JBL MI-15a User manual

Musical Instrument Loudspeakers
The new JBL MI Series Loudspeak-
ers are engineered with the latest
advances in transducer design and
technologies to give you response that
is flat and even ...in tune with the
sound of the 80’s. They let you add the
color you want. And, they give you the
satisfaction of knowing you’re using
the world’s most popular line of speak-
ers for producing your music.
A careful evaluation of the Ml Series
proves they give you a lot more. The
frames are die cast.. .not cheap
stamped baskets. A die cast frame
provides a better heat-sink allowing
greater power handling and because a
die cast frame can’t flex, it reduces
resonances from the frame.
JBL ribbon-wire voice coil.
Syfrmefncal magnet/c held _ _
mmefncal magnehc
.
Cross-sections of JBL (left) and conventional magnetic structures.
The voice coils are fabricated from
special wire that has been milled into a
flat ribbon. Flat wire can be wound
more tightly than round wire, putting
more conductor (wire) in the gap. The
design is more efficient and more
rugged.
The voice coils are precision flat
wound, in four layers with staggered
seams. This construction is physically
very strong and resists deformation
from heat. The result is greater effi-
ciency and increased power handling.
The Ml Series loudspeakers feature
JBL Symmetrical Field Geometry
(SFG) magnetic structure, a design
that contributes to the clean sound.
Typical magnetic structures, with non-
symmetrical magnetic fields, add
significant amounts of distortion
because of the nonlinear pull such a
field exerts on the voice coil. (See
illustration).
If you’re looking for a speaker that
will let you produce today’s music, lis-
ten to the Ml Series at your JBL dealer.
The Ml Series loudspeakers are avail-
able in lo”, 12” and 15” models. Their
efficiency and power capacity are
greater than many extended range
speakers in their size ranges.. giving
you outstanding dynamic range and
extremely high accuracy. Use the Ml
Series speakers for your guitar, key-
board, or P.A. system. They directly
replace conventional speakers used in
guitar amplifiers, organs, electric pi-
anos, or other applications.
Combine the new Ml Series loud-
speakers with all new cabinet designs
and JBL expertise in system design
and you have the all new Ml Series
Component Systems.

MI Series Loucheakers and Svstems
JBL MI Series Features
Flat-Front Bi-Radial Horn/Titanium
L’ Diaphragm Compression Driver
Specifically designed for the MI
Series Compact Sound Reinforce-
ment System to provide excellent on-
and off-axis frequency response in the
horizontal plane. It has 90” horizontal x
40” vertical nominal coverage, with
uniform on- and off-axis frequency
response in the horizontal plane from
630 Hz to beyond 16 kHz. The high
frequency driver features a titanium
diaphragm with JBL’s patented dia-
mond-pattern surround. The excep-
tionally high stress limit of titanium
together with the stronger surround
allows this design to achieve the per-
formance of more expensive and frag-
ile exotic materials. The driver uses a
high energy strontium ferrite magnet
for maximum efficiency and extended
response
Composite %-octave polar responses of a flat
front Bi-Radial horn from 800 Hz-16 kHz in the
horizontal plane.
MI-631 -
JBL’s titanium-diamond diaphragm combines
performance with reliability
Frequency Dividing Network
The frequency dividing network
used in the MI Series Compact Sound
Reinforcement System uses the high-
est quality electronic components-
non-inductive, non-polarized mylar
capacitors and air-core inductors and
are tailored to optimize the crossover
response.
MI Series
Component Systems
The Ml Series Component Systems
are the easy, professional way to give
your audience the sound they
deserve.
Newly engineered for music re-
production and general sound rein-
forcement in small to moderate sized
rooms. The systems feature JBL’s
specially designed flat-front Bi-Radial
horn and compression driver mounted
flush in the cabinet to eliminate the
problems of midrange narrowing and
high frequency beaming associated
with conventional horn designs. The
directional baffle enclosure increases
directivity for greater mid-range
punch, and low-frequency venting
extends bass response and lowers
distortion.
The cabinets are optimally tuned
enclosures engineered specifically for
each intended application.
And, they’re built to take the rigors of
the road. The cabinets are constructed
with a new wrap-and-fold technology,
using a high density wood-resin com-
pound for maximum strength and are
covered with durable industrial-grade,
reinforced pebble grained material.
Corners are protected with heavy
hi-632~ -

gauge metal.. .professional, recessed
road handles lock in place to prevent
unwanted vibration and noise during a
performance.. .input and output jacks
are recessed for protection. Naturally,
the drivers are protected by a heavy
mesh screen.
Audition the JBL Ml Series Systems
at your JBL dealer. ..their flexibility
makes them ideal for most of your
sound reinforcement applications.
MI-630 Vocal Reinforcement
System
Newly designed for vocal reinforce-
ment and general music reproduction
in small to moderate sized rooms. The
Model MI-630 and Ml-634 include integral
mounting hardware for use with the tubular
aluminum tripod stand, Model MT-4612.
MI-630 features the patented JBL flat-
front Bi-Radial’” horn and compres-
sion driver mounted flush in the cabi-
net to eliminate the problems of
midrange narrowing and high fre-
quency beaming associated with
conventional horn designs.
MI-631 Stage Monitor
Smooth, wide frequency response
(60 Hz-l 5 kHz), uncolored reproduc-
tion, and high directivity make this an
ideal stage monitor, acoustic instru-
ment system or even a small general
purpose vocal reinforcement system.
The system uses the Ml Series 12 inch
loudspeaker and flat front Bi-Radial’”
horn and compression driver.
MI-632A Horn-Loaded Sound
System
The MI-632A is a newly re-designed
system and features the new Ml-l 5A
380 mm (15”) woofer with its copper
ribbon voice coil, giving the MI-632A
balanced bass with a smooth and con-
trolled sound. A three-position HF
level control switch allows precise tai-
loring of the tonal balance between
horn and woofer.
Model Ml-634 Direct-Radiator
Sound System
The Ml-634 Direct-Radiator Sound
System is a newly designed vented
enclosure system using the JBL Flat-
Front Bi-Radial’” horn and compres-
sion driver and the new Ml-l 5A 380
mm (15”) low frequency driver to pro-
vide smooth, uncolored response and
wide bandwidth with bass response
down to 50 Hz and high-frequency
response to 20 kHz. The smooth,
natural sound of the Ml-634 makes it
ideal for vocal and acoustical instru-
ment reinforcement and general
sound amplification in small to mod-
erate sized rooms.
MI-291 High Frequency Power Pack
The MI-291 System offers the JBL
Flat-Front Bi-Radial’” horn and
compression driver as a separate add-
on system which allows simple instal-
lation to existing systems.
MI-ZY I
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MI-W4 -

MI Series Specifications
MI Series Loudspeaker Specifications
Specifications MI-l0 MI-12 MI-15A
Nommal Diameter 250mm 300mm 380mm
10 in 12 I” 15 I”
Nominal Impedance 00_ 8R 0R
Power Capacbty
AES or EIA Shaped Noise 150 W 150 W 150 W
Sensitivity * 1 W @ 1m (3.3 ft) 98 dB SPL 100 dB SPL 102 dB SPL
Frequency Range 70-8000 Hz 60-7000 Hz 40-6000 Hz
Voice Coil Drameter 51mm 51mm 51mm
2 in 2 I” 2 I”
Votce Co11Matenal -Alumrnum Rrbbon - Copper Rrbbon
Magnetrc Assembly Werght 2.5 kg 2.5 kg 2.5 kg
5% Ibs. 5% Ibs. 5% Ibs.
Flux Density 1.05 tesla 1.05 tesla 1.05 tesla
(10,500 gauss) (10,500 gauss) (10,500 gauss)
Frame Material
Baffle Cutout Diameter Diecast Aluminum
Front or Rear Mount
Depth
Net Wetght
22t3mm 281mm
9 I” 11-1161”
116mm 137mm
4% I” 5% I”
2.7 kq 3 ka
6 Ibs: 6%-lbs.
*Sensitivitymeasured with an input averaged from 500 Hzto 2.5 kHz
351mm
13-13116 in
162mm
6% in
3.2 ko
7 Ibs:
Thiele-Small Parameters Ml-l 0 Ml-l 2 MI-15A
f, W-4
75 65 40
R, (ohms) 5.6 5.6 5.6
Qts .33 .46 0.42
Qms 1.8 2.2 2.8
Qes 0.41 0.58 0.49
vas (L) 35 75 270
(cu ft) 1.25 2.7 9.6
Sn (m*) ,034 ,055 089
- (in’) 52.5 85.5 138
Xmax (mm) 3 3 4
(In)
.12 .12 0.16
VD (cm? 100 165 356
(in3) 6.0 10.1 21.8
f-e (mH) 0.6 0.6 0.8
~0 (Half space) (%) 3.5 3.5 3.5
MI Series Component System Specifications
Frequency Power Capacity
Range (Continuous Sensitivity’
(Continuous Nominal 1 W, lm Nominal Crossover
Model (-IOdB) Exterior Dimensions
Pink Noise) Program) Net
Impedance (3.3 ft) Dispersion Frequency (Height x Width x Depth) Weight
MI-291 1.5-l 5 kHz 150w 300 w 8
ohms 105dB 90h x 4Ov 1.5 kHz 127mm x 387mm x 248 mm 4.5 kg
5 in x 15% rn x 9% rn 10 Ibs
MI-630 60 Hz-l 5 kHz 150w 300 w 8 ohms IOOdB 90h x 40~ 2.0 kHz 533mm x 454mm x 287mm
i
22 kg
21 in x 17’/8 in x 11% rn 48 Ibs
MI-631 60 Hz-l 5 kHz 15ow 300 w 8 ohms 1OOdB 90h x 4Ov 2 kHz 349mm x 434mm x 530mm 21 kg
13% m x 17% In x 207/8rn 46 Ibs
MI-632A 45 Hz-15 kHz 150w 300 w 8 ohms 104dB 90h x 4Ov 1.5 kHz 826mm x 61Omm x 445mm 45.5 kg
32% rn x 24 in x 17% rn 100 Ibs
Ml-634 40 Hz-l 5 kHz 150w 300 w 8 ohms 102dB 90h x 4Ov 1.5 kHz 686mm x 559mm x 292mm 34 kg
27 in x 22 rn x 11% in 75 Ibs
‘Sensltlvrtymeasured with an Input averagedfrom 500 Hz to 2 5 kHz