While it is much lower in the procurement priority list, procuring and using digital effects processors is still something that requires a bit of thought. For professionals, choosing the right effects processor is more than the strength of the preset list or the user interface; it is a long-term investment and a gamble that the effects purchased will continue to be popular for many years of touring usage. Take the ubiquitous Yamaha SPX-90 effects processor; while very technically obsolete, it is still found today in many club installs, and the outboard racks of many regional and touring soundcos. Ditto for the Lexicon PCM-81, Roland SDE-1000, TC Electronic 2090 and Yamaha SPX-990. When I started doing live sound work, reverb was the hidden spring unit inside the mixing console, and delay was the cherished Effectron II that had a precious switch-selectable delay range that chose how many expensive computer memory chips to use and a fine adjust knob to vary the sample rate as a method of getting the delay time dialed in. Cabling to and from the Effectron II was just a couple of guitar patch cords, and noise floor was determined by how you used the 40- some dBs of dynamic range (8-bits). Thankfully, innovation moved forward, and the manufacturers started to offer better products in the digital electronics realm.
Hooking Up
Getting beyond guitar patch cords, today's effects offer fully balanced inputs and outputs with either TRS phone and/or XLR jacks. And modern effects offer stereo inputs and, usually, fairly flexible internal signal routing schemes, so that single or dual processor engines (DSP chips) can handle stereo-in/stereo- out, mono-in/stereo-out with the engines in parallel (dual effects) or serial (chained effects) configurations. While some of this flexibility is driven by usage in recording studios, some live sound engineers make the most of the configurability as well.
I consider myself a middle-of-the-road digital effects user, as I do not burn a bunch of mixing console auxiliary sends to drive all of the digital effects in stereo. Instead, I resolve to use the mono-in/stereo-out format, and let the effects processors widen the ambience of the signals routed into a simulated stereo sound field. This philosophy comes from the fact that I mix mostly in clubs, with just stereo speaker stacks, and mix most of my input channels center-panned so that nearly everyone in the venue hears the same mix of vocals and instruments. I allow my digital effects (reverb) processors to widen out the mono signals into stereo reflections or delay slaps that create a quasi-stereo mix to those patrons who can hear sounds from both speaker stacks. The figure shows my typical hook-up schematic.
Since virtually no one builds three cable assemblies of balanced mono-in/stereo-out effects signaling, I take three 15-foot TRS patch cables and loom them together using plastic spiral wrap sheathing pieces spaced in intervals throughout the length. Also, I use colored electrical tape on the cable ends to attempt unique combinations for quick patching at the mixing console.
I do leave the cable assemblies connected and stowed at the effects/outboard signal processing rack so that I am not hunting for jacks in the dark bowels of the rack every gig. Obviously, my next upgrade would be to gather up the effects assemblies together in one snake with one multi-pin disconnect near the console side. I tend to resist this last upgrade, as my gear configuration tends to change enough that I would be always modifying the snake ends for these changes.
Effects Gain Structure
Back when all audio and computers were 8-bit, digital audio was trying to push the boundaries with 12- and 16-bit wide samples. The reason for this was that each bit provided a theoretical 6dB additional dynamic range. Thus, in the beginning, we ran our signal as hot as we could, living with the occasional brick wall distortions on the audio crescendos. Today, with 24-bit wide processing and very fast sampling rates on digital effects, there is little need to heat up the signal levels to use every last dB of signal range. Typically, I leave the signals in the 0 to +4dBu peak range with little fear of hearing the processor noise floor.
And when returning the digital processor mixes my stereo preamps tend to be about unity in gain. When it comes actually employing effects, I find my touch on the stereo channel fader tends to be very light with the reverbs at about -20dB to -10dB if I need a drenching hall 'verb on a slow ballad. Digital delays follow about the same philosophy, from a light "Elvis '50s slap" (200msec, two repeats) at -20dB, punching in phrase repeats at -5dB to -10dB.
Choosing Your Weapons
I get pangs of jealousy when thinking about Steve La Cerra's SPX-990 sample and pitch shift effect he uses with Blue Oyster Cult on the song "Godzilla". As mentioned in other Theory and Practice articles, my effects needs tend to be very pedestrian, with plate 'verbs, hall 'verbs and a few basic slap delays (200msec, 375msec, 500msec). Of course, the acts you work with will specify the types of effects you will need and how many on any particular song.
I recommend, after you purchase a new digital effects unit, that you force yourself to spend an hour or more with headphones and a vocal mic, and run through each factory preset patch and get to know the variety of standard effects. And after running through the presets, make an effort to alter a couple of favorites and place them into user memory locations. This way, you gain a bit of training on the effects processor, and have a shot of doing it again, if requested, to store a custom effects type for the performance.
Contact Mark at marka@fohonline.com
