While the first 100 or so years were spent trying to reduce or eliminate noise introduced by the recording medium (tape, movie film, phonograph disc, etc.) with the arrival of digital recording, we came to a point where we could focus on reducing or eliminating noise that was actually part of the recorded environment, rather then the recording medium. 

While digital audio does represent a dramatic improvement in the ability to record sound via greater signal-to-noise ratios, lower distortion, increased dynamic range, frequency response and more, there are still noise issues in the digital world. Fortunately, these are minute compared to the days of analog.

Noise Types
There are essentially two types of noise we as recordists must deal with, and remember, you are the recordist – the machine is the recorder.
First is “natural” noise – the noise that is inherent in the environment we are recording in, whether it’s the sound of an air conditioner, hum from a guitar amplifier, or the wind blowing through the trees, it doesn’t matter if it’s human-made or nature-made – if it’s sound we don’t want, it’s noise.
Second is noise introduced by the recording medium: For analog tape, it was the hiss of the tape, or distortion introduced by driving the recording heads or an amplifying stage beyond its limits. For phonograph records, it was the lower end of the noise spectrum where the actual sound of the vinyl was heard as the needle dragged across its surface (referred to as “rumble”), or the pop or click of foreign matter as it made its way into the record’s groove.
Today, noise comes primarily from the shooting location, recorded at the same time we capture production sound. Typically, the less sophisticated your audio setup is for a given shoot, the more noise you will capture along with your production sound.
Must you deal with the noise?
Over the years, each of these noise issues was eventually addressed, with mixed results: Noise from recording to tape or film was dealt with by systems such as Dolby and DBX (a compressor-expander for increasing dynamic range) noise reduction. These were essentially “closed-end” systems, in that you had to encode the material as you recorded it, and then decode it upon playback. It relied on the tape deck being calibrated in a certain manner, but if the deck was not properly calibrated, it was met with sometimes disastrous results. (For some insight into what occurs when things go wrong with analog noise reduction systems, Denny Diaz, of Steely Dan, wrote some behind the scenes insight into what happened to the band’s  tune, Katy Lied – www.steelydan.com/dennys3.html, an album that gave DBX a little infamy.)
While analog tape noise reduction systems evolved with ever more spectacular results, attempts at reducing noise on phonograph records was met with less then satisfactory and sometimes even disastrous results, from such companies as SAE and dbx. Today, there are still a few devices and applications from companies such as CEDAR, that deal specifically with noise from phonograph records, ranging from freeware to very expensive hardware and software for the professional market, considering the narrow focus of the application. Fortunately for us, that’s all pretty much in the past, unless you have need to deal with legacy material from tape, optical soundtracks or phonograph records, and even then, there are lots of choices with more down to earth prices.
Reduce the Noise
Today’s noise reduction applications are designed to be single-ended, or open-ended, in that they don’t need to be encoded during the recording process to take advantage of their abilities. Where once it was quite a production to try to eliminate something as simple as a 60-cycle ground hum (usually with a notch filter and mixed results) – it’s a simple matter to punch up a filter either by way of equalizer (EQ) or by way of digital noise reduction, to reduce or practically eliminate the offending sound.
For most videographers, sound usually comes as an afterthought, usually only when there is “a problem with the sound” – otherwise, most shooters are quite happy with the audio, whether or not the talent is on-mic or off-mic. That attitude is slowly changing, as videographers discover higher quality sound is just as important as that high quality picture.
Learn to Hear the Noise
While your musician and audio friends have probably had more exposure to noise reduction applications, dealing with the quality of the soundtrack may be fairly new to most videographers, as they discover the pops, pings, clicks, whirrs and buzzes that come with shooting just about anywhere but on a sound stage. 
Where once the art of reducing or eliminating noise was in the realm of “the big guys” because noise reduction applications were so expensive – they have come down in price, while making amazing strides in the ability to clean up your soundtrack. Not only have they come down in price, they have become easier to learn. For most people, it’s hard enough to edit sound, let alone clean the sound. Think of it as using an intra-frame effects application. You are editing inside the waveform, just like you edit your video effects inside each frame.
So today is the day you become more aware of sound, and the noises that come with it. Just about anyone can cut picture, but a true editor will also ensure a pristine soundtrack.
Mark Speer is a video educator specializing in audio production.

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  1. I was a recording engineer in the 70s and have used the DBX noise reduction system very successfully for many years.  It was easier to use than Dolby and I personally find the DBX sound more pleasing.  I rarely used it for initial recordings, but it was great for 2nd generation recording and beyond. I read the Steeley Dan article you referenced and I'm not sure that DBX (or any noise reduction system…) was their only problem.


    The excess humidity is an obvious red flag. 


    In 1975 and earlier, the recording 'state of the art' was a lot more experimental and a lot less reliable than it is now.  Transistorized audio circuitry was fairly new and  transistorized consoles had only been around for 10 years or so and were still being developed. Even turning a system off, then on, could reak havoc — which is why we left everything running 24 hours a day once we got it up and working properly.   


    In 1975 temperature and humidity control were vitally important to maintaining 'state of the art' in the control room and many control rooms seemed to only work well in chilly temperatures.  Remember how cold audio and video control rooms always seemed to be?  That's why.  Variations could and did cause big problems.  Even little fluctuations meant phone calls to the electronic maintenance engineers and recalibrations and realignments and replacements. 


    And that's precisely why Steeley Dan's state of the art studio had a complex conditioning and humidity system designed to keep the temperature and humidity at perfect levels, which malfunctioned, and dumped huge amounts of steam into the studio.


    The Steeley Dan problem could have been a DBX problem or a problem with any other system in the studio.  It could have been the soggy tape, or soggy microphones, soggy circuit boards, soggy speaker cones, some conbination of the above, or anything else exposed to the excess humidity.


    I wouldn't be to quick to assume it was the just the DBX system. 


    Jonathan Zimmerman



  2. Hi Jonathan,

    First Thank You for the comments – As a fairly new contributor to Videomaker, it's exciting to see the responses that readers submit, and also displays just how truily on the ball our readers are…


    I would concede to your position that humidity played a significant part in the troubles that Steely Dan experienced on "Katy Lied".  Unfortunately, the "urban legend" that is associated with the album is merely  that "the DBX wasn't working properly", and with a limit on the number if words I could submit, I did perpetuate it.  This was not meant as an aspersion towards DBX, rather an attempt to generalize it so a broader audience would read it and not be sidetracked with the concept of "the weather in the studio" impacting on the record – most people have never had to deal with that. While DBX will forever be associated with this particular incident, whether rightfully or wrongfully, this was not meant to imply that DBX equipment was typically troublesome or substandard by any stretch of the imagination.  I have used DBX noise reduction and other products extensively, and with great confidence. One of the first times I used DBX NR was recording Peter Hammill at the Troubadour on a pair of Tascam 25-2's, and was simply amazed at the noise floor.  I also loved their 162 compressor/limiter, which I used extensively and exclusively, when I produced and mixed radio spots for one of Southern California's (then) premiere record store chains.

     It figured in no small way in my winning the contract away from the Beach Boys studios (amicably), where they had been recording up until then, and it also helped in no small way in raising the bar for the quality of regional spots played on L.A. FM radio back then . It was the '70's, and typically, agency spots were poorly duplicated, mixed for AM, mostly mono and tinny.  The national spots we got from the labels  were even worse – Casablanca Records were the biggest offenders, with fidelity that sounded like it came down a telephone line (really, I'm not kidding)- shameful for a spot trying to sell a record.  We were one of the first, if not the first, to mix for the FM audience, in stereo, and ship to stations at 15ips.  These might sound like minor things, but they actually did encourage everybody else to start putting out better product…..Anyway, I've digressed, but I wanted you to know that I didn't mean to sound like I was bashing DBX.  In those days, any of the noise reduction systems could be tempermental if they so desired- I recall Dolby having their adventure with one of the Doors early albums going through similar encode/decode problems. So the bottom line is that yes, all these systems had merit, No, I would not lay the blame solely on DBX for the issues with "Katy Lied", but that is the part that is most commonly remembered. All of these technologies went through growing pains.  It's just because they were legends, being used for recording legends, that they fell under a lot more scrutiny. I've heard horror stories about Dolby SR and others on feature films, but because these problems were fixed in the studio, before it went out the door, it never really was a "problem".  It's interesting to note in the Steely Dan web page talking about all this, that one of the problems they had was that the recording lathe simply couldn't track because it couldn't keep up with the transients from the condensor microphone recording the cymbals.  They literally were ahead of the technology available to them back in the day.  Besides, a poorly recorded Steely Dan track still towers over just about anything being recorded today


    All The Best,

    Mark Speer

  3. DBX and Dolby were relatively new in 1975 and there had been problems with getting Dolby right.  DBX was much simpler and seemed to always work OK for me right out of the box.  One of DBX's selling points, in addition to it being less expensive, was it was earier to use and more bulletproof.  It wasn't as customizable as Dolby, but it worked well in most situations.  Noise reduction technology was the new kid on the block and the most likely to be blamed… .


    But of course, anything in the building, including DBX, could have caused the problem.


    As a former radio person, I know how bad the radio spots could be, and having worked in studios where the spots were duplicated, it's a wonder they had any fidelity at all.  And at Gotham Recording in New York City we DID send the commercials down telephone lines.  They were balanced and dedicated lines, but phone lines nonetheless.  Most of the major recording studios and the network radio and TV stations in New York City were all networked by dedicated phone patches and if I recall correctly, the hub was at CBS.  We would send stuff back and forth regularly.  It didn't matter too much for AM as it was hard to tell on the tinny little AM car speakers, which were the market, but FM opened up a whole new world, as did AOR, which allowed people to listen to radio seriously.  The spots recorded for AM sounded like crap.

    Any good cutting lathe with a good fast head could usually cope with  transients that were in the audible range — it was the tape recording circuity that would crunch.  We'd get stuff in to master that had high spikes that could drive the cutters wild,  but they were easy to filter out.  The biggest problem we had with cutting was the improved low end that came with transistorized consoles and synthesizers.  If we weren't careful, the large cuts made by the low notes could overlap and cause all sorts of distortion.

    And now of course it's all digital.  I miss the hands on work we did — like putting a speaker at the bottom of an elevator shaft and a microphone suspended under the elevator.  When we mixed at night, and the building was quiet, we would adjust the reverb by parking the elevator at whichever floor gave us the best sound.  We also had mechanical reverbEMTs, and some really crappy Fairchild stuff.  The EMTs sounded great and I hear some studios are using them again, and I can understand why.   The elevator was the best, though —  especially when the city was quiet.



    Jonathan Zimmerman