ALESIS ProActive 5.1

Electronic Musician reviews the Alesis ProActive 5.1, a loudspeaker system designed for surround sound applications. The system features a subwoofer, four satellites, and a paperback-book-size control unit with several input options and surround decoding schemes.

When a salesperson showed me the Alesis ProActive 5.1surround speaker system, I was intrigued. I used to have a surroundsetup in my living room, but a roaming toddler and tipsy speaker standswere a risky combination, so I was seeking a worthy replacement. TheProActive speakers are small enough for easy wall mounting, and thefully integrated controller meant I didn't need to buy a new receiver.I figured I could leave my existing stereo music system intact and usethe ProActive system just for surround.

This Alesis-branded product is actually an OEM (original equipmentmanufacturer) version of the Z-680 system designed and manufactured byLogitech. Logitech sells their $399 list version through computerstores and other consumer outlets. Alesis's version is available atmusical instrument and pro-audio stores. For the extra cash, Alesisthrows in heavier gauge speaker wire and a free subscription to asurround magazine.

The ProActive 5.1 system includes a subwoofer cabinet containingamplifiers for all six speakers: the sub, three front satellitecabinets, and two rear satellites. An AC cord and hefty heat sinkoccupy the subwoofer's rear panel. The side of the subwoofer has a bassport.

The brains of the system is a controller tethered to the subwooferwith a nonextendable 4-foot multipin cable. A small infrared remotelets you adjust most settings from across the room. Alesis provides a6-channel analog audio cable (RCA-to-⅛-inch stereo miniplug) aswell as six RCA-to-¼-inch adapters.


The master controller sports a large knob that adjusts overallvolume or the currently selected parameter (Input Select, Level,Effect, Settings, and Mute). Parameters are cycled by repeatedlypressing front-panel buttons.

Coaxial and optical digital inputs and six analog line inputs (usingthree stereo ⅛-inch minijacks) are supplied on the controller'srear panel. The front panel has a stereo ⅛-inch aux input and an⅛-inch headphone output. You choose the source by pressing theInput button. Anything connected to the front-panel input jack is mixedinto the front left and right channels along with the direct 6-channelanalog source. You can use the front-panel inputs for a karaoke inputor to overlay system alert beeps from a computer. However, all inboundanalog signals are muted when either digital input is selected.

Once you've chosen the input source, several playback options areavailable. The Effects button actually selects one of many decoders:Dolby Digital, DTS, MPEG, Dolby Pro Logic II Music, ProLogic II Movie,6-channel analog input, Stereo ×2, or Stereo.

Dolby Digital and DTS will come in handy for watching DVDs ormonitoring surround mixes that are encoded into either of theseformats. Pro Logic II is the current version of Dolby's 2-channelsurround playback system. You feed Pro Logic II a stereo mix, and thedecoder derives center and surround information automatically. Thecenter-channel speaker is used in Pro Logic II Movie mode; in Musicmode, it is not. (Music mode also includes a number of surroundprocessing parameters not available in other modes.) Stereo ×2simply puts the same stereo mix in both front and rear speakers, andStereo is plain old stereo. It's a long list of options, but happily,the system makes the correct choice automatically when it sees adigital input signal.

ProActive 5.1
surround speaker system

PROS: Goodvalue. Fun for home theater.

CONS: Poorsonic integration between sub and satellite speakers. Coarse parameteradjustments.

tel. (312) 821-5000


Each of the satellite cabinets holds a single 2.75-inch speaker.This driver starts working at about 150 Hz; by about 200 Hz you'refully out of the subwoofer and into the satellite. Performance is crispin the midrange, aiding dialog intelligibility, but not especiallydetailed in the top octave. No polar plots of the speakers areprovided, but I believe that the high-frequency pattern narrowsconsiderably at upper frequencies.

Although the center-channel cabinet is larger than the other four,it also houses a single driver. If you stick your face up to thecenter-channel speaker, you can hear a low-level hiss while the systemis idling, but I never noticed this while playing program material.

The 8-inch subwoofer can put out a clearly audible 40 Hz signal andhas plenty of thump. Unfortunately, I was never able to get acompletely satisfactory balance between the subwoofer and thesatellites; the adjustments you can make to the sub's level are toocoarse. In two completely different acoustical environments, I had toset the sub to its lowest possible volume. One more click down, and thesub turns off entirely! Also lacking in any parameter adjustments areuseful measurement units such as decibels or milliseconds.

Aside from the sub/satellite balance problem, bass management ishandled appropriately and transparently. For example, when operating indirect 6-channel input mode, all low frequencies directed to the fivesatellites end up in the subwoofer output along with the signal sent tothe sub channel. Automatic low-frequency signal routing is an advantageof an integrated 5.1 system such as the ProActive.

The documentation is adequate, although light on placement andcalibration details. I created a test CD with band-limited pink noise(500 Hz to 2 kHz) at a level of -20 dBFS RMS, as described in TomlinsonHolman's book, 5.1 Surround Sound: Up and Running. I thencalibrated the system levels using that source to video reference (78dB) and later to film levels (83 dB SPL, C weighted at the listeningposition). Playback was loud and clear in both cases.

The system is THX certified as a multimedia device (for use, it'ssuggested, with a computer at a distance of 28 inches). Details ofTHX's measurement criteria are proprietary and, unfortunately, notavailable to customers or members of the press. However, I believe thatthe multimedia criteria is a less demanding spec than the more rigorousTHX pm3 certification met by systems such as Mackie's HR824loudspeakers. In other words, the THX label is reassuring, but Iwouldn't read too much into it.

ProActive 5.1Specifications
AudioFrequencyResponse (system)35 Hz-20kHzPeak OutputAmplifiers114dBPowerRating62W(satellites); 69W (center channel); 188W (subwoofer) at 100 Hz and 1kHzSignal-to-NoiseRatio100dBAInputImpedance10kžTotalHarmonic Distortion<0.01%PowerConsumption600W (fullprogram)SpeakersHigh-FrequencyDriver3" butyl rubbersuspension with aluminum phase plugLow-FrequencyDriver8"high-excursion, low-throw wooferInputConnectorscoaxial;optical; 6-channel direct (three stereo miniplugs); analog stereominiCrossoverCrossoverFrequency200HzEnclosureMaterialsatellites andcenter: ABS plastic; subwoofer: MDFDimensionssatellites 4.0"(W) × 5.0" (H) × 3.5" (D); center 8.5" (W) × 4.0" (H)× 3.0" (D); subwoofer 12.0" (W) × 12.0" (H) × 14.0"(D)Weight51


Most of my surround work involves the creation of natural and othersoundscapes rather than music. I reviewed some of my DVD-A multichannelprojects through the ProActive's analog inputs, and the soundtrackstranslated fairly well. I also listened to some of my recent raw fieldrecordings and generally found the midrange accurate, but felt a gapbetween the low mids and the boomy, high bass of the sub. One advantageof this extra low end is that if you test your mix on the ProActive 5.1you probably won't overlook any unintended low-end rumble. If it'sthere, you'll hear it loud and clear.

A few minutes of DVD playback from the extended version of Lordof the Rings: The Fellowship of the Ring illustrates the system'sstrengths and weaknesses. Starting at Disc 2, Chapter 4, as thefellowship marches from Rivendell, we hear a fully orchestrated versionof the “Fellowship Theme,” culminating with a rich brassclimax. Through the ProActive, the track exhibits plenty of midrangeclarity, but a lack of airiness. The low end of Gandalf's followingvoice-over (“We will march 40 days…”) feels a littletruncated, indicating a bit of a disconnect between sub and centerchannel through the crossover range. But moments later, the systemshines. While Gimli the dwarf dismisses an approaching flock of birdsas just a wisp of clouds, the score signals otherwise. The mutedstrokes of an orchestral bass drum are delivered with ominous authorityby the ProActive sub. Then, as the evil birds swoop in from therear-right, the listener is enveloped in wing beats and squawking— a wonderful sequence well served by the loudspeaker system.

I had a couple of hardware problems following my purchase. (Skimmingthe Web, I found a handful of users with similar complaints.) After myinitial setup, the system began blowing fuses, so my dealer provided areplacement system. However, the new sub developed a mechanicalinternal rattle around 110 Hz. Both issues were resolved. The poppingfuses seem to be attributable to an early version of the mastercontroller, and have since been fixed. Alesis will repair any rattlingsubs, but before you call tech support, be sure that the noise you hearisn't coming from objects on, near, or even across the room from yoursub.


After living with the ProActive 5.1 for a few months, I'm pleasedwith the purchase. The system is an excellent value, easy to set up andoperate, and great for listening to soundtracks of DVD movies —I'm still surprised at how much I enjoy these speakers as part of ahome-theater setup. Music playback is somewhat less satisfying, so myoriginal 2-channel playback system is still in place.

The ProActive 5.1 system is a good, low-cost way to get started withsurround sound. The monitors can be used as a real-world reference— like having a surround system of Auratones. While I wouldn'trely on them as my primary monitors for production work, they're loadsof fun as a playback system.

Rudy Trubittis a freelance audio producer in the SanFrancisco Bay Area. Visit him on the Web