I’ve been a fan of Roswell Pro Audio’s mics since they sprouted from the mind of Matt McGlynn, and even prior to that, with his MicParts kits and mic mod site (I built and reviewed their original 12-251 kit back in Tape Op #128). The Roswell Aztec is the logical evolution of both the MicParts 12-251 and V-251 models into a fully boutique mic (one that doesn’t need to be assembled by the end user) and ups the game as far as components and performance go. It’s also priced very reasonably for a fully handmade, multi-pattern tube mic that performs as well, if not better, than many microphones that cost considerably more.
The Aztec is loosely based on the Telefunken ELA M 251, but it’s definitely not a clone. The capsule is Roswell’s bespoke RK-251, and the circuit is also of their design. They use a carefully selected and tested 6072 tube in a single-triode configuration. There is a custom-wound European-made output transformer, and the rest of the components are all specifically chosen to ensure the highest possible quality of the recorded signal; they don’t source inexpensive parts to save a buck – they even go so far as to have custom electrolytic capacitors made for the Aztec and its power supply. The power supply is itself a work of art, fully regulated and running at a higher voltage than the standard off-the-shelf tube mic power supplies common with many lesser mics. The rectifier diodes and resistors in the power supply are all audio grade to ensure the best possible consistency of voltage to the tube and capsule.
The Aztec ships with a Gotham Audio cable terminated in Neutrik 7-pin connectors; these are wired in-house at Roswell and burned in for 72 hours. The package also includes an AudioQuest IEC cable, a shock mount, and a padded pouch for the mic, all within a hard case with laser-cut spaces for each component. It all feels very intentional.
The microphone is available in a striking matte black finish or a “vintage cream” powder coat like the original 251. The body of the Aztec is similar in length to an ELA M 251 but a bit narrower in diameter, giving it a very sleek profile. There are two switches just under the grille on the front side of the mic: a 125 Hz high-pass filter and a 10 dB pad. The Aztec doesn’t present an excessive proximity effect, even when quite close to the capsule, but having the filter is a great option; Roswell will even customize the value of the filter should you want something that allows more of the sub-lows to pass through (or a higher frequency, if that’s your jam!).
There are nine polar patterns available for the Aztec, switchable via the power supply, from omnidirectional through to figure-eight. In a good-sounding room, the omni setting is sublime when mic'ing an acoustic guitar – neutral and natural sounding, but with incredible detail and body. When I mentioned to Matt that I was going to try the Aztec as a mono drum overhead, he suggested setting the pattern two clicks off cardioid toward figure-eight; he wasn’t wrong! This tightened the focus toward the snare drum directly beneath the mic, but not at the expense of completely losing the cymbals to the sides of the kit. With the pad engaged, the Aztec never seemed to flinch at the heaviest backbeats, and the drums sounded just like I was standing in the room over the kit. Do I need a second Aztec for stereo overheads now?
I’m willing to be wrong, but I would guess that most people see a mic like this and think, “VOCALS!” Well, ya ain’t wrong! I have used the Aztec on a few hard rock/metal male vocal sessions, and it has an incredible presence but never gets harsh or sibilant; the low-mids/chest frequencies are smooth and full but never dominate or feel muddy. Hitting it on the way into Pro Tools with compression via an 1176 or a Distressor produces a vocal sound that feels almost mixed! I also tracked two female vocalists who I have worked with for many years. On both, I always struggled getting a vocal tone I was happy with; they sing incredibly softly, and sometimes this makes sibilance stand out more than the tonal parts of their voices. I don’t like vocals performed too close to most mics; the whole frequency balance sounds off, but otherwise I’m fighting noise floor if I’m using a ton of gain and post-preamp compression. The hot output of the Aztec meant I could ask the soft singers to step back about 15 inches from the mic, and I finally achieved the vocal sound I’ve been trying for on both of their voices! On the other end of the spectrum, I used the Aztec on a vocal jazz standards session – plenty of power there. We were punching in on some lines that had been tracked elsewhere on a Neumann M149 (no additional notes about preamp/compression were provided, so I multed my signal to capture a compressed and straight-from-the-preamp version just in case). The different takes blended extremely well, but the Aztec provided a less strident, smoother capture of the voice overall.
I had already purchased and used the Aztec before I inquired about reviewing it, so if I had any bias going into this review, it was only that I was already a huge fan of Matt’s creations (I have a pair of the Roswell Colares [Tape Op #129], their Cab Mic [#171], and a pair of their Mini K87s [#137], which are my go-to drum overhead mics, plus the MicParts kits that I have built). The Aztec only reinforced my feeling that these are some of the best mics available today; they may be a bit under the radar, but they deserve further investigation by anyone looking for no-compromise microphones from a builder you can actually contact. The Aztec isn’t inexpensive, but it’s an amazing mic that smokes a number of higher-priced offerings. Get one (or two…)!