Configuring Recording

During recording, the Windows sound subsystem is provided with a set of buffers into which it can place the incoming audio data.  When a buffer is filled, the subsystem notifies AudioExplorer, which then stores the new audio data, and queues it for the spectrum analyzer.  AudioExplorer then returns the buffer to the sound card to be filled again.  Since these procedures take both time and CPU cycles, at least several buffers need to be used, so that while AudioExplorer is working with one buffer, the sound card can continue filling other buffers with incoming data.  This prevents gaps or "dropouts" in the audio stream.

Note that until a buffer is filled, AudioExplorer does not have access to the new audio data.  This causes a slight delay, or latency between the time the sound data is generated and the time that AudioExplorer can analyze it and refresh the frequency display.  Therefore, for recording, it is advisable to use a modest number of relatively small buffers so that latency is minimized.

Ideally, the total buffering provided to the sound subsystem is equivalent to at least 0.5 seconds of audio activity.  As these settings are changed, the dialog will display the total buffering time.

Incoming audio data is saved and copied into a circular buffer.  When the circular buffer contains an amount of audio data equal to or greater than the samples per spectrum specified for the Power Spectrum Analyzer, the new chunk of data is sent on to the analyzer, and a portion of the oldest audio data equal to the samples between spectra is permanently removed from the circular buffer.  The transform buffer size specifies the total capacity of this circular buffer.

AudioExplorer maintains separate Power Spectrum Analyzer (PSA) settings for record and playback modes.  The current recording mode PSA settings are listed in this dialog, and can be customized by clicking the Change button and invoking the PSA Options Dialog.

Here you can select the input audio device used for recording, and define the format of the new audio file.  Presently, AudioExplorer only supports 16-bit resolution at 44,100 samples/second.