If you want high-fidelity audio with a retro aesthetic and zero latency for audiophiles, choose Koss CL/20; if you need active noise cancellation, wireless freedom, and a hybrid ANC headset for commuting or travel, choose Avantree Relay.
• Koss CL/20: Delivers balanced, accurate sound with a transparent design and 3.5mm wired connection; the trade-off is the lack of wireless capability and no active noise cancellation. This pick is for listeners who prioritize pure audio fidelity and style over convenience features.
• Avantree Relay: Offers Bluetooth 5.3 connectivity with aptX-Adaptive support and hybrid active noise cancellation up to 24dB; the trade-off is an in-ear form factor that may not suit everyone's preference for on-ear comfort. This pick is for travelers and commuters who need to block out ambient noise while staying connected wirelessly.
The Koss CL/20 stands out immediately because it refuses to hide its engineering. The clear, transparent enclosure allows you to see the internal components, from the headband to the cord, creating a unique visual experience that blends vintage aesthetics with modern transparency. For audiophiles who appreciate seeing the mechanics behind the music, this isn't just a pair of headphones; it is a piece of functional art. The design relies on lightweight yet durable materials, ensuring that the unit can withstand demanding environments without feeling flimsy. It brings back the 90s vibe but with a sonic performance that feels contemporary.
Sound quality is where this product truly shines for the critical listener. The dynamic drivers are tuned to deliver a frequency range spanning from 16 Hz to 20,000 Hz, which covers the full spectrum of human hearing. This wide range ensures deep bass, crisp highs, and a full midrange that many budget-oriented options struggle to replicate. With a sensitivity of 103 dB and an impedance of 60 ohms, the CL/20 offers a balanced and accurate audio reproduction that reveals details in your favorite tracks. The circumaural earcups provide acoustic isolation through plush leatherette and sponge cushions, meaning you get a focused listening experience without needing electronic aids to block out the world.
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-26 · 7 min read · Independent comparison
The connectivity is strictly wired via a standard 3.5mm jack, which is a double-edged sword. On one hand, it guarantees zero latency and absolute reliability; there is no battery to charge, no pairing process, and no signal compression from wireless codecs. You can plug directly into laptops, tablets, or gaming devices and start listening instantly. However, this also means you are tethered to your source device. If you value the ability to walk around your home or gym without a cable trailing behind you, this feature becomes a significant limitation. The adjustable sliding yokes ensure a perfect fit for various head shapes, making it comfortable for extended sessions, provided you do not mind the physical connection.
Who should skip this: Listeners who require wireless mobility, those who need active noise cancellation for loud environments like airplanes or busy offices, or anyone looking for a built-in microphone solution for calls without additional accessories.
The Avantree Relay takes a completely different approach by focusing on the modern necessity of wireless freedom combined with advanced noise management. This is not just a set of earbuds; it is a comprehensive solution designed for people who live their lives in transit or noisy spaces. The system utilizes Bluetooth 5.3 technology, which provides a stable and reliable connection across a wide variety of devices. Unlike older Bluetooth versions that might suffer from dropouts or interference, the 5.3 standard ensures that your audio stream remains consistent whether you are in a crowded airport terminal or a bustling city street.
What sets this apart for the discerning buyer is the inclusion of aptX-Adaptive codec support. This technology allows the device to transmit high-quality audio at low latency when paired with compatible listening devices. For gamers or movie watchers, this low latency is crucial to prevent the annoying delay between what happens on screen and what you hear. Beyond the transmission quality, the Hybrid Active Noise Cancellation (ANC) is a game-changer. By blocking up to 24dB of environmental noise, the Relay effectively creates a quiet zone around your ears, allowing you to focus on your music or calls even in chaotic settings. This level of noise reduction is something the purely passive isolation of the Koss cannot match.
Comfort and situational awareness are handled with equal care. The earbuds feature rounded tips designed for an in-ear fit, and the case includes a battery display so you can easily monitor your charging status at a glance. A standout feature is the Ambient Mode, which activates the built-in microphones to let environmental sounds through. This "transparency mode" is essential for safety when walking near traffic or for quick conversations without removing the earbuds. The ability to switch between total silence and awareness of your surroundings gives the user complete control over their auditory environment. While the color orange adds a pop of style, the functionality is what drives the value here, especially for frequent flyers who can use the included dual 3.5mm adapters to connect to almost any aircraft entertainment system.
Who should skip this: Audiophiles who prefer the open-back feel or the larger cushioning of on-ear headphones, users who dislike the sensation of having anything inside their ear canal, or anyone who wants a simple, non-electronic setup without the complexity of charging cases and touch controls.
• Best for Audio Fidelity & Visual Style → Koss CL/20: The transparent design and 16Hz–20kHz frequency response offer a pure, uncolored listening experience that appeals to purists.
• Best for Noise Isolation → Avantree Relay: The 24dB hybrid active noise cancellation physically blocks more external sound than the passive isolation of the Koss earpads.
• Best for Wireless Mobility → Avantree Relay: Bluetooth 5.3 and the absence of a cable make this the only viable option for movement without being tethered to a device.
• Best for Zero Latency Gaming → Koss CL/20: The direct 3.5mm wired connection eliminates any digital processing delay inherent in Bluetooth transmission.
• Best for Travel & Commuting → Avantree Relay: The combination of ANC, Ambient Mode, and airplane adapter compatibility makes it superior for long trips.
• Best for Battery-Free Listening → Koss CL/20: There is no battery to deplete; as long as you have a source, you have sound.
• Best for Low-Latency Streaming → Avantree Relay: aptX-Adaptive ensures high-quality audio with minimal lag for video content.
• Best for Durability in Transit → Avantree Relay: The compact case protects the earbuds, whereas the Koss requires careful handling to avoid damaging the visible internal components.
After weighing the technical specifications and real-world use cases, I would choose the Avantree Relay for my daily life. As someone who commutes frequently and spends time in noisy environments, the active noise cancellation and wireless freedom offered by the Avantree system are indispensable. The ability to block out 24dB of ambient noise and switch to transparency mode instantly gives me a level of control that the wired Koss simply cannot provide. However, if my primary goal were sitting down at a desk to critically listen to music or games with zero latency and maximum visual flair, I would switch to the Koss CL/20. For the general consumer seeking a versatile tool for modern living, the Avantree Relay is the more practical and powerful choice.
Both serve different needs, but the Koss CL/20 is often preferred by audiophiles for its wide frequency response (16Hz–20kHz) and transparent design that showcases the driver mechanics, offering a pure wired experience.
The Koss CL/20 does not list a built-in microphone, so you would need a separate solution for voice chat. The Avantree Relay includes built-in mics for calls and features transparency mode, making it suitable for gaming communication while staying aware of your surroundings.
Only the Avantree Relay supports active noise cancellation, capable of blocking up to 24dB of environmental noise. The Koss CL/20 relies solely on passive sound isolation provided by its leatherette cushions.
Neither product is a neckband style. The Koss CL/20 is an on-ear headphone with a headband, while the Avantree Relay consists of in-ear buds with a charging case.
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