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Powered Speakers: What’s The Voodoo?

There is nothing magical or strange about powered speakers—the amplifier has simply been relocated from a box that was in-between your console and speaker right into the speaker cabinet itself. The sound coming out will still reflect the signal coming into the speaker. It’s the same as it ever was.

[box] Note: This article is the result of a recent discussion in the Pro DJ/MC Senior’s Tour* (facebook) regarding the pros and cons of signal processing. While processors (such as compressor/limiters and aural exciters) typically reside in a processor rack between the mixer and loudspeaker, there were several comments suggesting that, with powered speakers, no processing is necessary. Stu Chisolm decided to run with this and (with his permission) we reprint his comments here.[/box]

Powered-Loudspeaker_DSP_ChisholmThat said, most powered speakers have incorporated Digital Signal Processors (DSPs) that process the signal to match the speaker’s dynamics. Remember the Bose and EV passive speakers that came with an external processor back in the day? (I have some ancient EV S-200s that have a switch that selects between “with EQ” and “without EQ”) If your active speakers have a built-in DSP, then you ARE running a processed signal.

Start with a basic system calibration.

This is best done outdoors using a spectrum analyzer, pink noise generator and calibrated mic. This will allow you to actually SEE what your system is doing. All components must be ON, but set to neutral. (Aural exciters/Sonic maximizers set to “bypass” and EQs flattened at 0.) Then, with the pink noise running, (CAREFUL! TOO LOUD can KILL a speaker!)  bring up the volume on ONE SIDE ONLY and adjust it to FLAT. When properly done, your sound spectrum should be a flat line. Repeat with the opposite channel. At this point, your system is acoustically neutral; you’ve eliminated any sonic artifacts introduced by your cabinets, cables, processing chain, etc. While sonically neutral, though, it will sound horrible at this point, since our ears are NOT acoustically neutral!

This is the starting point for “sweetening” the sound. Humans tend to suck at hearing the extreme ends of the sound spectrum, which is why you see equalizers set in the classic “V” or “smile” pattern. Short of having test discs/files, I just pick a piece of music that I know very well that has extreme low and high end content (mine are the old “Age of Love” techno track, along with Holst “The Planets” classical piece) and tweak until it sounds perfect. Unless you’ve got hearing damage, your ears are usually the best judges of sound you own. Mine do, sadly, so my tweaks are hawked by keeping a wary eye on the spectrum analyzer. Next, punch-in your other processors. Adjust as necessary until you’re 100% satisfied. At this point, your system is optimized. But wait… there’s more!

Every room “colors” your music.

The construction of the walls, floors, the floor covering (carpet, tile, wood, etc.), wall treatments, the type of cieling, the furniture (and chair/table coverings) and on and on ALL impact your sound. For us old schoolers, if your system has two EQs (one in the rack and one on the board or software) use THIS to tweak your sound for each room. Rather than run the whole pink noise profile in each room like I used to do, requiring me to arrive 45 minutes earlier, I instead run the analyzer and get my overall setting to look like it did when I optimized the system. What you see on the analyzer should also match what your ears hear. On those rare occasions when the two conflict, let your ears trump your eyes. Of course, when people arrive, it will throw the whole scheme off, but again, you’ve gotten as close to perfection as you’re likely to achieve.

dbx_DriveRack_Processor

One thing that has been a game changer since it was introduced is the The DriveRack PX Powered Speaker Optimizer from dbx. It has all of your processing in one unit: EQs; compressors; noise gates; limiters and on and on. Further, if you do decide to pink noise calibrate each and every room you frequent, you can then store the settings. If you change nothing, then your system can be instantly optimized to the room you’re playing at the touch of a button (It also contains auto-calibration software.) dbx has updated the unit as technology has progressed and does have a unit made especially for powered speakers. By the way, it’s inexpensive, especially when compared to the cost of having a whole rack full of gear. You can save a ton of money and weight. (And no, I don’t work for them or make a buck from ’em.)

Also See: Loudspeakers: Powered Or Unpowered by Jamie Rio

[box type=”bio”] About Stu Chisholm: Stu is a 30 year veteran Mobile Entertainer, still actively entertaining throughout southeast Michigan. He is a well-known speaker and presenter at DJ Trade shows throughout North America and a regular contributor to Mobile Beat Magazine. His book, The Complete Disc Jockey details over a dozen different money-making opportunities for DJs. Stu’s career as a mobile entertainer began in 1979. Over the past 35 years he has worked in broadcasting, nightclubs, underground raves, skating rinks, and done commercial voice-over work and Webcasting. In The Complete Disc Jockey, Stu discusses techniques and gear, shares business, marketing and promotional ideas and talks about how to develop your own unique personality and performance.[/box]

 

About the author

Stu Chisholm

Stu Chisholm had been collecting music since he was about eight years old and began his DJ career in 1979, when laid off from GM. A collision of events - a recession, jobs being scarce, and a friend’s wedding band breaking up the night before his reception - led Stu to the realization that being a DJ could be a real career option. Stu also had the benefit of being well known as a part of a community housing co-op, whose residents could be counted on to keep him supplied with a steady stream of weddings and other events, as well as coming out to various bar and club nights that Stu and then partner, Gary Merkel, would host. Without benefit of the internet or trade publications, Stu built his business by talking with technically inclined friends, scoping out events at area banquet halls (dominated by bands at the time) and a big dose of trial-and-error. Stu also attended the Specs Howard School of Broadcast Arts and, when a funding snafu derailed those classes, moved over to the local Macomb Community College to study the DJ arts with famous Michigan broadcaster, Bill Henning. Stu also interned at Detroit album rock powerhouse, WRIF. Not content with having a full weekend calendar, Stu looked to the local nightclub scene to fill up his remaining nights. Capitalizing on his self-promoted bar night history, he landed his first true club gig at CJ Barrymore’s in 1984. It was there he learned and improved on the art of beat mixing, and working with video. At the same time, Stu occupied his daytime hours by working at a local roller rink and at the Macomb County, Michigan AM daytimer, WBRB. Originally hired as air staff, when the station re-launch was delayed by technical problems, Stu worked with the engineering team to help bring the station back online and meet FCC specifications. He cut his first commercials there, which led to some part-time voiceover work. For the next few years, Stu’s nightclub experience included some of the Detroit area’s best known venues, including New York New York, The Ritz, Lipstick’s, The Landsdowne (later known as the Baja Beach Club), and the legendary Wooly Bully’s. In 2005, after a particularly well-received Letter to the Editor, Stu was invited to join the writing staff of Mobile Beat Magazine as a part-time contributor. He soon had amassed a sizeable body of work, enough so that his editor proposed he collect them together into a book form, as some of the other writers had done. Instead, Stu proposed a book of his own; an original volume that would mirror his own experience as a DJ, encompassing the opportunities available beyond wedding receptions. That book became “The Complete Disc Jockey: A Comprehensive Manual for the Professional DJ.” Released in late 2008, it became the basis of Stu’s first major appearance as a speaker at Mobile Beat Las Vegas and his seminar, “Supplement Your DJ Income… WITH DJ INCOME!” From there, Stu was asked to present on the DJ Cruise and at the Canadian Disc Jockey show. Today, Stu continues to operate his mobile company, Stu & His Crew, LLC, and has a regular column in Mobile Beat. Stu also offers classes to mobile entertainers on security issues in the Detroit, Michigan area.

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