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.
Dynamic microphones still operate using electromagnetic induction, and the basic concept of the condenser microphone is pretty similar to what it was when it was first invented [FYI, Western Electric developed a condenser microphone circa. 1917, and Neumann developed and marketed the CMV3 circa. 1928]. Of course, microphone technology has become incredibly refined over the years. We have stable and durable materials for diaphragm construction. Exotic magnetic metals yield increased output. Capsule construction has become a science unto its own, producing better sound, reliability and consistency. So where does that leave the ribbon microphone?
Well, as with moving coil and condenser microphones, the principle behind the ribbon microphone is essentially the same now as it was in the early 1930s when RCA introduced the 44A. A flat piece of metal is loosely suspended within a magnetic field. When sound hits that metal (the ribbon) it vibrates, moving back and forth within the magnetic field, thus creating voltage at the ends of the ribbon. Incredibly enough, that voltage is a pretty darn good representation of our audio signal. That this concept works so well is not as amazing as the fact that it works at all.
Pros and Cons
Microphone aficionados have observed that ribbon microphones have some distinct advantages and disadvantages. The high-frequency response of a ribbon mic tends to be very smooth and musical, and since the ribbon is relatively light in weight, the transient response of the ribbon is much quicker than that of a moving coil mic. If you’ve never tried a ribbon on an electric guitar amp, you owe it to yourself because it’s a wonderful thing. There are, unfortunately, a few disadvantages of using ribbon mics. The output level of most ribbon microphones is very low, requiring a preamp with a lot of gain and very low self-noise. Ribbons tend to be delicate, so much that a blast of air can stretch or even snap the ribbon, rendering it useless.
For those reasons, engineers have been cautious regarding the use of ribbons, and even through the mid-1990s ribbon mics weren’t very popular (though beyerdynamic continued to market their ribbons throughout that time, and still do). In the late 1990s, ribbon microphones experienced a resurgence in popularity. At the forefront of this renewed interest were AEA and Royer Labs, both of which are American companies that are well known for manufacturing ribbon microphones of modern design. They have since been joined by Crowley and Tripp, Cascade and Nady, plus a plethora of other companies that re-badge Chinese-manufactured ribbon microphones.
A Ribbon Resurgence
And why should we care? Because these companies have addressed two important issues that otherwise would keep ribbon mics off the live performance stage: output level and durability. Royer Labs (www.royerlabs.com) manufactures several models of ribbon mics that became popular for studio use such as the R-121, SF-12 and the active R-122. The R-122 was probably the first “active” ribbon mic ever produced: It contains a phantom-powered preamp used to increase the output level, and it has an impedance matching circuit that makes it useful with just about any preamp. These mics were mostly intended for studio use.
Last year, Royer introduced their Live Series of microphones. Based on their studio models, the Live Series mics employ a thicker, more robust ribbon that retains the sonic characteristics of the studio models. So far there are three mics in the Royer Live Series, including the R-121, R-122 and SF-24. Perhaps most interesting is the SF-24 phantom-powered stereo microphone. The SF-24 employs two matched ribbon capsules mounted one atop the other in a Blumlein coincident pair (two bidirectional microphones crossed at an angle of 90 degrees). This allows an engineer to place a single microphone overhead for stereo pickup of (for example) a drum kit and/or cymbals, while obviating the need to tediously tweak two mono mics into position.
At the Fall 2007 AES Convention, Crowley and Tripp (www.soundwaveresearch.com ) introduced their el Diablo microphone. This microphone uses the Crowley and Tripp’s proprietary Roswellite ribbon material, a high-strength, shape-memory ribbon technology designed to hold up under high-SPL situations. El Diablo can be used close-up on kick drum, horn and loud electric guitar amplifiers, as well as for vocals on open, outdoor stages without worry that the ribbon will break or stretch. Roswellite is also used in a version of Crowley and Tripp’s Naked Eye, a microphone that features what the company calls True Dual Voicing, whereby each side of the microphone delivers a distinct tone. The front side of the mic provides a “classic” ribbon response tailored for electric guitar, while the back of the mic has a significantly brighter, rising curve that mimics the frequency response of high-quality vocal condensers. The Naked Eye’s high-output, low-noise ribbon and high-efficiency transformer enable the mic to be matched with just about any mic preamp used for stage or studio.
Endless Offerings
No discussion of ribbon microphones would be complete without looking at the offerings from AEA (Audio Engineering Associates, www.ribbonsmics.com ). AEA’s R92 Big Ribbon mic is optimized for close miking at distances from three to eighteen inches. At such close range, some mics exhibit a ton of proximity effect, making the instrument sound muddy. The R92 was engineered for reduced proximity effect, so it can be used at close range without over-exaggerating the low frequencies. AEA designed the R92 to produce different frequency responses from the front and rear of the microphone. The front side is the “crisp” side while the rear is the “smooth” side, which, according to AEA, has a bit of a classic ribbon high-end rolloff that can help handle harsh transients in a refined and flattering way. The AEA 92 is capable of handling SPL up to 135 dB, which should be enough for most lead guitarists. If it’s not, then you can consider AEA’s R84, which is rated to handle SPLs up to 165 dB above 1 kHz.
The ability to use ribbon microphones onstage is a wonderful option for engineers because they produce tones unlike what we already get from moving coil dynamic and condenser microphones. Now that the major issues of durability and low output have been addressed, there’s no reason not to try a ribbon mic for use on stage.
Steve “Woody” La Cerra is the front-of-house engineer and tour manager for Blue Öyster Cult. He can be reached via email at Woody@fohonline.com
