On the Digital Edge

Anyone who knows me will tell you that I am a microphone freak, so any activity involving microphones is at the top of the gear lust chart for me. There are three thing you cannot have enough of: money, microphones and well, you can guess what else.

FOH has written a lot of information over the past year regarding FCC reallocation of the UHF band and how it will affect pro audio wireless. We’re not going to rehash the problems facing the pro audio industry in our efforts to continue using the UHF spectrum for wireless operation. If you missed it, revisit “Bleeding Edge” in the February, June, July, November, December 2007 and October 2008 issues.

The editors of FOH recently received an interesting e-mail from a gentleman who informed us that he was a university student studying computer programming and networking, and that he also did live sound on a part-time basis. He wanted to know if we had any ideas about how he might be able to apply his knowledge in the computer field to audio, enabling him to combine his two interests as a career. If this question was raised barely 10 or 12 years ago, the answer to that question would be an emphatic “no.” However, we’ve seen a long-term trend that goes something like this: Computer hardware and software developers create technology for moving data from place to place, and then the audio industry adapts that technology for use in moving audio from place to place. 

Before I jump into our usual high-tech trash talk, I have to relate a recent story regarding what could have been a complete audio disaster. We were doing a show at the Umatilla County Fair in Hermiston Ore., on a hot August day. As is often the case, heat + humidity = a multitude of weather-related anomalies including (but certainly not limited to) thunderstorms and hail. When my crew and I arrived for load-in, we were warned that there was a good chance for a hailstorm with 70-mph winds. In fact, there was a tornado warning for a few of the surrounding counties. We proceeded with our setup knowing that if a storm came we’d have to lower the roof of the stage and wrap up the PA system to protect the gear.

The basic tenet of Bleeding Edge is to look forward at cutting-edge technology and what it can offer us now, or perhaps might promise us in the future. Sometimes it can be fun (and quite educational) to look in the rearview mirror, so to speak, where technology is concerned. Since this month is AES month and we’ll be seeing a lot of new product from our favorite gear manufacturers, we thought it might be fun to set the time machine back to 1998 and have a look at the audio rage of the time and what has perhaps fallen by the wayside.

Since studios have been moving into less acoustic-friendly spaces (e.g. spare bedrooms that quite frankly have no business hosting a music production system), the need for some means of compensating for poor acoustics has materialized. Studio monitor manufacturers have responded by developing various types of room correction technology. At the most basic level, room correction analyzes the frequency response of a room/loudspeaker combination and produces compensatory equalization.

Over the past few years in the pages of FOH, we’ve had more than a passing discussion of digital recording technology. We examined the in-creased demand for live recordings (December 2006), the nature of digital data delivery (January 2007), and the use of optical technology for digi-tal audio transfer (September 2007). In fall of 2006, FOH reviewed the Sony PCM-D1 Linear PCM Recorder, a hand-held stereo digital recorder with a built in XY pair of condenser microphones intended for location recording. The PCM-D1 has the ability to capture linear 16- or 24-bit audio at sample rates from 22.05 kHz to 96 kHz into nonvolatile RAM. Using its 4 GB internal RAM, recording times range from 2 to 13 hours, depend-ing upon sample rate and bit depth, and recording time can be expanded by adding a Memory Stick. You can connect the PCM-D1 to your com-puter via USB, and it shows up on your desktop as a storage device. Note that the words “hard drive” are not mentioned anywhere in a discussion of the PCM-D1.

Every once in a while it’s nice to look over your shoulder and see how far technology has progressed. In the audio world that progression accelerates at an alarming rate, bringing us better and better technology at lower and lower prices with increased reliability, while breaking the sound barrier between studio and live sound gear. Although this is also true of microphones, the basic principles of microphone technology have not changed as radically as other areas of audio.

DiGiCo recently announced a new digital console, the SD7. This is not “just another digital console.” To understand why the introduction of the SD7 is significant, we have to first recognize that DiGiCo’s previous desks — the D5 Live, D1 Live, DS-00 and CS D5 — are already extremely advanced digital mixing systems. The D5 Live 56 boasts a 96-channel work surface split into sections of eight channels, each with an LCD touch screen. A companion DiGiRack stage interface includes 56 A/D and eight D/A converters, while a second DiGiRack resides next to the console and provides 56 external I/Os for inserts, effect returns, etc. Snapshot recall, MADI I/O and Opticore I/O are also furnished, making it easy for the D5 Live to support live multitrack recording.

If you’re a gear geek like I am — and since you’re reading FOH, I’ll bet that you are — you may have noticed that signal processing has been steadily migrating into power amplifiers. This is nothing terribly new: For years amplifier manufacturers have offered add-on processing. I can remember when I was a teenager (late 1700s) trying to lift a Peavey CS800 — the original CS800, many of which caused herniated disks and are still in service today — and seeing a weird circular socket on the rear panel. I was afraid to touch that socket, thinking I’d get electrocuted even when the amp was unplugged.

Audio professionals have very specific goals when presenting events. A wide-frequency spectrum in our audio program. Realistic dynamics. A bal-anced mix. Intelligibility. That’s a tough one. It’d be nice to make sure that our audience can appreciate the subtleties of the artist we represent, whether that be a snare drum hit, a quick run of guitar notes or a whisper. Unfortunately, as venue size increases, intelligibility typically decreases due to a multitude of factors, including increased reverb time, poor coverage and attentiveness (or lack thereof) on the part of the audience. You may have noticed that cream of the crop artists such as U2 recognize this issue and actually play their songs a hair slower in large venues to make up for the fact that the venue is messing with their clarity.

One of the issues that sound engineers deal with on a daily basis is that of hearing conservation. In the United States, advocates for employee safety such as OSHA  (Occupational Safety and Health Administration) and NIOSH (National Institute for Occupational Safety and Health, have set very specific guidelines for avoiding hearing loss due to exposure to loud noise. And let’s face it: Many sound engineers work under constant conditions of “loud noise.” Research by such organizations has produced a plethora of data regarding hearing conservation, some of which refer to the amount of time a person can be subjected to loud noise without damaging their hearing.