Record a Mobile Podcasts Ver. 1.0

This is a technical explination of the specific mobile podcasting gear I’m using as of late December 2004. This doc covers the audio recording process with this specific gear. I don’t go into the Internet sharing part of podcasting. I’ll leave most of that to another document.

The Gear

Microphone, unpowered Labtec AM-222
Headphones, earbuds (included with Yepp YP-T5V)
Mini-Disc Player/Recorder, portable Sony MZ-R50
MP3 Player/Recorder Samsung Yepp YP-T5V
Direct Connect USB adapter (included with Yepp YP-T5V)
1/8″; Stereo to 1/32″; Stereo audio cable (included with Yepp YP-T5V)
One AAA Battery  

A bit of Technical Explination

There are four essential parts to any audio recording process. The microphone, the pre amp, the recording device, and the audio monitoring device. In this example the Labatec is our microphone, the Sony Mini-Disc is our pre amp, the Samsung Yepp is our recording device, and the headphones are our audio monitoring device. Most audio recording devices built to work with external mics have a built in pre amp. The Samsung Yepp, our recording device, doesn’t have a pre amplified mic input so we need to provide one.

Why am I using a Mini-Disc recorder AND a Samsung Yepp together?

The biggest reason is that the Samsung Yepp can record straight to MP3 at 128 kbps. This removes several time consuming steps. I could record high quality audio on the Sony Mini-Disc recorder, but to put this audio on the Internet I would need to digitize the analog audio in real time. I’d end up with a large uncompressed audio file, such as a WAV or AIFF. In other words if the podcast I made was thirty minutes long I would have to spend about another hour rerecording it to a computer hard drive and encoding/duplicating/compressing the master audio file to a MP3. There is software that can record straight to MP3 but the encoding process requires a lot of CPU cycles and RAM. If your computer can’t provide this power errors can occur in your MP3 file resulting in skips or software crashes.

Unfortunatly the Samsung Yepp only has a 1/32″ line in. The signal required for this device to record is approximatly -20 dBu. Most inexpensive microphones can not provide this power. Thus the microphone must be amplified BEFORE it’s signal is connected to a line input. This is where the Mini-Disc comes in. It has a mic input that can amplffy an unpowered mic and a line out that ballences the signal further so it can provide the signal the Samsung Yepp needs. This process is also know as a mic level to line level converstion.

Part 1: Recording Levels

1) Connect the Microphone into the Mic input on the Mini-Disc
2) Plug the 1/8″ jack into the Line Output of the Mini-Disc
3) Plug the 1/32″ jack on the other end of the 1/8” into the ENC Input on the Samsung Yepp
4) Connect the 1/8″ jack on the headphones into the heaphone input of the Mini-Disc
5) Put the headphones on 🙂 Duh?
6) Press pause then push record on the Mini-Disc untill the words ‘manual record’ appear
7) Speak into the mic ex. “Mic checka’ 1, 2, 3”
8) Push the Forward button or the Back button to change the microphone input levels. Notice the change on horizontal bar and the difference in the vertical input levels.

Once you’ve found a good spot for you levels your ready to record with the Yepp. The goal of setting proper audio levels is to get the highest signal level without distorting the sound of the recording. Because you can’t be in pause record mode on the Samsung Yepp while setting levels on the Mini-disc acting as external preamp you need to do several test recordings to get it just right.

Part 2: Recording straight to MP3

1) Turn on the Mic (a lot of mics don’t have on/off switches)
2) Put on your headphones
3) Press pause then push record on the Mini-Disc untill the words ‘manual record’ appear
4) Press the record button on the Samsung Yepp
5) Wait until the time countdown on the Samsung Yepp starts. When it does your recording. If for somereason it doesn’t move in the first second or so, say somthing into the mic like. “Welcome” 🙂
6) Speak all that you have to say
7) When your done click the record button on the Samsung Yepp
8) Press play on the Samsung Yepp to listen to what you just recorded. Make sure that you can hear yourself well and that the recording appears loud enough.

Part 3: Downloading the MP3 off of the Samsund Yepp

1) Connect the small USB adapter or USB cable to the Samsung Yepp and your computer
2) Make sure the Samsung Yepp is on
3) Use your Finder on the Mac or the Explorer on Windows to look on the USB drive you just mounted. (Modern operating systems should make it very easy to mount a USB drive like the Samsung Yepp. Consult you operating systems website if you have problems. Searching is a good idea too)
4) Find the MP3 file you just made. It’s name is not discriptive but based on when you recorded it. Try listening to the MP3s you find to determine which one to copy.
5) Drag and drop or cut and paste the MP3 you just made to your computers hard drive.
6) Rename the MP3 you just copied to your hard drive to a name that describes the content of the audio. Here is the naming convention I use:
website abriviation_show abriviation[yearmonthday].MP3
ex. AA_3URLs_20041204.MP3

At this point you need to get your MP3 onto a web server. This can be done with ftp and a few other ways. Here are a few links about how to do that. A good ftp client I use for the Mac is called Transmit. FineFTP is a cool ftp client for the PC that’s also free. It’s an extension of the free mozilla based web browser Firefox.