Understanding the Recording Environment

Understanding the Recording Environment
So far we've spent the entirety ogling all kinds of cool audio equipment that will produce higher-quality podcasts. However, there's a very important element that we haven't even touched on: your recording environment. Any audio engineer will tell you that the environment is a huge contributing factor to the quality of your production. All recording studios are specially built to provide an environment where things sound good.

Building recording studios is very skilled work, because recording studios must be capable of recording anything that walks through the door, from audio books to rock bands. For podcasting, we're trying to create a neutral environment, so that the sound of the guest's voices cut through. The last thing you want to hear is the sound of the room you're recording in.

A classic example is the sound of bathroom tile. We all sing in the shower because the highly reflective tile surfaces around us reflect our voices back to us, bathing us in a sea of reverb. Everyone knows exactly what a bathroom sounds like. You can't record in there, because folks will know you're recording in the bathroom!

The same goes for small closets or even small offices. Our ears detect the size of rooms by the reflections we hear. Think about that the next time you're stuck on a boring conference call. You can tell in a split second how big the room is on the other side of the call, and the sound quality is almost always horrible. That's because offices with whiteboards, windows, and big wooden tables have lots of reflective surfaces that fill the room with reflected sound, which is what makes it hard to listen to for long periods of time.

What you really want is a room that is nice and quiet, one that doesn't have too many reflective surfaces. If your room doesn't sound good to start off with, it's not too hard to make it sound much better with some sound treatment.

Sound treatment
If you've ever been inside a radio station, you know that the studios are nice and quiet. If you look around, you'll notice that the walls are treated so that they absorb sound. They have to be built this way, because there are microphones all over the place and all they want to broadcast is people's voices — not the sound of the room. Because you probably don't have the money to build a studio from scratch, you can do the next best thing: Use acoustic panels to treat your walls.

Acoustic panels are large pieces of foam or some other sound-absorbing material (see Figure 1). These panels are attached to walls and ceilings to reduce the amount of sound that is reflected. This makes the room sound neutral, because no sounds are reflected to give our ears a sense of space. Consequently, the sound going into your microphone is just your pristine voice, and nothing else.


Figure 1: Acoustic tiles can turn a terrible sounding room into a great recording environment.

You can do other things to improve your environment, some of which are just common sense. For example, if you're recording a conversation around a large table, place a tablecloth on the table. Not only does the tablecloth damp down any reflections from the tabletop, but it also absorbs noises like people putting coffee mugs down, tapping pens, and doing lots of other distracting things. If your space has windows, consider buying curtains and closing them when you're recording. Anything you can do to minimize large reflective surfaces will help.

Studio layouts
If you're going to create a dedicated space for your podcast production, take some time to think about how you're going to use it. You should consider different studio configurations, depending on how you're going to produce your programming. The simplest is a single operator studio.

Single operator
If you're going to be the producer, engineer, and star of your own podcast (of course), then you're probably going to do everything in the same room. You need enough space to accommodate all the equipment you've accumulated after reading this post and enough space to accommodate however many guests you plan on having. Remember that your guests probably will want some table space of their own to put their coffee, their laptop, and whatever else they've brought along. Make sure they have access to power, because they'll want to recharge all their gadgets during the podcast. (Make sure they turn off their cell phones.)

Be sure to have your equipment mounted in a special rack, or on a separate table, to protect it from spilled drinks. Equipment racks often have the added benefit of being on wheels, so when your production is finished, you can roll the equipment out of the way until the next time.

Another thing to consider is the noise generated by your computer. If you're using a modern desktop machine with a high-powered processor, the noise made by the cooling fans may be picked up by your mics, particularly if you're using condenser mics. It's best to minimize this as much as you can. One good approach is to replace the standard fans and power supplies with low-noise versions available from vendors such as PC Power & Cooling (http://www.pcpowercooling.com). If you don't feel like shelling out the extra money for quiet fans, you can reduce the amount of noise picked up by your mics by moving the offending machine as far away as possible. You also can attenuate the noise with acoustic foam or small baffles.

Talent + engineer
If you're fortunate enough to have some help producing your podcast, you may want to consider setting up a studio where the talent (meaning your guests and you, the interviewer) is in a separate room from the equipment. This accomplishes a few things. First, the audio engineer works without worrying about keeping absolutely quiet. Second, audio equipment can be somewhat intimidating to some people, so doing the interview in another room can sometimes make for a more relaxed, natural interview.

Recording on an iPod?

Yes, in fact you can record on your iPod. However, there are a few drawbacks. If you're using an older iPod model (non-video model), they can record only 16-bit, 8 KHz files, which is basically telephone quality. This is fine for memos to yourself, but it's not broadcast quality. The newer models can record broadcast quality, but be careful because these high quality files are uncompressed .WAV files. WAV files require a lot of hard drive space and consequently burn through battery power because the hard drive constantly spins during the recording.

To use your iPod for recording, you need to purchase either Griffin's iTalk or the Belkin Universal Mic Adapter. (Note that these devices are not compatible with all iPods.) They're cheap, and they're ultra-portable, so it's not the worst idea to carry one around so that you can grab an unexpected interview when you're traveling.

Of course, if you're feeling brave, some very clever people have figured a way around the crippled recording capabilities of the older iPods. However, this isn't just a special sequence of keys you have to press. If you want to record pristine 16-bit, 44.1 KHz audio, you have to install Linux on your iPod.

Yes, you read that right. Some very clever people have figured out how to run Linux on an iPod, and it includes the ability to record. Needless to say, this is not something your authors can heartily recommend. In fact, forget you even read it here. We don't want any e-mails from people who break their iPods.

Podcast: Signal processors

Audio production techniques that you can use to optimize your podcast. These can be done using either hardware or software. Software is convenient because you can use presets or create customized settings for your podcast that you can use every week. Even more useful is the ability to "undo." However, sometimes hardware processing is handy. You can't beat the feel of real knobs, and who wouldn't like more flashing lights in his studio? A couple of hardware processors are shown in Figure 1.


Figure 1: Signal processing units: Presonus Comp16, EQ3B

Equalization (EQ) units
Equalization is a process whereby tone is altered by boosting (turning up) or attenuating (turning down) certain frequencies. The bass and treble knobs on your car stereo apply EQ. Most mixing desks include simple EQ, but you may want finer control of your tone at times. In this case, you'd buy an external EQ unit. You also can use EQ units to fight feedback problems (refer to the "Feedback: What It Is and How to Avoid It" sidebar).

Compressor
Audio compressors help control your audio levels. Compressors turn audio levels down when they cross a certain threshold. They're incredibly useful because they protect your equipment from distortion due to abrupt level changes — for example, if one of your guests suddenly starts yelling. You can place a compressor between your mixing desk and your audio interface as a protective measure or compress your input channels individually.

Effects units
Effects units enable you to add special effects to your podcast, like echo and reverb. Effects are often used in music production to make the band sound like they're playing in a large hall or club. For most podcast material, this simply isn't appropriate. If you listen to the radio carefully, you'll notice that special effects are used sparingly, and even then only on the "bumpers" (the show announcements) or on advertisements.

Audio interfaces
At some point, your analog audio signal must make the transition between the analog and digital worlds. This can be done at various points in your signal chain. Once upon a time, the only way to get sound into your computer was via a soundcard, but that is no longer the case. Audio interfaces can connect via USB and FireWire, mixing desks come with built-in audio interfaces, and you can even buy USB mics.

Soundcards
Virtually every computer sold these days comes with some sort of audio interface. Usually, there's a headphone and/or speaker output, a microphone input, and a line level input if you're lucky. The problem is that these soundcards are usually built with really cheap components and are low quality. Microphone inputs on soundcards tend to be very noisy. They're very vulnerable to electrical interference (of which there's plenty inside a computer). In general, you should avoid using the mic input on a soundcard.

This doesn't mean that you can't produce a podcast using whatever soundcard you're stuck with. Hey, the idea is to get podcasting as quickly as possible, right? If you must use the soundcard that came with your hand-me-down computer, and if you must use the microphone input, go right ahead. Just remember that when you decide it's time to improve the audio quality, the soundcard is probably the place to start.

Plenty of good soundcards are available today. You should look for a soundcard that uses professional 1/4″ or XLR connectors, because they're far more reliable and resistant to noise. Many soundcards these days come with a breakout box that you can place on your desk or a shelf, so you don't have to crawl behind your computer every time you want to plug something in. Check out the example in Figure 2.


Figure 3: Soundcard with breakout box: M-Audio Delta 44

External audio interfaces
Another way to get digital audio into your computer is to use an external audio interface. This type of stand-alone unit connects to your computer via USB or FireWire. Until recently, only a few of these were available, but now you have lots to choose from. One nice thing is that most of these units come bundled with tons of great recording tools, so if you don't have an audio editor, you might consider picking up an external audio interface just to get the software!

Like soundcards, external audio interfaces come in many shapes and sizes and have different features, such as number of inputs and so on, like the ones shown in Figure 5.14. One thing to consider is power; most of these units run off the power supplied by the USB or FireWire bus, but to get power on a FireWire cable, you need the larger six-pin cable. Some laptops come equipped only with the smaller four-pin FireWire input, so you'll have to supply external power if you're using a FireWire interface. For the ultimate in portability, you may want to go with a USB version.


Figure 4: External audio interface: M-Audio Mobile Pre (USB), PreSonus Firebox (FireWire).

Recording devices
You have a number of options for recording. The most obvious is to record directly to your hard drive. However, this may not be an option if you're recording on location, or if you don't want to lug your computer around with you everywhere you go. Of course, these days, people bring their laptops with them everywhere, but if you don't want to do that, this section discusses other options for recording your podcast.

You can record in many different formats. Some, like the cassette, have been around for ages, but are still entirely useful. Others, like tapeless recording, are relatively new. Tapeless recording is of particular interest to podcasters, because you can transfer the files from your recorder to the computer digitally and much faster than real-time transfers.

Cassette
Cassettes were initially developed as a dictation format and never designed to be high quality. But they caught on like wildfire, so manufacturers improved the tape quality and the electronics, and they even added noise reduction systems like Dolby. If you have a decent cassette deck lying around, you can use it, but be sure to buy high-quality chrome cassette tapes and set your record levels high so you don't hear tape hiss. Of course, you can always use studio trickery later on to get rid of (or at least reduce) tape hiss.

DAT
Digital Audio Tape, or DAT, appeared in the mid-1980s as a high-quality studio format, but found its way into the consumer market. Although it has largely disappeared in the past ten years, plenty of serviceable DAT machines are still out there, and they're very high quality.

MiniDisc
Sony has been trying to convince the world that MiniDisc is a great format, but few people have listened. MiniDisc just never seems to go away, no matter how poorly it sells. This is partly due to the fact that MiniDisc units use ATRAC compression on the audio signal, which is acceptable for spoken word content, but not really acceptable for recording music masters. As a portable podcast recorder, a MiniDisc unit can be quite useful, especially because you can find them on craigslist for under $50 and MiniDisc blank discs are cheap.

MP3 recorders
A handful of MP3 players include record functionality. Most of these units do not have external mic inputs. A few have a line input that you can record from, but this means having some sort of mixing desk for the mic pre-amps and feeding the line level output into your portable MP3 player — not exactly a compact setup. Of course, you can use the built-in mic these units tend to include. If you're in a quiet location, it's probably fine. But don't expect broadcast quality.

New tapeless options
If you want the latest and greatest, look no further. Several manufacturers have released high-quality tapeless recording options in the last year. You can see some examples in Figure 5.15. These units record to compact Flash memory cards, which you can pop out and put into a USB card reader connected to your computer, or you can connect the unit to your computer using a USB cable. This allows you to transfer files much faster than real-time transfers; the transfer time depends on the type of file you recorded.



Figure 5: The M-Audio MicroTrack 24/96, a portable recorder that records to Flash cards or microdrives

These tapeless units generally offer uncompressed recording in the WAV format, as well as MP3 recording at a variety of bit rates. Most come with built-in microphones, but for highest quality you'll want to use your own mics, of course. Some units offer XLR connectors, some 1/4″ or 1/8″. As of the writing, models are available from four manufacturers, but we're sure you'll have many more choices by the time you read this.