. Thanks to the excellent level of definition, the number of recreated planes multiplies with each note change, but disappears with the typical BA driver speed. As a result, there is no aftertaste and no bass intrusion in the midrange. If the A4 Pro’s low end is anything to go by, it’s its texture, although it’s quite descriptive, the pronounced control prevents a higher emotion, a more pronounced roughness that would provide a more passionate and unbridled point. But surely it would not have married so well with the character of this model.

Mids

As I said, a near midcentric tuning could be achieved by using the blue back cap and any of the black, champagne or blue nozzles. The result would be easy to place and would provide a very prominent midrange. But the great role of the low end and the excellent division of drivers allows the midrange to shine individually, despite the filters/covers used (except for the red nozzle). My favourite combination for the midrange is the black back cap with the champagne nozzle. Although the reference all-black combination is not to be underestimated either, not even the black cap/blue mouthpiece combination, which turns the IEMS into a brighter midrange. But back to the champagne nozzle, which has a boost at around 2kHz and a very slight high end shading. In this way, vocals become closer and filled with more body. Although the first half of the midrange is softly distant and there is no trace of warmth in the sound. In this way, the initial mass has a light weight, which tries to be corrected by this higher emancipation. While the substance has a light base, the projection has a greater range, hence the closeness of the voices, especially the female ones. However, if there is one thing the A4 Pro’s mid-range excels in, it is its resolution and definition, characteristics that make it a very detailed and analytical IEMS. Without being artificial or overly cutting or penetrating, due to their level of precision, these LZs maintain a very disciplined edge, where details and micro nuances are executed with a high degree of cleanliness. The result is a very clear, crystalline, concise, rigorous, meticulous and detailed sound, which is at the same time fast, quick in its execution and disappearance. There is no doubt that technically, the double BA midrange sounds as one and there is no hint of smearing, dullness or muddiness in the sound.
The cool texture is highly recognisable and is explicitly exposed, leaving no hint of it undiscovered. This overt sound can lack passion, something that can be noted in the thinner first half of the mids. In this way, the result can be detrimental to some genres, as they could be represented in a thinner form, with less sustenance and a less corporeal base. Although this is something that could be corrected by switching to the black nozzle, or even adding the red cap, the high cleanliness and subtlety of the initial part does not allow for a more complete solution on those rare occasions. It is thus clear that you cannot have warm and analytical IEMS at the same time, but you have to choose, despite the many options that these LZs offer.

Treble

For more emphasised treble, the black or blue nozzles can be used. But it is the latter that achieve a superior effect. And while they also emphasise the upper mids, the highs get more sparkle and energy. Add to this the analytical character of the A4 Pro and the level of expressiveness of the high end becomes clear. The W-tuning of the treble has narrow, sharp peaks. Although it presents that classic valley after the initial impact, this first zone enjoys a high energy, which makes them quite crisp and sharp. Moderation can be gained by using the champagne nozzle, but I think the mid-range of the black nozzle is the right reference for those who find the treble too expressive. Sometimes, though, that’s what it’s all about, gaining power and brilliance in the high end. So we have a shimmering, sparkling treble with the blue nozzle, which has a blazing speed, a modicum of control and can become quite sharp. In this way, the A4 Pro’s analytical character is elevated to its maximum expression.
The extension is quite good, but I find the amount of air somewhat more limited, perhaps lacking a little more transparency in the sound, or a quicker dissipation of the treble in the ambience.

Soundstage, Separation

The scene has excellent width and remarkable depth. Depending on the filters used, either three-dimensionality or height can be gained, without both characteristics being very pronounced. The sound is very clean, with a significant level of transparency and separation, as is usual for analytical IEMS. But I don’t find the recreation to be very holographic or corporeal. There is the ability to recreate a number of planes, but they are thin and with a relative distance between them. Both the speed and the precision of the sound provide good instrumental positioning, but one misses some more air to vaporise the notes, to gain three-dimensional spaciousness and a more ethereal feel. It is clear that the clarity and lightness of the IEMS, as well as the great low end, prevent any noticeable congestion in the sound of the LZ A4 Pro. But perhaps their high occlusiveness is somewhat counter-productive in enhancing their image, giving a sense that the sound could be more open or expansive.
However, there is little or nothing to complain about in terms of resolution, detail or micro nuances. This is where this model really shines. The level of definition can be fine-tuned almost to taste using the different nozzles. You can even adjust in which band you want more detail. While with the champagne nozzle you get more detail in the middle range, with the blue nozzle it expands to the upper range. With the black nozzle you get softer, but without losing it. Without a doubt, this is an achievement beyond the reach of any IEM.

Comparisons

NiceHCK Lofty

The Lofty is one of NiceHCK’s latest flagship IEMS and uses a 10mm dynamic driver with a pure beryllium diaphragm and a dual 1.8T magnetic circuit. Their price range is the same as the A4 Pro. As the brand’s flagship, it is presented and built to match its price. As for its sound, although its performance and features are remarkable, it has been widely criticised for its unevolved profile. The present LZs can be tuned in much the same way as the NiceHCKs, using the red back cap and black or champagne nozzle. For the comparison I opted to use the red back cap and the black nozzle.
Going into a bit more detail on the construction differences: metal capsule on the Lofty vs. resin capsule on the A4 Pro; 4-strand nylon-coated cable on the Lofty vs. 8-strand plastic-coated cable on the A4 Pro; single dynamic on the Lofty vs. 1DD+3BA on the A4 Pro; fixed configuration on the Lofty vs. interchangeable nozzles and back caps on the A4 Pro; choice of balanced cable on the Lofty vs. single 3. 5mm SE single plug.
In terms of fit/ergonomics, I prefer the fit/ergonomics offered by the LZs, due to their lighter weight, more occlusive and permanent fit, as well as a somewhat deeper insertion.
In the low end there are obvious similarities, in terms of technicality and even sonority down to the mid-bass. There is more energy, depth and naturalness in the sub-bass of the LZs, while the Lofty’s feel slightly coloured. Texture is more perceptible and resolving in the A4 Pro’s and that is something that provides superior value to their low end. In addition, the Lofty low end has a tendency to shift in presence, especially vocals. Possibly this is due to the greater warmth they have and the more focused tuning in the mid-bass, as well as the greater extension of the lower range.
In the midrange there is a greater smoothness in the Lofty, while the A4 Pro’s level of definition gives it a higher level of clarity and transparency. Vocals are much sharper and crisper on the LZs, where the NiceHCKs are almost fuzzy. There’s more warmth in the Lofty’s mids and that’s something that brings more body to the instruments and vocals, but the LZs offer a more focused, spread out and lead recreation, vocally speaking. And that’s noticeable from the black nozzle onwards. Thus, I prefer the vocal fullness of the LZs to that of the Lofty, and only in some genres of music would I prefer the warmth of the NiceHCKs to the thinner body in the first half of the A4 Pro’s mids. But even so, with the red back and black nozzle combination, this section is pretty evenly matched.
In the treble area, with the black nozzle, the excitation is smoother than with the Lofty. In the latter, a higher brilliance is noticeable. If you switch to the blue nozzle, the result is equal, although the LZs enter the control zone earlier. Despite the good performance of the beryllium driver, I think that the treble is faster on the A4 Pro, with a point of greater precision. I also think that the amount of air is greater in them.
In terms of detail, the Lofty has a very good level and outperforms the black nozzle combination right off the bat. Using the champagne or blue nozzles, the result is that all the nuances are enhanced and become more explicit. However, the Lofty achieves a good balance between the level of detail and the excitement of the mid-highs and highs. Surprisingly, with such a degree of smoothness, they are on a par in this respect against more analytical IEMS. Including the micro details, which are easily seen in the NiceHCKs, where they can become muddled amidst so much overexposed surface nuance in the LZs.
The Lofty scene is more expanded from the middle zone onwards. The softer, more pleasing exposure of this zone gives it a sense of extension, height and immersion that overcomes the greater analytical capacity of the LZs. The LZs appear more defined and finer, giving the sound greater transparency, but appear less homogeneous, more naked. The sound is more fluid in the Lofty, which aids a more gaseous, three-dimensional feel. However, the expansion and depth is greater in the low end of the LZs.

Conclusion

The A4 Pro’s sound profile is attractive and can be modified to suit individual tastes, either by boosting or reducing the bass or mid-range and treble. This is not an isolated or new development, but the combination of the two is a way of adding dynamism and added value to a price segment where the competition is really fierce.
The LZ A4 Pro is more than just 4 drivers per capsule, 4 pairs of nozzles, 3 pairs of back caps, a remarkable cable and a very comfortable semi-custom capsule. It’s an analytical alternative, in a trend towards more organic or analogue profiles. In times of a return to simple dynamic drivers, the use of BAs should be strengthened by their intrinsic properties, i.e. a high level of resolution, definition capability and a lot of detail. If there is also a respect for the timbre and if there is no artificiality, as is the case here, there can already be 12 tunings, because the objective is far surpassed.

Sources Used During the Analysis

• Burson Audio Playmate.
• Tempotec Sonata E35.
• Hidizs S9 Pro.
• Earmen Sparrow.
• S.M.S.L Sanskrit 10th MKII + iFi ZEN CAN.
• Tempotec V1-A + Hidizs DH80S.
• Zishan Z4.
• ACMEE MF02s.
• E1DA #9038D.