Tour De-Noise

Whether you are running online workshops, hosting a live stream, or recording audio or video content, optimal audio quality is absolutely essential. People in your audience might tolerate if your video is noisy or not perfectly sharp. But if your audio quality is poor, for example when something is constantly crackling or whooshing in the background or your voice is distorted, it gets irritating and annoying for your listeners pretty quickly.

I’m therefore constantly experimenting with various ways to improve the audio (and video) setup and the acoustics in my little home office in the attic. Last year, I added a dynamic broadcast microphone, the Røde Procaster, for spoken word which has a cardioid polar pattern and great off-axis rejection, meaning it primarily records what’s directly in front of it. I also added an audio interface with really clean preamps, the MOTU M2, and treated my room a bit. However, the key to recording impeccable audio is not only good technical equipment, but also making sure you record the right things in the first place. An important part of that: removing background noise as much as possible.

Cutting Out the Noise

Which type of background noise you have to deal with depends on the environment you are recording in. In my case, there is a street outside which can get quite loud at times. Unfortunately, there is not too much you can do to block that kind of outside noise from entering the room other than trying to improve the insulation of the windows or the door. The second type of background noise, however, is one that you often can in fact control. And that’s the noise inside your room. Be it an air conditioner, loud computer fans, or other appliances – you might want to turn everything off that makes noise before you hit record.

In the past, I had a monitor, for example, that made a constant, very high-pitched beeping sound which then turned up in the recordings as well. So I had to turn this monitor off when recording and eventually replaced it. This improved the noise floor of the audio considerably.

But there were still two pain points that I had to deal with: the hum of the fan of my key light, an Aputure Amaran 200d, and the whirr of a fan I attached to the back of my camera, a Sony ZV-E10, to prevent it from overheating during longer sessions like online workshops. Both sounds were still clearly audible on recordings and the way I had dealt with in the past was to pull down the respective frequencies with the live equalizer of the Blackmagic ATEM Mini, through which the audio runs for live streams:

Atem Software Control Equalizer

The equalization curve has those two visible dips at 176 and 8000 Hz, respectively. At those frequencies, I pulled the audio signal down to eliminate the unwanted fan noises.

This worked fairly well. But, of course, I wasn’t satisfied. I wanted to be able to record audio also without the ATEM Mini, only using the MOTU M2 audio interface. What I had tried in the past as well was to record a few seconds of silence and then use this snippet’s noise floor to eliminate the hum and hiss with a de-noise plugin. I got good results from that, too. But this is still another extra production step that you don’t want to have to do every time you record something. The best way to reduce noise and get a clean recording is still to eliminate the original sound source in the first place. So I went on a little quest to do exactly that.

Silencing the Amaran 200d

Aputure Amaran 200D

The Aputure Amaran 200d is an affordable LED light that can output a lot of light. It can therefore get quite hot and that’s why it has a fan built in. When I bought the light, there was no way to adjust the speed of this fan. Once you turned the light on, the fan would run at full speed, regardless of how hot the device actually was. But a few days ago, I had an idea: what if Aputure in the meantime had released a firmware update for the device? And in fact, there it was: a firmware update that allows you to switch the fan from “medium” to “smart” in the Sidus Link app controlling the light so that the fan adjusts its speed to the actual temperature. This immediately reduced the fan speed from 1500 rpm to under 1000 rpm and the hum was gone. First problem solved! 🥳

Amaran Fan Speed

Silencing the Noctua fan on the back of the Sony ZV-E10

Sony cameras are well-known for overheating in challenging situations. So one of the first things people do when they get a new Sony camera is to switch the “Auto Power OFF Temp.” setting to “High”. This prevents the system from shutting off too early to cool down. My ZV-E10, an entry-level mirrorless camera, has the same issues. When you record in 4K or are using the camera in USB cam mode, it overheats fairly quickly. I’d even say that this is a construction error, because it prevents you to use the camera as advertised. Using it as a USB camera is basically impossible. But there are a few things you can do to work around this issue:

  • Always open the flip out screen on the back so that the heat can dissipate better.
  • If the situation allows, never run the camera with a real battery, but use an AC adapter with a dummy battery instead.
  • To use it as a USB camera, connect the camera to your computer via the HDMI port and a capture card like the Elgato Cam Link, not via USB-C.

All those measures helped a lot already, but the camera still shut down at times after long usage or when the office got hotter in summer. So, as a last resort, I mounted a small Noctua fan to the back of the camera and connected it to a USB power adapter. The camera never overheated again.

But as it is the case with over-engineered solutions (👋, SPAs), as soon as you solve one problem you realize that you just created at least one new one. In my case, it was the aforementioned whirring noise of the fan which was, although the fan is already quite silent (max. 19.6 dB(A)), still audible in recordings.

So last week, I decided to finally tackle this problem with two a two-layered approach. First, I replaced the fan with cheap aluminium heat sinks. I had to cut off three rows of fins from one of the heat sinks to be able to affix not only one. In a perfect world, this will suffice to fix the problem. But because Murphy’s law, I re-added the fan as well, and ordered a USB fan controller to be able to adjust the output voltage and thus throttle the speed of the fan, just in case I’ll ever have to turn it on again. Second problem solved. For now. I guess…

Zv E10 With Heatsinks On The Back 2
Zv E10 With Heatsinks And Fan On The Back

I will never be able to close that display again…

The Details Are Not the Details

As you can see, sometimes it takes a bit of creativity and tinkering to optimize your setup. I’m fully aware that most of you won’t run into the same problems as I did. But maybe sharing this example of my tour de-noise helps you to approach similar problems with the same mindset. You might think that putting in that much effort into such seemingly small details isn’t worth the time and energy. You might be right. And you can and should definitely start recording anything without worrying that much about background noise. Yet in my experience, caring about and honing in the details often makes the difference between good and great. Regardless of what you’re building or creating, paying attention to the final touch is worth it and can be very satisfying. And you’ll also learn a lot along the way. For example, in which direction you should mount a cooling fan.*

Do you have a setup to record audio or video? Did you run into similar problems? What tricks and hacks did you use to improve your setup and the quality of your recordings? Let me know via Webmention, Mastodon, email, or – my personal favorite – in a response blog post.

*So that it pulls and blows the hot air away from the device.

~

2 Webmentions

Photo of @matthiasott
@matthiasott
@matthiasott Oof, I feel the challenges with eliminating fan noise, and nice rigging of that cooler fan. You're carrying on a proud tradition of makeshift gear modding 💪 As far as my setup: for now I'm only really doing screen recordings at home. The Izotope spectral de-noise + voice de-noise (in RX Standard) are some real sorcery. They're knocking out most of my PC's fan noise without much fiddling--on the ...
Photo of @marcthiele
@marcthiele
@marcthiele Hmm, probably I’d say something like “the balanced cable has two wires. One wire transports the complete audio signal and the other one picks up only the noise. And that allows the noise to be removed from the signal somehow.” 😁 And then I’d send them this link: https://youtu.be/rgfZb1pEIrU Balanced vs Unbalanced Audio | Do Balanced Cables Sound Better?