Download: MP3 (38.4 MB)

One of the ways to stand out from other podcasts is to pay attention to sound quality. One of the ways to get good sound quality is to have a great microphone and a quiet room to record in.

Depending on the room you’re in, you may hear echos from your voice (either in the low-mid frequency range, or in the high end). Echo becomes especially apparent if you’re recording with a condenser microphone instead of a dynamic mic.

Background noise and room echo creates a poor listening experience for your audience. They may get distracted from what you’re saying or annoyed by the constant reverb or background noises.

You don’t want listeners thinking about the noises in the background or the way your room sounds; you want them to focus on your message.

Eliminating background noise and room echo will give your recording a more professional sound. It will be more pleasing to listen to. Your audience won’t hesitate to share it with their friends.

That’s my goal for today’s episode; to help you get better sounding recordings.

Highlights, Takeaways & Quick Wins:

  • Eliminate background noises before you hit record. Turn off fans, AC, or heaters, and set your phone to airplane mode.
  • Listeners notice sound quality. Background noise and room echo is distracting and degrades the listening experience.
  • If you have a noisy room or a room with a lot of echo and you can’t treat it, record with a dynamic mic instead of a condenser.
  • Some materials are more sound absorbent than others. Look up Noise Reduction Coefficients (NRC) numbers before buying materials to help absorb sound.
  • It’s possible to improve sound quality a little bit with post production, but it’s better to fix the problems before recording.

Show Notes:

  • 2:35 I’ve noticed that a lot of people struggle with room echo and background noises, so I wanted to do this episode to help you start taking steps towards inproving the quality of your recordings.

Sound Proofing and Sound Treatment

  • 3:01 Sound Proofing is the process of sealing your room so that outside noises don’t get recorded by your microphone. This is normally done by installing special sound-absorbing fiberglass or mineral wool in the walls, floor or ceilings.
  • 4:02 You may not have much control over how sound proof your room is, but there are some things you can do to control the sounds being created in your space.
  • 4:08 Eliminate as much excess noise as you can.
    • If you have loud AC or heating, turn it off while you record.
    • Turn off notifications on your computer and phone.
    • Set your phone to airplane mode.
    • If you have pets, put them in a kennel or in a room far away from where you’re recording.
    • Put up a sign to let people know you’re recording.
    • Throw a thick blanket by the bottom of the door, or cover your windows to help reduce noise coming in.

Eliminate background noises before you hit record. Turn off fans, AC, or heaters, and set your phone to airplane mode.

  • 6:33 Sound Treatment is treating the way recordings made in the room sound by adding things like sound-absorbing foam panels, bass traps, and sound diffusors to prevent annoying low or high end reflections (reverb or echo).

The Different Kinds of Echo

  • 7:04 Standing waves happen in rectangular rooms when a sound wave bounces off one wall, then back and forth between the two walls until the energy dissipates. This is most common in low-end frequencies, but can happen in high frequencies as well. Too much energy in the low-mid range (200-500hz) can cause a track to sound muddy or boomy.

Listeners notice sound quality. Background noise and room echo is distracting and degrades the listening experience.

  • 7:43 Flutter Echo is a ringing sound caused by sound bouncing off of parallel walls. You’ll hear this in the high-end of the frequency range.

Choosing the Right Room to Record In

  • 8:09 We don’t always have a choice about the room we record in. When I started recording the seanwes podcast back in late 2013, I was recording in my “office” (which is just my dining room with a standing desk). It’s a small room with only a little furniture in it, so there was quite a bit of flutter echo in my recordings. I tried to compensate for this by bringing in some big couch cushions. I ended up moving to a spare bedroom and building some sound absorbing panels to help with the reflections.
  • 9:42 My spare bedroom still isn’t a great room to record in. I need to do more to treat the echo (it’s on my to-do list).
  • 9:58 The ideal room will actually be a room with quite a bit of stuff in it. Furniture like chairs, couches and bookshelves can all help absorb and diffuse sound waves.
  • 10:26 “Pretty much every room has its own sound, when you walk in the room, there is an enormous amount of factors that control what that room sounds like. The size of the room, the materials that make up the floor, the walls, any furniture in the room, all these things affect the sound of that particular room.” – Joe Gilder, Home Studio Corner

The Kind of Mic You Use Matters

  • 11:03 Dynamic microphones are less sensitive to background noise and reflections, but they do require more power than condenser mics, so you’ll need a good preamp or interface. I’ve found the SM58 works fine with the Scarlett 2i2, but the Shure SM7B need a lot of gain and the 2i2 has just barely enough to power it. If you’re going to buy a SM7B, it’s also a good idea to pick up a tube preamp or another preamp/preprocessor like the DBX-286 to provide additional gain to your SM7B.
  • 12:32 Condenser microphones are more sensitive, more detailed, but they pick up EVERYTHING. So if you have a perfectly treated room with good acoustics, a condenser mic will give you great sound. If you are in a room that hasn’t been treated and soundproofed, you’ll run into problems.

If you have a noisy room or a room with a lot of echo and you can’t treat it, record with a dynamic mic instead of a condenser.

  • 13:10 When I first started recording the seanwes podcast with Sean McCabe, I was using a Shure PG42. It’s a good USB mic, but I was recording in my dining room, so there was a lot of echo. If I had known then what I know now, I would have sold the PG42 and switched to a dynamic mic.

Mic Technique for Podcasters

  • 13:38 Mic technique is another big part of how much room sound you’ll hear in your recordings. The further away from the mic you are, the more room sound you’ll hear. You should try to stay between 3 and 6 inches away from your mic while recording.

How to Treat Room Echo

  • 14:45 I learned something new while doing research for this episode. It’s called NRC (stands for Noise Reduction Coefficient). The NRC is a single-number index determined in a lab test and used for rating how absorptive a particular material is. So 0 is not sound absorbant at all (complete reflection), and 1 is perfect sound absorption (no reflection). Here are the noise reduction coefficients numbers for some common materials:
    • Brick, unpainted .00 – .05
    • Carpet, indoor-outdoor .15 – .20
    • Cork, wall tiles (1″ thick) .30 – .70
    • Drapery, light weight (10oz.) .05 – .15
    • Fiberglass, 3-1/2″ batt .90 – .95
    • Fiberglass, 1″ Semi-rigid .50 – .75
    • Marble .00
    • Plywood .10 – .15
    • Moving Blankets 0.3 – 0.5

Some materials are more sound absorbant than others. Look up Noise Reduction Coefficients (NRC) numbers before buying materials to help absorb sound.

  • 17:18 If you’re interested in buying sound treatment materials, here’s what you need to know.
  • 17:37 1. Egg Crates. Almost worthless for low end frequencies, but decent for absorbing frequencies in the mid and high mid ranges. Pretty ugly, so I’d suggest buying acoustic foam instead.
  • 18:17 2. Portable Sound Shields. The idea here is to have a shield wrap around the back of your microphone to stop your voice from reflecting off the wall in front of you and bouncing around. These work well (from what I hear) and start at around $50.
  • 19:15 3. Furniture. Bookshelves, desks and couches/chairs can all help with sound absorbtion/diffusion, depending on the material they’re made out of.
  • 19:47 4. Blankets. Most blankets are only going to absorb the high end frequencies, and only if they’re thick. A good thick duvet will be your best bet.
  • 20:13 5. Carpet. Carpet can help a little. Thicker is better, but don’t expect too much.
  • 20:24 6. Bass Traps. Bass traps are usually wood frames with a lot of sound-absorbing mineral wool or fiberglass, usually at least 3 inches thick for absorbing extra low end frequencies. Very commonly places in the corners of a room.
  • 21:06 7. Sound Diffusors. Sound diffusers are designed to scatter or disperse sound by using irregular hard surfaces to break up and scatter the sound waves. So imagine a table top covered with pieces of two by fours cut to various heights, that’s what most sound diffusion panels look like. You can buy these online or build them yourself.
  • 22:35 8. Acoustic Foam. Most acoustic foam doesn’t do anything to stop low frequencies. It’s a high frequency absorber. If you hear a lot of flutter echo in your room, you can invest some money in some acoustic foam panels to help treat it.

DIY Solutions

Fixing Echo and Noise in Post Production

  • 24:30 You can use EQ to remove or reduce certain frequencies, 400hz for example. Listen to your recording and try to identify the frequcies where the room echo is most noticable, and then cut a couple db. Be careful not to remove too much; that will make your voice sound unnatural.
  • 25:40 Izotope’s new RX5 audio editing software comes with a de-reverb feature. It’s not a cheap solution ($299), but worth it if you want to be a professional podcast editor, or if you want to reduce the amount of echo in your recordings and you can’t do any acoustic treatment in your room. RX also comes with a fantastic dialogue denoiser (which I’ve mentioned many times before because it’s awesome).

It’s possible to improve sound quality a little bit with post production, but it’s better to fix the problems before recording.

  • 27:21 If you’re having problems with buzzing or other electronic noise in your recordings, you may have a problem with your power supply. Buy a Furman power conditioner ($60), plug your computer and audio gear into that, and see if that solves the issue. If it doesn’t, you may have faulty recording equipment or cables.

Q&A

  • 33:22 Kelsey asked, Can you discuss room noise related to living near an airport and frequent thinderstorms?
  • 33:29 Sound proofing is going to be your best bet here, but it’s going to be challenging because you’ll have to do some major construction to sound proof a room. Some people build a “floating room”, which is a room frame inside a room to make it more sound proof. You can read more about that here. Other than that, I would suggest learning more using post-production to fix or remove background noises. Something like RX4 has some great tools for fixing background noise.
  • 38:06 Terence Tang asked, Without A/C or fans on, it gets hot in the room. For podcasting, it’s fine because you can’t see the person sweating, but what about with video? I don’t want to be drenched in sweat on camera. Any suggestions?
  • 38:25 First; are you sure your viewers don’t want to see your drenched in sweat? Seriously though, you can buy a quiet fan to help push some air, or just run the AC at full blast until right before you hit record. If you’re recording with a shotgun mic, place the fan directly behind mic.

Addtional Reading: