z Gear Stories episode 35

Hey there, friends, it’s Gear Stories time again!


If you’ve never gotten a gear stories column before, here’s the skinny…  I only send them ten or eleven times a year, and it’s usually fun to read… (or at least, I TRY to make it that way!)  and if you don’t want to get it, no sweat, just tell me!


Usually, I start each column with a link to the month’s “deconstructed Song” where I post an mp3 and then explain the minutiae of how it was recorded… This month… I was busy moving my studio into a larger space… and it takes a lot of time to write those stories… so forgive me… I will have a really good one next month!  But be assured that I have a much bigger space to record cool things to post and write about now!



Let’s get right on to the heart of the matter.


Part one…



DBX DRIVE RACK… shooting the room!  (Why EVERYBODY with a P.A. System should have a Drive Rack!)


I will never forget the first time I experienced a real time analyzer.  It was in the early 80s when I was in college…  (OK.. do the math… I’m OLD!)


I was a volunteer on the stage crew for a concert at my school, Wheaton Conservatory of Music…  Two bands were playing, that were regionally fairly famous in certain circles at the time… “Sweet Comfort Band” and “Marty McCall and Fireworks” (the front man of which later formed the vocal band “First Call” which you may not know of, but it’s guaranteed that if you have watched more than twenty minutes of TV in the last two decades, you have heard them singing on jingles!)


Once the bands were all set up on stage, the musicians left the auditorium (gymnasium) and the sound man set up this funny, skinny microphone back by the board and then did something horrible!  He turned on NOISE!  Just nasty, awful staticky noise.  It was called “Pink Noise” but I often experience musical tones in a kind of color in my mind, and this did  not sound pink to me!


Wikipedia defines it thusly… Pink noise or 1/f noise is a signal or process with a frequency spectrum such that the power spectral density is inversely proportional to the frequency. In pink noise, each octave carries an equal amount of noise power.


Basically, if you put pink noise through an equalizer/real time analyzer,  it would create an absolutely flat line across the screen, since the energy is equal across the spectrum.  You might think, in theory, that that would be a pleasant sound, but in actuality, it is all pitches at the same time at equal volume with each other… and that is a HORRIBLE sound!  It’s rough enough when my cat steps on two keys of my keyboard at once… imagine ALL the keys at once, plus all the theoretical pitches in between the notes!


I don’t know if at the time the technology was in it’s infancy, or if the sound man did not know what he was doing, but he played that noise at a painfully loud volume level for at least ten minutes while he played with the sliders on his graphic equalizer… and THEN, the stage manager said, “OK, I’m glad you’re done with that, I’m going to lower the backdrop curtain now.


Oooops!  Since a ginormous thousand pound theatrical curtain changed the spectral response of the entire room, we had to start from scratch again.  I got to listen to about twenty minutes of pink noise at unbearably painful volume that day… and that was my lasting impression of what it was to “shoot a room.”


Zoom ahead to thirty years later, and there have been significant advancements in the technology, and at this point, there is a series of products available on the market that in my humble opinion, ANYBODY with a PA should not be without!  It’s by that time honored, reliable company called dbx, and the group of products are referred to as “Drive Racks”




First of all, what do they do?  Well, in effect, they “Shoot the Room” just like my slow friend back in the 80s… only they do it incredibly quickly and virtually painlessly.  I have experienced one of these units analyzing the spectral response of a room, and it works VERY quickly!  It’s much faster than anybody could do it by hand.  It takes only a few seconds.


The effect of shooting the room is that when you compensate for the frequency problems in the room, then the sound that reaches the audience is balanced and pleasing to listen to and is not full of peaks that stick out unpleasantly, or black holes where certain frequencies get sucked into, never to be heard from again…   Shooting the room is supposed to make you able to hear everything right.


Back in the 80’s, that’s pretty much all that this real time analyzer thingy did…  but now, Drive Racks do SO much more!  They are in effect, multi effect units that you put on the master output from your mixing console, right before the signal goes to the power amps.


Here are some other things they do.


FEEDBACK ELIMINATION…    Feedback is the pestilence and plague to all live sound engineers.  It is simply when the sound that is amplified (for instance, a person speaking into a mic) comes out the speakers, and then some of that sound gets picked up by the microphone again and goes back through the system again and is amplified even more, so it is picked up by the mic even more and that cycle continues over and over, REALLY fast, so all the sudden, the speakers start to squeal painfully!  The audience hates it, so then they hate the people on stage… the people on stage hate to be hated, so then they hate the sound man… it’s just lose/lose…


Drive racks have one of the  most affective feedback elimination circuits on the market.  Basically, it looks for sharp, narrow, peaks in the audio, and drops in equally sharp and narrow notch filters, all automatically, and almost instantly.


Just a few weeks ago, a representative from dbx was showing us some features on the Drive Racks, and took a handheld microphone that he was speaking through and walked directly in front of the PA speaker that was amplifying his voice, and then he pointed the mic directly into the speaker.  He simply made it impossible not to feed back!


And at first, I thought we were all doomed to premature hearing loss due to trauma… but there was a quiet squeal and then it hummed a tiny bit and disappeared… it was not painful… in fact, it was quieter than the level of the man’s voice… the Drive Rack simply saw the pattern of feedback developing with it’s smart little processors, and simply cut those exact frequencies out temporarily… BOOM!  No more feedback.


If it was that effective when the guy pointed the mic directly at the speaker, how much more effective will it be when the person wearing the lavaliere mic in the large lecture hall or sanctuary speaks in a normal voice from the stage!?


DELAY COMPENSATION…  Another feature that Drive Racks have is compensation for room delay… This feature is a bit less used, but it is very useful if you are trying to pump sound through a larger room and you have more than one array of speakers (such as in a church that has speakers in the balcony, or halfway down the sanctuary wall so the people in the back row that slept in can still hear what is being said!)


As I am sure you know, sound takes time to travel… It’s fast, but it does take time.  Jet’s have broken that barrier and flown faster than the speed of sound… so imagine if one of those jets passed through the room you were trying to run sound in, and it was going exactly the speed of sound… the time it took to get from the front set of speakers to the balcony speakers would be measured in milliseconds… but it makes a huge difference.  (Since the signal going through the pa cables goes at nearly the speed of light!)


If you have the sound from the front speakers reaching the people in the balcony a few milliseconds AFTER the sound from the balcony speakers, then it makes the sound jumbled and out of phase… hard to understand and unclear!


How the Drive Rack fixes that is that you can set a slight delay on the audio outputs for the speakers in the back of the room, so that the sound comes out of the those speakers at exactly the same time that the sound from the front speakers reaches the balcony… and suddenly, you  can understand what the person is saying!


Drive Racks also include compressor/limiters, comprehensive EQ sections, and a built in crossover.


They come in several different models… the Drive Rack PA+ is for conventional PA systems, and is a pretty basic model, the Drive Rack  PX is designed for powered speakers, and has the EQ algorithms pre programmed in them for most of the powered pa speakers that are on the market, (As well as ones that are no longer on the market!)  The Drive Rack 260 is a higher end version that comes with additional features for the more experienced sound engineer with more complex needs, and likewise, the Drive Rack 480 is the Rolls Royce of the line… with everything that you can imagine or need in dialing in the PA perfectly!


All of them come with a comprehensive set up wizard that gives you step by step instructions that are easy to follow to use them effectively to meet your needs.    SO if you have a small acoustic band, or a great big Rock band, or a Church or a live sound company… EVERYBODY with a PA system NEEDS a Drive Rack!


Take a look at the link… (here it is again…  http://www.sweetwater.com/store/search.php?s=dbx+drive+rack&go=Search ) and call me for any additional questions so se can get the exact one that’s right for you… It will truly end your PA problems!




Part two



Apogee Duet 2, Raising the bar on Digital Audio interfaces, AGAIN!


A few years ago now, the company called APOGEE released their first small format interface onto the world… It was called the Duet.


It was a very  simple, basic stereo audio interface that required a firewire port into a Mac computer to function.   The difference between the Duet and the dozens of other firewire interfaces out there at the time was that the Duet had super high quality analog to digital converters (and the mic pre’s were no slouches either).  It was really the first time that pro level electronics were available to the general public at what would be called a “competitive” price.  (meaning guys like me could afford it.)


So a guy with a Macbook could be sitting on the bus on his way to work mixing a song using high end digital conversion… or could take his laptop and a couple of nice mics to his buddy’s house and lay down tracks with high end studio quality pres and digital conversion, without having to haul a huge rack with him, and without having to spend an arm and a leg!  Many people use it for the main interface for their entire studio using Logic, Digital Performer, Pro Tools 9, Cubase, or any of the number of newer DAW programs.


The problem with raising the bar is that once you do it, everybody else starts trying to jump higher than you!  And over the years, several companies have stepped up their games to create interfaces that rival the original Duet in the small format interface market… (To mention names, particularly the MOTU Microbook, and the Avid Pro Tools mBox … third generation.)


Apogee is arguably the best… so they are not a company that is known for resting on their laurels… they went to the drawing board and redesigned the Duet to raise the bar over the competitors that have been trying to raise the bar on them!


Here’s what is new in the Duet 2


*  Completely redesigned mic preamps and converters

*  4 outputs, Independent speaker and headphone outs

*  Balanced outputs

*  USB 2.0 high speed connectivity

*  24-bit/192kHz recording

*  Full color OLED display

*  Configurable touch pads

*  Maestro 2 software

*  Breakout box (sold separately)

*  Redesigned Breakout Cable

*  Soft Limit


Here’s the link!  http://www.sweetwater.com/store/detail/Duet2


A couple of things you need to know about this baby… First of all, it’s Mac ONLY!  Sorry… still no Windows support on these.  Second, it’s not available YET.  We are expecting our first shipment in a few weeks, but they are selling out fast…  If you want to be the first on your block to get one, you  should pre-order this right away!  (Of course, we don’t charge you for it until it ships to you!)


Call me, or place your order online for this and get one from that first shipment!


And, or course, as always, I look forward to being of service.


Jon Gillespie, Sweetwater Sales Engineer


800 222 4700 x 1352

260 432 8176 x 1352 (outside the U.S.)

260 432 1758 FAX

[email protected]


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My own personal web site can be found here…  http://www.dreamrodeo.com/


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