Bluetooth headphones are just fantastic, and Bluetooth earbuds are a level higher than that. They sit snug in your ears, and their non-existent wires can never catch on a backpack strap, never bounce against clothes and conduct a boom into your ear, and never get tangled in your pocket. They sound great, the batteries last long enough, and some brands even have fancy augmented-reality tricks up their metaphorical sleeves. But one thing Bluetooth can never, ever do is eliminate that delay. “The delay on any Bluetooth transmission happens because audio information has to be encoded for transfer and then decoded once it’s received. No matter what you do, there will always be some delay to process this,” Christen Costa, CEO of Gadget Review, told Lifewire via email.
Latency
This delay is also known as latency. It’s not caused just by the wireless transmission itself—there are latency-free ways to do that. “Transmitting information using Bluetooth requires packing data bits with overhead bits into a stream,” professional radio engineer Sam Brown told Lifewire via email. “Then transmitting this stream of ones and zeros over the air using a complex modulation scheme. This is all done to ensure reliable over-the-air transmission. The processing at both the transmitter and receiver, to both pack and unpack these bits, results in latency that can practically never be zero.” For listening to music or podcasts, this doesn’t matter. The delay is only noticeable when you press play and is so short that you won’t notice it. With movies, your computer can automatically delay the video stream to match the Bluetooth audio delay, so audio and video stay in perfect sync. But with games and music-creation apps, even a tiny delay is noticeable. If you tap a piano key in GarageBand, you expect to hear the sound instantly. Even a minuscule delay will soon drive you crazy. Likewise with gaming. The background music sounds fine, but any sound effects tied to your on-screen actions will be similarly out-of-sync. Urbanista’s gaming mode uses a low-latency codec (encode-decode) to get the delay down to 70 milliseconds, which sounds short but is still pretty big. In 70ms, sound can travel almost 60 feet. If you ever noticed the delay between near and distant speakers at a live concert, it’s the same principle.
Alternatives
Speaking of live concerts, musicians get around this delay in a couple of ways. The old way was to have monitor speakers there on stage, cranked up loud, so they were the main audio source for the musician. The modern way is to use special wireless earbuds, called In Ear Monitors (IEM). The difference is that IEMs aren’t digital. They use good old-fashioned radio waves, which require no digital conversion and travel at the speed of light, i.e., way, way faster than the speed of sound. “IEMs have a latency of around 5 ms or less, while Bluetooth Aptx has a latency that is six times as high. So, in terms of latency, IEMs are better,” says Brown. These are fine for live musicians, but they’re impractical and still expensive compared to consumer-grade headphones for gaming. Also, says Brown, gamers prefer over-the-ear headphones, and IEMs are more like earbuds. The answer, then, is one that you might not want to hear: Wires. “Wired headphones are truly zero latency and robust to artifacts such as radio interference that can plague wireless systems,” says Brown. “The downside, of course, is a lack of mobility that results from being tethered.” Wires have their drawbacks. They tangle. They can get caught up. But for perfect lossless transmission, for instant, zero-latency listening, and for reliability, they can’t be beat. Wired cans will never drop a connection, run out of battery, or try to connect to your iPad instead of your iPhone. They’re also cheaper than their Bluetooth equivalents and, while Bluetooth audio quality has gotten great in recent years, wired can still sound better. They’re just not cool. But maybe sometime soon, there will be a revival, like with vinyl, cassettes, and film.
