JBL 305PMKII [15/22] Crossover settings and bass management

CROSSOVER SETTINGS AND BASS MANAGEMENT

“Bass management” is a term that refers to the practice of using a subwoofer to reproduce the bass frequencies

of the main channels. Because of the physiology of the human ear, low frequencies are largely non-directional.

Given an adequate listening distance, we can’t easily tell where bass signals are coming from. Thus, it makes

little or no difference to the listening experience whether the bass component in a sound comes from the

originating speaker—which may be off to your left or right, or even behind you—or from a dedicated subwoofer

which is better equipped and better positioned in the room to reproduce low frequencies. For that reason, you

may want to use an LSR310S subwoofer to reproduce all the bass frequencies in the system.

When using an LSR310S subwoofer in the system, bass management is accomplished by simply routing the

left and right mix channels to the LSR310S inputs and then from the LSR310S outputs to the left and right

speakers. The frequency at which the subwoofer divides signals to the sub and the left and right speakers can

be set using the CROSSOVER FREQUENCY selector switch on the input panel of the LSR310S.

The LSR310S offers three crossover settings:

• 80Hz

The 80Hz setting is recommended when the goal is a full range reference monitor system that accurately

portrays content below the cut-off frequency of the main speakers. The 80Hz setting provides a smooth

transition between the subwoofer and main speakers without audible localization of bass, creating the

perception of a full range system with no subwoofer.

• XLF

A trend in music production is the requirement for enhanced low frequency response in the control

room. Artists and producers involved in the production of dance music appreciate the ability to audition

their work as it might sound when played on a system with enhanced low frequency tuning, commonly

employed in dance clubs.

A JBL rst, the LSR310S includes a special XLF (Extended Low Frequency) setting that emulates the

response curve applied to a club playback system. When the XLF crossover setting is selected, a 120Hz

high-pass lter is engaged in conjunction with a 10dB boost at 60Hz with a bandwidth of 0.5 octaves.

Using this setting, the bass output more than doubles and the character of the low frequency energy

approximates that of a club system.

Continuous low frequency energy with very high peak SPL is made possible by JBL’s new long excursion

low frequency driver, working in concert with JBL’s patented Slip Stream™ Port, and powered by a 200

watt Class-D amplier. A protective circuit allows the LSR310S to continuously produce low frequencies

at high output levels without failure. In situations where positioning will allow, an additional 6dB of output

can be achieved by positioning the LSR310S subwoofer adjacent to a wall or at the intersection of two

walls.

• External

Select this setting when connecting the subwoofer to an external active crossover. Note that when the

External option is selected, the XLR LEFT and RIGHT OUT connectors are disabled.

SURROUND SOUND SYSTEMS AND LFE

The LSR310S subwoofer can be used to reproduce the LFE (Low Frequency Effects) or .1 channel in a surround

sound system. In lm production applications, the LFE channel contains low frequency effects, such as the

sounds of explosions and other sounds with a strong low frequency component. In music applications, the LFE

channel usually contains low frequency instruments such as bass, bass drum, and synthesizer elements.