Previous Page 
|
Previous Page |
Next Page |
The mixer tab of the control panel contains controls for selecting and mixing individual channels of a multi-channel audio file (e.g. a stereo .wav, .aif or .wac file has two channels) into a combined "mixed" signal. The combined signal is the output of the mixer which is then used to display waveforms and spectrograms, signal detection, and recognition.
For simple applications with only one microphone sensor (single channel), you only need to worry about the sample rate control described below.
For multi-channel applications (more than one microphone channel), beam forming is used to enhance the signal of a particular vocalization by digitally focusing the microphone array in a specific direction. The remaining controls are used for this purpose.
The sample rate control adjusts the sample rate from the audio source file to a sample rate used by Song Scope to display spectrograms and compare vocalizations.
The playback speed control adjusts the playback speed from the audio source file when played through your computer's sound system or saved to a .wav file. The default value is "Normal" speed. You can choose to playback audio at 1/2, 1/4, 1/8, and 1/16th speed.
The maximum sample delay control specifies the number of source audio sample times it takes for a sound wave to propagate across the microphone array. If the source recording is made at sample rate R, and the greatest distance between any two microphones is D, then this value should be set to at least R * D / S where S is the speed of sound. Note that S is equal to approximately 343.6 meters per second or 1127 feet per second, depending on temperature, barometric pressure, and other variables. The maximum sample delay control is used with Song Scope's built-in beam forming algorithm.
The per-channel enable check boxes are used to enable and disable the multi-channel mixing. Either only one channel is selected or all channels are selected. If one channel is selected, then this channel is the "reference" channel, and only that channel is used (other channels are effectively disabled). If all channels are selected, then the multiple channels are combined according to the gain and delay controls described below. The last selected reference channel is used by Song Scope's built-in beam forming algorithm.
The per-channel gain control adjusts the relative gain of the channels before they are combined by the mixer.
The per-channel delay control adjusts the sample delay (limited by the maximum sample delay described above). Each channel is delayed by the number of samples specified before being combined by the mixer.
|
Previous Page |
Next Page |