How to read to your kids when on a work trip

I’ve heard some studies say that one of the most important activities you can do with your children is to read to them.

Well, I’ve been traveling quite a bit for work lately,and as of this writing I’m averaging about 2 weeks of work travel a month now.  That’s about 8 evenings a month I don’t get to read to my kids (at least mom picks up the slack when I’m not home).

Through the use of available recording technology, here is a little something a traveling parent can do so your child can hear you reading to them whenever you are on travel (or when they want to hear your voice).  The cost is minimal and there are numerous positive benefits.  I did this for my boys so they could hear me reading to them whenever they wish.

  • Purchase a headset to connect to your laptop or computer (analog or USB is good, see my AV gear page)
  • Install & Use some audio recording software to record your voice (I use Audacity)
  • Read your children’s favorite books and record the audio (a WAV file would be nice to input to the Levelator)
  • Make a MP3 from the recorded and leveled audio.
  • Purchase a set of computer speakers (about $12) and a low end MP3 player (about $28), both pictured above
  • Put your recorded MP3 “audiobooks” on the MP3 player
  • Put the speakers and MP3 player and speakers in your child’s room where they read
  • Show your child how to select the audio for a book they want to read
  • Press play and let them read along with the audio (or just listen)

I know this in no way substitutes for real in -person reading with your child (so much more is communicated to your child through non-verbal language and touch), but it’s a great alternative for the traveling parent to invest some up-front time recording to allow your child to hear your voice later.  My little $40 investment in each of my boys will have future benefits that can’t be measured.

Here’s a small audio sample of a book I recorded so my kids can play and read along when I’m away from home.

Download the mp3 here.


– Dom

How to record and produce a MP3 file from a 2 person interview

When I record audio interviews, I usually choose between 2 hardware setups depending on the situation.

The first setup is for ultra-light portable field recording without any power nearby or audio mixer to plug into.  This comprises primarily of a Olympus LS-10 digital audio recorder, 2 lavalier/lapel wired microphones with 1/8 mono connectors, and a Y connector which connects each mono connector to the right or left stereo input on the LS-10.  Click on the image to see a larger version.

The second setup is also for field recording that gives me more options to either plug into an existing audio mixer, or use higher quality phantom powered wired or wireless microphones.  It’s made up of a Marantz PMD661 digital audio recorder and paired with a couple Shure Beta58A microphones (as pictured) or a couple Shure PGX wireless lavalier/lapel microphones (these require AC power nearby).

One of the more important points about recording interviews is microphone placement.  I prefer to use the lavalier/lapel microphones when I can because it allows me to place the microphone at a consistent distance from the mouth of the person talking and there is little chance for handling noise.  With hand-held microphones, moving of the hand on the surface of the mic can cause audio noise to be picked up by the recorder.

One tip on using the devices, the Olympus LS-10 can be setup to use Auto-Gain or Fixed-Gain, the gain applies to BOTH left and right channels at the same time, there is no individual gain for each channel.  On the Marantz PMD661, each channel has it’s own gain and can be adjusted independently depending on the person’s speaking volume.

Once I am done with the recording, I take the WAV file from either recorder, run the file through the Levelator, and edit them using Audacity (remove parts I don’t want).  Once all the editing it done, the audio is then rendered (or produced) into MP3 format.

Below is a video I made of the production process using Audacity & the Levelator (the audio used was recorded using the Olympus LS-10 setup):


– Dom

Here is the video link for those who can’t see the embedded viewer:

Here is the MP3 file so you can hear it outside youtube:

Here is the direct link to the MP3 file:

The video was made and rendered in 720p using Tech Smith’s Camtasia Studio 7.

Mobile podcasting hardware for less than $39.99

The SanDisk Sansa Clip Plus MP3 player has been very useful to me for capturing mobile audio and I’ve decided to write about it so others know about this useful little device.

I use the voice recording function of this MP3 player to capture presentation audio by placing (actually cliping) the device on the shirt of the person doing the presenting. By doing this I get the built in (omnidirectional) microphone very close to the audio source (person’s mouth) which greatly improves audio quality. This is the same microphone placement that makes professional wireless lapel microphones sound so good. The microphone is on the clip side of the device at the top, and since there are no wires the person is free to move around while talking. This device does employ a Automatic Gain Control (AGC) function, so it’s helpful if the presenter simply says something like 1 … 2 … 3 before really starting into their content. The AGC function is also helpful in capturing distant questions in the room.

All the audio is recorded to solid state storage inside the device (there are 2GB, 4GB, and 8GB models), the battery is self-contained (not removable) and can run up to 15 hours in playback mode. Record mode would be a bit less since the device is actively writing to storage, I have easily recorded up to 3 hours of audio at one time (I’m really curious to know how long it would record). Recorded audio consumes almost 3MB per 1 minute of audio, this means an hour of recording would take up about 180MB of space on the device, so even the 2GB model has plenty of space to do hours of recordings.

The Sansa Clip Plus records audio in WAV format (tech details are: 24kHz, 16bit, Mono = 384kbps, good enough for speech, not really good for music). I really like this particular file format because it allows for post-processing/editing. Recording devices that record directly to MP3 do not easily allow for this option without further loss of audio quality.

Here are the post processing steps I go through to get the best possible audio from this device.

1. I pull the files off the Sansa Clip Plus using the USB cable provided and copy the files to my computer (it just looks like another drive).

2. I use the Levelator software to enhance the WAV file before editing the audio (this software is free from the Conversations Network). The Levelator performs audio re-leveling on the entire file at a detail that is too manually intensive to do yourself. Here are some waveform examples captured from Audacity. If you want more detail on how this is done, please checkout the Levelator website.

This audio waveform is before running the WAV file through the Levelator:

This is the audio waveform after running the WAV file through the Levelator:

As you can see, some of the louder parts are reduced, and softer parts are enhanced. This is the magic of what the Levelator can do for your audio recordings.

3. I use the audio editing software Audacity (also free) to remove any unwanted audio parts (just highlight and delete). Once I have the audio in final form, I can then produce a MP3 file (there are steps to set this up on the Audacity website). I typically produce the MP3 file at 64kbps to keep file size down and still maintain a good quality sound.

Here are some samples of audio I recorded in the house (not the best since walls reflect sound).

Sample audio before using the Levelator at 64kbps (24 seconds):

Sample audio after using the Levelator at 64kbps (24 seconds):

Now I know the difference is subtle in these examples, and you might pickup the difference more if you use headphones. But the really nice thing about the Levelator software is the ability to amplify audio from sources that are distant to the microphone. If you want another example of this take a listen to the audio from my post “Engineering talk at SIPI”.

The title of this post is “Mobile podcasting hardware for less than $39.99” which means you can likely find the 2GB version of the device through a online retailer for less than the suggested retail price.

I hope this information was useful, I really like the SanDisk Sansa Clip Plus for mobile audio capturing and recording speeches/presentations. Just remember to re-charge the device before any long event recording.


– Dom