How to Improve Your Audio Quality (for Podcasts & Audiobooks)

By MLNobre

Audio content can be divided into four categories:

Category 1: Bad Content + Bad Audio Quality;
Category 2: Bad Content + Good Audio Quality;
Category 3: Good Content + Bad Audio Quality;
Category 4: Good Content + Good Audio Quality;

You’ve worked hard to create good content. But good content deserves good audio quality.
So here’s checklist for you.

Follow it and get your yourself into category 4. Rise above the competition.

Rule 1. Use Proper Recording Equipment

Look, gear is not everything — if you buy a nice microphone but don’t follow the checklist, your sound will continue to suck — but it’s still important.To sound better, try this:

1.1 Buy a better sounding microphone

There are microphones that just.sound. good. They usually cost more money but if yourbudget allows you to buy a good professional microphone, go for it! (And here’s a secret: you can sound great with the affordable Shure SM58, if you pair it with a good preamplifier).

Even if your budget is limited, you can still improve your microphone. We researched some budget USB microphones and wrote two articles about it: how to record your podcast under 100 dollars and under 55 dollars.

1.2 Buy a quieter microphone / preamplifier

If you’re getting noise (not background noise, but electronic noise) in your recordings, you may be:

  • Using a condenser microphone with a high self-noise level. When buying a condenser microphone look for a self-noise below 18dB (A).
    The RØDE NT1-A is a paradoxical microphone in that regard. It is affordable but has the lowest self-noise on the market, only 5 dB (A). Such low self-noise is worth thousands of dollars. Yet, it’s price tag is way below that.
  • Or you’re using a dynamic microphone with a cheap noisy preamplifier. Dynamic microphones have no self-noise but require a lot of gain from the preamplifiers they connect to. And those preamplifiers produce noise themselves. If this is happening to you, get a better preamplifier. The Focusrite Scarlett 2i2 is an affordable USB audio interface with clean preamplifiers.

1.3 Buy a microphone with better background rejection

Microphones have polar patterns, which determines how they record and reject sounds.

  • An omnidirectional microphone records sounds from all sides and rejects no sounds. If you’re using one of these (such as a lavalier microphone), you may need to upgrade to a more directional polar pattern;
  • A cardioid microphone rejects sounds from the back;
  • A super-cardioid microphone rejects more lateral sounds than the cardioid but records a bit from the back. You can get a better background noise rejection with a supercardioid microphone than with a cardioid, if  you know how to position it appropriately.

Finally we have:

  • Shotgun microphones: these are highly directional mics, rejecting lateral sounds. We would argue that they may suffer from the same problems of other small diaphragm condenser microphones (see below), but the fact is that many professionals in the industry use the Sennheiser MKH-416 for voice work while managing to get great results.

1.4 Avoid Small Diaphragm Condenser Microphones

Small diaphragm condenser microphones (aka pencil microphones, due to their shape and size) are great for many applications,but for voice work they suffer from two problems:

  1. They react to very fast sounds. This makes them very detailed in higher frequencies. Unfortunately, this also means that mouth/tongue sounds become more prominent in the recordings.
  2. They are very sensitive to pops/plosives (explained below).

The solution is to buy a large diaphragm condenser microphone or a dynamicmicrophone.

1.5 Use a Pop-Filter

Don’t record yourself without a pop-filter. Pops make you sound unprofessional. This is what a ‘pop‘ sounds like:

Avoid this by putting a pop-filter in front of your microphone.

Rule 2. Record Near the Microphone

When you’re recording yourself, there’s a powerful Physics law at play: the inverse distance law.

In practical terms, this law means that as you get closer to the microphone, the separation between you and the background noise increases exponentially! This is an extremely powerful piece of information.

The graphic below helps to visualize better what happens to the voice and background noise levels as you get closer to the microphone.

Simply stated: the closer you record to the microphone, the less background noise you get.

And as you do that, you also get something called the proximity effect: a boosting of the low frequencies of your voice. This may be desirable if you want to add ‘weight’ to your voice. Just make sure it doesn’t become overbearing! If that happens, back away a little bit.

Rule 3. Set your Levels Rights

Record yourself with the proper levels. You do this by making sure the levels are, on average, hitting somewhere between -24 and -12 dB. The image below shows you how it looks like:

Why -24 and -12 ? Because:

  1. If your levels are hitting numbers above-12dB on a regular basis, it means that you are leaving no room for any unpredictable louder words/laughs/etc. If these happen, they will most certainly hit the 0dB ceiling and be recorded with distortion.
  2. If your levels are recorded way below -24 dB, you will need to bring your recording levels up afterwards (a process known as normalization) to be able to hear your voice. But doing this will also expose all the low-level noise that would have never been heard, had not normalization been applied. Take a listen to this extreme example:

Rule 4. Record in a Quiet Space

We’ve talked about two ways to reduce background noise:

  1. Choosing an appropriate microphone polar pattern.
  2. Recording closer to the microphone.

But do you know what beats that? Having no background noise at all!

So let’s divide background noise into three categories and see what can be done to reduce it:

4.1 External Noises Beyond Your Control

Normally, you can’t silence these sounds. They include traffic, birds, dogs, children playing outside, other city noises and so on. You have three choices to deal with this:

Time: choose another time to record, when things get quieter. This typically will be at night.

Space: record in another location where there are no external noises beyond your control.

Soundproof your room: this is not realistic for many people but it’s still a solution and should be mentioned. It involves re-building your room to accommodate for soundproofing solutions (sound isolating walls, doors, windows, etc).  

4.2 External Noises Within Your Control

If you can silence a background noise, you must silence it. These include fans,roommates, TVs, etc.

A common problem for people who record themselves is their computer fans. There are three things you can do about this:

1. Turn off the computer fans while you’re recording;

2.Buy a silent computer tower + silent PSU,

3. Buy a portable audio recorder and record yourself with the computer turned off.

4. Also, use the microphone polar pattern in your favor: point the rejecting areas of the microphone to the computer fans.

4.3 And finally, the last source of background noise: You…

Most people are conscious enough not to make unwanted noise while recording, but some are not. We’re talking about paper rustling, keyboard and mouse clicks and squeaking chairs, stomach growls and so on.

These sounds are fine if they happen when you’re not talking – they can be removed easily.

But they must never, EVER occur while you’re talking. If it happens, re-do the sentence

Rule 5. Record in an Acoustically Dead Room

This means recording in a room without noticeable reverberation (what most people call echo).

Some rooms are more reverberant than others.
A room itself can have some spots that are more reverberant than other spots.

Being aware of those spots is important.

But to truly achieve good professional results, you need to add sound absorption to your room:

  • Avoid empty rooms with bare walls. Curtainssofas, mattresses and thick carpets all help to absorb some sound.
  • Buy some absorption panels and position them in strategic positions (your sides, behind you, above you). Doing this will dramatically deaden your sound (in a good way).
  • If you feel free like taking your sound absorption to the next level, we recommend the book Acoustic Design for the Home Studio, since it has all the information you need to get started, and it’s also a pragmatic book. Alternatively, search around the web for some articles – there’s a lot of good info out there.
Sound Bunker / Sound Booth

A quick and dirty solution…

Do you need a quick anddirty solution to get by until you buy real absorption panels? Cover yourself and the microphone with a heavy blanket. A few years ago we had to improvise an ‘acoustic bunker’ for a vocalist. It didn’t work too bad…

These are the 5 rules. Follow them to sound better.

And let us know the results: leave a link to your podcast / audiobook in the comments to show us!