12
HDCD
®
Gain-Matching
Some HDCD-encoded recordings are mastered at a level which is noticeably lower
(6 dB) than conventional recordings. To avoid unexpected changes in volume when
going from one disc to another, the Nº30.5 automatically reduces the volume of all
recordings to this “lowest-common-denominator” volume level, as required by Pacific
Microsonics, Inc. Thus, this “HDCD AUTO” gain-matching is the default setting as
shipped from the factory.
In our listening tests, we have determined that the only sonically transparent gain-
matching technique is to raise the volume of the preamplifier by the requisite 6 dB
when playing those few discs which require it.
All other design options intro-
duce a compromise in sound quality.
For Best Performance:
We strongly recommend that you turn off the HDCD AUTO gain-
matching in your Nº30.5 digital audio processor.
If you are using the Nº30.5 with a Mark Levinson Nº38 or Nº38S preampli-
fier
, simply name the appropriate input on the preamplifier “No30” (explained in
the preamp manual), and connect the two products with a Communications Link
cable. In this case, the Nº30.5 will tell the preamplifier to change its volume setting
as necessary to compensate for differing CD mastering techniques, and you never
have to think about it. (
The Nº38 display will show “HD+6” to indicate a change re-
quired by the HDCD recording being played through the Nº30.5; it will revert to nor-
mal and show “HD+0” when you return to conventional recordings. Older preampli-
fiers may require a new EPROM to take advantage of this feature.
) This technique
ensures that you always get the best possible sound from your system, without any
unexpected changes in level, with all recordings.
If you are using the Nº30.5 with any other preamplifier
, follow the steps be-
low. (You will have to turn up the volume manually on some HDCD discs.)
1
PRESS AND HOLD THE DIGITAL RECORD SELECT BUTTON
After a few seconds, the display will change to show
NAME
and the current
name of the selected input. (Ignore this for now. You’ll learn how to rename
your inputs to match your sources a bit later in this manual.)
2
PRESS THE POLARITY BUTTON UNTIL THE DISPLAY SHOWS “HDCD
MANUAL”
Repeatedly pressing the polarity button will toggle the display between
“
HDCD AUTOMATIC
” (
meaning that the output level of the Nº30.5 will be au-
tomatically adjusted to compensate for the differences in recording level be-
tween some HDCD discs and conventionally-mastered discs
) and “
HDCD
MANUAL
” (
meaning that gain-matching is turned off; HDCD-encoded discs
will still be decoded properly
). If you to change this mode of operation
while a Nº38 is Linked, the Nº30.5 will display “
No38 ACTIVE!
” (indicating
that the Nº30.5 and Nº38 will override your action).
In this case, you will have to turn up the volume on some HDCD recordings
manually. This is no great hardship, since most people adjust the volume of their
systems from one recording to the next in any event. Changing to “manual” gain-
matching ensures that the HDCD digital filter always operates at its maximum
resolution.
