Creativelabs - Audigy2 NX

Introducción

Tarjeta USB externa. Los detalles técnicos de la misma se encuentran aquí:

Detalles sobre la tarjeta

Signal-to-Noise Channel Ratio (A-Weighted):

  • Front/Rear/Center/Sub: 102dB @ 2Vrms
  • Headphone/Side: 96dB @ 2Vrms

DAC:

  • 24-bit/96kHz Analog-to-Digital Converter (ADC) for various analog inputs
  • 24-bit/96kHz Digital-to-Analog Converter (DAC) for up to 7.1 channels output
  • Supports Sony/Philips Digital Interface (S/PDIF) format input signal of up to 24-bit/96kHz quality
  • Recording/Playback: up to 24-bit/96kHz (USB 2.0 audio support is required for 24-bit/96kHz Multi-channel playback, and simultaneous playback and recording. USB 2.0 is only supported in Windows XP and requires online software update from Microsoft and Soundblaster.com when available)
  • SoundFont 2.1 Support for Midi playback

Chipset:

  • CA0186
  • EP7309

Modificaciones a la tarjeta

Fuente de información interesante

Si ejecutamos:

cat /proc/asound/card1/stream0

Veremos algo como lo que sigue:

Playback:
  Status: Running
    Interface = 1
    Altset = 5
    URBs = 3 [ 8 8 8 ]
    Packet Size = 388
    Momentary freq = 95999 Hz (0xb.fffa)
  Interface 1
    Altset 3
    Format: S16_LE
    Channels: 2
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 1
    Altset 4
    Format: S24_3LE
    Channels: 2
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 1
    Altset 5
    Format: S16_LE
    Channels: 2
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 1000 us
  Interface 1
    Altset 6
    Format: S24_3LE
    Channels: 2
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 1000 us
  Interface 1
    Altset 7
    Format: S16_LE
    Channels: 4
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 1
    Altset 8
    Format: S24_3LE
    Channels: 4
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 1
    Altset 9
    Format: S16_LE
    Channels: 4
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 1000 us
  Interface 1
    Altset 10
    Format: S24_3LE
    Channels: 4
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 125 us
  Interface 1
    Altset 11
    Format: S16_LE
    Channels: 6
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 1
    Altset 12
    Format: S24_3LE
    Channels: 6
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 1
    Altset 13
    Format: S16_LE
    Channels: 6
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 125 us
  Interface 1
    Altset 14
    Format: S24_3LE
    Channels: 6
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 125 us
  Interface 1
    Altset 15
    Format: S16_LE
    Channels: 8
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 1
    Altset 16
    Format: S24_3LE
    Channels: 8
    Endpoint: 1 OUT (ASYNC)
    Rates: 48000
    Data packet interval: 125 us
  Interface 1
    Altset 17
    Format: S16_LE
    Channels: 8
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 125 us
  Interface 1
    Altset 18
    Format: S24_3LE
    Channels: 8
    Endpoint: 1 OUT (ASYNC)
    Rates: 96000
    Data packet interval: 125 us

Capture:
  Status: Stop
  Interface 2
    Altset 5
    Format: S16_LE
    Channels: 2
    Endpoint: 2 IN (NONE)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 2
    Altset 6
    Format: S24_3LE
    Channels: 2
    Endpoint: 2 IN (NONE)
    Rates: 48000
    Data packet interval: 1000 us
  Interface 2
    Altset 7
    Format: S16_LE
    Channels: 2
    Endpoint: 2 IN (NONE)
    Rates: 96000
    Data packet interval: 1000 us
  Interface 2
    Altset 8
    Format: S24_3LE
    Channels: 2
    Endpoint: 2 IN (NONE)
    Rates: 96000
    Data packet interval: 1000 us

De aquí obtenemos bastante información:

  • Por un lado, la comunicación con el USB es asíncrona. Esto quiere decir que se usa el propio reloj de la tarjeta de sonido (frente a las adaptativas).
  • Según la interfaz seleccionada dispondremos unas frecuencias de muestreo y unas profundidades de bits determinadas. Por ejemplo, con "hw:1,0" podemos seleccionar la tarjeta funciona con 48000hz o 96000hz pero siempre con 16 bits (S16_LE).
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