To operate DART XP Pro in the real-time processing mode choose the Real-time command from the Restore menu. Depending on the input/output specifications DART XP Pro can work in four different real-time regimes.
input : audio device connected to the input of the sound card (tape deck, phonograph, tuner)
output : audio device connected to the output of the sound card (loudspeakers, tape deck, DAT recorder, on-line CD-recorder)
When operated in this regime DART XP Pro does not engage the computer hard disk to store neither input nor output data, i.e. it processes samples collected at the input of the audio card on-the-fly and sends the results directly to the output. In cases like this the computer serves merely as a memoryless processing unit. To save the results of processing an external recording device should be connected to the output of the audio card. The output data can be stored either in an analog (tape deck) or digital (DAT, CD-recorder) form.
input : wave file
output : audio device connected to the output of the sound card
All details are identical as in the case 1 above except that the input audio data are fed from the disk wave file. The main advantage of this operating mode is that one doesn’t need to create a separate disk file to keep the results - the restored audio can be sent directly to the external recording device.
input : audio device connected to the input of the sound card
output : wave file
All details are identical with those in the case 1 above except that the output audio data are saved in the disk wave file. The advantage is one doesn’t need to store the original audio data prior to its restoration.
input : wave file
output : wave file
This variant is almost identical with classical off-line processing except that the rate of processing is synchronized with the sampling/playback rate allowing you to listen to the results while they are generated.
NOTICE
Only the full-duplex audio cards will allow you to listen to and/or record the results of real-time processing in cases 1, 2 and 3 specified above. Otherwise two audio cards are required - the first one to sample the input signal and the second one to audition the output signal.
In order to use DART XP Pro in the real-time processing mode proceed as follows:
1. Connect audio device(s) to the input and/or output of your audio card(s).
2. Evoke the Real-time dialog by choosing the Real-time command from the Restore menu.
3. Select the processing function, the source of the input signal and the destination of the output signal.
4. Press the Start button to initialize processing.
5. Start the output audio device (unless the results are written to a disk file).
6. Start the input audio device (unless the input signal is taken from a disk file).
7. Press the Stop button when finished.
When operated in the real-time mode DART XP Pro will allow you to change different program settings during processing. Since some of the complex restoration functions introduce a considerable processing delay the effects of the changes may not be heard immediately. Each time you modify any of the settings the green READY
light will go off - it will be switched on again as soon as the results obtained under the new settings are available. If your computer is too slow to perform real-time processing the red OVERFLOW
indicator will burn continuously or at least from time to time (in case you don’t listen to the results). Since the buffer overflow results in audible signal distortions it should be avoided.
NOTICE
If the values of processing parameters are chosen incorrectly (e.g. the lower cutoff frequency of a bandpass/bandstop filter exceeds the higher cutoff frequency) the corresponding items are displayed in red. The inappropriate settings are ignored by the system until they are defined correctly (the last correct settings are used instead).