Audio Engineering

(Barry) #1
Other Digital Audio Devices 617

may be needed. Some cassette decks allow you to vary the output, which is an ideal way
of tackling the problem.


The computer type of drive is well suited to CD copying and to making compilations from
a variety of discs. This is not to say that these actions cannot be carried out on the hi-fi
type of deck, but you can be certain that the computer type is using direct digital transfers,
not converting the CD output into analogue and then converting back to digital in the
recorder. The main advantage of using the computer drive is that you can add images, text,
and other data into the same CD if you wish (and if you can cope with the mixture). This
is particularly useful if you want to make multimedia shows of sound and images.


We shall look at audio and other fi le transfers for the computer CD-R/RW drives in
more detail in the following sections, as many of the steps are almost identical. For the
moment, a description of a popular hi-fi CD-recording deck will give you an idea of what
is currently “ state of the art ” in this fi eld.


The Philips CDR 770 ( Figure 21.1 ) was launched in September 1999 and was initially
marketed mainly in Germany, where the main demand for CD recorders seems to be at
present (as an Internet search will confi rm). The initial price in Germany was DM 699,
roughly £ 233, which compares well with earlier models from other manufacturers. The
CDR 770 uses the 43.5-cm width that is now standard for hi-fi components. Like any
other recorders, the CDR 770 allows consumers to make their own recordings from
digital sources, as well as from any analogue sources connected to their audio system.


The CDR 770 performs analogue to digital conversion using the Philips system called
DLR (Direct Line Recording). This uses the normal CD 44.1-kHz sampling frequency for
bit-by-bit conversion, and for CD copying actions it ensures highly accurate recordings
by matching the speed of the recording disc to that of the playing (source) disc. For work
with other digital sources, different sampling rates are automatically detected, allowing
the CDR 770 to deal with any sampling rate from 11 to 56 kHz.


Figure 21.1 : The Philips CDR 770 CD recorder deck.
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