We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-28 · 6 min read · Independent comparison
If you want the more established, comfort-first earbud with a clear battery story and a touch of noise cancellation, choose Panasonic True; if you need an open-fit design that keeps you aware of your surroundings with a newer Bluetooth version and a bigger driver, choose Defunc True Basic.
• Panasonic True — biggest strength: A snug, sealed in-ear fit with premium 6mm drivers, a MEMS microphone with a labyrinth noise-reducing structure, and touch/voice controls including Alexa.
• Panasonic True — biggest trade-off: The sealed in-ear design blocks out your surroundings, which is great for focus but less ideal if you need to stay aware of traffic or coworkers.
• Defunc True Basic — biggest strength: A patented MultiTip semi-in-ear open-fit design with silicone ear wings that stays secure without pressure, plus Bluetooth 6.0 and a large 13mm bass driver.
• Defunc True Basic — biggest trade-off: The open-fit design lets sound in and out, so it won't isolate you from background noise the way a sealed earbud will.
• Who Panasonic True is for: Buyers who want a traditional sealed in-ear earbud with strong call clarity and a long battery case.
• Who Defunc True Basic is for: Buyers who want an open, pressure-free fit they can wear all day while staying aware of their environment.
The Panasonic True (model RZ-S300W) is built around a classic sealed in-ear formula. A 6mm dynamic driver covers a 20Hz–20,000Hz range, and the earbuds are designed to conform snugly to your ear canal for a stable, isolating fit. If you've used traditional in-ear buds before, this will feel familiar — the seal is what gives you that fuller, more enclosed sound.
What stands out to me is the connectivity engineering. Panasonic uses a touch-sensor antenna with an independent left-right signaling system, which is meant to keep the connection stable even in crowded areas where wireless interference is common. That's a real-world benefit if you commute through busy train stations or work in a dense office. The MEMS microphone paired with a labyrinth structure is specifically tuned to reduce wind noise, so calls should come through clearly outdoors.
Battery life is a strong point. Panasonic lists roughly 7.5 hours of playback per charge, with the compact charging case extending total listening time, plus a quick-charge option that gives you about 90 minutes of playback from a short top-up. The case itself is ultra-compact and contoured, and the earbuds weigh just 4 grams each — genuinely light.
Who should buy it? If you want a sealed, comfortable in-ear bud for music, podcasts, and calls, and you value a stable connection in busy places, this is a sensible pick. Who should skip it? If you dislike the plugged-up feeling of sealed earbuds, or you need to hear your surroundings while you listen, the open-fit approach of the Defunc will suit you better.
The Defunc True Basic takes a different philosophy entirely. Instead of sealing your ear canal, it uses a patented MultiTip semi-in-ear design with soft silicone ear wings. The idea is a secure fit that doesn't create pressure — you get stability from the wings rather than from plugging your ears. The result is that you stay naturally aware of the sounds around you, which is ideal for commuting, walking, and working in an office where you still need to hear a colleague or a doorbell.
The audio hardware leans toward bass. Defunc uses a 13mm bass driver — noticeably larger than Panasonic's 6mm unit — with 16 ohm impedance. A bigger driver generally moves more air, so I'd expect a fuller low end, though the open fit means you won't get the isolation-boosted punch of a sealed design. It's a trade-off, not a flaw.
Connectivity is where Defunc pushes forward. It runs Bluetooth 6.0, which the brand describes as offering faster pairing and lower latency than older versions. There's also the Defunc AI App, which includes an OpenAI-powered Chat AI assistant for hands-free Q&A, translation, and brainstorming, plus four built-in microphones (two per earbud) for voice pickup.
Battery is rated at up to 22 hours of total playtime with the charging case. The earbuds and case are IPX4 water resistant, so sweat and splashes are fine. The case measures 7cm x 3.5cm x 2.5cm and weighs 35g.
Who should buy it? If you want an open, pressure-free fit you can wear for hours, a bass-forward driver, and the latest Bluetooth with app-based AI features, this is aimed squarely at you. Who should skip it? If you need maximum noise isolation for loud environments like planes or busy trains, the sealed Panasonic will serve you better.
• Best for noise isolation → Panasonic True: Sealed in-ear fit plus Active Noise Cancellation blocks more of your surroundings.
• Best for staying aware of your environment → Defunc True Basic: The open-fit semi-in-ear design lets ambient sound in.
• Best for the latest Bluetooth → Defunc True Basic: Bluetooth 6.0 versus Bluetooth 5 on the Panasonic.
• Best for call clarity in wind → Panasonic True: The MEMS mic and labyrinth structure are specifically designed to cut wind noise.
• Best for bass-forward sound → Defunc True Basic: A 13mm bass driver versus the Panasonic's 6mm unit.
• Best for battery life → Defunc True Basic: Up to 22 hours total playtime, against roughly 7.5 hours per charge plus case on the Panasonic.
• Best for app and AI features → Defunc True Basic: The Defunc AI App with Chat AI and quad microphones.
• Best for a quick top-up charge → Panasonic True: A short charge delivers about 90 minutes of playback.
In my opinion, the right choice comes down to fit philosophy more than anything else. If you want a sealed, isolating earbud with strong call performance and a compact, lightweight build, I'd pick the Panasonic True. If you'd rather have an open, pressure-free fit you can wear all day while staying aware of your surroundings — and you want the newer Bluetooth plus a bigger bass driver — I'd pick the Defunc True Basic.
Personally, I'd lean toward the Defunc True Basic, because the open-fit comfort and Bluetooth 6.0 feel like the more modern, everyday-friendly package for commuting and long listening sessions. But if isolation and wind-resistant calls are your priority, the Panasonic True is the better fit. Either way, check the current price on Amazon before you commit, since that can shift.
Both are IPX4 water resistant, so they handle sweat and splashes. The Defunc's silicone ear wings are designed to keep the bud secure without pressure, while the Panasonic's sealed fit stays put through a snug ear-canal seal. For intense movement, the Defunc's wing design is a strong argument.
It uses passive noise cancellation, not active. Its open-fit design deliberately lets ambient sound in, so it won't isolate you the way the Panasonic True's Active Noise Cancellation does. Choose the Defunc if awareness matters; choose the Panasonic if blocking noise matters.
The Defunc True Basic is rated for up to 22 hours of total playtime with its case. The Panasonic True lists about 7.5 hours per charge with a charging case that extends total time, plus a quick-charge option. On the headline total figure, the Defunc comes out ahead.
It has four built-in microphones (two per earbud) for voice pickup, and the Defunc AI App adds voice-assistant features. The Panasonic True counters with a MEMS microphone and a labyrinth structure aimed at reducing wind noise. For windy outdoor calls, the Panasonic's design is the more targeted solution.
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