There are many ways to screw up a podcast recording Electronic hum, bass hum, bass rumbles, pops, clicks, distortion caused by clipping, and so on. And there are multiple ways to fix these issues. Some are easy, some aren’t; some free and some cost a lot of money.
I’m going to start a series of episodes covering how you might fix poor recordings.
Let me start by saying:
An ounce of prevention is worth a pound of cure!
Always do your best to make sure you DON’T have issues with your recording.
Monitor your recording for its entirety, or in part to make sure everything sounds good.
And here’s another idea:
If it’s really bad, record it again!
Even if you have to interview someone a second time, give it a shot! If it’s really bad, it’s not worth fixing.
On the other hand if the interruption is short don’t worry about it! Unless it’s going to hurt your listener’s ears (in which case just cut it out, or bring the level down) then just let it go. You don’t have to worry about every little sound. Even in this podcast I let little things go. And I’m extremely obsessive when it comes to audio engineering.
If you practice prevention, re-recording when it’s really bad, and letting little mistakes slide you’ll be just fine 98% of the time.
And if you’re following my blueprint for podcasting prevention will be really, really easy.
But so will post-production repairs! So, in those cases where you do need to fix up your audio you will be in good hands. You’ll have plenty of space to work with your recorded file – because you’ve recorded at a great level, you’ve separated your signals into different tracks while recording, and you’ve done all of this with little recourse load on your computer by the way.
So, in this case, you’re ready to repair your audio. But let me tell you, by the time I’m done you may think to yourself, “ugh, it sounds like I should just record this again, or forget about it.”
In today’s episode I want to take a look at fixing consistent background hum, because this is the easiest thing to do deal with in most cases.
Background low frequency hums, and some electronic hums will be relatively easy to eliminate with the right tools – but unless you’re willing to pay between $100, and somewhere in the thousands, there’s going ot be a trade off. Your background noise may be reduced, but your foreground noise will sound a little funny. I’ll give you an example in a minute.
Noise reduction, low-cut, and proper gating
I’m going to briefly describe the tools and how they work, but I will also release some free video sessions.
If you’re following my course you already know about using low-cut to reduce low frequency hum. Use an EQ plugin – there are free EQ plugins available online, and I show exactly how to use some of them in my course – to roll off the low frequencies until you’ve heard that the frequency containing the hum is low enough as to be inaudible. Again, I suggesting using the built in low-cut in the Zoom H6. That will take care of this issue before it becomes a problem. However, this can lead to this particular recording sounding a lot different than your other recordings.
The second tool you can use is noise removal, or noise reduction. You’ll find these tools in Adobe Audition, and Audacity, among other DAW. There are also noise reduction plugins you can purchase that work very well, but are generally very expensive.
Some of these tools work in different ways.
Fader-based noise reduction plugins
Some are fader-based, and set a threshold for each band, so that they can apply noise reduction that has no noticeable effect on the sound quality…but these are quite expensive (thousands of dollars) and are used mostly by hollywood studios.
Perhaps close to your price range is the WNS Noise Suppressor for $500. It doesn’t work as well, but it’s an attempt too offer a similar product at a reduced price. It works on both windows and mac. It’s a great tool in my opinion, but out of the price range of most podcasters. You simply use the faders to apply reduction to various frequencies of your choosing. It has a release, which controls the speed at which the noise reduction is released once the volume level falls under a certain threshold. If you use a plugin like this just save the settings for your own voice, and it should be ready to use again in similar conditions.
when using plugins like this you want to set the threshold high, at first, and then work your way down. So -5db for example. The threshold, as usual, tells the noise reduction at what level the noise reduction should kick in. For example, if it’s set at -5db then the noise reduction will kick in when the level of that frequency reach -5db.
The W43 Noise Reduction Plugin works similarly, but not as well. It is a bit easier to use. It’s $143.00.
Another option is the Z-Noise plugin. You have to adjust the threshold and the noise reduction amount until the frequency you’re trying to reduce (in this case the lower frequencies) sounds right. What’s nice about this plugin is the “difference” option that allows you to hear just the part of the frequency that you’re reducing. you can also adjust the attack and release, and I would set the attack as quickly as possible.
Then there’s the Waves NS-1 plugin. This is going to be the plugin of choice for most podcasters for 3 reasons:
1) Ease, and speed – There’s only one knob. A single fader that controls the amount of the effect.
2) Price – It happens to be on sale right now for $50.00
3) It works well on vocal audio (as opposed to music)
Here’s a sample. If you listen closely you can hear when the Wave rep who made this audio recording turns the plugin effect off, and on. You’ll hear the difference.
These sorts of plugins can be used to process live streaming audio without using too much system recourses.
Graphical Noise Reducer Plugins
There are other plugins for reducing consistent background noise. They’re known as Graphical Noise Reducers. They’re used more in misc production, they’re not to be used in live streams (because they will eat up system recourses), and they often have a noticeable effect on the foreground audio. So your voice will end up having a warbling sound to it if you add too much of these effect. In some cases this can end up sounding worse than the original audio recording.
When using these plugins you highlight a sample of only the noise you want to reduce from your audio recording. Then the plugin uses that voice as a basis from which to apply the voice reduction to the rest of the audio recording. Some of the plugins in this category include: iZotope RX series, Wave Arts’ MR Noise, the Sonnox Oxford DeNoiser, and Z-Noise. Audobe Audition, and Audacity also have versions of these kinds of plugins.
The iZotope RX series of plugins are the best of the Graphic
al Noise Reducers. As I mentioned earlier, you’ll select a part of your audio with just the background noise audible. This creates a profile that the plugin will use to determine how to reduce that noise. Select the “best” option form the Algorithm drop down list. Select “learn” once you’ve selected your audio. Then turn up the noise reduction knob, and preview a section of the audio with you talking aver the background noise. Play with the noise reduction fader, and the smoothing fader (which is just a release fader – the kind I mentioned earlier) until you’re satisfied with the sound and are ready to apply the effect.
This is all done with the “denoise” section of the plugin. This plugin handles other audio issues as well, but we will cover those on another show.
Just be sure not to turn up the noise reduction too much! it will make your voice sound really strange.
The noise reduction features in Adobe Audition, and Audactiy work similarly, but aren’t nearly as good in my opinion. However, many podcasters use them.