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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-04 · 7 min read · Independent comparison
• Csasan Earbuds biggest strength: A genuine IP7 waterproof rating plus a 13mm dynamic driver, 40 hours of total playtime and a 10-meter Bluetooth 5.3 range — a rugged, simple everyday set.
• Csasan Earbuds biggest trade-off: Its noise control is ENC (Environmental Noise Cancellation) aimed at cleaning up your voice on calls rather than actively silencing the room around you.
• TOZO NC9 biggest strength: Hybrid active noise cancelling rated to a 45dB reduction depth, a Transparency Mode, 32 EQ presets in an app and up to 60 hours of total playtime.
• TOZO NC9 biggest trade-off: You pay for that feature set in complexity — app pairing, more modes to manage, and a bulkier charging case.
• Who Csasan Earbuds are for: Runners, gym-goers and students who want fuss-free sound, sweat resistance and long battery without fiddling with settings.
• Who TOZO NC9 are for: Anyone studying, commuting or working in a noisy room who wants the outside world turned down and the sound tuned to taste.
The Csasan Earbuds (model J90 Pro) are built around a 13mm composite diaphragm driver with AAC codec support and a 20Hz–20kHz frequency range. In plain terms, that's a big driver for this class of earbud, and the tuning leans toward a full, bass-forward presentation rather than a thin, clinical one. If you mostly listen to music, podcasts or lecture recordings at a desk or on a treadmill, that's a pleasant place to land.
What stands out most in the specs is durability and simplicity. The IP7 nano-coating seals the earbuds against sweat, rain and airborne moisture, which is why Csasan pitches these as a sport headset — running, yoga, cycling. You get three sizes of ear tips (S/M/L) and a pressure-dispersing earplug shape, so fit is adjustable without hunting for aftermarket tips. Bluetooth 5.3 handles pairing, and once you've connected the first time, opening the case auto-connects the buds. Each earbud can also work independently, so you can share one with someone or run mono while the other charges.
Battery is the other headline: 6–8 hours per charge, four extra charges in the case, 40 hours total, and a 1.5-hour charge time. The LED display on the case shows remaining power for both the buds and the case, which removes the guesswork. Touch panels on both earbuds cover playback, volume, track skipping and call handling.
TOZO NC9: Who It's For
The TOZO NC9 is a different animal. Its core feature is Hybrid Active Noise Cancelling with a maximum reduction depth of 45dB. That's the spec that matters most for study: active cancellation uses microphones and inverted sound to reduce steady ambient noise — fans, air conditioning, engine drone, the general hum of a busy room — rather than simply filtering your voice for a call. It also offers a Transparency Mode so you can let the outside in without removing the buds, which is genuinely useful when you need to hear a train announcement or someone calling your name.
Sound is handled by 10mm dynamic drivers with TOZO's OrigX Acoustic 2.0 processing, tuned for deep bass and clarity, with a 20Hz–20KHz range, 32-ohm impedance and 120dB sensitivity — meaning these are easy to drive and should get loud without strain. Audio latency is listed at 60ms, which is low enough to keep video and games in sync. The real differentiator is the TOZO app: 32 EQ options, adjustable bass, noise-cancellation modes, firmware updates, plus a sharing zone where you can post your custom EQ. If you like tuning your sound, that's a lot of room to play.
Call quality gets six microphones with ENC ambient noise reduction, so both the NC9 and the Csasan address calls — TOZO just throws more mics and hybrid processing at it. Fit is covered by six sizes of replaceable ear caps, which is the widest range here and the reason TOZO can credibly claim all-day comfort. Battery runs up to 60 hours total with ANC off and 40 hours with ANC on, with 14 and 10 hours respectively per single charge, a 2-hour full charge, and an LED display on the case. Water protection is IPX8 — the highest rating in this comparison, covering sweat, rain and splashes. Bluetooth 5.3 with a 20-meter range rounds it out.
Who should buy it? Anyone treating earbuds as a study and commute tool first: the noise cancelling, the EQ app and the battery life all point that way. Who should skip it? If you want zero setup, no app, and the lightest possible case in your pocket, the extra modes and the larger charging case may feel like more than you asked for.
• Best for blocking out a noisy room while studying → TOZO NC9. Hybrid ANC at up to 45dB is the only real noise-cancelling option of the two.
• Best for battery life → TOZO NC9. Up to 60 hours total (ANC off) versus 40 hours on the Csasan.
• Best for workouts and heavy sweat → Csasan Earbuds. IP7 sealing plus a sport-focused design; TOZO counters with IPX8, so this one is closer than it looks.
• Best for sound customization → TOZO NC9. 32 EQ options and app control; the Csasan has no companion app.
• Best for a simple, no-app experience → Csasan Earbuds. Open the case, auto-connect, touch controls, done.
• Best for the widest fit options → TOZO NC9. Six ear-cap sizes against three on the Csasan.
• Best for hearing your surroundings without removing buds → TOZO NC9. Transparency Mode.
• Best for long-range stability around the house → TOZO NC9. A rated 20-meter Bluetooth range versus 10 meters.
• Best for tightest fit on a smaller driver → Csasan Earbuds. A 13mm driver in a compact shell, with pressure-dispersing tips.
In my opinion, the TOZO NC9 is the one I'd buy if studying is the priority. Active noise cancelling with a 45dB reduction depth, a Transparency Mode, six ear-tip sizes and 60 hours of total playtime directly address the things that break concentration. The app-based EQ is a bonus I'd actually use, not a gimmick. That said, if your study happens somewhere quiet and your real problem is sweat and charging, the Csasan Earbuds are the simpler, tougher pick — and the 13mm driver gives them a fuller low end than their feature list suggests. For noise cancelling in-ear earbuds for study, I'd go TOZO NC9.
Yes. It uses Hybrid Active Noise Cancelling with a maximum reduction depth of 45dB, which actively reduces steady background sound. The Csasan Earbuds use ENC, which is aimed mainly at improving call clarity rather than cancelling your environment.
The TOZO NC9 lasts longer: up to 60 hours total with ANC off and 40 hours with ANC on, versus 40 hours total on the Csasan Earbuds. Per charge, TOZO lists 14 hours (ANC off) and 10 hours (ANC on), while Csasan lists 6–8 hours.
They can be, especially in a quiet room or library where you just want music or lectures with long battery and a secure fit. For loud shared spaces, the lack of true active noise cancelling is the limiting factor.
On paper the TOZO NC9 edges ahead with IPX8 protection, which covers sweat, rain and splashes. The Csasan Earbuds are rated IP7, also suitable for workouts and wet weather. Both handle gym use; TOZO's rating is the higher of the two.
No — touch controls on the earbuds handle the basics. The TOZO app is where you unlock the 32 EQ options, noise-control modes and firmware updates, so it's optional but it's where much of the NC9's flexibility lives.
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