Clean and Flat Is Where It’s At
By Ethan Winer

   By Guest Contributor   Categories: Audio EquipmentRecording

My preference is to record most things (though not fuzz guitars) clean and flat. You can add a little grit later to taste when mixing, but you can’t take it away if you added too much when recording. To my way of thinking, any preamp that is not clean and flat is colored, and I’d rather add color later when I can hear all of the parts in context. A coloration that sounds good in isolation may sound bad in the mix, and vice versa. So my personal preference is to defer all such artistic choices until making the final mix. If I decide I want the sound of tape or tubes, I’ll add that later as an effect.

Not to go off on a rant, but one big problem with vacuum tubes is they’re not stable. So their sound changes over time as they age, and eventually they need to be replaced. Few tube circuits are as clean as modern solid state versions, and tubes can also become microphonic. When that happens, the tube resonates, and it sounds like someone is tapping a microphone. This resonance is especially noticeable if the tube is close to a loud source such as a bass amp. Further, tube power amplifiers require a specific amount of DC bias voltage to avoid drawing more current than the tube can handle. An amplifier’s bias is adjusted using an internal variable resistor, but the optimum bias amount drifts over time as the tube ages and needs to be adjusted occasionally. Setting a tube’s bias is not a task most end users are capable of doing correctly. Tubes also have a high output impedance, so most tube-based power amps include an output transformer that further clouds the sound. Finally, with some modern tube gear, the tube is tacked on for marketing purposes only and is operated at less than its optimum power supply voltage. 

This point was made exquisitely by Fletcher* in a forum post about the value of tube preamps and other tube gear. Fletcher said, “You guys need to understand that the people building ‘tube’ stuff back in the day were going for the highest possible fidelity attainable. They were going for the lowest distortion possible, they were trying to get the stuff to sound ‘neutral.’ They were not going for the ‘toob’ sound; they were trying to get away from the toob sound.”

On this point I completely agree with Fletcher. In the 1950s and 1960s, the electronic and chemical engineers at Ampex and Scully, and 3M and BASF, were aiming for a sound as clean and transparent as possible from analog recorders. They were not aiming for a “tape” sound! This was also true of Rupert Neve and other big-name console designers of the day. The transformers they used were a compromise because they couldn’t design circuits to be quiet enough without them. Today, transformers have been replaced with modern op-amps whose inputs are very quiet and are inherently balanced to reject hum. If boosting frequencies with a vintage Neve equalizer distorts and rings due to its inductors, that’s a failing of the circuit design and available components, not an intended feature.

Indeed, the problems I hear with most amateur productions have nothing to do with which preamps were used and everything to do with musical arrangement, EQ choices, and room acoustics. If a mix sounds cluttered with a harsh midrange, it’s not because they didn’t use vintage preamps. In my opinion, this fascination with the past is misguided. People hear old recordings that sound great and wrongly assume they need the same preamps and compressors and other vintage gear to get that sound. Every day in audio forums I see a dozen new threads with “recording chain” in the title, as a newbie asks what mics and other gear were used to record some favorite song or other. This ignores that the tone of a performance is due mainly to the person playing or singing and the quality of their instrument or voice. I once saw a forum thread asking, “How can I get that Queen layered vocal sound?” I’ll tell you how: Capture a super-clean recording of people who can sing like the guys in Queen!

*Fletcher is a colorful character who founded Mercenary Audio, a pro audio reseller based in Foxboro, Massachusetts. He’s known in audio forums for his strongly worded opinions, often peppered with salty language.

The always colorful, widely followed Ethan Winer has, at various times, worked as a studio musician, computer programmer, circuit designer, recording engineer, composer/arranger, technical writer, and college instructor. He’s had nearly 100 feature articles published in audio and computer magazines including Mix, PC Magazine, Electronic Musician, EQ Magazine, Audio Media, Sound on Sound, Keyboard, Pro Sound News, and Recording.  In 2002 he started the company RealTraps to manufacture bass traps and other acoustic treatment, which he continues to this day. Ethan is also the author of the book The Audio Expert, recently published by Focal Press.  Above is an excerpt from Chapter 5.



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