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Using a Dell DJ MP3 player for field playback of bird songs. Rev A2, November, 2005
© Copyright Stuart Healy www.aztrogon.com Page 21 of 25
PRACTICAL MATTERS
About the only downside I’ve found since abandoning tape players and switching to CDs and now to
MP3, is the fact that two pieces of equipment are required -- the player and the speaker-amplifier.
However, now that I’ve used the system for a while and figured out the best way of physically managing
the equipment, I feel fairly comfortable with its operation.
As it turns out, most of the time it’s the speaker-amp that is being operated not the MP3 player. After a
species is selected, judicious playback involves on/off operation and volume level adjustment. Obviously,
then, these functions need to be optimized.
I modified the Radio Shack speaker-amp shown on page 4 to facilitate easy operation. Even though there
isn’t much room to work with inside the unit, I was able to add an on/off push button in exactly the
location that I wanted. I wired it in series with the existing on/off switch that is integral with the volume
control. During operation, I leave this switch in the on position and the volume set at a moderate level.
Adding the push button solved two problems -- the unit cannot be powered on inadvertently when stowed
in my day bag (both switches need to be on) and the volume need not be adjusted each time the unit is
powered on. It also minimizes the likelihood of a failure since the volume control is a rather flimsy
potentiometer/switch of the type often found in cheap electronics, transistor radios, etc. If I had to use this
switch to turn the unit on and off many times a day, I know that it wouldn’t last long.
Looking at the unit in the orientation shown in the photo on page 4, I hold it in my right hand with the
bottom right hand corner resting in my palm. My index finger operates the push button and my thumb can
easily rotate the volume control.
Managing the two units is definitely a pain when I have lots of other stuff to carry. However, I give pride
of place to the speaker-amp and carry that it in my right pants’ pocket (I’m right handed); the DJ is in my
left pocket. The connecting cord is behind me passed through my belt loops.
DJ Settings
After setting the date, time, owners name, display contrast (I use 50%) and idle shutdown time (I use 15
minutes), the day to day changes required are minimal.
Play mode is the only parameter that I change on a regular basis -- “track repeat” for bird song playback
and “normal” for music.
For daytime use I set the backlight to off and either a 15 or 30 second timeout at night.
I leave the DJ volume set at 17 (max 25) and use the volume control on the speaker-amp.