Active Loudspeakers
Thom Moon’s review of Blue Sky’s Sky
System One 2.1 speaker system got me thinking about one of my favorite hi-fi topics:
active loudspeakers.
Though there seems to be no strict definition about what an
"active" loudspeaker is, most designers I’ve talked to agree that it’s
safe to describe it as a self-powered loudspeaker. In other words, an active
speaker system comes with its own amplification and crossover. Speakers that are not
active are called passive.
In an active speaker system, the amplifier and crossover
might be built right into the speaker, as in the Sky System One 2.1, but the electronics
can also be housed in a separate chassis, as with NHT’s Xd and Aurum Acoustics’
Integris Active 300B, products I reviewed on SoundStage! a couple of years ago.
Two benefits of fully active speakers are simplicity and
convenience. You can drive them directly from a preamplifier’s outputs using a pair
of interconnects, or, if you have a CD player or DAC equipped with a volume control, you
might not need a preamp at all. Either way, active speakers give you quite a bit less to
worry about than do passive systems.
But there’s more to it than that. Many feel that
active speakers are the best way to go because the designer can simultaneously optimize
the performance of the amplifier, crossover, and speaker so that they work together to
create the best possible sound. This is significant; most experienced audiophiles know
that one key to getting great sound is to partner the right amp and cables with the right
speakers, a hit-or-miss proposition when you go at it yourself. With the active approach,
nothing is left to chance -- the designer has done the mixing and matching for you.
Another benefit of active speakers that’s seldom
discussed in the audiophile press has to do with where the crossover is placed in the
signal path. In many top-flight active systems, the crossover is implemented at line
level, ahead of the amplification stage. This is quite different from conventional
passive speakers, in which the crossover is placed between the amplifier and the drivers.
Derrick Moss, Aurum Acoustics’ president and chief designer, feels that the
line-level approach results in a superior loudspeaker design. He says that a passive
speaker’s high-level crossover acts as a "sponge" that the amplifier must
work through, and that this reduces the amplifier’s control over the drivers. In an
active design, the only thing between amp and drivers is some wire, which, according to
Moss, results in better control of the drivers by the amp and, thus, better sound.
There are probably other benefits to the active approach,
but my point is this: active speakers have inherent advantages that can lead to
better-sounding speakers.
Although active speakers make a lot of sense, and are
staples of professional audio (recording studios and the like), they’ve never caught
on in audiophile circles. In fact, many audiophiles prefer instead the haphazard approach
of mixing and matching their speakers, amp, and cables, and ignore the potential benefits
that active technology can provide. There are many reasons cited for this, most of them
revolving around the notion that audiophiles like to pick and choose their components
separately. But this resistance has meant that active speakers are rare, and that some
companies have stopped making them. The best example of the latter is Paradigm, one of the
most successful speaker companies in the world. Their Active line of speakers received
high praise from critics and should have been a surefire hit -- I reviewed the Active/40
in 2001, and bought the review pair. But regardless of how good they were and how
reasonably they were priced, the demand from audiophiles was low, and Paradigm left the
active-speaker market in late 2001.
Other companies continue to make active loudspeakers. Blue
Sky, obviously, is one of them; Audioengine, whose A2 speakers we reviewed in July,
is another; and there are others. But the technology isn’t thriving as I think it
should. In my opinion, more audiophiles need to be aware of the benefits of active
loudspeakers, and to give this very worthwhile technology a try. Maybe now is the time
when active speakers will finally catch on. Let’s see.
. . . Doug Schneider
E-mail comments to the editor@goodsound.com.
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