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ITunes-QuickTime for Windows - Setup Guide

From Benchmark

Benchmark's guide for configuring Windows-based media players

General strategies for setting up your computer for high quality audio playback

1 Overview
2 Recommended Player Settings
3 Known Problems
4 Article Outline

Overview

iTunes uses the audio engine built into QuickTime to play its audio (and video) files. In other words, iTunes is a sort of media file manager that plays its media using QuickTime, just like a website might play its media with QuickTime. Therefore, the information in this section will apply to both players, and we will address both players simultaneously.

Certain information within this article is very specific to the version of the software being used. Please check your software before acting on this information.

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Recommended Player Settings

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Set word length to 24-bit and sample rate to that of the audio being played

Word length should be set to 24-bit, regardless of the word-length of the audio file being played.
Sample rate should be set to match the sample rate of the media (music).
- The sample-rate conversion in iTunes 7.X will not add significant distortion to the audio. The user should not be discouraged from setting the sample-rate to 96 kHz as a permanent setting, even when the audio is less then 96 kHz.
These settings can be set in QuickTime (even when using iTunes) by going to:

QuickTime->Edit->Preferences->QuickTime Preferences->Audio->Sound Out

For more information about why this is important, read more about sample-rate and word-length.

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Set iTunes volume to "Full"

Volume settings below "full" may cause severe distortion, depending on which version of iTunes you are using.
- This does not refer to the track-specific "Volume Adjustment" settings found in the "Get Info" menu. The "Volume Adjustment" setting should always be set to "None" for all tracks.
- The volume controls in iTunes versions 7.X will not cause significant distortion. The user should not hesitate to use the volume control in iTunes v7.x
Read more about how digital volume controls affects audio

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Bypass all audio DSP and plug-ins (EQ and any other audio 'enhancer')

For iTunes, disable 'Sound Enhancer' and 'Sound Check' by going to:

 iTunes->Edit->Preferences->Playback

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Known Problems

*this section of the article was researched using iTunes Ver 6.0/ QuickTime Ver 7.1. Some information in this article may not apply to different versions of this software. Email us to report any errors or discrepancies, or if you would like more information on this topic.

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Settings in QuickTime affect iTunes performance

Sample-rate and word-length settings in QuickTime also control those respective settings for iTunes.
Several other settings in QuickTime also transpire as different settings for iTunes.

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Always truncates audio to 16-bits

Word-lengths of longer then 16-bit are truncated to 16-bit, rather then being dithered.
Truncation will cause severe distortion.
Read more about the effects of word-length reduction.

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Static sample-rate and word-length

QuickTime and iTunes will not adjust the sample rate and bit length of its playback engine to correspond to the media its playing. It will convert EVERYTHING (or have Windows Kernel Mixer convert everything) to the sample rate and bit length that is set in the QuickTime Preferences (see below for instructions to set these).
Read more about sample-rate and word-length.

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Poor Volume Control

The volume control built into QuickTime and iTunes adds significant amounts of distortion when it is not set to 100%.
Read more about the effects of digital volume control.

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'Skipping' Audio Due to Hardware/Driver Compatibility Issues

QuickTime (and iTunes) sometimes has difficulty streaming audio to certain hardware and/or drivers, resulting in skipping, stuttered audio. This can usually be fixed within QuickTime by going to Edit->Preferences->QuickTime Preferences->Audio->Devices and selecting Safe mode (waveOut only).

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