In the golden olden days of speakers, the issue of whether the first motion of a cone was inward or outward, or polarity, was not uniform. Eventually it became standardized. Most speakers have an initial outward movement. When JBL started making speakers, they arbitrarily adopted reverse polarity and their speakers had an initial inward movement. This continued until JBL developed their musical instrument series speakers which used ¼” jacks. The use of these jacks required that JBL change their polarity to fit into what had become industry standards. Therefore, many of the older JBL speakers have reverse polarity, while newer models match what has become the industry standard.

Does this really matter” You can equate this to taking a 1 mile walk. It really won’t matter if you start with your left foot or right foot. Remember, we stock or can order JBL Recone Kits and JBL Diaphragms and a variety of other speaker parts.

JBL has published a technical bulletin regarding this. In it they define the terminology and list each specific speaker and its polarity.

**Terminology: **Positive systems: A system or transducer is said to be positive if a positive-going voltage applied to its red (or non-black) input terminal causes a positive pressure at the acoustical output of the device. For cone transducers, the cone will move outward and can be easily seen. For compression drivers, a positivegoing pressure can be measured at the driver’s exit. Many systems and transducers do not have color-coded input terminals, and in these cases one terminal is usually labeled with a + sign. Consistent with the positive standard, a positive- going signal at the positive terminal will result in outward motion of the cone. Negative systems: A system or transducer is said to be negative if a positive-going voltage applied to its red (non-black) terminal causes a negative pressure at the output of the device.

**Polarity of JBL Professional systems and ****transducers: **The following is a comprehensive listing of former and current JBL Professional systems and transducers by product category. Within each category models are indicated as positive or negative. The obsolete models included here are those that are still supported by company repair service and spare parts.

Musical instrument transducers: The following models are negative: E110-8 E120-8, 16, E130-8 E140-8, E155-4, 8. The following models are positive: M121-8, M151-8

Control Monitors: all models are positive: Control 1, Control 1 Plus, Control Micro Control 1AW/70, Control SB Micro Control 5, Control 10L, R, Control SB-1, Control SB-5, Control 12SR

Control Contractor Series Studio Monitors: All 4300-Series models (except models 4311 and 4312L, R) are negative. The following models are negative: 4406, 4408L, R, 4410L, R 4412L, R, 4425L, R 4430L, R, 435L, R. The following models are positive: 4206, 4208, 4311, 4312L, R, 4408A-L, R 4410A-L, R, 4412A-L, R 6208, DMS-1 LSR4300-Series, LSR-Series LSR6300-Series

Compression Drivers: the following models are negative: 2402H, 2404H, 2405H, 2426H, J, 2427H, J 2446H, J, 2447H, J 2450H, J, 2451H, J

Cone Transducers: the following models are negative: LE8T-H 2105H, 2118H, J 2123H, J, 2202H 2206H, 2220H, J 2226H, J, 2235H 2240G, H, 2241G, H 2245H. The following models are positive: 2012H 2020H, 2242H

Coaxial transducers: the following models are positive: 2142H, 2152H, 2155H

Cinema systems: 3000-Series systems; the following models are positive: 3622N, 3677, 3678, 3632, 3632T 3678-LF, 3639,

4000-Series systems; the following models are positive: 4622, 4622N, 4632, 4632T. 4000-Series systems; the following models are negative: 4670D, 4675C, 4675C-4LF 4765C-8LF

5000-Series systems; the following models are negative: 5671, 5672, 5672Bi, 5674. Cinema subwoofers; the following models are negative: 4642, 4645

Cinema subwoofers; the following models are positive: 3635, 4641, 4642A, 4642A-GS, 4645B, 4645C

Cinema surround systems: the following models are negative: 8330, 8333, 8340. Cinema surround systems: the following models are positive: 3310, 8325, 8330A*, 8340A* (*Note change from previous model numbers)

Enclosed utility systems: The following models are positive: SLT-1 4612OK, 8216A 8216AT. The following models are negative: 4660A, 4671OK, 4652.

Application Engineered Series (Prefixes AM, AC, AL, ASB, SH): all models are positive. Architectural Series (Prefix AS): all models are positive Array Series (Models 4890A, 4892, 4893, 4894): all models are positive Cabaret Series (Models 4602, 4612, 4622, 4623, 4625, 4627, 4680, 4690, 4695): all models are positive.

Concert Series (Models 4825, 4828, 4842, 4845, 4847, 4850, 4851, 4852, 4853, 4860, 4861, 4862, 4863, 3866, 4870, 4871, 4872, 4873): all models are positive Control contractor Series: all models are positive

EON Systems (Prefix EON): all models are positive HLA Series (Prefix HLA): all models are positive JRX Series (Prefix JRX): all models are positive MPro Series (Prefix MP): all models are positive

Marquis Series (Prefix MS): all models are positive MR Series (Prefix MR): all models are positive Precision Directivity Series (Prefix PD): all models are positive Soundfactor Series (Prefix SF): all models are positive Sound Power Series (Prefix SP): all models are positive SR Series (Prefix SR): all models are positive SR Series X (Prefix SR): all models are positive SR Series II (Prefix SR): all models are positive SRX Series (Prefix SRX): all models are positive TR Series (Prefix TR): all models are positive Venue Series (Prefix VS): all models are positive Vertec Series (Prefix VT): all models are positive VRX Series (Prefix VRX): all models are positive