Important Note; Chassis Grounding - Rane ac22b Operating & Service Manual

OPERATING INSTRUCTIONS
Bcfore altempting any audio equalization with the ME 60,
it is imponant 10 optimize th€ CHANNEL LtrVEL control
setting. Impropcr ganr distribulion is a common cause of
headroom loss and increased noise in audio systems.
The Ml.l60 provides you with an overall BYPASS swilch
and nrdicalo. as well as an OL (overload) LED as useful tools
for optimiz;Dg this gairr ser up. The BYPASS switch is useful
f o r m a k i r g q u i c k A ' B c o m p a r i s o n s , i . e . , c o n r p a r i n g e q u a l i z c d
(BYPASS out, LED ofi) versus unequalized (BYPASS in,
LED on) sound. To do this ficely, without danger ofsystem
d a n l a g e , r c q u i r c s y o u s c l t h c l c v c l t h r o u g h t h e M E 6 0 t o
approximalcly unity. Irailurc to do so can produce alarming
' l h c
g a i n . a n g e o f t h e M E 6 0 i s O f f l o + 6 d B f o r u n b a l -
a n c e d o p e r a t i o n , o r O f T t o + l 2 d B f o r b a l a n c e d u s c . T h c M L 6 0
i s a l w a y s u n i t y g a i n i n b y p a s s , s o i f y o u a d d o r r c d u c e g a i n
(bcyond EQ makc-up gain) thc levcl diflc.ences between
BYI'ASS switch bcmg in or out can be startling. Therefore
y o u r v a n l l o a c t t h c C I I A N N E L L E V E L c o n t o l s f o r e q u a l i n /
T o g c l s l a r l c d , l n a k e t h c l b l l o w i n g i n i t i a l s c t u p
L C H A N N E L A Y P A S S s w i t c h c s d c p r c s s c d ( e q r a l s b y p a s s e d
c o n d i l i o n = r c d I - I ] D o n ) .
2 . C H , { N N E L L E V E L c o n t r o l s p o s i t i o n e d a i 7 " f b r u n b a l -
a n c e d , o r ' 6 " i o r b a l a n c e d u s e .
3 . A l l s l i d e c o n t r o l s i n c e n t e r - d e t e n t p o s i t i o n s ( 0 d B b o o s t / c u t ) .
4 . A p p l y s i g n a l t o t h e s y s t e r n .
5 . C h c c k t h a t a n O L i n d i c a t o r i s n o t o n . I f a n O L L E D i s o n ,
m o v e i r s C H A N N o L L E v E L c o n t r o l d o w n j u s t e n o u g h f b r
it 1o go o t. Iror optimunr noise pcrlbrn]ancc always takc :ls
m u c h g a i D a ! p o s s i b l c w i t h o u l c o D t i n u o u s l y I i g h t i r r g t h e O L
l i g h t .
6. Rclcasc lhc IIYI'ASS switch and you arc rcady 1o staft
c q r a l i z i n g t h e s l s t c n r .
S i n ( c r . o u n r c c ^ n n ( n . , i . r . , n d r o n c c o n r o L , r i n j a r e t w o
ol the most common uses lbr equalization. here are a few
A C O U S T I C C O M P E N S A I l O N . A c o u s l i c c o m p c n s a l i o n
i s c o D t r o l l e d n i c c l y w i t h a d c v i c c s u c h a s t h c M E 6 0 . T h c b c s t
wuy to '\ec
whal room acoustics are doi,rg lo your sound is
1o lsc either a real time analyzer or any ofthe many conlputer-
ized measurcnrcnt s)'sicms such as limc delay spcctromciry or
o t h e r s i m i l a r d e v i c c s . T h i s t c s t c q u i p m c n l l c t s ) o u a n a l y z e t h e
r e s p o n s e o f l h e r o o m a n d t h c s o u n d s y s t e m : n d i s t h c o n l y
accurale nreans lvailabl. for seltiDg an cqunlizcr properly.
I t i s a v e r y g o o d i d e a r o a l w a l s u s c a s l i l l l e e q u a l i z a t i o n a s
possiblc. tl modesl a ounts (try to not use more than 6-8dB)
o f c q u a l i z a t i o n d o n o t s o l v e t h e p f o b l e m . t h e n o t h e r n r e a n s
Use the BYPASS switch to conpare €qualized with
unequaljz€d sound. Compare the two and set the equalizer as
besl you can using controlled noise sources, sweep signals. or
sourcc male.ial drat you are very fanliliar wirh. Try io avoid
adding too nuch low end. This is an area where equalizers arc
ltequcntly abused, causing lots ofunDecessary stress on
amplificrs and speakers. This is padicularly imporrant when
using any soft ofvented enclos rc low liequency drivers. Too
much level applied to a woofer belolv the cutoti frcqucncy of
its enclosure carscs very large speaker excursions nnd very
shon 1iIc.
TONE CONTOURINC with the ME 60 is accomplished
nainly by car. This you know how to do. Be careful rbough.
nol 1o inlroduce loo much boosi to lhc upper bass area (of the
sub-bass arca as in the last warning). Bc awarc $at the ME 60
is upable ofboosring signah up to l2dB (4 times as largeli
a level at which great carc should be taken lo prcvcnt scismic
IMPORTANTNOTE
CHASSIS GROUNDING
Rane professional equalizers are supplicd witb a rcar
rnounted ground lift switch. The unit is shippcd !vnh dris
switch in the "grounded" position, iying circuit ground
to chassis ground. Ifalter hooking up your system it
exhibits excessive hun o. brzzing,lhere is an incompat-
ibility in the grounding configuration betweer units
somewherc.
Your mn.ioF \hould \ou Jc.ep' it. i. ro
discover how your particrlar system wants to be
grounded. Herc are some things to try:
l. T.y combinations oflifting grounds on units rhat
are supplied with ground 1ili switches or links.
2. Ifyour equipmenl is in a rack. v€rify that all
chass's are tied to a good earth ground, eilhcr through
the line cord grounding pin or the rack scres$ to anolhcr
L Units with oulboard power supplies do NOT
ground the chassis through the'r I'ne €ords. Make sure
these units ar€ grounded eitherto anolher chassis which
is earth grounded, or directly to the grounding screw on
an AC outlet cover by ineans ofauire connecled io a
screw on the chassis with a star washer to guarantee
OR:rne CorDoration 10802 47th Avenue Wcst. Mukiltco WA 98275-5098 TEL(206) 355-6000 FAX(206) 3,17-7757
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All terturcs & spcciticalions subjcct lo changc +irho nolice 520-41I lLJNt5