How We Made The World’s First Bluetooth Microphone
Before the Hooke Verse, bluetooth microphones didn’t exist. Sure, there are the Bluetooth microphones in our headsets, but they operate over the A2DP bluetooth format which only allows for mono audio in the range of 3kHz – 5kHz (the median frequency range of the human voice) to be transmitted. This is hardly acceptable for field recordists, musicians or any other maker looking to use a microphone to record sound wirelessly. The Hooke Verse is the first Bluetooth microphone capable of streaming dual channel, 16bit 48kHz, 20Hz – 20kHz .wav files over Bluetooth to a smartphone. Here’s how we made it.
1. There was no off the shelf Bluetooth codec that allowed a device to stream multiple channels of audio to a phone. So we built it.
There are a ton of Bluetooth headphones and speakers on the market. The majority of these Bluetooth products use the A2DP format to stream audio (some use the APTx format which allows for higher quality streams). But both codecs allow for the phone to TRANSMIT stereo audio to devices and receive mono audio (3kHz – 5kHz). NOT receive stereo audio at 20Hz – 20kHz. So we built a custom codec that allows us to stream this dual channel high quality audio to both Android and iOS.
2. Android and iOS are not natively set up to receive dual channel high quality audio over Bluetooth. So we made apps to accept our codec.
It’s a simple line of code that Android and iOS would need to integrate in order for this reception to occur natively within their camera apps, but they have not implemented it…yet. So we have built the World’s first 3D Audio recording apps to make the handshake with our codec as it arrives at the phone.
3. Bluetooth can cause latency, so we stripped away everything we didn’t need to get .0042ms of latency.
If you’ve ever worked in a DAW like ProTools or Logic, you know that the more plugins you add to a channel strip, the more latency you’ll get. Same goes with Bluetooth. Today’s off the shelf codecs have a ton of features that most companies don’t even use in their product. With more stuff, comes more weight and latency can occur. When you strip everything else away and use the codec JUST for streaming you can eliminate latency considerably and get shocking results.
Listen to this video made by one of our customers. As you can see he is standing nearly 15 feet away from the phone during this recording and is experiencing unnoticeable latency.
4. No microphone has ever sent high quality audio over Bluetooth bits before, so we created a file format system unlike anything you’ve ever seen.
You probably noticed in the diagram in 1. that the analog mics inside of Hooke Verse capture audio at 16bit 48kHz. However, the packing and transmitting of this audio is unlike any other microphone on the market. The analog microphones at the Verse pick up omni directional 24bit 48kHz audio. This audio is then digitally packed into bits which are sent over Bluetooth to the phone for unpacking.
It is very precise how many bits are sent and at what frequency so as to ensure optimum performance and eliminate the chance of bluetooth packet loss. So the app receives the bits and unpacks them into a desired file format. Currently the app stores audio only recordings as .mp3 and video as m4a, however it is not the standard .mp3 in which you are normally accustomed to. Since the 16bit 48kHz audio has been transmitted over Bluetooth bits from analog microphones, the sample rate is still in fact 16bit 48kHz, but the final naming is .mp3. Listening back to Hooke recordings, you’ll notice that it does not sound like .mp3, it sounds like a .wav. That’s because it is.
Can you hear the difference in quality compared to a wired binaural smartphone microphone? I can’t.
5. We conquered the sleep screen by enabling background record.
Ever tried to start recording a video on your phone and then put it to sleep? You’ll notice that the video ends when you hit that sleep button. A major pain, but something baked into your phone’s OS that is hard to get around. We found a way tho, and are proud to say Hooke Verse can continue streaming audio to your phone during record, even when it is asleep.
6. We made it versatile
Hooke Verse isn’t just the World’s first Bluetooth microphone. It’s also a pair of Bluetooth headphones. When the Hooke App is not open, Hooke Verse uses the A2DP codec to allow for music listening and hands free calling. When the app opens it immediately kicks in our custom codec and turns the Verse into record mode. Just by opening the app. Not only that, but the Verse comes with a recording cable that allows for wired recording to any device without Bluetooth.
7. We got it certified
Besides needing to meet the product codes & regulations in over 40 countries, Hooke Verse had to undergo an Apple MFi (made for iPhone) certification in order for our Hooke App to be launched on the Apple app store. A long, frustrating process which you can read about in detail below. New tech can be very scary for the platforms you’re looking to work on! They need to properly vet it to make sure it does not damage their internal systems. And when it comes to a produce with no prior examples of testing to pull from, this can be a very lengthy process.
8. Most importantly, we made it fun.
Changing the way you record the world does not mean adding another piece of gear to your life, it means enhancing it. That’s why we’ve added sound filters to our app (things like reverb, delay, stereoscoper and concert) to enhance your recordings, we even added a public feed where users can share their binaural audio captured from all around the World. Even the shipping box turns into a dummy head for you to record binaural audio without wearing the Verse. Capturing great audio should be fun, not just technical.
At Hooke Audio, we’re sick of capturing flat mono audio on our phones and we’re also sick of having to use cumbersome attachments or external mics with cables in order to upgrade. We hear the World in 3D, we should be capturing that way. That’s why Bluetooth recording inside a pair of headphones just makes sense.
Thanks for reading and if you have any other questions about this ground breaking tech, please comment below!
For more info on Hooke Verse and binaural audio:
From one ear to another,
Founder, Hooke Audio