Noise floors are like council tax bills. We all have one, and we’d all like it to be lower. This is a blog about shaving a few dB off your noise floor. I can’t help with your council tax I’m afraid.
I’ve written previously about noise floors and the big steps you can take to ensure yours is as low as it can be, but in this blog I want to think further about that, and also give a few tips that could lower the amount of noise ingress that gets onto the recordings. This can be very useful not only if you’re planning and setting up your studio, but also if you need to work when you’re away from your studio – in a hotel room, staying with friends or family or maybe even just recording a quick demo on your phone for your agent (is that still a thing?).
Tip #1 – Choose your room
Let’s start with the most obvious one. You need to find the quietest and least reflective room available to you. But you also need to think around the edges a little. If you’re setting up a space that will be used for a longer period of time you might need to predict future noise levels as best you can.
Take a look out of the window, is there a school or a pub close by? How busy will that road get in rush hour? Also think about what’s on the other side of the walls of the room. Are you setting up next to a library, a bathroom or a drum-playing teenager’s room (do teens still play drums?)?
Tip #2 – Mic choice
There are a couple of things to consider mic-wise that can help lower your noise floor.
Firstly is the polarity of your mic
Polarity is the area in which the mic picks up sound – or the directionality of the mic. If you’ve done your homework you’ll know that it’s recommended that voiceovers use a cardioid mic, so-called because the active area looks vaguely heart shaped. It actually looks more like a kidney, but a renal microphone makes it sound like it might get shoved somewhere uncomfortable.
Cardioid mics pick up from the front and a bit less from the sides. An omnidirectional mic picks up from all round. This would correctly suggest that the cardioid mic will pick up less noise from the room we’re in than the omnidirectional mic would. There are other mics that pick up an even tighter angle. Hyper-cardioid and super-cardioid mics pick up a smaller area in front of the mic, but they do have a small active area at the back of the mic that the regular cardioid doesn’t. And we could even go right down to the shotgun mic that has a very narrow hot spot at the front of the mic and rejects almost all noise from the sides. These mics can be used in noisier environments with greater success than cardioids. But the trade-off is that it’s much easier to go off-axis with these mics, so you do have to keep stiller when you voice than you do with a cardioid.
The other thing you could consider is a dynamic mic
Dynamic mics convert acoustic energy into electrical energy different from how a condenser mic does, and the physical differences in the mic construction mean that dynamics aren’t as sensitive as condensers. This would mean less unwanted sounds getting picked up and getting onto your recordings. However, it’s not that simple. That physical construction that makes them less sensitive also means their high frequency response isn’t good enough for voiceover work, so they’re generally not recommended. The exceptions to that are the Shure SM7B or the EV RE20. These mics do have high frequency response good enough for voiceover work. Also, dynamics tend to have a lower output and higher self-noise than condensers, so you may well need to crank the gain up on your interface or get some kind of preamp or mic booster like a Cloudlifter or FetHead. So what you gain from less noise ingress, you may lose in higher equipment noise.
Tip #3 – Mic position
Having now thought about the mic we can get back to thinking about the room we’re recording in and using the mic’s directional properties to our advantage.
There will be a weak point in the soundproofing of a room. It’s likely to be a window or door, but not always. Once you ascertain where the weak point is you can set your equipment up on the other side of the room from the noisy bit. You can also set your mic up so the back of the mic (on a cardioid mic) is facing the weak point. This will ensure that the mic picks up as little of the noise that’s getting in as possible. This is all very well if there is only one weak point, but if you have a window and a door that are letting sound in then you may need to do some experimenting to find the point in your room that picks up the least unwanted noise. Even if you’re in a booth or booth-sized space changing the mic position can yield noticeable results.
Tip #4 – Work around the noise
This one may sound like an obvious statement, but this can genuinely be a part of your noise reduction schedule. If your noise ingress issues are predictable and not too constant then simply not recording during the noisy times can pretty easily be built into your work schedule. Don’t forget that you can edit perfectly well in a room that’s too noisy to record in, you needn’t just do admin or marketing during those times. It could just be once a week when the binmen are due or every day around the time the postman’s due because you know the dog will go nuts, but not voicing at these times would save you having to re-record. In my travels around the UK I’ve seen many examples of people who are quite successfully working around the noisy times. The most extreme was visiting a VO who lived underneath the final approach of Heathrow airport. They did all their voicing after 11pm. Not a solution that would work for everyone and no good for live directed sessions for UK or US clients but it was a solution that worked for that VO.
Tip #5 – Use a high pass filter
I’ve been saving this one for last because you all knew it was coming. I’ve written an entire blog about high pass filters, so you should go and read that (after finishing this one, of course) because I can’t be bothered to write it all out again. But I will say this (again) if you have your soundproofing sorted pretty well then the majority of your noise floor should be very low frequency noise, so the high pass filter can work very well to clean it up and knock your noise floor down a chunk. I’m honestly not joking when I say that I’ve seen a fairly gentle HPF lower a noise floor by 20dB. I’ve seen it more than once. It doesn’t knock things down that much all the time, but it usually does something. You can add a HPF in post, but if you have a HPF on your mic or interface you can engage it as you record and knock that noise out before it’s even recorded. And if you don’t have a HPF switch on your hardware you can buy one and add it between your mic and interface.
Tips to help lower your noise floor
So there you go. 5 things you can do which will help lower your noise floor and get you better quality recordings. And don’t forget that if you’re struggling with noise there’s a nice friendly person who you can get some help from.
How Rob can help you lower your noise floor
- Contact Rob for studio support
- Book a Power Hour with Rob
- Read: Noise floors – what are they and how to reduce them
- 1-2-1 sessions: Home studio consultation
- In-person home studio support: Studio Tickling Tours