HiFi Module
The Bpod HiFi Module stores audio waveforms and play them back on trigger.
Audio waveforms are rendered by HiFiBerry DAC2 Pro and DAC2 HD cards.
Our firmware directly drives these cards with Teensy 4.1 for superior timing precision.
An isolated TTL output channel signals audio playback onset and offset.
Synth functions are provided for programmatic control of white noise and pure tones.
Hardware for the two modules is identical except for the enclosure and HiFiBerry card used.
A single firmware file can be set to compile for either module.
More details are available in the product release article here.
Key specs are:
- Sampling rate: 44.1, 48, 96 or 192kHz
- Bit depth: 16
- Audio channels: 2 (Stereo)
- Audio waveform slots: 20
- Max audio samples per slot: 5,760,000
- Playback latency on trigger: 0.22ms +/- 0.01ms
- USB audio data transfer speed: 40-50Mb/s
- Audio signal voltage range: +/- 3V
- TTL sync voltage: 3.3V
- Max AM onset/offset Envelope samples: 2000
- Synth waveforms supported: White Noise, Sine
The HiFi module is controlled from MATLAB with the BpodHiFi class.
Its interfaces to the Bpod State Machine and USB are documented here.
This table contrasts the HiFiBerry cards in the 'SD' and 'HD' versions of the module: