Warm Audio has achieved considerable success creating “tributes” to classic audio products, including microphones, preamps, and compressors. The company’s ability to capture the essence of these products, manufacture them using modern production techniques, and offer them at reasonable prices is an appealing formula for engineers and studios looking to recreate the vibe of vintage gear without breaking the bank.
 With that goal in mind, Warm Audio has introduced the WA-84. Based on the excellent German-made KM84, the WA-84 is a small-diaphragm cardioid condenser microphone featuring discrete Class-A circuitry and high-quality components in the audio path. A custom-made capsule specified by Warm and manufactured in Australia was designed to reproduce the sound of the original capsule, and the output is coupled using a nickel-core CineMag transformer. Warm’s choice to use an output transformer pays homage to the original design and is a key element of the sonic character of both microphones.

A BRIEF HISTORY LESSON

The original KM84 was introduced in 1966 and was the first microphone to use phantom power. One of its strengths is a classic cardioid pattern with an extremely smooth off-axis response. Sounds reaching the capsule from the sides exhibit a very similar frequency response and lack of coloration compared to on-axis pickup. The KM84 was discontinued in 1992 and eventually replaced by the KM184, which uses the same capsule but is otherwise a different design.

The WA-84 is available in nickel or black finishes and looks very similar to the KM84. It has the same distinctive side ports and a similar profile, although the WA-84 is slightly thicker and about an inch longer than the KM84.

Like most KM84s, the WA-84 has a -10 dB pad switch, though it differs in design from the original. Also like the original, the WA-84’s capsule can be removed, which makes me wonder if Warm Audio plans to release an omni capsule in the future. Its frequency response differs from the KM84’s, extending down to 20 Hz instead of 40 Hz, and the WA-84 has a gentle boost of about 2.5 dB around 15 kHz. The WA-84 operates on 48-volt phantom power.

Warm sent Mix a stereo pair of WA-84s for this review. The set is packaged in a foam-lined, hard plastic case with compartments for the microphones, windscreens, hard mounts, and shock mounts, all included. The manual provides useful information about cables, pop filters, and using a pair of WA-84s in spaced pair and XY stereo configurations.

LINE ‘EM UP

I’m fortunate to own three original KM84s: a pair with consecutive serial numbers that look like they just left the factory, and a single one that’s not quite as nice cosmetically but sounds just as good. I’ve used these microphones for drum overheads, acoustic guitar, piano, percussion, vocals, and occasionally on snare drum—but only if I really trust the player! I also have access to multiple pairs of KM184s, so it was natural to do an A/B/C comparison between the microphones.

Mercy College Music Studios Manager Sam Stauff and I set up spaced pairs of WA-84s, KM84s, and KM184s overhead a Ludwig Legacy Mahogany Series drum kit with Zildjian K Custom Dark cymbals in Mercy Studio A. Sweet.

All microphones were routed through a Focusrite ISA828 preamp for a fair comparison and recorded into Pro Tools HD. Gain on the ISA828 was set the same for all microphones; generally, output levels from the WA-84s and KM84s were within a few dB, while output from the KM184s was a bit hotter than the other two.

The results were interesting. The WA-84s and KM84s sounded very similar. The KMs had a smoother top end but less punch in the lower frequencies than the WA-84s—probably due to the WA-84’s ability to reach down to 20 Hz.

The midrange from the KMs was beautiful, and although the WAs were close, they didn’t produce the grind you can get when the KM transformer saturates. Snare drum was more focused and imaging was better with the WA-84s than the KM84s, which speaks to the matching of the two WA-84s. The transformerless KM184s were quite different from the others, as expected. They were the brightest of the group but somewhat plain—though I might prefer that for certain applications. In terms of brightness, the WA-84s fell between the KM84s and KM184s.

We then compared the three microphones on a vintage Gibson J-45 acoustic guitar, this time using an API 3124V (4-channel) preamp. In this application, it was difficult to tell the microphones apart. Low mids were slightly more emphasized by the WA-84, but if you switched tracks when someone left the room, they probably wouldn’t notice the difference when they returned. The KM184 was a bit thinner, brighter, and quieter than the other two microphones—though noise was really not an issue with any of them. For fingerpicked acoustic guitar, the KM184s produced more presence, but when the guitar was played with a pick, we preferred the WA-84 and KM84.

Back at my studio, I put the WA-84s and KM84s through more A/B comparisons, first close-miking a Ludwig Supraphonic snare drum from the late 1970s. I used a Grace 201 preamp, not because it would be my first choice for a snare but because it’s very transparent and I wanted to hear differences in the microphones as clearly as possible.

The KM84 generated that nice midrange saturation and an extended top end, while the WA-84 was more polite, well-controlled, and tighter sounding—which I preferred over the KM84’s sound. Hi-hat leakage was more noticeable in the KM than in the WA.

When used to record a strummed acoustic guitar with the Grace preamp, the WA-84’s extended low end easily revealed the sound of the player tapping his foot on the floor, whereas the KM84 did not.

The KM84 had more breath on a male vocal while the WA-84 produced more thickness, giving it a “larger-than-life” character (almost like proximity effect), but again, they were difficult to tell apart. This lower-mid character is a plus when using the microphones for drum overheads, as it adds impact and presence to the toms. Imaging of the WA-84s arranged in an ORTF stereo array was excellent: the ride, hi-hat, and crash cymbals were positioned exactly where they should be.

One of the KM84’s attributes is its ability to capture off-axis sound without adding coloration, and the WA-84 shares that trait. Sounds arriving at the WA-84 from 90 degrees off-axis sounded almost the same as at 0 degrees, except for a little “air” at the top and a slight reduction in low end.

I then used both microphones to record various percussion instruments, including glockenspiel, wood blocks, shakers, and tambourines. Full disclosure: I prefer ribbon microphones for percussion, but the WA-84 and KM84 sounded very good in this application. The WA-84’s high-frequency response produced more definition on the attack’s leading edge, but not annoyingly so.

One minor complaint I have about the WA-84 is the pad switch, which requires a small screwdriver or paper clip to access; I suppose that also means it can’t be changed accidentally. It’s worth noting that the KM84’s pad switch was also tricky and could be damaged if one wasn’t careful.

Purchasing a pair of original KM84s will cost anywhere from $2,000 to $4,000 depending on condition, and you might be taking a risk on whether they’ve been used, abused, or modified. A pair of Warm Audio WA-84s costs a fraction of that and sounds very close to the originals.

The WA-84’s accessories are somewhat generic—you don’t get the stylish packaging you’d expect with a high-priced microphone—but the mic definitely captures the spirit of the KM84, and you can place it on a snare drum without having a heart attack. If you’re looking for the KM84 sound but hesitate to make that kind of investment, the WA-84 would be an excellent alternative.