JBL 4338 User Manual

1.01 Mb

15 Inch 3-Way Studio Monitor

Model 4338

Owner's Manual

Model 4338 is a new member in the JBL4300 series of 15-inch 3-way studio monitor systems.

With the introduction of the advanced technology fostered by the development of "Project K2 S9800", together with the inline unit layout for realizing a brilliant sound image positioning, a new generation bi-radial horn that constructs accurate sound field without requiring an acoustic lens, and the slim and advanced cabinet that makes these technologies possible, the system is a result of innovative system engineering that fuses tradition and revolution.

This is a new generation monitor speaker system that enables a full-spec monitoring of high-bit/high-sampling digital source.

JBL Incorporated

Studio Monitor Model 4338

1: Introduction

Thank you for purchasing the JBL 3-Way Studio Monitor 4338.

In order to better understand and correctly use this product, please thoroughly read this Owner's Manual before using the product.

2: Unpacking

The product should have been delivered complete in appearance and functionality. However, if you find any scratches or defects, please directly contact the store where you purchased the product.

We recommend that you keep the original box and packing material after unpacking. Please note that if a product must be shipped for a repair service, JBL Incorporated will not be responsible for any damage incurred during shipping caused by insufficient packing.

3: Installation

Avoid placing the monitors near power amplifiers or radiators that generate large amounts of heat, or in very humid or dusty places, and any places exposed to direct sunlight. Also place them on a firm, solid floor.


Start the setup using a recorded sound source that has a distinct virtual center image. Once the center point between the speakers is obtained by measuring equal distances from the left and right speakers, adjust the distance between the listening position and the speakers, as well as the distance between right

and left speakers, so that a precise center image is obtained.

These monitors are designed to reproduce the most accurate stereo sound stage when the interior angle between the lines connecting from each speaker to the listener is between 40 to 60 degrees. Additionally, it is ideal that a distance of approximately 50 cm or more is maintained from the left and right walls.

The center of the speaker's sound image is in the vicinity of the HF (high-frequency) unit. Set the speakers so that the HF unit is aligned at ear-level. In addition, to avoid acoustical interference with the floor surface, it is recommended that you set a sturdy base (cube or block shaped) with a thickness of 5 – 20 cm under the speakers.

4: Connection


When connecting the speakers to the amplifier, always do so after turning off the power. Connecting the speakers while the power is on may damage the amplifier or the speakers.

The two groups of input terminals on the 4338 support bi-wiring and bi-amping configurations. Follow the instructions below for each type of connection method:

I. Single Wire Connection Using One Set of Speaker Cables

Connect to either the upper or the lower terminals, leaving the short wires with the gold plated ring sleeves connected.

II. Bi-wire Connection Using Two Sets of Speaker Cables

Remove the short wires with the gold plated ring sleeves, and connect the high-frequency and the low-frequency cables to their respective terminals.

III. Bi-amp Configuration Using Two Power Amplifiers and Internal Networking

Remove the short wires with the gold plated ring sleeves, and connect the high-frequency and low frequency amplifiers to their respective terminals. Although the two power amplifiers do not need to be identical, they should have similar output performance and same gain, or gains set to the same level in advance, through input adjustments.

The positive terminals of the speaker have a red ring, and the negative terminals have a black ring. Be sure to connect with out mistaking the polarity. The speakers are designed so that when a positive signal is applied to the positive terminal, the woofer moves in the forward direction (positive phase operation).

When using the short wires with the gold plated ring sleeves, be sure that both the sleeves and the conductors are securely fastened to the terminals. In addition, use extra caution so that the cable conductors do not touch other sleeves and short out.

In order to safely and securely connect to the terminals, we recommend that you use the Y terminals or banana plugs on the cable ends.

5. Attenuator Adjustment

Independent, continuous variable attenuators are used for each unit to adjust the HF (high-frequencies) and the UHF (ultra-high frequencies) levels to the speaker’s woofer level. The 0 dB position for each volume knob indicates a flatlevel position in a test room, where there is little reverb. Make adjustments appropriate to the reverb in the actual room, and to your liking. In general, for most speakers, it takes about 1 – 2 months after initial use until the unit's vibration system yields optimum performance. As the level balance is expected to initially change with use, we recommend that you readjust the level accordingly.

6: Attaching the Grills

The speakers are shipped with the grill installed.

The purpose of the grill is to protect the units. The grill may be removed and re-attached as necessary.

7: Maintenance

When doing any maintenance, wipe the surface of the cabinet with a dry cloth to remove dust. Damp cloth or cleaning paper may dull the finish on the cabinet surface. Do not use volatile liquids such as benzene, paint thinner, alcohol, etc, and do not spray insecticide near it.

If dust gets into the grill netting, use a vacuum cleaner to remove it. In doing so, adjust the suction power of the vacuum cleaner so that it does not suction too strongly. Furthermore, do not wash the grill in water. The grill may sag or its color may become uneven.

If the surface of the speaker unit becomes dusty, use a soft, dry calligraphy brush or a paint brush to carefully sweep the dust away. Never use a damp cloth.

•The speaker system is a durable consumer good. In particular, the edges of the woofer, which support rapid movement of the paper cone, undergo a great level of stress, and there is a limit to the number of years of its practical use. Also, the speakers' lifespan may be shortened by the effects of temperature, humidity or ultra-violet radiation. Please avoid exposing the speaker to strong lighting such as from lighting equipment or direct sunlight and avoid placing the speakers in high temperatures such as near the air conditioner exhaust pipe or a heat radiator.

Studio Monitor Model 4338

8: Specifications


3-way floor type

Units used

38 cm pure pulp cone woofer 1500FE


75 mm aluminum compression driver 435AI


25 mm pure titanium compression driver 045Ti




8 Ω

Allowable input

300 W (RMS)



Output sound pressure

93 dB (2.83 V/1m)



Frequency response

35 Hz – 40 KHz (-6 dB)



Crossover frequencies

750 Hz, 9 kHz,



Dimensions (W x H x D)

597 x 1080 x 400 mm ,with grill 425 mm, (36-1/4” X 21-5/8” X 13-


1/8”, with grill 14-3/4”)


90.4 kg (140 lbs)



JBL Incorporated, Northridge, CA USA

P/N: 354997-001