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AD1885 – the main codec of this sound card

The main codec of our today’s sound solution is AD1885 chip from Analog Devices. Among its major features I would like to stress adjustable sampling rate (you can modify it from 7040 to 48000GHz), Creative stereo-base expansion feature and the ability to work in a dynamic range of up to 90dB.


AD1885 schematic

AD1885 boasts an enabled codec increase function, although it is not implemented on the graphics card we are reviewing today. The codec features a headphones amplifier and PHAT Stereo 3D Enhancement from Advanced Logic. From the functional point of view, AD1885 is an analogue pre-processor for preliminary data processing. The use of this particular codec in sound cards and voice modems allows to reduce the system CPU workload quite noticeably. The codec architecture is based on a dual-chip design. The first chip is a digital audio controller, while the second one contains high-quality analogue components including DAC/ADC converters, a mixer and the corresponding I/O elements. The major architectural peculiarity of  AD1885 is a high-quality analogue mixer, dual-channel sigma-delta converter and DDS-generator (Data Direct Scrambling).

All in all, AD1885 is a low-end AC’97 codec, which you can see in some mainboards with integrated sound onboard. Sound Blaster MP3+ uses Philips TDA1308 chips as double operational amplifiers. Some high-end components haven’t been actually implemented in the device, that is why we cannot promise any remarkable performance of the device during our test session. Anyway, let’s pass over to the actual benchmarks and you will see what I am talking about.

Testbed and Methods

Since I was going to play with an external USB sound card, which requires much more of the system resources than a standard internal one, I decided to try it out in such resource hungry applications as 3DMark03 and Comanche 4 Demo. For this test session I will use the same system, as the one that was involved into PCI sound cards tests not so long ago. Here is the testbed configuration for your reference:

  • Intel Pentium III 1000MHz CPU;
  • 512MB PC133 SDRAM by Hyundai;
  • ATI Radeon 9700 Pro graphics card;
  • Quantum Fireball AS40 HDD;
  • Creative PC-DVD Encore 12x DVD-ROM;
  • Creative Inspire 2.1 Digital 2800 speaker system;
  • Windows XP Pro SP1.
 
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