Plussound is a company from California, USA and specializes in producing custom cables for in-ear monitors. They have started out on their own iems – Spectrum, Prism and Gamut. In this review, I will be reviewing the Plussound Prism which is a dual balanced armature iem – 1 for the high frequency and 1 for the low frequency. I would like to thank Plussound for this review unit. The unit I will be reviewing is black in colour. At the moment, you can purchase the Plussound Prism from .


Unboxing & Accessories

The Plussound Prism comes in a nice black package that has the Plussound logo at the front. After opening the package, I see 2 metal tins – 1 is black in colour and  1 is silver in colour. In the silver tin, there is the iem while in the black tin, there are a Plussound card, Comply care instructions manual, 2 packs of T-500 Comply foam tips (S&L) , 3 packs of TS-500 Comply foam tips (S, M & L), 1 MagicFiber cloth, 2 stacking bands and 1 cleaning brush.

IEM Build & Design

The Prism has a glossy black surface to it and it is circular in shape. On the back of the iem, there is “PS” logo printed on it. The shell is made out of an acrylic material. It is rather light weight. There is a silver vent on each side of the iem shell. The nozzle is straight without any mesh. It is quite long. There are no L & R markings on the iem to differentiate between left and right. It utilises mmcx connectors. The Prism is manufactured using Plussound’s in-house 3D printers. There is good build quality to it.

Cable Build & Design

The Prism comes with the Plussound Exo 28AWG Copper Type 6 Litz cable. It is not the usual stock cable but an upgrade cable. The build quality on the Exo is of a high standard. It is soft and flexible. On each of the connector, there is a Plussound logo in blue and red to differentiate between left and right respectively. Moving down, there is a rubber chin slider and a y-splitter. Lastly, the jack is 2.5mm balanced gold plated. It has a rubber-like protective cover on the jack housing and it sports the Plussound brand name in green colour.


Sound Analysis


The Prism has a good sub-bass extension with an average rumble. The mid-bass is laidback and soothing. Some may prefer more slam for the extra punch. The bass is tight and controlled. The decay is average and the bass note is being presented smoothly. I find the Prism to be warm and smooth. The nature of the bass leans towards the slow side and music takes on a less exciting approach. The bass texture is rendered very smoothly and it is still clean. The bass helps to boost the lower mids.


The midrange is quite balanced and the presentation is leaning towards the smooth approach. The lower mids on the Prism has quite a good body to it and the amount allows male vocals to be rendered effectively. The upper mids are slightly forward but there is a small amount of veil that restricts the vocals presentation. The definition on the midrange is quite good. Although it may not be the most detailed, I feel the Prism showcases details rather well. There is good balance of musicality and technicality. The midrange is smooth and warm with only the upper mids not providing the extra bite for liveliness.

The treble is extended rather well with a  good linear presentation. There is no sibilance and harshness. There is no graininess and it is presented very smoothly. The crisp is rather decent and I feel with a slight sparkle, it will help to energise the overall presentation. The air at the top end has a good amount and it helps to prevent the sound from being too congested. The clarity is quite good with an above average details retrieval.


The Prism tackles both aspects of soundstage well with a good width to aid the vocals and instruments positioning and prevent congestion. The depth is not too close in and there is space for the presentation. I find the Prism to have a surround feel.



Plussound Prism vs Noble Sage

The Prism has less sub-bass quantity and extension than the Sage. The Sage has the advantage in its sub-bass reproduction and it is slightly more superior in the quality. The mid-bass on the Prism is more controlled. This allows the Prism to excel in tracks with less pace. The Sage has a more engaging slam. The bass texture on the Prism is being rendered with more finesse and smoothness. The bass note on the Sage is slightly more accurate with a faster decay. The bass control on both is very similar but the bass nature is different. The Sage has slightly more body in the lower mids department and male vocals are expressed better. For the upper mids section, I find the Prism to be more controlled in presenting female vocals but there is a slight restriction as compared to the Sage. At this point, it depends if you prefer a smoother or exciting approach to your sound. Next, in the treble section, the Sage is being expressed with better articulation and extension. There is no sibilance and harshness on both. The amount of air rendered is similar and the Sage has extra sparkle. In terms of soundstage, the width on the Sage is slightly better but the depth on the Prism is not too closed in. Vocals and instruments positioning is more precise on the Sage. Both are not congested. Resolution on both is approximately the same.

Plussound Prism vs InEar StageDiver 2

The Prism sub-bass have more quantity but does not extend as deep as the SD2. On the SD2, it is slightly more clinical and refined. The mid-bass on the Prism has a heavier weight in its note while on the SD2, it is more pacey. The decay on the SD2 is faster. The bass nature on both is different. Prism presents the bass in a warm and smooth way while the SD2 has the clinical edge in its bass reproduction. The lower mids on the Prism has more body than the SD2 and it is thicker as such. Male vocals are presented better. The SD2 is dry and less engaging in this aspect. The SD2 has slightly more forward upper mids than the Prism and with the added crisp, the vocals performance is more organic. Female vocals sound sweet here. In the treble section, the SD2 has more air and sparkle while the Prism is more smooth at the top end. SD2 has the extra bite which makes its treble stand out. Treble articulation on both is quite precise and the details retrieval is good. I feel it depends individually as both operates on different approaches. For the soundstage, SD2 has similar width as the Prism and Prism wins in the depth. Layering and separation on both is very similar. The resolution on the SD2 is slightly better.

Plussound Prism vs CTM VS-2

The sub-bass quantity on the Prism is more than the VS-2 and it has better extension. On the Prism, it has slightly more definition in its bass reproduction. The mid-bass of Prism has slightly more weight and authority. Bass texture on the Prism is rendered with more finesse. I feel each bass note on the Prism is presented with more control. The lower mids on the Prism has more body and it is thicker. The VS-2 is slightly more forward in the upper mids and it sounds more organic at the top end. The details retrieval is very similar. For the treble section, the VS-2 has slightly more air than the Prism and clinical in its presentation. There is no sparkle on both. In terms of soundstage, the Prism has the edge in both width and depth. Vocals and instruments positioning on the Prism is more accurate. The resolution on the Prism is better.


The Prism is a dual balanced armature iem in Plussound iem lineup. It provides a smooth and warm sound that one can listen to for a long listening session. Furthermore, resolution is great with a high standard of details retrieval. There are many accessories and the iem comes with an upgrade cable. I enjoyed listening to the Prism.