We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-01 · 6 min read · Independent comparison
If you want a wired, plug-and-play connection with lossless-grade audio and a wide 16Hz–40kHz frequency range that digs deep into sub-bass, choose Koajim USB-C; if you need true wireless freedom, Bluetooth 5.4, and a charging case that pushes total playtime toward 36 hours, choose Btootos Earbuds.
• Koajim USB-C — biggest strength: Dual 6mm dynamic drivers plus a built-in DAC chip, supporting lossless audio up to 24-bit/192kHz across a 16Hz–40kHz range — an unusually wide spec for wired in-ears, and the foundation for its punchy bass.
• Koajim USB-C — biggest trade-off: It's wired with a 5ft cable and needs a USB-C port, and Koajim itself notes it may not suit very small ear canals.
• Btootos Earbuds — biggest strength: Bluetooth 5.4 with a 15m range, 14.2mm composite drivers, ENC call noise reduction, IP7 waterproofing and up to 36 hours total battery with the case.
• Btootos Earbuds — biggest trade-off: Wireless audio over AAC/SBC can't match a wired lossless connection, and its frequency range tops out at 20kHz.
• Who each is for: Koajim USB-C suits listeners who prioritize bass depth and lossless sound on a phone or laptop; Btootos Earbuds suit anyone who wants untethered convenience for sport, commutes and calls.
The Koajim USB-C (model BASS 710C) is a wired in-ear set built around a dual 6mm dynamic driver system and a high-performance DAC chip. That combination matters for the "deep bass" question: the driver pairing handles low frequencies with more authority than a single small driver typically can, and the DAC bypasses your phone's built-in audio output to feed the drivers a cleaner, higher-resolution signal. The claimed frequency range of 16Hz–40kHz and support for lossless audio at up to 24-bit/192kHz tell you this is aimed at listeners who care about the low end and the detail above it. The 106dB sensitivity and 16-ohm impedance also suggest it's easy to drive straight from a phone or laptop with no amp.
Who should buy it: anyone who wants wired reliability with no charging, no pairing and no latency — gamers, people on calls all day, and listeners who want the deepest bass their phone can deliver. Who should skip it: iPhone or Android users without a USB-C port, and anyone with very small ear canals, which Koajim explicitly flags as a fit concern.
Btootos Earbuds: Who It's For
The Btootos Earbuds (model A90 Pro) take the opposite approach: total wireless freedom. The Bluetooth 5.4 chipset promises a faster, more stable link with low latency and a 15m range, so you can leave your phone on a desk or in a bag and keep listening. The dual 14.2mm low-distortion composite dynamic drivers are notably large for true wireless earbuds, and that size is exactly what you want for bass presence — bigger drivers move more air. AAC and SBC coding cover the standard streaming formats, and ENC noise reduction focuses on making your voice clearer on calls.
Battery is where these pull ahead for all-day use. You get roughly 6–8 hours per charge, with the case adding up to 30 hours for a total of about 36, and the case charges via USB-C in around 1.5 hours. The LED display on the case shows the charge level for both the case and the buds, which removes the guessing game. IP7 waterproofing plus a nano coating means sweat and rain aren't a problem, and touch controls handle play, skip, calls and voice assistant without reaching for your phone.
Who should buy it: runners, gym-goers, commuters and anyone who hates cables. The silicone tips in three sizes and lightweight in-ear shape suit long wear. Who should skip it: critical listeners who want a lossless wired signal, and anyone who prefers physical buttons over touch controls.
Side-by-Side: Which Should You Choose?
• Best for battery life and freedom → Btootos Earbuds. Up to 36 hours total with the case and no cable to snag.
• Best for workouts and rain → Btootos Earbuds. IP7 waterproofing and a wireless design make them the obvious pick for sweat and weather.
• Best for calls and low latency → Koajim USB-C. A wired connection has zero Bluetooth latency, and the inline mic plus remote keep control simple.
• Best for travel and commuting → Btootos Earbuds. Bluetooth 5.4 with a 15m range and a pocketable charging case.
• Best for durability of the cable and plug → Koajim USB-C. Fiber-reinforced cable and aluminium alloy plug housing target the usual break points.
• Best for device flexibility → Btootos Earbuds. They pair with phones, laptops and tablets over Bluetooth, while Koajim requires a USB-C port.
• Best for a sealed, noise-isolating fit → Koajim USB-C. Ear fins plus softer 45A tips are designed specifically to seal and block ambient noise.
If deep bass is your priority, I'd buy the Koajim USB-C. In my opinion, the dual-driver setup, dedicated DAC chip, 16Hz low-end extension and lossless support give it the clearest path to genuinely deep, controlled bass — and the wired connection means nothing is lost in transmission. The Btootos Earbuds are the better choice if you can't stand cables, need all-day battery or sweat through your workouts, and their 14.2mm drivers are impressively large for wireless. But for pure bass and audio fidelity, I'd go wired. Check the current price on Amazon before you decide.
FAQ
Good bass is punchy and controlled rather than muddy. The Koajim USB-C is tuned for punchy bass with warm mids and crisp highs across a 16Hz–40kHz range, and the Btootos Earbuds pair their 14.2mm drivers with a sealed in-ear fit for solid low-end presence.
Bass is the low-frequency part of the audio range, roughly the bottom end of the frequency response. The Koajim USB-C covers 16Hz–40kHz and the Btootos Earbuds cover 20Hz–20kHz — the lower the starting figure, the deeper the sub-bass the headphones can reproduce.
For bass, look at driver size, fit and seal. The Btootos Earbuds use dual 14.2mm drivers with silicone tips in three sizes for a tight seal, and the Koajim USB-C uses dual 6mm drivers with ear fins and softer 45A tips built to isolate ambient noise and preserve low-end output.
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