PlusSound Volta & Sonora

A Sonorous Shift after the First Movement.

PROS: a choice of more neutral natural laidback tuning (Volta) or a more energetic resolving balanced tuning (Sonora), powerful 2DD driver performance, expanded soundstage, beautiful all metal shell designs, custom hardware PS Copper XL cables, and premium collection of accessories.

CONS: price, the fit (subjective), universal only.

The product was provided to me free of charge for review purposes in exchange for my honest opinion.

Manufacturer website: PlusSound. Available for sale directly, Volta and Sonora, or from authorized retailers.

Intro.

I’m sure it caught some audiophiles by surprise when two years ago, right before the New Year, PlusSound Audio decided to wrap up its 10th anniversary with a big announcement of the Allegro IEMs. While it is no longer shocking to see cable manufacturers collaborating with popular IEM brands to give the release more credibility and higher visibility, I find it rare when a cable manufacturer has enough confidence to move forward with an independent high-end IEM release under their brand name. Of course, at the end of the day tuning is what matters the most. Still, you also have to convince audiophiles that a well-known and established cable manufacturer can go head-to-head with other well-known and established IEM manufacturers they are competing against instead of collaborating with.

As I mentioned in my Allegro review, it was a bold move because this is not just about throwing together a handful of drivers that look good on paper but also having to tune it to be worthy of a flagship status and price tag. Allegro surprised me with a mature level of sound tuning and overall design. I enjoyed its vivid sound presentation that never crossed the threshold of being harsh or fatigued. It was a rather limited release, probing the water, which made me wonder if they were cooking something new. Turned out they were, and not just one pair of IEMs, but two, Volta and Sonora. I was curious to hear the follow-up to Allegro and ended up with a double surprise which I can’t wait to share with my readers after spending the last month with both. Here is what I found.

Unboxing and Accessories.

Both IEMs feature a very similar unboxing experience, varying only in color theme to distinguish between Volta and Sonora. The packaging itself is very compact, 6.5”x4.75”x2.5”, and filled to the top with many useful and well-thought-out accessories, no fillers here. Starting with the exterior sleeve, the front showcases the design of the faceplate in their corresponding colors and has a round cutout aligned with either silver (Volta) or gold (Sonora) PS logo on the top cover of the box. Logically, the back of the sleeve showcases the design of the shell in their corresponding colors. With the top cover removed where the sides of the box are also in the corresponding silver and gold finish, you will find a traditional PlusSound plexiglass insert with their proud message of “Designed and Hand Assembled in Los Angeles, California, USA”. Keeping up with a color scheme, the message is printed in silver (Volta) and gold (Sonora). While some people don’t care about unboxing and skip this section, manufacturers put so much thought and heart into designing the packaging which I look forward to and enjoy acknowledging.

Inside, you will find many accessories, common to both IEMs. The only difference is the color of the leather storage case, either grey (Volta) or reddish (Sonora), and grey (Volta) or black (Sonora) leather storage drawstring pouch, leather double-pocket drawstring IEM bag, and leather cable organizer band. The rest are a cleaning tool, cleaning cloth, metal warranty card (covering 2 years), a Thank You card with Christian Oliver (PS founder) welcome to the family message and link to the digital start guide, metal eartips card, and 3 sets of eartips which you will find packed tightly under the organizer insert inside the storage case. There are PlusSound Silicone eartips (S/M/L), Symbio W hybrid (old style) eartips (S/M/L), and Comply Foam eartips (S/M/L).

The leather storage case is custom, in grey (Volta) or reddish (Sonora). It’s a rectangular case with a heavy-duty gold-plated metal zipper and exterior dimensions of approximately 6” x 4” x 2” and internal storage space of about 5.5” x 3.75″ x 1.75″. The exterior material is real genuine high-quality leather with a stamped PS logo on the top cover. Inside, the case is lined with a soft felt material to keep everything protected and scratch-free. Under the cover, you have a large polyester pocket, a bit tight, though with enough room to store microSD cards, a cleaning cloth, and a cleaning tool.

Inside the case, there is a removable insert, lined with the same felt material. Instead of having adjustable or fixed partitions, the insert features 2 semi-enclosed corner pockets for IEMs (or CIEMs). The pockets have plenty of room even for large custom shells, and allow for the cable to remain attached while letting it extend down the middle to wrap around the organizer spool below it. There is more than enough room for a thicker XL or 8-wire cable and a large 4.4mm plug, keeping it away from the shells. Btw, as an optional accessory, PS also offers a Leather Stand based on the design of the insert, but made out of leather, the same premium material as the case. That optional stand features a cutout for IEM nozzles and a kickstand to use it stand alone without a case.

The cable.

The included cable for Volta and Sonora is a premium PS Copper XL. This cable is based on Type 6 litz, except after experimenting with a different wire geometry, PS decided to combine the wire in 6x Type 6 bundles (Type 6×6 Litz), each with 36 groups. The resulting XL cable features two conductors, Left and Right, each 18 AWG in thickness. While it does look thick, I found it to be soft and pliable and with minimum microphonics. It was even softer than PS Plus series cables, thanks to their proprietary insulation and multi-varied dampening cores. I have covered Copper XL in one of my previous reviews which you can search for on Tw6, but what makes this version stand out is the custom hardware with a matching color/design two-tone Y-split with an insert that matches the surface artwork of the corresponding Volta/Sonora shells. Also, the cable plug and connectors have either black (Volta) or red (Sonora) custom accent touches.

Bonus Accessories.

One optional bonus accessory I received for testing was PS’s new Micro-Connector adapters ($49, link).

With 3 popular IEM connectors, 2pin, mmcx, and p-ears, audiophiles who have all these IEMs are faced with the dilemma of buying the same cables with three different connectors. Some manufacturers offer a modular cable design, such as the ConX or Versa system, but you are limited to using only cables from those specific brands. For all other cables with 2pin connectors, PS came up with their own very compact micro-connector adapters, about 6-7mm in length. These are very compact, and both housing and connectors are made out of high-grade gold-plated tellurium copper. According to PS, they also added PEEK insulation for superior dielectric strength and heat resistance over connectors that utilize standard Teflon insulation. Plus, there is a laser-engraved PS logo facing front and center to ensure proper connection.

These micro-connector adapters have a 2pin “input” and either mmcx or p-ears “output” so you can convert any 2pin cable into mmcx or p-ears connectors. I tested these micro-connector adapters with Campfire Audio IEMs (mmcx adapter) and Elysian Audio IEMs (Pentaconn-ears, p-ears adapter), and found it to work great with a secure connection of adapter’s 2pin sockets and connectors with corresponding IEM shells. It does create a slightly bigger loop around your ear due to an extra 7mm extension of the cable connector, but it is a useful alternative for the cables that don’t come with ConX or Versa system.

Another optional “bonus” accessory I received shortly after Volta and Sonora was their new Tri-Layer series Coax Type litz cables. The ones I received were their SPC (Silver Plated Copper) and SG (Silver + Gold) cables, and as I was working on this write-up, PS also announced the Copper Tri-Layer Coaxial version of the cable. For a long time, PS was using 26 AWG thickness Type 6 Litz design wires, until recently when they introduced the new generation of these budget-priced cables with an updated 25 AWG thickness Coaxial Type Litz design featuring three layers of varied-size strands in both clockwise and counterclockwise rotation with ZERO dampening cores inside. In my cable pair-up section of the review, I will feature both of these new soft ergonomic Tri-Layer SPC and SG cables to describe how they affect the sound of Volta and Sonora relative to a stock Copper XL cable.

Design.

Similar to the unboxing and accessories, I’m going to cover both IEMs in the same section due to an overlap in their design.

Volta and Sonora feature a tribrid design with DD/BA/EST drivers. Volta uses 6 drivers per side, 2xDD 10mm drivers in isobaric config (covering sub-lows and lows), 2xBA drivers (covering mid-lows, mids, and mid-highs), and 2xEST drivers (covering highs and super-highs). Sonora uses 8 drivers per side, 2xDD 10mm drivers in isobaric config (covering sub-lows and lows), 4xBA drivers (covering mid-lows, mids, and mid-highs), and 2xEST drivers (covering highs and super highs). The drivers are partitioned across a 6-way crossover network and arranged inside the 3D-printed acoustic chamber.

The exterior design is beautifully crafted and features a polished, anodized, and cryogenically treated aluminum faceplate and body, and a shorter/wider nozzle with a lip to secure eartips and 3-bores at the tip. Volta has a dark grey line pattern faceplate and gunmetal modern pattern body, while Sonora has a gold line pattern faceplate and red modern pattern body (Iron Man style!). Similar to Allegro, there was one long slit-vent on the back, possibly for DD drivers, and still with decent sound isolation and no driver flex. Also, the 2pin socket is partially recessed, but not deep enough to hide the 2pin cable connector. According to PS, the 2pin connector is their in-house designed cryogenically treated 0.78mm rhodium plated tellurium copper with PEEK insulation. The internal wiring is also custom, a matching (to Copper XL cable) Copper XS in-house designed cryogenically treated Type 6 UP-OCC wires with proprietary PC insulation.

Volta

Sonora

Inside out, it’s a mature design, very similar to Allegro, which brings me to the topic of how it fits. Sound tuning is up to a personal preference while the fit is up to your ear anatomy. With Allegro, the combination of a bulbous shape of the shell body and a short nozzle could be a problem for some ears, and it took me a little while to find the right set of eartips to extend the shell a little bit further out to fit more comfortably in the concha area of my ear. Volta and Sonora feature an updated shell body with a less bulbous and more ergonomic design that feels more comfortable. However, I still found the upper corner of the shell, opposite of the nozzle, to dig a bit into the concha area of my ear, something which could be resolved with different eartips. I know you can’t please everybody. Still, the Volta/Sonora shell design is an improvement over the Allegro even to my picky ears.