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Sendy Audio Apollo Pro
Sendy Audio's Apollo Pro is a new open-back planar magnetic headphone designed around a lightweight nano-diaphragm driver, wooden earcups and a comfort-focused construction intended for longer listening sessions. The model sits in the increasingly competitive middle ground of the headphone market, where buyers expect more than a basic planar driver and a nice finish. In this case, Sendy Audio is putting emphasis on diaphragm technology, a lighter mechanical structure, upgraded materials and a more complete accessory package.
The core of the Apollo Pro is a 78-mm planar magnetic driver using what the company describes as a nano-scale composite diaphragm. The diaphragm uses a sandwich structure with a magnetic cutting layer under 800 nm thick, a detail that matters because reducing diaphragm mass is one of the main ways to improve response speed in planar headphones. Sendy Audio says this structure is intended to enhance resolution and transient behavior, which are exactly the areas where planar magnetic designs are usually expected to perform well.
The driver also uses EB evaporation deposition technology. In this process, aluminum circuits are precisely deposited onto the nano-scale diaphragm surface using electron beam evaporation. According to the company, the dense and uniform coating creates an atomic-level columnar structure that helps control vibration more accurately and stabilizes the frequency response. In practical listening terms, the goal is not just to make the driver technically lighter, but to keep its movement more controlled, which should support cleaner layering, better separation and a more stable presentation across the band.
The Apollo Pro is an open-back over-ear headphone, so it is clearly aimed at home and desktop listening rather than commuting or isolation. Open designs generally trade isolation and privacy for a more spacious and natural presentation, and that fits the way Sendy Audio is positioning the model. The specified frequency response is 20 Hz - 40 kHz, which on its own should be treated less as a promise of hearing ultrasonic content and more as an indication that the driver is designed to operate with wide bandwidth and headroom beyond the conventional audible range.
The electrical figures suggest that the Apollo Pro should be reasonably manageable, but still worth pairing with a proper source or headphone amplifier. Sensitivity is listed at 93 dB, while impedance is 27 ohms. That combination means the headphones are not extremely high-impedance studio-style models, but the moderate sensitivity also suggests they may benefit from a capable DAC/amp or desktop amplifier rather than being treated as casual phone headphones. The supplied cable uses a 4.4-mm balanced connector, which further points toward use with modern balanced headphone outputs on portable players, dongles, DAC/amps and desktop systems.
Weight is listed at 354 g, which is a useful figure in this category. Planar magnetic headphones can easily become heavy because of their magnetic structures, so keeping the Apollo Pro around this level should help with long-term comfort. Sendy Audio has also worked on the physical design to reduce fatigue, using an ultra-thin sunburst-pattern metal mesh, refined zebrawood earcups, CNC-machined aviation aluminum components and a flexible adjustment system that allows the headband and earcups to adapt more naturally to the user's head.
The earcups combine dense zebrawood rings with a compact chamber structure. This gives the headphones their visual identity, but also contributes to the lighter and more refined construction described by the manufacturer. The contrast between the dark open grille, sunburst mesh pattern and polished wood gives the Apollo Pro a more traditional hi-fi appearance than many purely technical planar headphones, while still keeping the mechanical layout relatively open and modern.
Comfort has clearly been treated as part of the product concept rather than as a secondary detail. The headband uses soft lamb leather, chosen for a smoother feel and durability, while the earpads use a breathable velvet lining. Sendy Audio says the wider, softer pads are designed to improve breathability and reduce heat buildup during extended wear. That is important for an open-back headphone intended for long sessions, because comfort problems often become more obvious after one or two albums than in a short demonstration.
The cable is another area where the company has added detail. The detachable cable uses a triple composite structure combining Furukawa OFC, silver-plated copper and enamelled gold-plated copper. The construction consists of 30 strands of 0.05-mm Furukawa OFC, 10 strands of 0.05-mm silver-plated copper and 10 strands of 0.05-mm enamelled gold-plated copper. Rather than turning this into a list of exotic materials, the practical point is that Sendy Audio is treating the cable as part of the complete package, with a hybrid conductor structure intended to support resolution and stable signal transmission.
The cable also includes a graphene-reinforced PVC inner layer, which acts as both insulation and electromagnetic interference shielding. This dual shielding structure is intended to improve tensile strength and durability while reducing interference. For a full-size headphone used at a desk, in a rack-based system or with portable balanced players, that matters because the cable has to be flexible enough for daily use, but robust enough not to feel like the weak point of the package.
The accessory set is generous. The Apollo Pro comes with a leather carrying case, a hemp bag, a 4.4-mm balanced audio cable, a 3.5-mm single-ended to 4.4-mm balanced adapter and a 6.35-mm to 3.5-mm adapter. This means the headphones should work with a wide range of sources straight out of the box, from balanced portable outputs to more traditional desktop headphone amplifiers with 6.35-mm sockets. Apollo Pro is priced at €499/£449/$449. Info and photos by Sendy Audio.
