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WF182BD17/18/19/20     7” die cast, black coated paper/glass fiber cone

 

 

 

 

 

 

Balanced Drive

The 7” transducers WF182BD17 and WF182BD19 (both 4 ohm), and WF182BD18 and WF182BD20 (both 8 ohm) were designed as high performance bass and midrange units for  monitors and high-end hi-fi speakers. They offer outstanding deep bass performance and dynamic and detailed midrange.

Mid/woofers WF182BD17/18/19/20 are black coated versions of models WF182BD09/10/11/12.
No other differences.
Specifications are identical coated/non-coated.

Frequency resp.
Downloads
Specifications
Dimensions
Ordering info

Above: Round version (WF182BD17, WF182BD18)
Below: Truncated version (WF182BD19, WF182BD20)

FEATURES

WF182BD19_20_front_view
  • Balanced Drive motor structure for optimal drive force symmetry resulting in largely reduced even order harmonic distortion
  • Copper cap on center pole to reduce voice coil inductance and to minimize variations in voice coil inductance as a function of voice coil position
  • Cone made of a new paper/glass fiber mix with improved consistency and stability
  • Rigid die cast alu chassis with extensive venting for lower air flow speed reducing audible distortion
  • Vented voice coil former for reduced distortion and compression
  • Vented center pole with dual flares for reduced noise level at large cone excursions
  • Heavy-duty black fiber glass voice coil former to reduce mechanical losses resulting in better dynamic performance and low-level details
  • Large motor with 39 mm voice coil diameter for better control and power handling
  • Built-in alu field-stabilizing ring for reduced distortion at high levels
  • Low-loss suspension (high Qm) for better reproduction of details and dynamics
  • Black motor parts for better heat transfer to the surrounding air
  • Conex spider for better durability under extreme conditions
  • Gold plated terminals to ensure long-term trouble free connection

FREQUENCY RESPONSE

WF182BD17/19 SPL & Impedance response

Measuring conditions, SPL
Driver mounting: Flush in infinite
     baffle, back side open  (no cabinet)
Microphone distance: 1.0 m
Input level: 2.83 VRMS
Smoothing: 1/6 oct.

Measuring conditions, impedance
Driver mounting: Free air, no baffle,
     back side open (no cabinet)
Input signal: Semi-current-drive,
     nominal current 2 mA
Smoothing: None

WF182BD18/20 SPL & Impedance response

Measuring conditions, SPL
Driver mounting: Flush in infinite
     baffle, back side open  (no cabinet)
Microphone distance: 1.0 m
Input level: 2.83 VRMS
Smoothing: 1/6 oct.

Measuring conditions, impedance
Driver mounting: Free air, no baffle,
     back side open (no cabinet)
Input signal: Semi-current-drive,
     nominal current 2 mA
Smoothing: None

Downloads
SPL and impedance response curves as text files

WF182BD17/19 SPL response

WF182BD17/19 SPL response

WF182BD17/19 impedance response

WF182BD17/19 impedance response

WF182BD18/20 SPL response

WF182BD18/20 SPL response

WF182BD18/20 impedance response

WF182BD18/20 impedance response

Important!
Please observe that these text files for download are actual measurements of the drivers measured in infinite baffle and without any enclosure. Measuring the drivers in a finite baffle (like the baffle of most speaker cabinets) and in any size of enclosure will lead to different response curves.

NOMINAL SPECIFICATIONS

Notes

  Parameter

WF182BD17 and WF182BD19

WF182BD18 and WF182BD20

Unit

Before burn-in

After burn-in

Before burn-in

After burn-in

 

Nominal size

7

7

[inch.]

 

Nominal impedance

4

8

[ohm]

 

Recommended max. upper frequency limit

2.5

2.5

[kHz]

1, 4

Sensitivity, 2.83V/1m (average SPL in range 200 - 1,000 Hz)

88.5

86

[dB]

2, 4

Power handling, short term, IEC 268-5, no additional filtering

400

400

[W]

2, 4

Power handling, long term, IEC 268-5, no additional filtering

250

250

[W]

2

Power handling, continuous, IEC 268-5, no additional filtering

80

80

[W]

 

Effective radiating area, Sd

131

131

[sq.cm]

3, 4, 6

Resonance frequency (free air, no baffle), Fs

33

28.5

34

29.5

[Hz]

 

Moving mass, incl. air (free air, no baffle), Mms

23.4

21.9

[g]

3, 4

Force factor, Bxl

6.5

8.2

[N/A]

3, 4, 6

Suspension compliance, Cms

1.0

1.33

1.0

1.33

[mm/N]

3, 4, 6

Equivalent air volume, Vas

24.3

32.4

24.3

32.4

[lit.]

3, 4, 6

Mechanical resistance, Rms

0.44

0.46

0.44

0.46

[Ns/m]

3, 4, 6

Mechanical Q, Qms

10.9

9.1

10.5

8.8

[-]

3, 4, 6

Electrical Q, Qes

0.37

0.32

0.44

0.38

[-]

3, 4, 6

Total Q, Qts

0.35

0.31

0.42

0.37

[-]

4

Voice coil resistance, RDC

3.2

6.4

[ohm]

5

Voice coil inductance, Le (measured at 10 kHz)

0.10

0.17

[mH]

 

Voice coil inside diameter

39

39

[mm]

 

Voice coil winding height

16

16

[mm]

 

Air gap height

5

5

[mm]

 

Theoretical linear motor stroke, Xmax

+/-5.5

+/-5.5

[mm]

 

Magnet weight

725

725

[g]

 

Total unit net weight excl. packaging

1.95

1.95

[kg]

3, 4, 5

Krm

131

117

[mohm]

3, 4, 5

Erm

0.30

0.34

[-]

3, 4, 5

Kxm

17.5

37

[mH]

3, 4, 5

Exm

0.47

0.43

[-]

Note 1

Measured in infinite baffle.

Note 2

Tested in free air (no cabinet).

Note 3

Measured using a semi-constant current source, nominal level 2 mA.

Note 4

Measured at 25 deg. C

Note 5

It is generally a rough simplification to assume that loudspeaker transducer voice coils exhibit the characteristics of an inductor. Instead it is a far more accurate approach to use the more advanced model often referred to as the “Wright empirical model”, also used in LEAP-4 as the TSL model (www.linearx.com), involving parameters Krm, Erm, Kxm, and Exm. This more accurate transducer model is described in a technical paper (PDF) here.

Note 6

After burn-in specifications are measured 12 hours after exiting the transducer by a 20 Hz sine wave for 2 hours at level 10/14.1 VRMS (4/8 ohm version). The unit is not burned in before shipping.

HARMONIC DISTORTION

WF182BD17/19 harmonic distortion

Measuring conditions, harmonic distortion
Driver mounting: In sealed enclosure, internal volume 5 lit.,
Microphone distance: 0.5 m
Input signal: Stepped sine wave, 5.65 VRMS (WF182BD09/11) / 7.75 VRMS (WF182BD10/12)
Smoothing: 1/12 oct.

WF182BD18/20 harmonic distortion

OUTLINE DRAWING AND NOMINAL DIMENSIONS (mm)

WF182BD17/18/19/20 outline drawing
WF182BD17_18_outline_DWG
WF182BD19_20_outline_DWG

TERMINAL NOMINAL DIMENSIONS (mm)

WF182BD terminals

PACKAGING AND ORDERING INFORMATION

Part no. WF182BD17-01

4 ohm version, individual packaging (one piece per box)

Part no. WF182BD17-02

4 ohm version, bulk packaging

Part no. WF182BD18-01

8 ohm version, individual packaging (one piece per box)

Part no. WF182BD18-02

8 ohm version, bulk packaging

Part no. WF182BD19-01

4 ohm version, truncated frame, individual packaging (one piece per box)

Part no. WF182BD19-02

4 ohm version, truncated frame, bulk packaging

Part no. WF182BD20-01

8 ohm version, truncated frame, individual packaging (one piece per box)

Part no. WF182BD20-02

8 ohm version, truncated frame, bulk packaging

Latest update: January 30, 2025

 

Specifications are subject to change without any further notice.
Copyright © by Wavecor Ltd., China. All rights reserved.

 

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MORE INFO

WF182BD17/18/19/20 specificationsPDF data sheet

 

Balanced Drive technical paperBalanced Drive technical paper

 

 

 

 

 

 

 

 

 

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