Groove Tubes Microphones and M-Audio DMP3 Microphone Preamp

Near the turn of the millennium, large diaphragm condenser microphones started creeping into the market with sub-$200 price tags and many recording hobbyists pulled out their credit cards. I bought one myself, and while gaining the utility of a large diaphragm mike for such a low price got me that much closer to the big sound I was after, my excitement died down when I realized that these bottom-of-the-line mikes sound like good mikes draped in wool blankets-muted highs and muddy lows. To get clear, detailed sound you still have to shell out some more bones.

Today, the prices on quality capsules are coming down, and a new crop of Groove Tubes microphones has brought to the market a line of affordable, versatile and impressive sounding condensers every hi-fi-aspiring home recordist and studio engineer should consider.

Two large diaphragm and two small diaphragm condensers make up the line and despite the word “Tubes” in their brand name, only two of the four are actually equipped with valves; the other mikes are powered by solid state, FET technology. The large diaphragm models, the GT67 (tube) and the GT57 (FET), both sport hand-assembled 1.10-inch diameter capsules and 3-micron thick, evaporated-gold diaphragms. The diaphragms are also outfitted with a resonating disc on their faces that boosts high frequencies (14-15k) often lost with other microphones in this price range.

Every microphone has its own character, and these mikes color their signal with a certain robustness, especially when the sound source is close. If someone were interested (for research purposes only) in listening to the vocal tracks I laid to tape with the GT57 and GT67, they’d surely notice the fattening effect the mikes had on my thin voice. Recording a drum kit with just the tube GT67 positioned at about 10 o’clock from the drummer’s perspective, and raised just a few inches higher than the top of the snare, revealed that as room mikes they have great transparency and can capture the deep pulse of the kick as well as the shimmering highs from the ride cymbal. I tracked drums for a number of songs in this manner and the detail was so rich I never regretted forgoing individual mikes on the snare and kick when it came time to mixdown.

Sound quality aside, the versatility these mikes offer makes them hard to beat for the money. The GT67 ($1,299) has four switches circling its casing that allow for high-pass filtering, a -10db pad and choice between cardioid, supercardioid, omnidirectional and figure 8 patterns. The GT57 ($799) has a -15db pad, high-pass and pattern selector, but doesn’t have the supercardioid option.

As small condensers go, the GT44 (tube, $999) and the GT33 (FET, $599) are among the smartest designs I’ve seen. Again, both are the same save for the tube and feature a .75-inch diameter capsule and a 6-micron thick diaphragm, but each has the ability to have its cardioid capsule removed and replaced with either a supercardioid or an omnidirectional patterned capsule (each sold separately). Each also has a high-pass switch and a signal level reduction switch. Compared to the larger mikes, the small diaphragm models provide just as high quality a sound, but were a bit less airy and more focused. They also have a reduced proximity effect that makes them more suited to capturing low frequencies up close. I tracked bass with both, and while each captured the rumbling lows and the midrange punch, the GT44, with its tube, smoothed the sound and made it rounder. The FET mikes aren’t harsh, but the tube models do possess the warmth only a tube can add and they are better mikes because of it.

I recommend the FETs to every home recordist looking for all-purpose condensers. They’re a heck of a lot clearer than any of the condensers in the $100-$200 price range, and ponying up the extra cash will pay off in the end. If you’re running a studio, or if you’re a hobbyist who can afford a little more luxury, pick up the tube mikes. I’ve seen the GT67 offered on the Web for under $1,000, which for a tube mike of this quality is a bargain that’s hard to beat.

As a side note, the Groove Tubes mikes are being distributed by Midiman/M-Audio, who also sent me their new dual-channel microphone preamp, the DMP3. Often overlooked by many home recordists, the microphone preamp is essential to opening up the sound of a mike and sending a strong signal level into your recording gear. The DMP3 can be a little noisy if you don’t spend time to balance your levels properly, but it’s shockingly transparent for a preamp with a $250 list price. It also provides phantom power and accommodates both 1/4-inch and XLR connections, two things missing from most 4-tracks and lots of other portable studio units. Combining the DMP3 with the Groove Tubes mikes is a great way to upgrade a home studio for much less than what this kind of quality used to cost.

Originally Published September 1, 2002