Custom Search

Fountain Products
 Cave Surveying
Cave Survey Software
 Free Utilities, Tools
Web Image Tracker
Sports Audio Delay
Time Calibrator
Spectrum Analyzer
Used Car Evaluater
Terrain Modeling
Free Topo Maps
XEdit Text Editor
EXPL Language
 Fun Stuff
  Games
     Arachnid-32
     Eight-X Solitaire
 Math, Computers
  3D Mandelbrots
  Super-Spirograph
  6502 Memorabilia
 

If you like our Programs Please Leave A TIP

Connecting A Laptop Computer

Top  Previous  Next

To use the Audio Delay program, you must bring audio signal from an external radio into these inputs. Normally, you will connect the radio to the computer through the Line-In inputs. However, Laptop computers are different from Desktop computers in that they have fewer inputs. A desktop computer will usually have a dedicated "Line-In" input that is ideally suited to receiving the signals from radios. If your laptop has a dedicated "Line-In" input, you should use it and skip to Step-II below.

I. Microphone Jack. If your laptop has a microphone jack, you may be able to use it in place of a Line-In input, but the process is a little more complicated. Microphone jacks are designed to pickup the very weak signals produced by microphones. These signal are in the range of 0.01 volts. The signal coming of a radio maybe around 1 volt, or about 100 times bigger. As a result, if you plug the radio directly into the microphone jack, the signal will be very distorted with only the softest sounds intelligible.

There are several ways to solve the problem depending on the computer you are using.

1. Reconfigure the Microphone to be Line-In. Most modern sound card can be configured so the jack on the back perform different functions. The sound cards normally come with a utility that allows you to configure the sound card. You need to configure the sound card so it has a "Line-In" input. The image below shows the typical configuration utility for the RealTek sound card.

As you can see, the bottom pink connector shows a microphone symbol just to the right. This means the input is configured to accept microphone voltage levels.

To change the configuration, you can click on the microphone and the program will display the configuration window shown to the right.

MicConfig1

The "Mic In" option is checked, which is what sets the input to be configured for a microphone.

Checking the "Line In" option and pressing OK, will change the input from a Mic-In to Line-In. As you can see, the icon next to the pink plug as changed from a Microphone Symbol to a Line-In symbol.

Not all laptops use Realtek sound ICs, so you may find different sound setup programs on your computer. Even  laptops that do use Realtek sound ICs, may have a different setup program from the one pictured here, so it may take some exploration to find the controls that set the sound ports.

MicConfig2

Generally speaking, you need to use the setup program for the sound card or sound chip, and not the Windows configuration programs. The Windows configuration programs usually don't allow you to control low-level options like sound port assignments.

2. Reduce the Signal Level. If you can't find a way to configure your microphone input to be a Line-In input, another option is reduce the signal level. One way to do this is with an adaptor that contains an attenuator. The picture to the right shows an attenuator will reduce the signal level enough to make Line-Level signals work with a microphone input. Here is one that is available off the web:

Line to Microphone Attenuation Cable

Attenuator1

Warning: Be careful and make sure the plugs for any adaptor you use match the radio and computer you are using. For example, miniature plugs like these can be either monaural or stereo. AM Radio outputs tend to monaural, but computer inputs tend to be stereo. If you plug a stereo jack into a mono socket, it may short out part of the circuitry and do damage to your Computer or your Radio. Radio Shack generally has adaptors that can convert stereo to monaural, as well adaptors to convert between different sizes.

If you are handy and know to build simple electronic projects, you can make your own attenuator. Here are some web site with instructions and circuits. You can usually buy all the part at Radio Shack or in the worst case, from Digikey. Here are some links to circuits that will attenuate a line-level signals for a microphone.

Line level signal to microphone input adapter

Line level signal to microphone input adapter

3. Turn Down The Volume. If all the above suggestions fail, you may be able to plug the radio directly into the microphone jack and then use very low volume levels. This will require that you turn volume down to very near the off-position. This can be quite tricky to do because very small changes in the position of the volume control can make big changes to the volume. Some radios just won't let you get the volume low enough to work.

II. Cables and Adaptors. You will also need a cable that will connect between the radio and your computer. If you are lucky, the radio and the computer will have the same kind of connector so you can just use a cable with identical jacks on each end. Most of the time this will not be true so you will need different jacks on each end of the cable or adaptors that will convert one type of jack to another.

Pay particular attention to whether the jacks are stereo or monaural. Most computer jacks are stereo and some radio earphone jacks are monaural. For example, if the radio has a mono-head phone jack, you will need to get a mono adaptor; if it is stereo, you will need a stereo adapter like the one shown to the right.

You can tell stereo jacks from monaural jack by carefully examining the tip of the jack and counting the number of conductors. Stereo jacks will have three; monaural jacks will have two.

Adapters

 Warning: Be careful and make sure the plugs for any adaptor you use match the radio and computer you are using. For example, miniature plugs like these can be either monaural or stereo. AM Radio outputs tend to monaural, but computer inputs tend to be stereo. If you plug a stereo jack into a mono socket, it may short out part of the circuitry and do damage to your Computer or your Radio. Radio Shack generally has adaptors that can convert stereo to monaural, as well adaptors to convert between different sizes.

Contact Us

Custom Search