KDiT Live @ SQLBits 2023

We’ve been dreaming for years about getting to record an episode in front of a live audience at a technical conference. Due to late speaker cancellations at SQLBits 2023, we were offered a slot and we jumped at it. Our age-old dream was about to come true.

But it very nearly didn’t.


Let’s rewind a bit and I’ll show you the equipment I opted to use for this endeavour. I needed simplicity and versatility, and I prefered not do much post-processing. I bought a Rode RodeCaster Pro a while back, and I’ve been itching to use it outside of my home.

It is essentially a studio in a box - plug in power and microphones and press record. The result can be uploaded straight to our podcast host Acast. The thing also sports good line out audio that we could pipe straight into the room audio at SQLBits to make sure the audience heard us. A few years ago I standardized my power needs to one single 110/220V HyperJuice USB charger. That thing gives me USB-C and USB-A out and have interchangeable physical connectors for different plugs around the world. In a fit of brilliant insight I bought a Rode DC-USB1 adapter to power the RodeCaster through this. This thing is way smaller than the included power brick and cable, making the RodeCaster slightly less cumbersome to lug around.

Little did I know that this was about to bite me in the posterior, especially as in another brilliant flash of insight I decided that I didn’t need to bring the Zoom H6 as a backup.

I tested everything over and over again at home, and while much larger and bulkier than the Zoom H6 we’ve used for field recordings previously, I felt that the RodeCaster was the better choice.

Issues mounting

On site we used the ProCaster for recording an interview with a relatively new member of the community. It went absolutely great, and the ProCaster was as simple and quick to use as I had hoped. It was - literally - just put in power and mics and go. The H6 is a great piece of kit and it has served us well for years, but it is a bit more fiddly and it requires post processing to get to the quality we want.

Late night after the SQLBits party on Friday I decided to take a listen to the recording. It turned out that the recording was riddled with a deep ground hum - making it completely useless. I tried for a bit to clean up the audio, but I couldn’t get it anywhere near useable, forcing me to accept that the interview was useless. That left me with trying to figure out why this was happening in the first place, and to come up with a solution for the live recording the next day.

I spent a few hours trying to understand where the hum was coming from, and after discounting all three microphones, I came to the conclusion that it was the device itself. But how could that be? It worked great back home? I had an idea, but no way to test it. Time to switch focus from getting the ProCaster to work, to finding an alternative solution.

Richard Campbell to the rescue

On Saturday morning, I spotted Richard Campbell of RunAs Radio at breakfast. I walked up to him, and he said good morning and asked me how I was. “Not great”, I responded. “My recording equipment is borked, and I’m doing a live recording today. Is there any way I could borrow some stuff from you?”. He leaned forward and without hesitation said: “What do you need?”.

That’s how we found ourselves recording the live episode on the same kind of Zoom H6 that we’ve always used, and of course it performed flawlessly. I had to do some work on the recording, but at least I had a recording in the first place. Richard saved the KDiT bacon that day, and we will be forever in his debt.

The recording went great, and the conversations with the audience was fantastic. Recording an episode in front of a live audience - albeit a small audience - was even more fun than we had ever imagined. We can’t wait to get to do this again.

Finding the culprit

As soon as I got back home I went to test out my theory of why I had the incessant ground hum in the first place.
Remember my brilliant idea of powering the ProCaster through USB? Yeah, that turned out to the problem. The signal coming through the USB charger was noisy like you wouldn’t believe, and that noise gets fed straight into the phantom power used to power our condenser microphones. There seem to be zero filtering of power, and that is a huge issue for anyone trying to use a condenser microphone. For some reason UK mains are even worse than Swedish mains. The noise was there at home as well, I just didn’t listen enough for it before I went to the UK. As all that noise went straight into the recording, I was left with an unusable result. Had I used the standard power brick to power the ProCaster, it is likely that none of this would ever have happened, and had I used a dynamic microphone (that does not rely on phantom power), this issue would never have appeared.

Yet again the road to hell is paved with good intentions - I was trying to save some weight and bulk, and in doing so, I all but guaranteed that any recordings would be unuseable. Adding insult to injury by not bringing a spare recorder was the icing on the cake.

TL; DR: don’t try to save weight when you don’t have to, and the old adage of “one is none, two is one” is applicable when you have a backup available.

Audio is hard, yo.