7071A Studio 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.

Bass Management System handles multichannel low frequency content.

The principle of bass management is that the bass content of the main channels and the Low Frequency Effect (LFE) channel are directed and reproduced only by loudspeakers capable of handling them, whether they are main system loudspeakers or one or more subwoofer(s).

In stereo reproduction, signals from 20 Hz to 20 kHz need to be replayed. Large multi-way monitoring systems will reproduce such a wide bandwidth evenly. With multichannel audio, professional and consumer audio systems must also be able to reproduce audio between 20 Hz and 20 kHz for each channel. To achieve this, main monitors, subwoofers and crossover electronics should work together.

A Bass Management system uses either analogue electronic circuitry or software based filtering which will filter low frequency information from the main channels and route that information to one, or more, subwoofer feed.

The dedicated LFE channel can also be monitored via that subwoofer and added to the low frequencies of the other main channels. Therefore, the Bass Management’s basic and main goal is to ensure that the entire audio bandwidth of all channels can be accurately monitored.

The benefits of the Bass Management System:

• The subwoofer extends the system frequency response down the lower limit of the audible range
• Monitor can produce a higher maximum sound level when not reproducing low frequencies
• Optimized low frequency reproduction by selecting adequate subwoofer location; monitors can also be placed more freely
• Subwoofer’s output are aligned in level and phase with monitors allowing flat and accurate reproduction down to 19 Hz and across the crossover point
• LFE channel output level (0 or +10 dB re. main channels) can be selected for accurate reproduction depending on the source type
• The ability to bypass the subwoofer allows to evaluate the audible impact of the subwoofer

Laminar Integrated Port (LIP™) allows for precise bass reproduction.

Genelec’s choice for vented (or bass reflex) enclosures dates back to 1978 and the first active monitor developed by Genelec, the S30. Research to improve the performance and efficiency of reflex ports has been pursued ever since.

A typical reflex port enclosure features a tube and an opening area. To avoid turbulences in the tube the air flow should not meet any acute angles as this would generate noise, compression, distortion and losses of the total radiated energy. To minimize the air flow speed, both the tube and its cross section have to be large. Often, the outer enclosure dimensions become a limitation, because a long tube will not fit in the available volume anymore.

The M Series features two vent tubes having opening stretching across half of the enclosure depth to address these specific issues. The novel patent-pending Laminar Integral Port, LIP™, has been flow-optimized using computer-based finite element models to achieve low distortion and high efficiency even at very high audio output levels.

The reflex ports are integrated in the NCE enclosure during the moulding process, avoiding the need for separate additional components. The cross-section plot (Figure) demonstrates the efficient flow characteristics of the port. The natural installation orientation of the M Series is vertical and to allow easy placement of the monitor against a wall, the M Series ports opening face downwards, in the space under the monitor.

The novel Laminar Integrated Port, LIP™, bass reflex system provides accurate low frequency response and faithful tonal reproduction characteristics.

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.