Killer Interviewing Tips for Podcasters, Part 2
Pages: 1, 2, 3, 4

Removing Pops

If your guests aren't familiar with microphone technique, they will often create pops in the signal by speaking directly into the face of the microphone. Ideally you can prevent this by demonstrating some proper microphone technique beforehand, and by using a pop screen or windscreen.

If you find the pop during the editing phase (it will probably look like a spike or flat-top in the waveform), there are several ways to remove or reduce it. You can

  1. Use nondestructive volume envelopes
  2. Select the pop and change the level destructively (using the editor's Change Gain function)
  3. Select the pop and use a low-cut EQ to reduce the thump
  4. Snip a few milliseconds out of the pop sound

We'll demonstrate these techniques in a future article.

Avoiding the Up-cut

Speech styles vary from individual to individual, but you'll find certain patterns fairly often. One of these is a slight elevation in volume (or pitch) going into a short pause, the kind of pause that is represented in print by a comma. This is a speaker's way of letting listeners know that while they are taking a quick break, they still have more to say.

If you cut the audio right after the pause, you will have an audio fragment left that ends on a rise. That almost never happens in regular speech and it will sound very unnatural. It's a dead giveaway that you have made some harsh audio edits. Always work to avoid the up-cut.

Removing Periodic Noise

When it's impossible to turn off the air conditioning or the computer fan, you will have a complex periodic noise in your signal. Audacity has a periodic noise filter built in. But you may want to look at commercial products like BIAS Sound Soap if you have serious noise issues in your signal. (See Seven Steps to Noise-Free Digital Audio.)

Adding the Final Polish

To finish off the interview you will want to normalize the volume by using the editor's Normalize function, applying a volume envelope manually, or by using dynamic compression. Enveloping is particularly import and very easy to do in Audacity. The top part of Figure 11 shows a signal that starts soft and gets louder because the recordist boosted the input level during recording. Obviously it would have been best to have consistent volume, but the signal is what it is. The bottom part shows the same signal after it's been enveloped to normalize the sound from start to end.

Fig. 11: Volume Envelope

Figure 11. The original signal (top) gradually increased in volume as the recording engineer raised the input level. Applying a decreasing volume envelope (bottom) evened out the levels.

Because the overall volume of the signal was reduced, I also boosted the channel gain by 6dB to bring it back up into an acceptable range. Here's the finished result:

You may also want to add a small amount of reverb to add some depth to your voice or your guest's voice. All of these final polish steps should be applied only after the initial micro-edits are made to remove pops, ums, and other small problems.

One piece of editing advice that I live by is to always listen to the original and the new version of the audio after compression and reverb are applied, to make sure that you are making real improvements. Sometimes a natural sound is best.

Extreme Vocal Editing

Fuzzy Math

"Fuzzy Math," by the Bots, chops political speech into astounding new shapes.

Ed. Note: Although this article focuses on ways to get a natural sound through audio editing, Brian "BC" Coburn has taken vocal-slicing to extremes. At his George W. Bush Public Domain Audio Archive, Coburn painstakingly assembled and tagged some ten gigabytes' worth of phrases from political speeches. He then deconstructed that source material to produce the amazing presidential parody songs at

In "Fuzzy Math," George W. Bush appears to sing, "Now is the time to give corporations the people's money!" In the raunchy "Rock the House," Bill Clinton confesses, "I need sex with Ms. Lewinsky."

In many places the vocals flow so smoothly that you wouldn't know they were fake if there weren't techno music pumping along. I asked Coburn how he's able to chop up and recombine phrases so seamlessly, particularly with speakers like Bush who slur their words together. He sent back these tips. —David Battino

There are some simple techniques for producing good results with the Bush archive. Find a strong positive or negative statement. Look around in that same folder and see if you can find the perfect word to substitute for the subject of the original statement, so that it reverses the meaning in humorous fashion. For example, you find the phrase "I love freedom," and in that same folder, you find the statement "they are evil." Open the files in your audio editor. Cut the last word off the first phrase and paste in the last word from the second phrase. Save your new file ILoveEvil.wav and you will have a new and unique addition to your personal version of the database.

When editing and making your own phrases, you will have much better results if you match words from the same speech, rather than between speeches. In other words, find another phrase from the same folder before you start searching for keywords in the entire database. Because each speech was given in a different room, and under different conditions, words will more easily pair with other words that are from the same speech.

When people speak, words tend to run together. You will find many places where you can't cleanly edit that word you need from one phrase into another because the words are all running together. The pitch profile and duration may also change depending on where a word appears in a sentence. In the "I Love Evil" example above, notice that the edited words both appear at the end of the original phrases. Neither "freedom" nor "evil" was running into another word, because they're both at the end of the phrase. In general, words at the beginnings and ends of phrases are easier to work with.

If you have to use run-together words from the middle of phrases, try to find ones that are coming out of or going into the same phonetic sound as your target.

In your audio sequencer, create an envelope for your reverb send amount. You can smooth out differences in room tone between your samples by varying the amount of reverb send.

Learning from the Best

As with almost any skill, the easiest way to learn something new is to imitate someone who does it well. For emotional interviews, where you are telling a person's story, there are two great interviewers I'd recommend listening to, and you can hear them for free on the Web. The first is Tony Kahn of the Morning Stories podcast. Tony is a seasoned professional broadcaster who has rekindled his passion for people's unique stories using his podcast. He interviews an average person for an hour to get enough material for a five- to ten-minute podcast story.

The second master of the emotional interview is Ira Glass of This American Life. For an example of his work, listen to the "Squirrel Cop" segment that is archived on the site. He also does a long interview in person where he walks around with the person to get into their head as he tells their story.

For informational interviews I like to listen to Brooke Gladstone of On the Media. She is both an interviewer and an editor who aggressively edits interviews into a tight package that gets right to the point. On the flip side of that is Terry Gross of Fresh Air, where the banter is more jovial and the editing is a bit looser with longer gaps between questions and answers.

On the documentary side, you should check out the work of Errol Morris in films like The Fog of War. Morris uses super-long interviews (often ten hours) to get into as much detail as he can, then condenses it into a documentary narrative. Even though his medium is video, there is a lot to be learned from his use of contemplative pauses and expressions. All too often in interviews the guests are allowed to settle into a scripted answer. It's important for the listener to understand when you have asked a question that has gotten your guests off script and made them think.

You can also learn from interviews that you didn't like. When you turn off an interview, try to figure out what it was that made you switch off. Was it the guest? Was it the interview style? Was the interviewer too pushy, or phrasing questions in a way that limited the conversation? What questions would you have asked instead?

Good Night and Good Luck

All killer interviews have one thing in common—killer content. It's not the style of questioning, the voice of the interviewer, or the audio quality that matters. What matters is having an interesting topic plus questions and answers that inform and entertain. That is where you should concentrate your time and preparation. Know the topics that you are asking questions about and ask the insightful questions that illuminate those topics in compelling ways. If you do that, then people will listen through tin cans connected by shoestrings if need be.

Jack Herrington is an engineer, author and presenter who lives and works in the Bay Area. His mission is to expose his fellow engineers to new technologies. That covers a broad spectrum, from demonstrating programs that write other programs in the book Code Generation in Action. Providing techniques for building customer centered web sites in PHP Hacks. All the way writing a how-to on audio blogging called Podcasting Hacks.

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