HTS4B Home Theater Subwoofer

Active crossover operating at low signal levels.

Audio electronic crossovers allow the audio signal to be split into separate frequency bands that are separately routed to individual power amplifiers, which are then connected to specific transducers optimised for a particular frequency band.

Active crossovers come in both digital and analogue varieties. Genelec digital active crossovers include additional signal processing, such as driver protection, delay, and equalisation.

Genelec analogue active crossover filters contain electronic components that are operated at low signal levels suitable for power amplifier inputs. This is in contrast to passive crossovers that operate at the high signal levels of the power amplifier's outputs, having to handle high currents and, in some cases, high voltages.

In a typical two-way system the active crossover needs two power amplifiers — one for the woofer and one for the tweeter.

The active crossover design offers multiple benefits:

• The frequency response becomes independent of any dynamic changes in the driver's electrical characteristics or the drive level.
• There is increased flexibility and precision for adjusting and fine-tuning each output frequency response for the specific drivers used.
• Each driver has its own signal processing and power amplifier. This isolates each driver from the drive signals handled by the other drivers, reducing inter-modulation distortion and overdriving problems.
• The ability to compensate for sensitivity variations between drivers.
• The possibility to compensate for frequency and phase response anomalies associated with a driver’s characteristics within the intended pass-band.
• The flat frequency response of a high-quality active loudspeaker is a result of the combined effect of the crossover filter response, power amplifier responses and driver responses in a loudspeaker enclosure.

Using the active approach enables frequency response adjustments and optimisation of the full loudspeaker system, placed in various room environments, without expensive external equalisers. The end result is a simpler, more reliable, efficient, consistent and precise active loudspeaker system.

Each transducer is driven by its own optimised amplifier.

Audio electronic crossovers allow to split the audio signal into separate frequency bands that can be separately routed to individual power amplifiers, which are then connected to specific transducers optimised for a particular frequency band.

In a typical 2-way loudspeaker system, the active crossover needs two power amplifiers — one for the woofer and one for the tweeter. The power amplifiers are connected directly to the drivers of an active loudspeaker, resulting in the power amplifier’s load becoming much simpler and well known. Each driver-specific power amplifier has only a limited frequency range to amplify (the power amplifier is placed after the active crossover) and this adds to the ease of design.

The active design principle offers multiple benefits:

• The power amplifiers are directly connected to the speaker drivers, maximising the control exerted by the power amplifier’s damping on the driver’s voice coil, reducing the consequences of dynamic changes in the driver electrical characteristics. This may improve the transient response of the system.
• There is a reduction in the power amplifier output requirement. With no energy lost in the passive crossover filter components, the amplifier power output requirements are reduced considerably (by up to 1/2 in some cases) without any reduction in the acoustic power output of the loudspeaker system. This can reduce costs and increase audio quality and system reliability.
• No loss between amplifier and driver units results in maximum acoustic efficiency.
• Active technology can achieve superior sound output vs. size vs. low frequency cut-off performance.
• All loudspeakers are delivered as a factory aligned system (amplifiers, crossover electronics and enclosure-driver systems).

Sophisticated drive unit protection circuitry for safe operation.

When working in critical audio production environments it is essential that monitoring systems remain reliable and functional at all times. One of the main reasons behind Genelec’s excellent success in broadcasting environments is the reliability of our products and a key element behind the reliability is the internal protection circuitry found in all products since 1978.

The protection circuitry prevents driver failures by detecting signal levels, and in case of sudden peaks or constantly too high levels, taking the signal level down automatically. Of course this feature does not affect the sound quality in any way when working within the specifications of the loudspeaker, but only prevents inadequate input signals from breaking the loudspeaker.

Protection circuitry features and benefits:

• Reduces the output level when required, (e.g. when driver voice coil temperature reaches the safe limit), which highly improves system reliability.
• Appropriate protection circuitry design in every loudspeaker and subwoofer enables the maximisation of system output sound level.

Precise room response compensation for optimizing in-room performance.

The interaction between room acoustic and loudspeaker radiation is complex. Each room changes somewhat the monitor’s response in a unique way, e.g. reflective vs. damped rooms, or placement against a wall vs. on a stand away from the walls.

All Genelec loudspeaker systems feature room response adjustments to compensate for the room influences and retrieve a flat frequency response at the listening position.

Analogue Systems

Genelec analogue loudspeaker systems provide versatile Room Response Controls. They include (depending on models):

• Bass Roll-Off and Bass Tilt
• Treble Tilt and Treble Roll-Off
• Bass Level
• Midrange Level
• Treble Level
• Desktop Control

At low frequencies two main controls are provided. The Bass Tilt control, which acts as a shelving filter together with the Bass Roll-off control allowing you to optimize the low and very low frequency response of the system in different installations. Bass, midrange and treble level controls are provided in large systems. These controls allow to optimize the relative balance between the various pass bands.

The operating manual and datasheet of each loudspeaker contains a list of preferred room response control settings for different installations. These have been specified out of long practical experience and measurements of various kind of typical acoustic environments.

Smart Active Monitor (SAM™) Systems

Genelec SAM Systems offer a comprehensive, solution-oriented, intelligently networked product range which all feature Genelec Loudspeaker Manager (GLM™) software and its automatic calibration system called AutoCal™.

Genelec AutoCal provides the industry’s first integrated process for complete automated measurement, analysis, and adjustment of every monitor on the GLM control network. The system measures the response in the listening area and applies relevant compensation in the low and low-mid frequencies to minimise the detrimental room acoustic anomalies as well as the differences between various listening positions. AutoCal also aligns relative levels, time-of-flight, as well as adjusts correct crossover phase (called AutoPhase) for all subwoofers on the network.

The Acoustic Response Editor provides accurate graphical display of the measured response, filter compensation and the resulting system response for each monitor, with full manual control of acoustic settings.