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Technotes Online > Earthworks Omni Condenser Microphone

Earthworks Omni Condenser Microphone
Sweetwater ItemID: QTC30MP
Retail: $1890.00
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Tired of searching for inner peace, I go looking for answers of another kind...and actually find them!

Issue #4
December 1, 2003

What is the deal with the people at Earthworks?

While the rest of the contemporary music community seems to be producing overly hyped, wildly EQed and in some cases, thoroughly nastified audio, Earthworks is still working hard to build the world’s most accurate mics, monitors and preamps.

To say that Earthworks is an “old school” manufacturer is an understatement, but in no way do I mean that as a criticism. In fact, far from it! To them, there is no such thing as “close enough.” But that’s really not surprising, as the company’s founder was none other than David Blackmer, the founder of dbx. David’s dream was to upgrade the entire audio chain to create high definition audio that more closely reproduced the wide dynamic range of a live performance.

Of course, I didn’t know any of that when I bought my first dbx product, a small module that allowed dbx-encoded polyvinyl chloride records to be played back with an ultra wide dynamic range, but without all the clicks, snaps and pops that were a staple of the black plastic LP. In later years, dbx went on to license its proprietary noise reduction to manufacturers of audio cassette recorders, as well as building a wide range of dynamics processors

Still, it wasn’t until the mid-1990s that I heard my first Earthworks products, when Electronic Musician asked me to review their OM1 and TC30K microphones. At the time, I was doing a lot of digital sampling using one of the most popular large diaphragm condenser mics of all time. Okay, I don’t mind admitting now that I was a bit smug — after all, how good could these new mics be? Could they possibly hold their own against my highly-acclaimed condensers?

Up until that point, I had little need to ever record using an omnidirectional set of mics, and both the OM1s and TC30Ks were strictly omnis. Not only that, but there was nothing on either mic: No “on-off” switch, no -10dB pad and no low frequency rolloff controls. In short, they looked like some futuristic laser tool for dentists and that’s certainly not a look that’s going to make me feel all warm and fuzzy about them. Still, they did have a nice solid feel and a classy brushed steel barrel . . . Hmm.

When I have one chance to get it right, I grab a pair of Earthworks

Well, I won’t keep you in suspense: Both mics performed incredibly well, and eventually the TC30K (deservedly) received Electronic Musician’s “Editors Choice” award for best mic in 1997, while their slightly upscale TC40Ks was up for a TEC Award that same year. Since then, the company has continued to win awards, as well as accolades from thousands of musicians and engineers around the world. But what about me? Well, let’s just say that nine out of ten times, when I only have one chance to get a recording right, I now reach for a pair of Earthworks TC40Ks. Yes, I was sold on Earthworks products as soon as I began reviewing them, and they have deserved every word of praise they have garnered throughout the audio community. But unlike many companies who are quite happy to rest on their laurels, no matter how well-deserved they might be, Earthworks kept producing new products that adhered to their original goals of audio excellence.

In the years that followed, the company released three Zero Distortion Technology mic preamps whose response was so close to ruler flat that it has been a laboratory standard for testing other equipment (that’s 2Hz to 100kHz plus/minus just 0.1dB for those who are interested). They also answered the prayers of those who wished for a cardioid version of the TC-Series mics with the SR77 30kHz cardioid and SR78 30kHz hypercardioid. If there was any knock at all on the TC30K or 40K, it was that both had a bit more self-noise than most engineers would like (though both mics’ sensitivity figures were such that in the real world, noise would never really be an issue). Still, this led to the introduction of the QTC1 Omni, which boasts a 4Hz to 40kHz frequency response (±1dB) with a self-noise level of just 22dB (A-weighted). And while there was much joy in the high end pro audio world, serious project studio or even some of the smaller pro installations found that it was priced out of their reach.

Precise sound at a price within reach.

Earthworks heard this and went about building a mic whose performance would be virtually indistinguishable from the QTC1s — unless listeners had both “golden ears” and precision lab instruments to measure frequency response in an anechoic chamber. Thus, though I have taken the long way around to introduce the Earthworks QTC30s, I think you’ll appreciate my review even more when you have all the “backstory.” What is so impressive about the QTC30s ($800 list each or a matched pair at $1700), is that the sound is so precise, yet at the same time still able to capture some of the room sound (or “air”) even when relatively close-miking a solo instrument or an ensemble. But beyond that, the thing that impressed me most about the QTC30s is their ability to deliver great sound with a minimum of positioning hassles.

Quite often, when recording using other mics, moving them even a few inches can result in a dramatic timbral shift, so great care has to be taken to guarantee the best audio. Meanwhile, if push came to shove, the QTC30s, just like the TC40Ks, can be set up in a hurry and still achieve stunning results. And sometimes one shot is all we get! As I put the QTC30s through their paces, I used them on a solo piano recording, a string quartet and a series of recitals my neighbor, a tremendously gifted viola player, performed with piano and clarinet, and later piano and flute. I grew up loving classical music just as much as the Beatles, Stones, Cream and Hendrix, so I jump at every opportunity to record classical compositions, particularly the smaller, more intimate ensemble pieces, where you can clearly hear the interplay between the various instrumental voices. The string quartet and the two recitals were performed in the best small hall at Florida State University, which seats about 120 people. This is a wonderfully clean recording environment, with a solid wood stage and specially designed acoustics to minimize the “mushiness” that often plagues halls that are too “live” and thus prone to nasty early reflections.

I had made similar recording previously with my TC40Ks and was quite pleased, so I was very anxious to hear how much difference I could hear when recording with newer Earthworks microphone designs. The final recordings were made using an Oram MWS preamp into an Alesis MasterLink recorder, which is a combination that delivers stunning fidelity. I hurried home after the various sessions and ran the digital outputs from the MasterLink directly into a MOTU 828 interface. My amplifier is a top-of-the-line 120-watt per channel Yamaha and I was able to monitor using my trusty Tannoy PBM8s (admittedly well over a decade old), along with a pair of brand new powered Alesis ProLinear 720 DSP monitors, as well as the Earthworks Sigma 6.2s. I’ll be doing in-depth reviews of both of the latter systems in future columns, but for now, I was thrilled to sit back and just listen. And what I heard was so impressive, I found myself listening to everything several times.

Nothing short of breathtaking...

Taking the speakers out of the equation, the Earthworks QTC30s were nothing short of breathtaking, even when sent through a pair of AKG headphones. Every detail and subtle nuance was captured perfectly. The sonics were so silky smooth that I found myself wondering just how much better the more expensive QTC1s could possibly be.
Though I was not able to switch mics in the middle of the performances to evaluate the mics in direct comparison to my trusty TC40Ks (can you imagine that audience reaction?), I did feel that the newer QTC30s had a tiny bit more detail in the upper frequencies, and just a tiny bit more “air” in the overall sound. The stereo spread was (to my ears) equal with both mics, though my impression was that the QTC30s had just a bit more directionality. By that I mean that as an omnidirectional mic, I felt that there was just a bit more focus to the instruments which were positioned directly in front of the mics, and just a tiny bit less off-axis response. But this may even be a result of any number of factors, including the number of people in the audience or even my imagination.

I will admit, that when you are comparing recordings made with mics of such high standards, it’s quite difficult to really pick out differences. The bottom line is that the QTC30s delivered audio that was as good as any mic I have ever used. Its versatility is astonishing! You can go from the sweet sound of a solo violin to the solid thump of a kick drum without a second thought. Would I trade my TC40Ks for QTC30s? Probably not, but if I were needing a matched pair of omnis that deliver on the promise of remarkably precise sonics at what I would consider a much lower list price than their performance would indicate, I’d jump at the QTC30s in a heartbeat. My feeling is that these mics would come within a cat’s whisker of matching the audio delivered by any mics selling at two or even three times their list price. Yes, they are indeed that good.

For our audio samples this time around, we are including excerpts of the recitals I recorded at Florida State University. Naturally, we have to compress the files down to manageable size, so you won’t hear a perfect representation of the sonics, but I know you will hear the details of each instrument and the wonderful stereo sound field. Enjoy!

About the recordings:

All recordings were done on July 24th and 25th, 2003 in Florida State University’s main recital hall, which seats approximately 120 people.

1. Dvorak String Quartet (four movements)
2. Solo Viola with piano accompaniment
a. Grainger “Carol”
b. Carter “Elegy”

Note: The piano was recorded with the lid in the full down position so that the piano will not interfere with the viola’s harmonic structure. The viola used here was built in the 1700s and has an amazing cello-like tone in the lower registers.

3. Ensembles
a. Three pieces by Bruch (IV, V and VII)
for Viola and Clarinet with piano accompaniment.

Note: Piano was recorded with the lid in the full down position
so that it does not overpower the other two instruments, nor compete with their harmonic interplay.

b. Seranades 1, 2 and 6 for Flute, Violin and Viola.

All recorded using Earthworks QTC30 microphones set approximately in the third row center. The signal was passed through an Oram MWS preamp with no equalization and then into an Alesis MasterLink ML-9600. The recordings were made at 44.1kHz and with 16-bit resolution. No other processing was done to these recordings, other than normalization using BIAS Peak 3.21 for the Macintosh.

QTC30 Recordings
» Bruch IV 5.2 MB
» Bruch V 7.2 MB
» Bruch VII 4.8 MB
» Carter Elegy 5.3 MB
» Dvorak 1 9.4 MB
» Dvorak 2 11.1 MB
» Dvorak 3 5.6 MB
» Dvorak 4 7.2 MB
» Grainger Carol 4.9 MB


To maintain sound fidelity, the sample files were saved as high quality MP3 files and are therefore very large. We recommend a broadband (cable or DSL) connection.


Questions, comments, rants, suggestions, unwanted ‘62 Stratocasters and any other form of correspondence can be addressed to jim_miller@mindspring.com.

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