Lambda Labs professional acoustics


General questions General technical questions TX-1A TX-2A TX-3A CX-1A & CX-1B CX-2A CX-3A MF-15A DH-18 KW-18

How many setups do I have on the active module?

The active modules have four pre-programmed factory-set presets. These are optimized for each speaker type and its possible applications.

What kind of setups do I have?

Following presets are available for the MF-15A:

  • Preset Mode 1 – Subbass Crossover Mode 80Hz
  • Preset Mode 2 – Subbass Crossover Mode 100Hz
  • Preset Mode 3 – Subbass Crossover Mode 140Hz
  • Preset Mode 4 – Cardioid Mode for Setup 1 or 2

When should I use the cardioid mode?

In this operating condition the bass array forms a cardioid-shaped, polar radiation characteristic with maximized rearside damping. For the cardioid mode there is at least one MF-15A operated in the setups 1-3. Additionally there is at least one MF-15A driven in the setup 4 and turned backwards. Is the rearside damping planed to take effect at a higher distance, it is advisable to put one Manifold frontwards (setups 1-3) and one backwards (setup 4). Is the rearside damping achieved directly behind the bass array, the output level of the backwards aligned Manifold has to be reduced. Alternatively and for a better efficiency in the front, the use of 1 backward and two frontward oriented Manifolds is recommended.

Can I program the active modules by myself?

Due to the complexity of the signal structure, a self-programming is not supported by Lambda Labs. The integrated setups already implicates most common applications. To allow access to the EQ or delay, a controller can be inserted in the signal path to adapt the active speaker to each acoustical situation. For any questions you might have we’ll be at your disposal.

How should I combine the MF-15A with the corresponding loudspeakers for the high-mid frequency range?

The subbass crossover modes (setups 1-3) has a 24dB/oct. Linkwitz-Riley low pass filter at 80/100/140Hz. Accordingly, the loudspeaker for the high-mid frequency range should have a 24dB/oct. Linkwitz-Riley high pass characteristic at 80/100/140Hz. The delay has to be adjusted in a way that both systems have matching phase responses in the crossover region. Especially in case of subwoofer systems which exhibits larger propagation delay (especially horn loaded systems) larger delay values have to be set.

Which setup should I select for the TX-series compact boxes?

The according setup for the TX-Series to combine them with the MF-15A is the setup 3 (100Hz mode). The MF-15A should be driven with the setup 3 (100Hz mode).

Alternatively, the TX-3A can be driven with the setup 2 (80Hz mode) and MF-15A accordingly with the setup 1 (80Hz mode). You can find more detailed information in the FAQs of the individual TX-Series:
TX-1A, TX-2A, TX-3A

Which setup should I select for the CX-1A?

The according setup on the CX-1A to combine the MF-15A is the setup 2 (140Hz mode). The MF-15A should be driven with the setup 3 (140Hz mode).

Which setup should I select for the CX-2A or CX-3A?

The according setup on the CX-2A or CX-3A to combine the MF-15A is the setup 2 (100Hz mode). The MF-15A should be driven with the setup 2 (100Hz mode).

How much amping power do I have with the MF-15A?

The amplifier delivers 1600W RMS amping power to the 15" long excursion driver. The peak power has to be multiplied by a factor of two.

Where should I connect the XLR cable?

Both jacks are connected in parallel. The signal can be feeded to each of the jacks and looped through from the other one.

What’s the maximum input voltage?

When the gain control is at its maximum position, the maximum input voltage before clipping is 5Vrms (+/- 7V peak). This value increases proportionally by turning back the gain control. In the 12 o’clock position, the input signal is reduced by 6dB. Therefore the maximum input voltage before clipping increases to 10Vrms (+/- 14V peak) accordingly.

+/-15Vpeak (~+22dBu) at the input shouldn’t to be exceeded in any condition.

Full power output triggering the limiters is already reached with smaller input voltage. At which level the full power output is reached is frequency dependent and with music signals strongly related to the crest factor.

What do I have to take into account when measuring a frequency response?

On measurements with high energy signals (MLS, Sin-Sweep, noise), the high frequency range seems to be attenuated at extreme high output levels. This measuring signals have low crest factors and can activate the RMS limiter of the high frequency rage. Just reduce the level and try again. Use multiple averaging to increase the signal-to-noise ratio if required.

When does the red (LIMIT) LED on the active module light up?

If the red LED flashes, one of the integrated limiters for the lowmid driver (distortion limiter, continuous output limiter, continuous current limiter, peak current limiter) is triggered. Together they serve to ensure sound quality and safe operation. Short flashing at high SPL output conditions is a completely normal and usual operational status.

Heavily flashing or even continous light means an overdriven signal chain and affects the sound quality. Extreme or permanet overdrive is hazardous for the low frequency driver - especially on high ambient temperature or with stationary use of sine signals with frequencies in the range of the loudspeakers minimal electrical impedance.

When does the yellow (TEMP) LED on the active module light up?

The yellow LED is a temperature monitoring for the active module and lite up under extreme conditions only. A slow flash is a indicator for a high temperature. This status is just for your information.

A rapid flashing will follow if the temperature rising further, and causes a reduction of the output level to lower the temperature to an uncritical status again. When playing music, this protective mechanism should only appear if the ambient temperature is very high or the equipment is exposed to direct sunlight.

Continous light causes a temporary muting of the output.