极限测试!看看HDAUDIO到底有多大能耐

    本文转载于itocp论坛，原文作者Dr.BT，原文地址http://www.itocp.com/viewthread.php?tid=2765&pid=33357&page=1&extra=page=1#pid33357

    本文作者在文章一开始就提到了，本次测试的平台超级豪华，虽然是集成的声卡，但其他配置都是发烧级别，虽然有些发烧的硬件与本次测试无关。。。。。虽然集成的CODEC一样，但是在不同的板子上不同的用料以及使用不同的电源等都会对集成声卡造成影响，所以本次测试确实是一次比较罕见的YY的集成声卡测试。

    4年前HDAUDIO就诞生了吧，集成声卡开始支持2496，这是非常大的飞跃，同时3D音效也有长足进步，进一步挤压独立声卡，闹得现在独立声卡全给挤到专业和高端领域去了。不是支持2496就能达到2496的好效果的，同样，不是能放cd就能把cd放出色的，所以，HDaudio究竟能到什么层次，这是需要仔细测试的。

    老规矩

    wm 8776数据：

    * Audio Performance
    * 108dB SNR (‘A’ weighted @ 48kHz) DAC
    * 102dB SNR (‘A’ weighted @ 48kHz) ADC
    * DAC Sampling Frequency: 32kHz – 192kHz
    * ADC Sampling Frequency: 32kHz – 96kHz
    * Five Stereo ADC Inputs with Analogue Gain Adjust from +24dB to –21dB in 0.5dB Steps
    * Programmable Limiter or Automatic Level Control (ALC)
    * Stereo DAC with Independent Analogue and Digital Volume Controls
    * Stereo Headphone and Line Output
    * 3-Wire SPI Compatible or 2-Wire Software Serial Control Interface
    * Master or Slave Clocking Mode
    * Programmable Audio Data Interface Modes
    * I2S, Left, Right Justified or DSP
    * 16/20/24/32 bit Word Lengths
    * Analogue Bypass Path Feature
    * Selectable AUX Input to the Volume Controls
    * 2.7V to 5.5V Analogue, 2.7V to 3.6V Digital Supply Operation

    alc888t数据：

    High-performance DACs with 97dB SNR (A-Weighting), ADCs with 90dB SNR (A-Weighting) Ten DAC channels support 16/20/24-bit PCM format for 7.1 sound playback, plus 2 channels of independent stereo sound output (multiple streaming) through the front panel output Two stereo ADCs support 16/20/24-bit PCM format, one for stereo microphone, one for legacy mixer recording All DACs supports 44.1k/48k/96k/192kHz sample rate All ADCs support 44.1k/48k/96k sample rate 16/20/24-bit S/PDIF-OUT supports 44.1k/48k/96k/192kHz sample rate 16/20/24-bit S/PDIF-IN supports 44.1k/48k/96k/192kHz sample rate Up to four channels of microphone array input are supported for AEC/BF applications High-quality analog differential CD input Supports external PCBEEP input and built-in digital BEEP generator Software selectable 2.5V/3.75V VREFOUT Two jack detection pins each designed to detect up to 4 jacks Supports legacy analog mixer architecture Wide range (–80dB ~ +42dB) volume control with 1.5dB resolution of analog to analog mixer gain Software selectable boost gain (+10/+20/+30dB) for analog microphone input All analog jacks are stereo input and output re-tasking for analog plug & play Built-in headphone amplifiers for each re-tasking jack Two GPIOs (General Purpose Input and Output) for customized applications Supports anti-pop mode when analog power AVDD is on and digital power is off. 64-pin LQFP 'Green' package Meets Microsoft WHQL/WLP 3.0 audio requirements WaveRT-based audio function driver for Windows Vista EAX™ 1.0 & 2.0 compatible Direct Sound 3D™ compatible A3D™ compatible I3DL2 compatible HRTF 3D Positional Audio Emulation of 26 sound environments to enhance gaming experience 10-Band Software Equalizer

    官方数据并不支持24/88.2

    不过我实际用foobar 可以ssrc到24/88.2，但是rmaa测不到24/88

    （这里补充一点关于alc888t的中文介绍：ALC888T音频解码芯片，这款芯片不仅能输出符合HD Audio标准的8声道音频，还首次融合了Skype IP语音真强技术，可以实时提升IP语音质量而无须额外硬件帮助。）