This Week in Nuclear

Updated 12-2012

Table of Contents:

1. Introduction
2. Hardware for Recording to Computer
   • USB Headset Microphones
   • USB Studio Microphones
3. Hardware for Recording to Portable Devices
   • Olympus WS-300M
4. Sound Files and Formats
   • MP3 File Bitrate
   • Wave File Frequency and Sample Rates
   • Stereo vs. Mono for Podcasts

Introduction

I’m one of the podcasting “early adopters” – I started in December 2005, only about 6 months after the historic implementation of RSS feeds into iTunes that put podcasting on the map. Since then I’ve tried tons of hardware and software in an effort to get the best possible sound quality, and to cut down on the time that it takes to put out a weekly show. Here’s a run down of what I’ve learned, along with some links to hardware and software that will get you podcasting in a hurry.

You’ll notice there are links on this page to specific products from well-known vendors. I want you to know that I will only mention and link to equipment that I have either used myself, spoken to someone who has used it, or done exhaustive research including reviews by podcasters who have used the equipment. I want you to learn from my experiences and avoid wasting time and money on hardware or software that won’t do the job.

Recording to Computer

All you really need to get started in podcasting is a computer and a microphone. A lot of what you read will say any old microphone will do. Don’t believe them! Using the $10 analog microphone will be nothing but a source of frustration as you spend hours trying to figure out how to get acceptable sound quality. Basic analog microphones plugged into the motherboard sound card on a laptop or PC rarely give satisfactory sound. This is because of all the electromagnetic interference in and around modern computers causes noise on the analog line. Save yourself hours of frustration and get a USB microphone!

USB microphones bypass the sound card on your computer so you get a digital signal from the mic all the way into the sound editing software. That improves the quality of the sound considerably. You don’t have to spend a fortune to get a good recording.   There are several from Plantronics and other leading component manufacturers for around $50 that will work fine.

For only a little more (~$80-$100) you can a USB condenser microphone (you’ll want a mic stand for $10 to $15 to mount it on). A great example is the Blue Snowball. I’ve tried many microphones over the years and the best I’vve found is the Rode Podcaster. It costs considerably more (around $220) but the sound quality is superb  It also has an audio out jack built into it which allows you to monitor your recorded auido as you speak.

Recording to Portable Devices

Because I travel so much, I searched high and low for a portable podcast recording device that would be easy to use, give great sound quality, and run on AA or AAA batteries.  There are several out there that yield with pretty good results. They are reasonably priced, small, and seem to work well.  Also, they have “Mic IN” ports that take external microphones.  The best I’ve found are dedicated digital audio recorders from Olympus. I have one that I carry most anywhere I go.

I use the Olympus Digital Voice Recorder for recording meetings and speeches.  On ocassion I use it for podcasts.  It’s only about $78.00 and gives good quality sound.  Plus, the files that can be transfered to PC without a cable for editing and mixing.  They are definitely something to consider if you’re looking for something basic and portable that gives decent sound quality.

Sound Files and Formats

One of the things that baffles new podcasters is the seemingly endless variety of sound file formats, bit rates, sample rates, frequencies, mono vs. stereo, and the list goes on and on. I’ll try to cut through all this information and tell you exactly what you need to know.

MP3 Bitrate: The final audio file that you post on the web as a podcast will be in the MP3 format. The quality of an MP3 file is determined by its “bitrate” measured in kilo-bits per second or KBPS. Higher bitrates have better quality but are larger in size. Most podcasts are saved as 96 kbps files which is fine for spoken word and produces a smaller file size than high bit rates. You will find some podcasts encoded at 48 kbps but with memory becoming cheaper and cheaper that’s becoming less typical because some quality loss for spoken word audio can occure at 48 kbps.

Wave File Frequency and Sample Rate: At some point in time during recording or editing your audio file will probably be a wave (*.wav) file. The industry standard for wave file format is a “frequency” or “sample rate” of 44.1 KHz (44,100 samples per second), and 16 bits per sample. If you try to mix sound clips with different frequencies you’ll get either a “chipmonk voice” or an excessively slow and low audio clip. You can avoid that problem by using the “import audio” function in your audio mixing software to import one clip into another (rather than doing a copy and paste). If you stick to 44.1/16 you’ll be unlikely to run into compatibility problems.

There are a number of proprietary audio formats out there, and every audio editing application uses it’s own project file format, but they all will import and export wave and MP3 files.

Stereo vs. Mono: There’s a lot of discussion on the Internet about the right choice of stereo or mono for podcasts. Here’s what you need to know:

• Stereo files are best for music.
• Mono is best for spoken word. Spoken word in stereo can cause a distracting shifting in the sound from one side to another.
• Stereo files are twice as large as mono files.
• Most podcasts are mono unless they are music podcasts.

Depending on the equipment I’m using, I may record spoken word podcast tracks in either stereo or mono, but when I use stereo I always mix down the stereo clips to mono during editing. I use a stereo music track for my intro and exit because I like the way it sounds. This way the spoken part of the podcast is in mono but the music part is in stereo. The stereo and mono tracks get mixed and encoded as a stereo MP3 file, so my file sizes are a little larger than they would be if it was all mono. I may go entirely mono if I change my intro and exit music to a mono file.