JBL 12MB3P Rev.00 06 Ing Spec Sheet

User Manual: JBL JBL - Manuals+

Open the PDF directly: View PDF .
Page Count: 2

SPECIFICATIONS

Nominal diameter .............................305 (12) mm (in)

Nominal impedance..................................8 Ω

Minimum impedance @ 306 Hz.......................6.4 Ω

Power handling

Musical program¹...........................1000 W

AES²......................................500 W

Sensitivity (2.83V@1m) averaged from 200 to 2,000 Hz . . 101 dB SPL

Power compression @ 0 dB (nom. power) . . . . . . . . . . . . . . 2.6 dB

Power compression @ -3 dB (nom. power)/2. . . . . . . . . . . . 1.6 dB

Power compression @ -10 dB (nom. power)/10. . . . . . . . . . 0.8 dB

Frequency response @ -10 dB . . . . . . . . . . . . . . . . 90 to 4,000 Hz

1

2 AES Standard (200 - 2,000 Hz).

THIELE-SMALL PARAMETERS

Fs...............................................61 Hz

Vas.........................................51 (1.80) l (ft³)

Qts.............................................0.48

Qes............................................0.50

Qms...........................................12.55

ηo (half space)...................................2.28 %

² ²

Sd......................................0.0530 (82.2) m(in)

3 3

Vd (Sd x Xmax).............................66.3 (4.05) cm (in)

Xmax (max. excursion (peak) with 10% distortion) . . . 2.75 (1.1) mm (in)

Xlim (max.excursion (peak) before physical damage).10.0 (0.4) mm (in)

Atmospheric conditions at TS parameter measurements:

Temperature...................................24 (73) °C (°F)

Atmospheric pressure............................1,016 mb

Humidity..........................................50 %

Thiele-Small parameters are measured after a 2-hour power test using half AES power .

A variation of ± 15% is allowed.

ADDITIONAL PARAMETERS

βL .............................................14.7 Tm

Flux density .....................................1.02 T

Voice coil diameter .............................100 (4) mm (in)

Voice coil winding length. . . . . . . . . . . . . . . . . . . . . . 18.0 (50.0) m (ft)

Wire temperature coefficient of resistance (α25). . . . . 0.00410 1/°C

Maximum voice coil operation temperature. . . . . . . . 304 (582) °C (°F)

θvc (max.voice coil operation temp./max.power) . . . 0.6 (1.14) °C/W(°F/W)

Hvc (voice coil winding depth) . . . . . . . . . . . . . . . . . 13.5 (0.53) mm (in)

Hag (air gap height)...........................8,0 (0.31) mm (in)

Re..............................................5.3 Ω

Mms....................................52.0 (0.1146) g (lb)

Cms............................................130 µm/N

Rms.............................................1.6 kg/s

NON-LINEAR PARAMETERS

Le @ Fs (voice coil inductance @ Fs) . . . . . . . . . . . . . . . . . 1.666 mH

Le @ 1 kHz (voice coil inductance @ 1 kHz). . . . . . . . . . . . 0.475 mH

Le @ 20 kHz (voice coil inductance @ 20 kHz). . . . . . . . . . 0.123 mH

Red @ Fs.........................................0.36 Ω

Red @ 1 kHz......................................2.18 Ω

Red @ 20 kHz....................................14.85 Ω

Krm...............................................8.1 mΩ

Kxm .............................................24.3 mH

Erm..............................................0.64

Exm .............................................0.55

Power handling specifications refer to normal speech and/or music program material,

reproduced by an amplifier producing no more than 5% distortion. Power is calculated as

true RMS voltage squared divided by the nominal impedance of the loudspeaker.

ADDITIONAL INFORMATION

Magnet material.......................................Barium ferrite

Magnet weight................................2,640 (92) g (oz)

Magnet diameter x depth. . . . . . . . . . . . . . 200 x 24 (7.87 x 0.95) mm (in)

Magnetic assembly weight . . . . . . . . . . . . . . . . . . . 6,600 (14.55) g (lb)

Frame material ..........................................Aluminum

Frame finish ...........................................Black epoxy

Voice coil material........................................Aluminum

Voice coil former material.....................................Kapton

Cone material........................................Long fiber pulp

3

Volume displaced by woofer . . . . . . . . . . . . . . . . . . . . 4.6 (0.162) l (ft )

Net weight.................................7,450 (16.42) g (lb)

Gross weight ..............................8,200 (18.07) g (lb)

Packing dimensions (W x D x H). . 35,5 x 34,5 x 16 (13.9 x 13,6 x 6,3) cm (in)

MOUNTING INFORMATION

Number of bolt-holes..................................8

Bolt-hole diameter.............................7.0 (0.28) mm (in)

Bolt-circle diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 (11.57) mm (in)

Baffle cutout diameter (front mount).. . . . . . . . . . . . . 281 (11.06) mm (in)

Baffle cutout diameter (rear mount). . . . . . . . . . . . . . 275 (10.83) mm (in)

Connectors................................Silver-plated push terminals

Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . Positive voltage applied to the positive

terminal (red) gives forward cone motion

Minimum clearance between the back of the magnetic assembly and the

enclosure wall....................................75 (3) mm (in)

Dimensions in mm.

12" for midbass professional sound reinforcement.

Offering high power capacity, outstanding mid range response

and exceptional long-term performance, this transducer is ideal for

compact enclosures (closed, vented or horns). This transducer exhibits

excellent acoustics with work horse construction. Designed for smaller

enclosures, the 12MB3P is a versatile high performance midbass.

General construction includes a sturdy cast frame, impregnated

cloth surround, stable spider and a large central vent channel for

reducing long-term heat build-up.

8x ø 7

ø 208

ø 279

ø 312

ø 294

118

46 61 11

MIDBASS

12MB3P

145.7 (8.90) cm³ (in³)

HARMONIC DISTORTION CURVES MEASURED AT 10% AES INPUT

POWER, 1 m

IMPEDANCE AND PHASE CURVES MEASURED IN FREE-AIR

TEST ENCLOSURE

24-liter volume, sealed box.

SUGGESTED PROJECTS

HB1206A1 HB1205A3 HB1205D1 PAS1MA1 PAS2MA1 PAS3MA1

PAS3MA2 PAS4MA1 PAS5MA1

For additional project suggestions, please access our website.

RESPONSE CURVES (0° AND 45°) IN A TEST ENCLOSURE INSIDE AN

ANECHOIC CHAMBER, 1 W / 1m POLAR RESPONSE CURVES

20 200 2k 20k

60

Hz

70

80

90

100

110

dB

Response Curve at 0°.

Response Curve at 45°.

20 200 2k 20k

0

Hz

50

100

150

200

ohms

Impedance Curve.

Phase Curve.

-90

-45

0

45

90

degrees

60

80

100

140

dB

200 20k

Hz

Response Curve.

Distortion Curve, 2nd harmonic.

20

120

Distortion Curve, 3rd harmonic.

HOW TO CHOOSE THE RIGHT AMPLIFIER

The power amplifier must be able to supply twice the RMS driver power. This

3 dB headroom is necessary to handle the peaks that are common to

musical programs. When the amplifier clips those peaks, high distortion

arises and this may damage the transducer due to excessive heat. The use

of compressors is a good practice to reduce music dynamics to safe levels.

FINDING VOICE COIL TEMPERATURE

It is very important to avoid maximum voice coil temperature. Since moving

coil resistance (R ) varies with temperature according to a well known law,

E

we can calculate the temperature inside the voice coil by measuring the

voice coil DC resistance:

T , T = voice coil temperatures in °C.

AB

R , R = voice coil resistances at temperatures T and T , respectively.

AB A B

α= voice coil wire temperature coefficient at 25 °C.

25

POWER COMPRESSION

Voice coil resistance rises with temperature, which leads to efficiency

reduction. Therefore, if after doubling the applied electric power to the driver

we get a 2 dB rise in SPL instead of the expected 3 dB, we can say that

power compression equals 1 dB. An efficient cooling system to dissipate

voice coil heat is very important to reduce power compression.

NON-LINEAR VOICE COIL PARAMETERS

Due to its close coupling with the magnetic assembly, the voice coil in

electrodynamic loudspeakers is a very non-linear circuit. Using the non-

linear modeling parameters Krm, Kxm, Erm and Exm from an empirical

model, we can calculate voice coil impedance with good accuracy.

















α

+−















−+=

25

A

A

B

AB

1

25T1

R

R

TT

Polar Response Curve.

MIDBASS

12MB3P

www.seleniumloudspeakers.com

Specifications subject to change

without prior notice.

Code: Rev.: - /

00NA 06 06

270°

50 Hz

30°

210°

60°

240°

90°

120°

300°

150°

330°

180°

0

-6

-10

-20

dB

100 Hz

30°

210°

60°

240°

90° 270°

120°

300°

150°

330°

180°

0

-6

-10

-20

dB

250 Hz

30°

210°

60°

240°

90° 270°

120°

300°

150°

330°

180°

0

-6

-10

-20

dB

500 Hz

30°

210°

60°

240°

90° 270°

120°

300°

150°

330°

180°

0

-6

-10

-20

dB

800 Hz

30°

210°

60°

240°

90° 270°

120°

300°

150°

330°

180°

0

-6

-10

-20

dB 90°

1,25 kHz

30°

210°

60°

240°

270°

120°

300°

150°

330°

180°

0

-6

-10

-20

dB

2 kHz

30°

210°

60°

240°

90° 270°

120°

300°

150°

330°

180°

0

-6

-10

-20

dB