Podcast Audio Production Explained: Space, Equipment and Mixing
In many ways, audio recording and production is a magic trick. The rich, deep tones you're used to hearing on high-quality podcast productions don't sound like a person talking to you in real life, in the same way a band playing in a pub doesn't sound like they do on a record. Audio production is about tricking your brain into receiving audio in a pleasing and elevated form, pushing it beyond the everyday to draw out qualities that immerse the audience.
For example, on an audiobook or a true crime podcast, you might want a detailed, close sound that gives a sense of intimacy, like you're hearing a secret told in hushed tones. For a news or documentary podcast, you might want more of the ambient sound of the environment to bring the audience into the scene, while keeping the dialogue clean and even.
So how do you achieve this? Audio production relies on three key things, which we'll look at in turn: Space, Equipment and Mixing. Each impacts the other, but if you learn to consider each individually, the sum of the parts will always improve your audio production.
Space
Always at a premium in modern cities, this is the part of the equation you sometimes have the least control over. Studio environments are typically designed to be quiet and produce even recordings. Fitting studios out this way has never been more expensive, so top audio environments come at a premium. They're achieved through a combination of sound-proofing (keeping other sounds out of the recording space), absorption (reducing reverb in the space), and diffusion (allowing sound to reflect in a more natural way).
If you're recording at a professional studio space like Bison’s podcast studio, this is taken care of for you. But if you're recording at home, or in another space you have access to, you can still adapt it to make it suitable. Sound-proofing often isn't possible, but you can usually choose a space that's naturally quieter. A room at the back of a house is often calmer than one at the front. Choose a meeting room that isn't next to a main corridor. Once you've found the right room, think about lowering what we call the "noise floor", all the other noise that isn't what you want to record. Close windows and doors, turn off appliances that hum, and remove jewellery or anything else that might make noise on a recording.
Secondly, think about reducing reverb in the space. Reverb is the reflection of sound from a room. When your voice bounces around and comes back to a microphone, it arrives later than the original sound, which we hear as reverb. Depending on the reflections and the energy involved, that delay, known as decay, may be longer or shorter. The aim is to reduce decay time. Choosing your space wisely goes a long way here. A large, hard-floored space with hard surfaces (like a kitchen or bathroom) will significantly increase decay time. Small spaces with soft furnishings and carpeted floors (like bedrooms) absorb sound energy faster, and naturally reduce it.
Equipment
A few quick pointers to help you get started. There are three main types of microphone you might use for podcasting or content: dynamic, condenser and lapel.
For podcasting, dynamic microphones are the default. They reject environmental noise well and produce a professional, rich sound, particularly up close. Famous dynamic microphones include the Shure SM7B and the Electro-Voice RE20 (which we use at Bison). The downside is that you need to be close to them, and they're limited in the amount of detail they capture.
Condenser microphones, such as the Neumann TLM103 (also used at Bison), give you excellent detail and are perfect for voiceover or audiobooks. However, they reject far less sound, so in a poor space you'll hear more of the room. Use two or more microphones for a podcast and you'll also get more bleed between them.
Lapel mics are excellent for on-location and video podcasts, though unless you're using high-end equipment, quality can vary. They also leave you open to mishaps: talent accidentally knocking them, noise from clothing, and bleed between mics.
Each type has its pros and cons, and knowing when to choose the right microphone for the space is the trick. You could have the most expensive microphone money can buy and still be disappointed if the space it's in isn't right. An experienced engineer with a £100 microphone will produce better results than an inexperienced one with a £1,000 microphone in the wrong room.
Beyond the microphone, you'll need an interface and a digital audio workstation (DAW) to record the audio, a whole subject in itself. But work to your own level. A USB-C mic plugged into your iPhone will produce great results in the right setting.
A note for video podcasts: it's tempting to think that once there's something to look at, audio matters less. In practice it's the opposite. Poor audio instantly undermines the whole production, distracting the audience, and it's far more likely to make someone switch off than a slightly soft shot, or messy set. If you're investing in video, it's worth investing in the sound to match.
Mixing
We have extensive experience mixing and editing for a range of podcast, audiobook and commercial productions, and you can find more information about our audio production services here. Much like cooking, mixing depends on the quality of the ingredients and tools you have. If you have two individual channels of a well-recorded podcast in a quiet, close space, your job as a mix engineer becomes not only easier, but more rewarding, because you can really make that audio shine. If you receive something more difficult, most of the work may be about moving it up to an average level.
Going back to the magic trick, there are a few tools which are used on every podcast recording. EQ, to balance frequencies, giving a voice more or less bass and air, or reducing resonant frequencies. Compression, to level out the volume of a voice over time. De-essing, to reduce sibilance. Noise reduction, to isolate the voice from other sounds in the environment. Limiting, so the audio never clips when it's brought up to a broadcast level. All of these trick your brain into hearing a voice as close, full and rich, allowing the listener to focus on the content, communicated with authority and clarity.
AI-powered tools have made real progress on some of the grunt work in audio production. As a company at the forefront of content production, we use AI routinely in everything we do. But it takes experience and trained ears to know when AI is actually elevating content, rather than just processing it. Used well these tools are genuinely useful for speeding up a workflow, but they can't create detail that was never captured. AI may make a poor recording sound passable, but good mixing still starts with good recordings, which requires well thought out space, equipment and recording technique.
The Takeaway
Space, equipment and mixing all work together. Get one wrong and the other two are working overtime to compensate. Get all three right, and the audience never thinks about the sound at all, they feel what you want them to, and get pulled into what's being said. That's the invisible hand. The trick.
Learning to produce great audio can be a long journey, so if you'd rather skip the DIY, or need support for your project, get in touch and we'll work some magic for you!
