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Help: Short tutorial - Stereo Tool 3.10
FM transmitter support: Configuring Stereo Tool
  • In the main Stereo Tool window, click on the FM Configuration button.

Due to some limitations for Winamp plugins, Stereo Tool needs to bypass the normal Winamp output to be able to send FM Stereo and RDS information to the sound card.
  • In the window that appears, enable "Direct Soundcard Access". Set "Send to Winamp" to Nothing.

  • Select a 192 kHz capable output sound card.
    Note: Due to some limitations, Windows only reports if a sound card can handle 96 kHz or more. Currently Stereo Tool cannot distinguish between 96 kHz capable sound cards and 192 kHz capable sound cards. If a sound card is reported to support 96 kHz or more, it might be a 192 kHz sound card.

  • Make sure that the audio is playing through the selected sound card.
Next, configure the things that you want to broadcast:
  • Enable the Pre-emphasis setting for your area. Also enable Pre-emphasize output.

  • Enable the "FM Stereo Encoder".
    Check that no errors are reported in the Status overview at the left top of the window. (Note: Make sure that some audio is playing before checking.)

Stereo Tool should now be sending FM Stereo information in the output signal. Connect the output to your FM transmitter, and check on an FM receiver that the audio is really stereo. Check this by listening to the sound - the fact that the stereo indicator on the receiver is turned on does not mean that the audio is really stereo. If the indicator is on, and the sound is still mono, the audio is apparently being resampled to 44.1 kHz.

Only continue if you can hear a stereo sound, otherwise check the bottom of this page for possible solutions.
  • Enable the "RDS Encoder".
    Check that no errors are reported in the Status overview at the left top of the window.

    Check on an FM receiver that supports RDS that the RDS signal is really received. (Use for example a car radio for this.)
If everything works fine, the status overview should look like this:

Note that "Probably OK" means just that: Stereo Tool is sending the data at the correct sample rate to the sound card. But Windows or the sound card may still alter the sound, causing the FM Stereo and RDS signal to be deformed or lost.

If the sound on the FM transmitter is mono or there is no RDS reception If the sound on the FM transmitter is mono or there is no RDS reception, it may be caused by any of the following problems:
  • You are broadcasting too soft or too loud. Compare the volume of your sound with that of other stations. If the difference is big, that might be the problem (Too soft -> stereo signal is also too soft. Too loud -> distortion disrupts the reception.)
  • Your sound card does not support the 192 kHz sample rate. See sound card requirements for a list of supported sound cards.
  • The sound card output is being resampled to a lower sample rate by Windows. You might need to configure your sound card or Windows to output 192 kHz data. Windows may also start downsampling if another application was using the sound card when you opened the connection to it. Close any other application that is playing or recording audio, then disable and re-enable Direct Soundcard Access.
  • The sound card deforms the output. If you have a Creative (SoundBlaster, X-Fi) sound card, it won't work. Otherwise, try if you can turn off any audio processing that is done on the sound card.

    If you are experiencing hiccups
    If you are experiencing hiccups in your Direct Soundcard Access output signal, please try the following steps:
  • Increase the buffer size. With a larger buffer size, more data is sent to the sound card, so the chance that the sound card "starves" (has no more data to play) decreases.
  • If that does not help, check the buffer indicator to see if the buffer is (almost) empty when hiccups occur. If the buffer slowly becomes empty, your processor might not be able to handle the processing. In that case it might help to turn some processing steps off, or to reduce the output quality (see Help: CPU usage setting).
  • If that does not help, or the buffer indicator never shows an (almost) empty buffer, you might need to increase the buffer size or latency of your sound card. For many sound cards, this buffer size is specified in samples. When playing at a higher sample rate, the amount of time that fits in the buffer is a lot lower. Please check your sound card driver or configuration utility for this.

  • This website is © Copyright 1999-2014 by Hans van Zutphen
    Stereo Tool is shareware. You are free to give Stereo Tool to others, publish it on shareware CDs/DVDs, websites etc.