It's rare that Apple has a misstep with its products, and yet the company is now months behind on the release of the AirPods, the much-hyped wireless Bluetooth earbuds that were announced in September alongside the iPhone 7.

Adding insult to injury, the company has also failed to ship the BeatsX in-ear headphones, another device by Apple's Beats by Dre brand that uses the same Apple W1 chip used by the AirPods. Those headphones won't be released for at least another two to three months, according to a report by AppleInsider. Meanwhile, Apple said it won't ship the AirPods -- originally slated for an October launch -- until the products are ready.

"We don't believe in shipping a product before it's ready," the company told the Wall Street Journal. "We need a little more time before AirPods are ready for our customers."

So what gives? What's keeping Apple, the top tech hardware manufacturer in the world, from releasing two of its most anticipated new products during the key holiday shopping season? That would be the difficulty of developing truly wireless earphones, say several entrepreneurs in the earbud market.

There are many challenges to developing and selling working wireless earbuds, but chief among them is getting the connectivity to work right. For entrepreneurs in this space, the obstacle is getting the audio signal to sync properly between each bud. As audio is beamed from the iPhone to the earbuds via Bluetooth, only one of the buds is able to receive the signal. It must then transmit that signal at the precise time to its counterpart.

"Bluetooth is a radio frequency, and radio frequency can't go through water," says Jamie Roberts Seltzer, CEO of Alpha Audiotronics, which makes the $219.99 Skybuds. "Your head is a giant bag of water, so when you're outdoors and the radio frequency signal can't bounce around, you get frequent drops in one of the earbuds. This makes using a Bluetooth-only solution difficult."

To get around this problem, some companies have switched to other solutions. Alpha Audiotronics and Nuheara, which makes the upcoming $299 IQbuds, both use near-field magnetic induction technology to transmit the signal instead.

Apple, however, is believed to be using Bluetooth. It's unclear if Apple is transmitting Bluetooth to a single bud and then trying to relay the audio, or if Apple is sending the signal via Bluetooth to each bud simultaneously. Both solutions are tough to master.

"Removing the wires adds a massive level of complexity, creating a major engineering challenge -- connectivity to the phone and then connectivity between two earbuds themselves," says David Cannington, co-founder of Nuheara. "Most underestimate how hard the ear really is to solve for."

Another challenge is that of the sheer tininess of these devices. These days, consumers are used to having headphones that can be used throughout the day for listening to audio as well as making calls and interacting with voice assistants such as Siri. That means that the typical earbud requires a bundle of components, ranging from Bluetooth chips to microphones and a battery.

"It is a technical tour de force in this minute little AirPod," Apple marketing chief Phil Schiller said in September after announcing the earbuds. Schiller had just listed all the parts included inside the skinny devices -- Apple's W1 chip, dual accelerometers, dual microphones, a battery, an antenna, and dual sensors.

Fitting all of that into a tiny device that is supposed to fit within your ear comfortably and securely is a tough task.

That's why several other players in the market have had to deal with delays in their own products over the past few years. Among those that have come out, many have received harsh reviews due to problems with issues such as connectivity.

"We're just not there as an industry," says Luc Pierart, CEO of PKparis, which makes the K'asq earbuds. "We have not reached the point of being able to mass-produce quality earpods in the timeframe that the public is demanding."

This is why some companies have decided not to go completely wireless just yet. Robin DeFay, CEO and co-founder of Zipbuds, chose to keep a wire between the two buds on his company's upcoming Catalyst earphones to ensure consumers get a quality product.

With truly wireless earbuds "you have to charge both earbuds individually, you run the risk of losing one of the earbuds and having to purchase a replacement, and the cost will definitely be greater to the customer because of the extra components needed to produce a truly wireless set of earbuds," DeFay says.

For Apple in particular, the challenge of creating this kind of product is much steeper than it is for startups from a manufacturing point of view. While startups may be looking to sell a couple thousand units, Apple is playing in the big leagues. The demand it receives is up in the hundreds of thousands of units, says Johnson Jeng, executive vice president of North America for Erato Audio, which makes the $299.99 Apollo 7 earbuds.

And while startups simply hope and pray someone will review their products, Apple has the opposite problem. When its devices go on sale, every gadget reviewer in the world gets his or her hands on one and goes through it meticulously. Any problems will be found, and fast.

"At the end of the day, Apple is trying to create something different," DeFay says. "Although difficult, if anyone could pull it off in a smaller package, my money would be on the engineers over at Apple."