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 CX-1A:

  • Preset Mode 1 – Fullrange 80Hz
  • Preset Mode 2 – Crossover Mode 140Hz
  • Preset Mode 3 – Floor Monitor 75Hz
  • Preset Mode 4 – Floor Monitor 90Hz

When should I use the monitor setup?

The monitor setup is principally intended for stage monitor applications with ground-positioning. Big and acoustical hard boundary surfaces just off to the speaker are causing a shift in the tonal balance in the low frequencies. This aspect is considered and compensated in the monitor setup.

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 CX-1A/B with the corresponding subwoofers?

The Crossover Mode (Setup 2) has a 24dB/oct. Linkwitz-Riley high pass filter at 140Hz. Accordingly, the subwoofer should have a 24dB/oct. Linkwitz-Riley low pass filter characteristic at 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 setups should be used for the MF-15A?

The corresponding setup for the combination of the CX-1A is the setup No. 3 on the MF-15A. For further detailed information please read the manual or the FAQs regarding the MF-15A.

How many MF-15A are reasonable for a CX-1A?

The quantity of the recomended subwoofers depends on the personal hearing habits and the given music genre. Especially in small rooms the quantity may vary down too. The information of the recomended quantity of subwoofers always relates to a fully driven CX-1A speaker used in large rooms or open air. Of course the compact box can be combined wich any arbitrary number of subwoofers, having in mind that the maximum SPL for music reproduction could be limited by eighter the subwoofer or the compact box first.

A well-proved combination would be 1 MF-15A for one CX-1A each side.

How many CX-1B speakers can I connect to a CX-1A?

The maximum power of 500W RMS for each CX-1A/B can be reached with one CX-1A combined with one CX-1B. The operation of two CX-1B on one CX-1A is possible. Hereby, each CX-1A/B will get 400W RMS delivered.

Attention! Never connect more than two CX-1B on one CX-1A, because a critical low impedance will be reached for the active module. Furthermore 2 different CX-1A must not be connected with their speakon outputs in any case.

Do I need a special cable for the CX-1B loudspeaker connection?

The CX-1B operates in bi-amped mode. Therefore, the speakon connector has to be wired with 4 poles. Make sure that you never use a crossed cable, because this could lead to a damage of the high frequency unit.

Which of both speakon connections do I use on the CX-1B?

Both jacks are connected in parallel and can be chosen freely. When connecting two CX-1B parallel on one CX-1A, a connection cable must be laid between the two CX-1B. A connection to a further CX-1A must be prohibited in any case.

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.

How is the high frequency unit protected?

The high frequency driver is protected by an RMS limiter. This one is inactive while playing music, but reduces immediately the gain and therefore the maximum output level in case of an acoustic feedback. This helps to avoid excessive levels in the high frequency range, while the dynamic reproduction of musical impulses remains fully preserved.

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.