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. The 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 rad iator gradually comes into effect,

reaching

full output above 7 kHz. This ultra-high frequency transducer, with an effective diameter of 1% inches, gives silky, effortless delineation of high-pitched transients and musical overtone

s.

Enclosure

As

in all

J8L

toudspeaker systems, transducer

s,

electricat network 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 the 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 unrelo

uch

ed

photo Sl

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ll 51nl:

wave

signa

l al 35 Hz A

laboldlory

..

micropho

ne

was used

10 PI' k up

Itl

ound

from

Model

4310.

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.,

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rcin

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microphone

.....

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direclly

to

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11

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rn

the

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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

cal ibrated

before

tests were run.

The

on-axis

response

of a

typical

system

does

not

vary

more

than ' 3 dB 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

frequ ency transducer.

Architectural specifications

The

loudspeaker

system shall co nsist

of

three

direct-

radiator

transducers

and freque ncy

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 approximat

ely 1

%"

and

a

gap

flux density

of

at

least 16,000 gauss.

The freq

uency

dividing network

shall

include

two

controls, a

ccessible

from the front

of

the system, to

adjust

relative intensities

of

"presence"

and "brilliance"

ranges respectively.

Set for flattest response,

th

e free-fi eld 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.

Performance claims

which

are

extrapolated

from the response

curves

of

individual

loudspeakers are

not

acceptable.

The

loudspeaker

system shall hav e a nominal

impedance

of 8 oh ms and a

power

capacity

of

at least

50

watts

program

materia

l.

The EIA sensitivity

of

the system

(30 feet on-axis with one milliwa tt i

nput)

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.

Lansing

Sound, Inc.

3249

Casitas

Ave

.,

Los

Angel

es,

Caltf.

90039

PPB.

431

0 117 3

P'ln1.

n U S

.A.