The Outlaws’ Guide to the Marantz AV7005
Audio Formats and Listening Modes
Because the AV7005 supports the new lossy and lossless digital audio formats used by
HD-DVD and Blu-ray as well as the older digital audio formats used by DVD, HDTV,
DVD-Audio and SACD,
and
more generic audio data such as analog, stereo PCM, and
multichannel PCM, the number of different input formats that users may encounter is
large. Additionally, the processing modes available to use in conjunction with those
formats are even more numerous. To assist in understanding the supported input
formats and processing modes of the AV7005, we are devoting one section of this guide
to two separate subjects: audio formats (the incoming audio data), and listening modes
(the decoding and processing schemes which can be applied to that audio data).
Know Your Inputs
As our home theaters have evolved over the last decade, the input audio formats have
expanded to include an ever-growing number. Before we study the surround processing
modes offered by the AV7005, it is important to understand what these formats are and
when they appear.
Analog Stereo and PCM Stereo
These two sources are treated the same way by the AV7005. The first is analog stereo
connections, similar to what you might find from a VCR or some game consoles
(Nintendo Wii, for example). The second is digital connections with stereo PCM signals,
including sources such as CDs and some digital cable channels. The first case (stereo
analog) is converted to stereo PCM by an analog-to-digital converter (ADC), so both
inputs may be handled by the digital signal processor (DSP).
Dolby Digital
Dolby Digital was first called AC-3 when it appeared in the 1990s on LaserDisc, and it
was the first format to provide true multichannel digital audio for consumer use. When
the DVD specifications were established a few years later, Dolby Digital (often
abbreviated “DD”) was included as the default audio format. Dolby Digital offers up to
five discrete full-range channels (left, right, center, left surround, and right surround) and
a low frequency effects (LFE) channel; these six channels are often referred to as “5.1”
because the LFE channel is limited to low frequency data only. To allow these tracks to
fit on media such as DVD and be passed across digital connections originally designed
for just two audio channels, lossy compression is used to compact the original data into
a smaller size, allowing the audio tracks to use much less space than would be required
for an uncompressed multichannel track.
Dolby Digital soundtracks are not required to use all six channels, so you will often
encounter Dolby Digital 2.0 tracks (stereo) or even Dolby Digital mono tracks. Those
mono tracks sometimes include two channels (left and right) with identical data in both
(or “Dolby Digital 2.0 Mono”), but other times they contain a single channel (“Dolby
Digital 1.0”).
Audio Formats and Listening Modes
Marantz AV7005
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