What Is Active Noise Cancellation (ANC) and How Does It Actually Work?

Short answer: Active Noise Cancellation uses tiny microphones to listen to the noise around you, then plays an inverted copy of that sound wave through the driver so the two cancel out. It works extremely well on steady low-frequency noise — aircraft cabins, bus and train rumble, air conditioners, ceiling fans — and poorly on sudden or high-pitched sound like speech and car horns. Good ANC starts around Rs 2,490 in India for the Sony WH-CH520 class and gets genuinely excellent by the Sony WH-CH720N at Rs 5,890.

Prices are live as of 6 September 2026 and move with stock — check the linked product page for the current figure before you decide.

How does ANC actually work?

Sound is a pressure wave. If you take a wave and flip it — so its peaks line up with the original’s troughs — the two add up to nearly nothing. That is destructive interference, and it is the entire principle.

An ANC headphone does this in four steps, thousands of times per second:

1. A microphone samples the noise reaching your ear.
2. A dedicated chip calculates the exact inverse of that wave.
3. The driver plays the inverse alongside your music.
4. A second microphone inside the earcup checks what actually reached your eardrum and corrects the error.

Headphones with only step 1 use feedforward ANC. Ones with only the inside microphone use feedback ANC. The good ones use both, which is called hybrid ANC — and hybrid is what you should look for on a spec sheet.

Why does ANC kill engine noise but not voices?

Because of timing and wavelength. Low-frequency sound has a long wave — a 100Hz rumble is about 3.4 metres from peak to peak. The chip has ample time to measure it, invert it and play it back before the wave has moved on. It is also predictable: an aircraft engine sounds the same this second as it did last second.

Speech sits around 500Hz to 4kHz, with waves a few centimetres long, and it changes constantly. By the time the chip has calculated an inverse, the sound has already changed. This is a physics limit, not a budget limit — a Rs 30,000 headphone cannot cancel conversation either.

What is passive isolation, and why does it matter more than you think?

Passive isolation is just physical blocking — the earcup seal or the ear tip. It handles exactly the frequencies ANC cannot: the high ones. Good over-ear pads or well-fitted silicone tips can cut 15-25 dB of high frequency on their own, before any electronics are involved.

This is why fit is the single biggest variable in real-world performance. A Rs 12,000 headphone with a broken seal will underperform a Rs 3,000 one that fits you properly. If you buy earbuds, try all the supplied tip sizes; most people are using tips that are too small.

What ANC costs, and what you get, in India today

Live unboxed stock as of 6 September 2026:

Who should NOT buy ANC headphones

• Anyone who needs to hear traffic while walking or cycling. This is a safety issue, not a preference. Use transparency mode or open-ear headphones.
• Anyone whose main complaint is office chatter. ANC will disappoint you here. Well-sealed in-ear monitors plus a podcast do more.
• Anyone sensitive to ear pressure. Some people feel a pressure sensation from strong ANC, similar to altitude change. Try before you commit, or buy from somewhere with a real returns window.
• Anyone whose budget is under Rs 1,000 and who wants great sound. At that price, ANC is added at the cost of audio quality. A good non-ANC pair will sound better.

What we can ship today

Every unit below is in stock as this page was last checked, with a 6-month NewAsNew Assured Warranty, GST invoice, 7-day returns and no-cost EMI. If it is listed here, we can dispatch it.

Prices checked on 29 September 2026 — stock and prices move, so the linked product page is always the truth.

Browse all headphones in stock · Ask us on WhatsApp which one fits you

Frequently asked questions

Does ANC damage your hearing?

No. There is no evidence that noise cancellation harms hearing. In fact it usually protects it, because you stop raising the volume to overcome background noise. That volume-raising is the real hearing risk.

Why do I feel pressure in my ears with ANC on?

Your brain receives a signal of reduced low-frequency pressure without the matching physical sensation, and interprets it as pressure change. It is harmless and most people stop noticing within a few days. If it stays uncomfortable, many headphones offer a lower ANC setting.

Does ANC drain battery?

Yes, typically 20-30% of runtime. A headphone rated 50 hours with ANC off might give 35 hours with it on. Manufacturers usually quote the ANC-on figure, but check.

Is ANC useful in India specifically?

Very. Ceiling fans, air conditioners, metro and local train rumble, generator hum and traffic drone are all steady low-frequency noise, which is precisely what ANC handles best.

Does ANC work without playing music?

Yes. On almost every model you can switch ANC on with no audio playing and simply get quiet. Some models produce a faint hiss in this mode; better ones do not.

What is the difference between ANC and noise isolation?

Isolation is physical blocking by the earcup or ear tip and works best at high frequencies. ANC is electronic cancellation and works best at low frequencies. Good headphones use both, which is why fit matters as much as the chip.

Are unboxed ANC headphones as good as new ones?

Unboxed means the box was opened, not that the product was used in any meaningful way. Every unit passes our 50-point check, which for headphones includes 12 test areas covering drivers, ANC function, microphones, battery and charging. Only 2 to 3 in 10 devices reaching our bench pass.

Related guides

• Unboxed headphones and earbuds: the full guide
• Sony vs Bose vs Sennheiser ANC compared
• Best unboxed noise-cancelling headphones
• Best unboxed earbuds under Rs 3,000

Still deciding? Talk to a human

Send us the work you do and your budget on WhatsApp and we will tell you honestly whether we have something for you — or whether you should wait. Chat with NewAsNew on WhatsApp (+91 79822 35917).

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Written by Atul Pandey, co-founder of NewAsNew (NextG Serve Private Limited, New Delhi). We came from four years of offline electronics retail in Prayagraj before building NewAsNew. Only 2 to 3 out of every 10 devices that reach our QC bench pass; the other 7 to 8 go back to the supplier. The exact figure moves month to month with the stock we are offered, so we publish the range rather than one flattering number. Read our story.