Audio Routing

Operating systems are quite good at managing multiple screens. And multi-monitor configurations are an absolute standard in today offices. Very often a laptop hooked to external monitors provides a yet another screen. Traveling a lot - I also use an iPad (connected over USB) as a secondary screen for my Windows laptop. It all works great.

Audio, unfortunately, is a completely different story.

While I can seamlessly drag application windows across multiple screens, and set the screens to duplicate or extend each other, there is almost no control over how audio is rendered. It is not possible to easily switch an application to output sound to a different device. Some applications offer this as their native features, but there is no system level control over it. And this is not a Windows - specific problem. All operating systems (including mobile) suffer from that.

What you see in the attached picture here is a very ugly hardware workaround for the lack of a simple audio routing feature in iOS. My requirement was really simple: connect the USB-C iPad to a video projector (for video) and an audio amplifier (for audio). I even found a very nice hub designed to do just that: it has 3.5mm audio jack output, HDMI output, a generic USB-A port and a USB-C port for a power supply.

First connected the audio jack and voila - the audio started playing though the external speakers. Then plugged in the video projector's HDMI cable and voila - the video started playing on the big screen.

But the speakers went silent. And the volume control slider on the iPad disappeared.

It turns out that iOS, when connected to HDMI, routes audio to HDMI only and there is no way to override that. To be precise, it routes audio to the most recently connected output, so in the days of a 3.5mm jack, you could unplug and plug the jack and the audio would return to the analog port. But today the jack is gone and the same trick on the hub does nothing...

To overcome the issue (which, I believe, is very common - when using overhead projectors people rarely have speakers connected to the projectors and use standalone audio systems instead), I had to implement a hardware solution - the HDMI audio extractor, which makes the overall setup very ugly. I mean, you can hide all those cables, and luckily the audio extractor can be powered from the hub's USB port, but it is still very ugly overall. A simple audio routing option in the iPad would solve it nicely. Unfortunately, it is not available...