Orban OPTIMOD-PC 1101 Operating Manual page 72

2-16
INSTALLATION
18. If appropriate, install the Microsoft Windows SRC Hotfix for Windows 7
and Server 2008.
The Windows 7/Server 2008 Sample Rate Converter (SRC) Hotfix improves the
performance of the Windows Core Audio Record Sample Rate Converter by
greatly reducing aliasing distortion. Not all installations will benefit. If you need
the hotfix (see below) download it from:
http://support.microsoft.com/kb/2653312
Install it according to the instructions that Microsoft provides.
• This hotfix can improve the performance of Optimod-PC's WAVE inputs and
outputs. It only does this if at least one application connected to the WAVE
I/O operates at a sample rate other than 48 kHz. For example, if you are driv-
ing Optimod-PC through a WAVE connection from a playout system that plays
out 44.1 kHz files, install this hotfix.
• It is unnecessary to install the hotfix if you are only using Optimod-PC's hard-
ware inputs and outputs and are not using the host computer for any other
audio applications.
Any audio record or encode application that uses the Windows Audio
Wave/DirectSound API and relies on Windows Core Audio for sample rate
conversion will benefit from this hotfix. This includes most audio re-
cord/encode applications such as audio editors, Sony SoundForge, Audac-
ity, and most streaming audio encoders that rely on the Windows sample
rate converter.
Adobe Audition CS5.5 is unaffected because it uses its own sample rate
conversion in conjunction with the new Microsoft WASAPI API, which
does not support native sample rate conversion. Audio applications that
use ASIO or any other third-party audio API are also unaffected.
Windows 7/Server 2008 Audio Devices present themselves to Windows
based on sample rate. If a record/encode application operates at a differ-
ent sample rate than that listed by the audio device, either Windows
Core Audio or the application must do sample rate conversion. If Win-
dows Core Audio provides the sample rate conversion, the audio signal is
subject to the performance of that conversion algorithm. It is therefore,
very important that this conversion be performed as cleanly as possible.
This hotfix will not be available as a Windows Update because these are
generally reserved for software security updates. As of this writing, we
believe that it will be included in Windows 7/Server 2008 Service Pack 2.
Anyone working with computer digital audio is urged to update all Win-
dows 7/Server 2008 computers with this Hotfix.
We would like to thank everyone at Microsoft for the resources to make
this Hotfix available.
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