JBL 4310 User manual

RECORDING CONSULTANTS, INC .
po. f,OX 86
KENSINGTON, MD . 20795
(301 ) 770·7790
The 4310 was developed by JBL in cooperation with leading
recording studios
to meet the need for a powerlul, yet compact,
professional monitor. The ability of the 4310
to reproduce the full
audible frequency range at loudness levels required in professiona
work make
it a perfect choice lor control room installations,
small studios,
mixdown facilities and portable playback systems.

JBL Model 4310 control room monitor
Loudspeaker components
Frequencies up to 1500 Hz are reproduced by a powerfut long-
excursion
12" woofer having a 3-inch diameter edgewound
copper ribbon voice coit operating
in a magnetic field of 9,200
gauss. The magnetic assembly weighs six pounds; free air
cone resonance is a very low 27
Hz .
The transition from the low frequency loudspeaker
to the
midrange transducer
is made through a crossover frequency of
1500
Hz . Above thi s point, the midrange unit provides the clarity
and freedom from distortion required in professionat work, even
at
very high loudness levels.The husky 5-inch transducer weighs 2.85
Ibs. and has a Va" diameter edgewound copper ribbon voice coil
operating in a magnetic field
of 16,500 gauss. Th e 4-inch diameter
edge-damped cone operates as a true piston, giving smooth
response and wide dispersion through its operating range.
Above 3 kHz a third direct radiator gradually comes into effect,
reaching full output above 7 kHz. This ultra-high frequency trans-
ducer, with an effective diameter of 1% inches, gives silky, effort-
less delineation of high-pitched transients and musical overtone
s.
Enclosure
As in all J8L toudspeaker systems, transducer s, electricat net-
work and acoustical enclosure are designed and tested to work
together
as a single integrated system. The 4310 enclosure is
solidly constructed of
%-inch stock throughout, with lock-mitered,
wood-welded joints
to prevent unwanted resonance. All loud-
speakers are removable from
th e front of th e enclosure. The
high frequency transducers are mounted on a raised auxiliary
baffle for widest possible dispersion, and to suppress cavity
resonances and diffraction effects. A ducted port provides added
acoustical loading
in the very low frequency range to increase
efficiency and reduce distortion.
T his un relo uch ed photo Sl 10W5 Ill. acousllc ou l pu at Ihe 5ysilOm
when Jdv n ~y a 50 Wa ll 51nl: wave signa l al 35 Hz A laboldlory ..
micropho ne was u sed 10 PI' k up Itl ound from Model 4310. The .,
sign<ll f rcin IIle microphone ..... ,lS connecled direclly to ;"In nsci l lo-
scope dnd the tl ace pholO rilpll d
Susla i ned p"dOrmal11 e al IhlS Inl enslly ',(Ju lJ not be encoun l erpJ
J urinq n, r ma l us~ 01 ourse A 50 • <lit <,Ino ~ l\ e slgndl Is , "
more drfflclli t jub I r th!> pf'ak r Ih"n rt~ r rlt'd r 'rdClly of 50 watts
prog r am nlaterr 11 espec i ally rn the v Iy lov. fro 'Ill n<"y range Even
so It Cdn be seen 1I1i.(1 I lle 43 10 plodllr .. '.In tlrno~t per l ect repl lril
tJf ttle Inpu t sional I alow 50 HI mo I mOllltul IJudspcdhels p,o-
dure ~\Jhst,H1tl3 l distal ti OIl will i olily ;J It 'I, ,',;tIts m[lll i J
L oudsped"el l~mp nenls of M d,' 14310

Adjustable response contour
Recessed front panel controls allow separate adjustment of the
1500-7,000 Hz
"presence " range and the 7,000-15,000 Hz "bril-
liance " range. Controls are continuously variable from maximum
to full off. With suitable settings of the two controls , the fre-
quency response contour of the 4310 can be altered to compen-
sate for almost any acoustical environment, and to achieve the
exact tonal
balance desired. Control scales are clearly marked
so that special settings can be logged and easily reset
when needed.
Performance characteristics
The accompanying graphs and specifications were compil ed
from
measurements made under standard laboratory test con-
ditions : The loudspeaker system was mounted flush in the center
of a large flat baffle in an anechoic environment. A calibrated
condenser microphone was suspended at a known distance from
the sound source, sufficiently far to be safely out of the near
field. All associated electronic equipment was checked and
calibrated
before tests were run.
The
on-axis response of a typical system does not vary more
than ' 3dB from 45to 15,000 Hz. Because of the wide - angle
characteristics of the high frequency transducers and their physi-
cal orientation , response measured up to 45 ' off-axis, either hori-
zontally or vertically, does not deviate more than 6 dB from on-axis
response at 2 kHz or more than 10 dB at 8 kHz. The 4310's lack
of distortion is equally outstanding . Distortion is inaudible even at
high pow
er levels and very low frequencies, as shown in the
photo at left.
While the specifications indicate that Model 4310 has impres-
sive performance characteristics, they cannot convey the full
impact of an extended listening evaluation . Clean, crisp , wide
range performance even at very loud levels, .. powerful bass
fundamentals
without doubl ing ... lifelike voice projection ...
these are
qualities found in few loudspeaker systems regardless
of size or price. When heard from a monitor occupying less than
2.5
cubic feet, the effect is little less than awesome. No other
loudspeaker system approaches the JBL 4310 in its combination
of versatility, performance quality and small size.
, ,S
'10
's
-s
-'0
-,s
20
"s
11 0
-s
-10
- ,s
20
(
---.::........~---~
'00
Frequency In Hz 1000 '0.000
Response contour of system with controls set "flat."
(Presence sel
at "2, " Brilliance sel at "7. ")
Measured
on-axis response of a typical 4310, including
all peaks and dips,
docs not deviate more than 3 dB
from above curve.
'00
Frequency In Hz 1000 10, 000
Response contours showing effects of various "pres-
ence" and " brilliance" control settings ,
Section drawing of 12-inch low frequency transducer.

Architectural specifications
The loudspeaker system shall consist of three direct-
radiator transducers and frequency dividing network
installed in a tube-port ed enclosure. Loudsp eakers, ne t-
work and enclosure are to be manuf actured and assem-
bled by a single
manufactur er. Components shall be
removable from the front
of the enc losur e. High fre-
quency transducers shall be mount ed on a raised baffle
to suppress cavity and diffraction effects .
The low frequency loudspeaker shall have a 3" edge-
wound copper ribbon voice coil operating in a magnetic
fi eld of at least 9,000 gauss. A heavy duty 5" transducer
shall reproduce the range from 1500 to 7,000 Hz. It shall
have a
7'8 " edge wound copper ribbon voice coil operating
in a magnetic field of at least 16 ,500 gauss. Frequenc ies
above 7 kHz shall
be reproduced by a third direct radia-
tor having a cone
diameter of ap proximat ely 1 %" and
a
gap flux density of at least 16 ,000 gauss.
The fr eq uency dividing ne twork shall include two
controls, a
ccessible from the front of the system, to
adjust relative intensities of "presence" and "b rilliance"
ranges respectively.
Set for flattest response,
th e free-field response of a
typical system shall not vary
mor e than ±3 dB from 45
to 15 ,000 Hz. Response measured up to 45' off axis,
either hor izontally or vertically, shall not deviate
more than 6 dB from on-axis response at 2 kHz, or
more than 10 dB at 8 kHz. These specif ications include
the effects of the dividing network and any interaction
between transducers. Performanc e claims which are
extrapolated from the response curves of individual
loudspeakers are not acceptable.
The
loudspeaker system shall have a nominal impedance
of 8 ohms and a power capacity of at least 50 watts
program materia l. The EIA sensitivity of the system
(30 feet on-axis with one milliwatt i
np u t) shall be
approximately 42 dB.
The enclosure shall be solidly constructed of 3/
4
-inch
stock with all joints tightly fitted and glued. Overall
dimensions shall be no greater than 24" x 15 " x 12"
deep. Finish shall be textured gray with charcoal
grille fabric.
Model 4310 specifications
Power capacity
50 watts program
Crossover 1500 and 7,000 Hz
Nominal impedance 8 ohms
Dispersion 90 " horizontal and vertical
Frequency response 45-15,000 Hz : +: 3 dB
Sensitivity 42 dB at 30 feet with one milliwatt in-
put, averaged 500 to 2500 Hz,
with
controls set for flattest response.
(Because of its uniform response
over the full audible frequency
range, the sensitivity of Moder 4310
below 500 Hz or above 2,000 Hz may
be
considerably greater than that of
other systems with higher published
sensitivity ratings.)
Finish Oiled walnut or textured gray with
charcoal grille fabric.
Dimensions
23%" x 14%" x 11%" deep
60 x 36 x 30 cm
deep
Shipping weight 51 Ibs.
23 Kg.
Jam es B. Lans i ng Sound , Inc. 3249 Casitas Ave ., Los Angel es, Caltf. 90039
PPB. 431 0 1173 P'ln1. n U S .A.