5.Internal Adjustments

Speaker-Level Input Impedance Adjustments

The speaker level inputs of the GTS300 and GTS600 come factory set with 100K ohm input impe- dance. This will provide the lowest distortion operation from the speaker outputs of most modern head units by reducing the power the amplifier in the head unit must deliver to practically nothing.

On some older, or lowerpriced head units, this load will not facilitate proper fader operation. To provide for this, we have provided the ability to change the input impedance of the speaker- level inputs to 15 ohms. This is accomplished by connecting the jumpers as shown in the diagram below.

JUMPER SELECTOR

SELECT 100K OR 15 OHMS

Crossover Frequency

Adjustments

The GTS300 and GTS600 ampli- fiers include built-in frequency selectable crossovers. One crossover is connected in series with the amplifier circuitry and the other crossover is connected to the preamp level output jacks. These crossovers can be set in either the “flat” (full bandwidth operation), Low Pass (Subwoofer operation), or High Pass (satellite operation).

• The crossover frequencies are

set by “chips” inside the

amplifier. These “chips” are

simply a set of resistors,

connected across the pins and

molded into a single package.

The crossover frequencies may

be changed to any value desired

by changing the resistor

network. JBL has “chips”

available in the popular values

listed in the table below. If none

of these suit your system, you

BALANCED

 

 

 

INPUTS

 

 

LEFT

 

OHM

100K

15

 

ZIN

 

SPEAKER

SEL

 

 

 

 

 

IMPEDANCE

 

 

 

INPUT

 

 

 

SELECTOR

 

 

 

BA

40

 

GND

 

40A

 

 

FUSE

 

 

 

 

OUT

 

 

 

REM

 

 

 

 

RIGHT

 

ZIN

 

SEL

 

OHM

100K

15

BRIDGED

 

 

–

 

R

–

+

 

L

 

+

 

– R

+ INPUTSPEAKER LEVEL

 

R

R

 

 

L

L

 

 

INPUT

OUTPUT

LINE

 

PREAMP

 

may pruchase compatible

resistor networks from a local

electronics store, or you may

build you own custom values

from discrete resistors mounted

on a 14-pin “DIP Header” using

the instructions which follow.

•If the head unit has 4 channels of builtin amplification and/or an electronic fader control, you should leave the jumpers in the factory set position.

•If the head unit has 2 channels of amplification, with a speaker- level fader, the jumpers should be set to the 15-ohm position. This will always be a rotary-type control, not one controlled by elecronic pushbuttons.

Frequency

Resistor

JBL Part

 

Value

Number

50 Hz

47 K

GTM 50

80 Hz

33 K

GTM 80

120 Hz

20 K

GTM 120

200 Hz

12 K

GTM 200

250 Hz

10 K

GTM 250

500 Hz

4.7 K

GTM 500

2.5 Hz

1 K

GTM 2500

5 Hz

470

GTM 5000

6

Page 5 Page 7
Page 6
Image 6
JBL GTS300, GTS600 manual Internal Adjustments, Speaker-Level Input Impedance Adjustments, Crossover Frequency Adjustments
Page 5 Page 7

GTS600, GTS300 specifications

JBL has long been a leader in the audio industry, and the introduction of the GTS300 and GTS600 speakers reinforces their commitment to delivering exceptional sound quality. Both models embody the cutting-edge technology that JBL is known for while providing a range of features designed for both casual listeners and serious audiophiles.

The JBL GTS300 offers an impressive audio performance with its powerful drivers and advanced engineering. The speaker features a robust woofer that delivers deep, resonant bass, ensuring that music enthusiasts feel every beat. The innovative design of the driver minimizes distortion, allowing for a clear and well-balanced sound across a wide frequency range. This model is also equipped with a high-frequency transducer that produces shimmering highs, making it perfect for various music genres, from classical to modern pop.

On the other hand, the JBL GTS600 takes sound quality to the next level. This model is engineered with larger drivers and an enhanced cabinet design, which contributes to its impressive soundstage. The GTS600 is designed with a focus on clarity and detail, ensuring that vocal performances and instrumentals are represented with precision. The speaker incorporates advanced sound dispersion technology, allowing for a wider listening area, which makes it ideal for larger spaces or gatherings.

Both the GTS300 and GTS600 feature JBL’s proprietary technology that enhances the listening experience. One of these key technologies is the implementation of digital signal processing (DSP), which optimizes sound output according to the acoustics of the environment. This offers listeners a tailored audio experience, irrespective of the room setup. Furthermore, the speakers are compatible with various audio inputs, ensuring easy connectivity to a range of devices, from smartphones to home theater systems.

In terms of aesthetics, the GTS series boasts a sleek and modern design that will complement any setting. The durable build and high-quality finish ensure that both models not only look good but are also built to last.

In conclusion, the JBL GTS300 and GTS600 speakers represent the pinnacle of audio innovation, delivering exceptional sound quality, a variety of modern features, and robust design. Whether for personal enjoyment or professional use, these speakers are a valuable addition to any audio setup, capturing the essence of accurate sound reproduction that JBL is renowned for.
Top Page Image Contents