Q: "How do I connect my new powered speakers to my powered mixer - should I just use the 'speaker out' jacks on my mixer?"
A few questions like these have appeared on our forums recently so we thought we'd better address them here in inSync. This seems to reflect the fact that for some people in live sound reinforcement, powered speakers are still a relatively new concept.
A Powered Speaker (sometimes referred to as "Active Speakers", though it depends upon your definition of active) is simply a unit in which the speaker(s), power amplifier(s) and other electronics are all combined in the same cabinet. This eliminates the need for separate and heavy amplifiers, external crossovers, bulky speaker wire and added cost. It also presumably allows the amp to be precisely matched to the speakers, which can provide a more economic route to optimized sound (in theory at least). If the speaker design is a two-way system including a woofer and a tweeter (or horn and compression driver), a built-in electronic crossover splits the signal frequency and routes highs and lows to two different amplifiers, which feed the two different transducers. This is where the term "bi-amplification" comes from (a three-way system (lows, mids, and highs) would be tri-amplified).
"Speaker Out" jacks on your mixer suggest you are trying to connect outputs from a powered mixer or power amp to your unpowered (or passive) speakers. Speaker Out signals carry more than just the audio; they also carry significant electrical energy (power, which drives the speakers) that the line level audio inputs on powered speakers can't handle. DO NOT connect these to powered speakers! Serious and costly damage will be done to your amplifiers, crossovers and/or speakers.
The most common connection between mixer and powered speaker is a balanced or unbalanced line. The superior noise rejection of a balanced line allows long runs of cable between the mix station and the speakers without interference or noise. Most powered speakers have balanced XLR or TRS jacks, or both. Almost all current mixers have balanced output jacks, again with XLR, TRS, or both connectors.
It's possible (though rare) that your mixer only has unbalanced outputs. These are problematic in long runs, and are more susceptible to picking up noise and interference. Usually a maximum length of 20-30 feet is recommended for these; longer runs greatly increase the noise risk. There are a variety of methods for converting unbalanced signals to balanced ones, but these are beyond the scope of this tech tip. Feel free to search the inSync archives for more info.
Some powered speakers now also have digital inputs. Included in the powered speaker cabinet is a D/A converter (DAC) that converts the digital signal into analog before it goes to the crossover. If the speaker only accepts S/PDIF signals again you will face practical length limitations (20 to 30 feet or less). AES/EBU signals are balanced and can travel much further.
