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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want a wireless, noise-cancelling, do-everything headphone that adapts to the world around you, choose Bowers & Wilkins FP39691; if you need a wired, open-back planar-magnetic headphone built purely for serious listening at a desk, choose SENDYAUDIO Apollo Pro. These two barely compete for the same buyer — one is a travel-and-office companion, the other is a dedicated listening instrument.
• Bowers & Wilkins FP39691 — biggest strength: adaptive active noise cancellation plus a smart sensor system that pauses music when you lift an ear cup and sleeps when you set the headphones down. Wireless freedom with up to 22 hours of Bluetooth with ANC on.
• Bowers & Wilkins FP39691 — biggest trade-off: it is a closed-back Bluetooth 4.1 headphone, so it will not deliver the open, airy staging or the raw resolution that a large planar driver can, and it needs the companion app for firmware updates and control tweaks.
• SENDYAUDIO Apollo Pro — biggest strength: a huge 78mm planar magnetic driver with a nano-scale diaphragm and an EB-evaporation aluminium layer, paired with a detachable 4.4mm balanced cable for a wide, layered, open-back presentation.
• SENDYAUDIO Apollo Pro — biggest trade-off: it is fully wired, has no noise cancelling at all, and its open-back design leaks sound both ways — it is a stay-put headphone, not a commute headphone.
• Who each pick is for: FP39691 for travellers, commuters and office users who want one headphone for everything; Apollo Pro for home listeners with a decent DAC/amp who care about soundstage and detail above all.
The FP39691 is the headphone you grab on the way out the door. Its adaptive noise cancellation is designed to adjust to your surroundings — a plane cabin, a noisy street, a shared office — and the tuning is meant to be customised to your own preference rather than locked to one factory setting. That flexibility is the whole point: it is a headphone that changes behaviour depending on where you are.
The smart-sensor side is what makes it feel effortless in daily use. Lift an ear cup and playback pauses; put the headphones down and they drop into a power-saving sleep; pick them up again and they resume. Battery figures back that up in practical terms: up to 22 hours over Bluetooth with ANC on, up to 29 hours over Bluetooth with ANC off, up to 33 hours wired with ANC, and up to 50 hours wired with no ANC. You can run it passively over the 3.5mm jack when the battery is empty, which is a genuinely useful safety net on long trips.
Buy it if you want one wireless headphone that handles flights, streets, offices and calls without fuss, and you value ANC and smart pause/resume over absolute detail. Skip it if you listen mainly at a desk, already own a dedicated amp, and want the widest possible stage — the closed-back, Bluetooth-first design is simply not aimed at that.
SENDYAUDIO Apollo Pro: Who It's For
The Apollo Pro is the opposite philosophy. There is no battery, no Bluetooth and no noise cancelling — just a cable, a driver and an open-back frame. That 78mm planar magnetic driver is the headline: it is a very large diaphragm with a nano-scale composite structure, and the EB evaporation deposition treatment lays down a dense, uniform aluminium circuit on its surface. In plain terms, that combination is aimed at fast transient response, controlled vibration and stable frequency behaviour — the qualities that make planar headphones sound quick and clean rather than boomy.
The open-back build matters just as much. The 354g body uses an ultra-thin sunburst metal mesh and compact zebrawood earcups, which is a design choice aimed at letting air move freely behind the driver. The result, in use, is a naturally open presentation with a wide sense of space — the kind of staging that closed-back wireless headphones struggle to match. Weight sits in the middle of the planar market, and SENDYAUDIO addresses long sessions with a soft lamb-leather headband and breathable velvet ear pads intended to cut heat build-up and pressure.
Electrically, the Apollo Pro is rated at 27 ohms with 93 dB sensitivity and a frequency response extending to 40 kHz — low enough impedance to be driven by many sources, but planar drivers of this size generally reward a proper amplifier. The supplied cable is detachable and uses a 4.4mm balanced connection, built from a triple-composite mix of Furukawa OFC, silver-plated copper and enameled gold-plated copper strands for stable signal transfer. Colour is zebrano, the earpiece shape is oval, and the warranty is one year.
Buy it if you listen seriously at home, have a DAC or amp with a 4.4mm balanced output, and want an open, detailed, spacious sound. Skip it if you need portability, noise cancelling, or any wireless convenience — the Apollo Pro will not give you any of those.
Side-by-Side: Which Should You Choose?
• Best for pure soundstage and openness → SENDYAUDIO Apollo Pro. The 78mm planar driver and open-back mesh structure exist for exactly this.
• Best for wireless freedom → Bowers & Wilkins FP39691. Bluetooth 4.1 with aptX-HD, no cable required.
• Best for desk listening with a dedicated amp → SENDYAUDIO Apollo Pro. The 4.4mm balanced cable and planar driver are designed for a stationary setup.
• Best for all-day ease of use → Bowers & Wilkins FP39691. Lift an ear cup to pause, set them down to sleep, pick them up to resume.
• Best for long listening sessions without ear heat → SENDYAUDIO Apollo Pro. Velvet pads and a lightweight open frame are aimed at reducing heat and pressure.
• Best for working in noisy shared spaces → Bowers & Wilkins FP39691. ANC is the whole argument; the open-back Apollo Pro would leak and let noise in.
• Best for upgrading an existing wired rig → SENDYAUDIO Apollo Pro. A detachable balanced cable and 27-ohm planar load slot naturally into a home setup.
For most people asking me this question, I would buy the Bowers & Wilkins FP39691. In my opinion it is the more useful headphone for real life: ANC, wireless, smart pause/resume, a 3.5mm fallback and a long battery spec mean it works on a plane, in an office and at home without you thinking about it. The SENDYAUDIO Apollo Pro is the better listening headphone — I would recommend it without hesitation to someone with a home amp who wants an open, wide, detailed presentation and never needs to leave the desk. If you only buy one and you move around, take the Bowers & Wilkins. If your listening happens in one chair with a good source, take the Apollo Pro.
FAQ
Yes — adaptive active noise cancellation that is designed to adjust to your environment and be customised to your preference. The Apollo Pro has no noise cancelling at all.
Only the FP39691 has a battery. It is rated up to 22 hours over Bluetooth with ANC on, up to 29 hours with ANC off, up to 33 hours wired with ANC, and up to 50 hours wired with no ANC. The Apollo Pro runs off your source, so there is nothing to charge.
In my opinion the SENDYAUDIO Apollo Pro, if you have a suitable amp. Its 78mm planar driver and open-back design are built for spacious, detailed sound, while the FP39691 is a closed-back wireless headphone optimised for versatility rather than maximum resolution. Whichever you pick, check the current price on Amazon before deciding.
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