NHT 3.3 User manual

Tower
Models
3.3,
2.5i,
VT-2
and
VT-l.2
Subwoofer
AmplifiersSA-3
andSA-2
NowHearThis
535GettyCourt
Benicia,CA94510
800-NHT-9993
707-747-1252tax
www'nhthifi.com

Howdoyou
turn
the
passive
subwoofer
section
ofanNHT
towerspeaker
intoafully
adjustable
pow-
ered
subwoofer?
Howdoyou
customize
low
frequencybalance
forany
room?How
doyou
increase
thedynamics
and
power
handlingofyour
speakers?
Takeadvantage
ofNHT'Soutboard
subwoofer
amplifiers
tobiamplily
any
NHTtower
speaker!
Biamplification
istheuseoftwoseparate
amplifiers,
one
topower
thelow
frequency
(subwoofe0
dri-
versand
onetopower
theupper
lrequency
(midrange
/ tweeter)
driversTheadvantages
ofbiampli-
ficationinclude
reduced
distortion,
increased
dynamic
rangeand
power
output.since
both
ampli-
fiersarespared
the
taskofreproducing
theentire
frequency
range,
both
areabletoconcentrate
all
oftheir
power
toward
a specific
lrequency
range.When
thespeakers
are
driven
tohighly
elevated
listening
levels,it
islikelythe
subwoofer
amplifier
willclip
first,but
this
distortion
willbe
isolated
from
the
upper
frequency
ranges
because
theyareamplified
separately.
Biamplifying
towerspeakers
withthe
NHTsubwoofer
amplifiers
results
inadded
benelits,
asittrans-
forms
th;ir-built-in
subwoofer
sections
intofully
adjustable
powered
subwoofers.
Using
theSA-2
or
SA-3's
onboard
bass
tuning
functions,
theuser
canfine-tune
atower
loudspeaker's
bass
response
foraspecific
listening
environment.
Forexample,
ifthe
speakers
areused
inaroomthat
tends
to
under-emphasize
orbver-emphasize
lowfreqUencies,
itis
possible
to
increase
ordecrease
the
vol-
ume
level
ofthesubwoofer
sections
independently
ofthe
upper
driversections,
Additionally,
the
subwoofer
amplifier's
low-pass
crossover
allows
theuser
toadjust
the
rollotf
oflowfrequencies
to
thesubwoofer
sections
of
thespeakers,
for
furtherfine{uning
oflow-
tomid-bass
frequencies.
Towers
maybebiamplified
monaurally
using
asingle
subwoofer
amplifier
(her6alter
called
"sA') and
afull-range
main
(stereo)
amplifier,
orbiamplified
in
stereousing
twosA's
and
amainamplifier.
Additiona'ily,
thetowers
maybe
biamplified
either
inseriesor
in
parallel.
Wired
inseries
(Method
#1),the
m;inamplifier
receives
afiltered
line-levelsignal
via
thehigh-pass
output
from
theSA
Wiiedin
parallel(Method
#2),
boththemain
amplifier
andthe
SAreceive
full-range
signalsdirectly
fromthe
preamplifier.The
main
amplifier
maybeastand-alone
stereounit,
dual
monoblocks,
orthe
amplifier
sectionof
anintegrated
amplifier
orfuV
receiverthat
teatures"Pre-Out"
and
"Main-ln"
lacKs.
AllNHT
tower
loudspeakersare
designed
withdualsets
ofbinding
posts
toallow
forbiamplification.
The
followingchart
providesguidelinesfortheoptimal
biamplification
configuration
foranyNHT
towerspeaker.
Inallcases,
twosA'smaybesubstituted
forone
toprovide
enhanced
performance.
MODEL SUB,AMP

This
connectionmeihod.outes
thefull-range
linejevel
signalfromthe
preamplifier
through
theSA,which
passes
ona
high-pass
tilleredsignal
tothemain
amplifierand
powers
thesubwoofer
seclionsotthe
speakersdirectlywith
alow-pass
filtered
signal.Do
!q! uso
theroceiver's
"subwoofer
out"
jacks
toconnect
thesA,asthissignal
alreadycontains
low-
Pass
filtoring.
1.Run
a pair ofRCAintorconnect
cables
fromthe
preamplifier
outputtothe
SA,sLINEIN
iacks.
2.Run
apair ofRCAinterconnect
cablos
fromlheSA,s
LINEOUT
jacks
tothemainamplifie/stine-level
inputs.
3.Remove thebinding
post
jumpef
slrapsfromthetowor
speaker
(VEFY
tMPORTANTI).
4.Flun
speakercablesfrom
themain
amplifier'sspeaker
outputterminalstothetowerspeakers,
upper
pairs
ot
bhding
posts.
5.Run asecond
pair
ofspeakercablesfrom
theSA's
SUBWOOFEROIJTPUT
terminaltothe
towerspeakers,
lower
pairs
ofbinding
posts(both
sp€akers).Since
there
js
ontyone
SUBWOOFEROUTPUT
terminatonthe
SA,conneclboth
speakercablestothesingleterminal,
Note:When
biamplfyingwithtwo SA's (onefoteachtowetspeaket),tun theleftchannetRCAinterconnect
cable
totheleftchannelSA'sLINElN "L"lack, thenoutfrcn itsLINEOIJT
"L jacks.Runtheight channetRCAintet-
connectcableto therightchannelSA'6LINEtN,'n,'jack, thenoutfrcn iE LiNE
OUT"R. jack.
NHfTowerBlndlng
Polb
Hlsh/Ml.l
;;.Bf4Yfr
NHTSubwoofer
Amplifl.r

3.
Thisconnection
methodresultsinsendingafull-rangeline-levelsignaltobolhthemainamplifierand
theSA. lfyou
haveareceiverwith"Pre"Out"jacksbut
no
"Main-ln"
jacks,
you
canusethe"Pre-Ouf'jacksloconnoct
lhe
SA,
wilhout
havingtoroutethesignalbackto
thereceiverDo
ngt
usethereceive/s
'Subwoofer
Out'
jacks
toconnect theSA,as
thissignalalreadycontains
low-passfillering.
llyou haveaseparate
preamplilier
that
featurestwosetsoflineouiputs,eachset
is
connected
tooneamplifierlfthe
preamplifier
featutesonlyonosotofline outputs,
use"Y'-adaptorslosplitthesignal.
'1.
Run
a pair
ofRCAinterconneclcables
from
preamplifier
output#1totheSA'sLINE
lN
jacks.
2.Runasecond
pair
ofRCAintorconnectcablesfrom
preamplifier
output#2tothe
mainamplifier'slineinputs,
Removethebinding
posi
iumper
straps
fromihetowerspeaker
(VERY
IMPORTANTI).
Flunspeakercables
from
the
main
amplifier's
speakeroutputterminalstothetower
speakers'upper
pairs
of
binding
posls.
5,
Runasecond
pair
ofspeakercables
fromthe
SA'sSUBWOOFER
OUTPUTterminaltothetowerspeakers'
lower
pairs
ofbinding
posls(both
speakers).Since
thereisonlyoneSUBWOOFEROUTPUT
terminalonthe
SA,conneclbothspeakercables
tothe
single
terminal.
Note:WhenbiamplifyingwithtwoSA's,run
RCAinterconnectcablestoeith€rtheSA'sleftottightLINEtN
iacks.Fol
morc
gain,
usea "Y"-adaptor
toutilizeboth theleftandight inputs.
NHTTowcrAlndlngPotb
High/ ld
NHTSubwooferAmplifier

Thisconnection
method
maybeemployed
ifyour
receiverhas
noline-level
preamplifier
outputof
anysort.Thespeakers
andthesA-2areconnected
inparallel
offthereceive/sspeaker
output
ter-
minals.
lfyour receiver
hastwosets
ofspeaker
outputterminals
("Speaker
A"and
"Speaker
B"),
you
mayconnect
thespeakers
directly
from
"Speaker
A"andconnect
theSA-2
from
"Speaker
B".
L Removethebinding
post
jumper
straps
fromthetower
speaker
(VERY
IMPORTANT!)'
2,Run
speakercables
from
thereceiver's
"Speaker
A"outputterminals
tothetowerspeakers'
upper
pairs
ofbinding
posts.
3,Funasecond
pair
ofspeaker
cablesfrom
thereceivels
"Speaker
B"output
terminals
tothe
SA-2's
INPUT
FROMAMPLIFIER
barrierstrip
terminal
lfthe
receiver
hasonlyoneset
of
speaker
output
terminals,connect
both
pairs
ofspeaker
cables
in
parallel
fromthesame
ter-
mtnar.
4.Bun
two
pairs
of
speakercables
fromtheSA'2's
SUBWOOFEF
OUTPUT
tothetower
speakers'lower
pairs
otbinding
posts(both
speakers)
Since
there
isonlyone
SUBWOOFER
OUTPUT
terminal
ontheSA-2,
connectboth
speakercables
tothe
singleterminal
Do
nql
usetheSA-2's
OUTPUTTO
SATELLITES
barrierstrip
terminal.
NHT
TowerBinding
P6sts
High/lvlid
NHTSubwoofer
Amplifier

r RecommendedSASettings
forBiamplification:
1.
SUBWOOFER
PHASE:O'. lfthemainamplifier
inverts
phase,
use180".lf
you
areunsure
about
this,selectthesettingthatresults
inhigher
bass
outputwiththevolumecontrol
unchanged.
2.SUBWOOFER VOLUME:Adiustfor aecuracy,
listeningforseamlessblendingbetween
upperand
lowerfrequencyranges.Whenchangingelectronics,
itmaybecome
necessaryto
re-adjust
the
SA's
volumeievel,sincethecorrect
volumesettingdependsonthesensitivity
of
partnering
electronics.
3.SATELLITE/ HIGH-PASSFc(High-pass
filter):Set
to lowest
position(50H2
on SA-2;
65Hzon SA-3). THISSETTINGONLYAPPLIES
TABIAMPLIFICATION
METHOD#1. IF
YOUAREUSING
METHOD#2 OR#3, IGNORE
THISSETTING.
SettheSA's
high-passfilterto itslowestsettingtoensure
thattheSA'shigh-pass
filter
does
notinterfere
withthetowerspeaker's
passive
crossover.
Inotherwords,theSAsends
only
informationfrom50Hz-up
tothemainamplifier
(and
consequently
thespeaker'supper
range
drivers).
Thespeaker
itselfthenfiltersthesignalfurther,according
tothelow-pass
filter
designed
intoitspassive
crossover.
4,SUBWOOFER / LOW-PASS
Fc(Low-pass filter):Setto highsstposition(l50Hz), Setthe
SA's
low-passfiltsrtoitshighest setting
sothattheSA'slow-pass
filterdoesnotinterferewith
thetowerspsaker's
passive
crossover.
Inotherwords,theSAsendsonly
informationbelow
150H2tothespeakelssubwoofersection,
Thespeakeritselfthen
filtersthe
signal
further,
according
toth6high-pass
lilter
designed
intoitspassive crossover,
r BassTuning
Functions
Thefollowingtwobasstuning
functionscan
beemployedtofurther
"dialin"atower speaker's
bass
response,
usingtheSA's onboardlow-pass
filter
1.ll thereisexcessive
mid-bass,
lowertheSA's
low-pass
setting
(SUBWOOFER
/ LOW-PASS
Fc)until
themid-bass responseissmoothedout. LoweringtheSA'slow-passsettingallows
gradually
increasedfilteringofthebassinformationbeforethesignalreachesthespeaker's
passive
crossovernetwork.
2.ll thereis notenoughlow bassoutput,lowertheSA'slow-passsettingandincreaseitsvol-
ume.Thisbasstuningmethod
allows
thelistenertodecrease themid-bassresponse,
but
in
conjunctionwithincreasedoutputfromthe
subwooferamplifier.
This
effectively
increases
the
audibilityoflowbassinformation.
3.Experimentwith phase.