AEA: KU5A Ribbon Microphone

It's no secret I'm a big fan of AEA microphones. When my studio High Bias Recordings first opened the Michigan Ave. location, I bought a pair of AEA R84s [Tape Op #38] and the rest is history. In the years since, I have amassed a moderate collection of their mics and have fallen in love with each and every one. The luxury of knowing exactly what a mic will do, and not do, and using it not only to capture a performance, but also to front load the sonicprocess as I move forward on a recording, is priceless to me. Aside from rock-solid craftsmanship and reliability, the above characteristics are what define AEA mics for me. Back in the '80s way before everyone was on about branding, I knew what I was getting when I bought an SST or Sub Pop record. There was a certain economy to those labels, and you knew your money was well spent. I feel the same way about AEA – there aren't a lot of audio manufacturers I can say that about! If these guys made a vacuum cleaner I would buy it, so when Sammy, Charlene, and Wes of AEA started talking to me about this new supercardioid mic they were making, I immediately threw my hat into the ring as a beta tester for this secret mic. Much to my delight that is exactly what happened.

The prototype I initially received differed slightly aesthetically from the production model that arrived months later, but even so, you could see the physical resemblance to its inspiration, the RCA BK-5A [#65]. Knowing Wes and AEA's penchant for the RCA lineage, I'd always wondered if this somewhat lesser-known cousin of the RCA family would ever see its due, and when I opened the box I was stoked to see it had. I've been a huge fan of the RCA BK-5A since I got my first pair 20 years ago, so I was excited to see what AEA had come up with. For those who don't know, the BK-5A was released in 1955 by RCA specifically for sound stage use in TV and film. It was initially noted for being uniaxial, with a very high SPL rating. It had internal protection of the ribbon and a tight polar pattern providing for improved isolation. Because of these features, its lightweight, smaller footprint, and inconspicuous appearance (TV gray!) it became a staple. Wolfman Jack made it his choice (adding to the RCA BK-5A's historical significance), but it wasn't until the late '90s, when Fletcher (of Mercenary Audio [Tape Op #34]) began touting it as a fantastic guitar mic, that I bought mine. The BK-5A is a great mic, and while they share a similar design and several features, AEA's KU5A is very much its own mic destined for its own legacy.

What sets the AEA KU5A apart from the RCA BK-5A (or any other ribbon for that matter) is its polar pattern. It has the most rejection of any ribbon ever. The KU5A accomplishes this via a super intense dual path acoustic labyrinth behind the ribbon and a few of what the designer calls "leaks" on the sides. The terminology matters little, but suffice it to say the rejection this microphone presents, while still sounding natural, is bordering on the absurd. The KU5A also has a seven-layer protection screen in front of the ribbon, so no pop filter is needed unless you're going for the kick drum. The response of the KU5A is +/- 3 dB at 20 Hz to 20 kHz, with a slight bump around 2 kHz. It can handle 135 dB SPL, and all this glorious audio exits the microphone via the same transformer found in all the AEA active ribbon mics, using an active buffer to ensure it works well with all consoles and interfaces. Oh, and there's also a 6 dB/oct high-pass filter at 283 Hz.

First, I took the KU5A on the road with the Shigeto Live Ensemble. Some of you may remember that Zach Saginaw of Shigeto is a long-time client and main homie of mine. His primary gig is as a solo artist, but for this record and subsequent touring he linked up long time collaborators and college jazz bros Ian Finkelstein and Marcus Elliot on keys and saxophone respectively. The band is playing mostly Zach's tunes, but the presentation is Ptah... era Alice Coltrane meets Eddie Henderson's Realization. We did a West Coast run last fall that were some of the most gratifying gigs I've mixed. It seems oddly rare when dudes at the top of their game know when to listen to each other and serve the jam. Anyhow, saxophonist Marcus Elliot is a total monster on his instrument; to call the guy lyrical is a disservice. His playing is also fairly dynamic, so I was stoked to find a new home for the KU5A. We double mic'd his sax for these shows. One mic was a beyerdynamic M160 [#60] through some pedals and into a Rupert Neve Designs DI [Tape Op #113], and the KU5A went straight into the console. Mic'ing saxophone live in a rock club can be a frustrating experience, and when you add pedals to the equation it can get pretty weird quickly. When we did have problems, we were able to do very useful things with phase at both monitors and FOH on either mic to avert feedback issues. This was clinical in its effectiveness, due in no small part to the tight polar pattern of the KU5A. Sonically I was blown away. The horn was particularly present without being harsh at all. The mic has a really nice top end that feels enhanced for what you'd expect from a ribbon yet sounding natural and not hyped. The bleed is nonexistent, so cymbal hash is not even an issue. I was able to jack the sax level when the band got loud and still get gratuitous with the Oto Machines BIM (12-bit stereo delay), and BAM reverb (review soon) while never having to worry about feedback. This first test was definitely a trial session, and the KU5A passed with flying colors!

I met trumpet player Kris Johnson during a Black Milk session a few years back. He came in like a tornado, masterfully arranging, then stacking horns like pancakes for a few tracks and really smashed it. He was so fast that it was a challenge for me to make tracks quick enough! I've since worked with him a bunch as a producer and the vibe is equally as dialed and challenging – the last time during a tracking session for the staggeringly good Lulu Fall album. Local drumming badass Nate Winn was the drummer on this date. Recording Nate is a real joy; he's one of those guys that makes it easy. His pocket is fierce, and he seems to know how to hit the kit the way mics want to hear it. On this session we used the KU5A on the snare drum. The results were profound – big, authoritative low end without being overbearing, and a transient response that can only be described as flattering; present and dry without sounding dead at all. Kind of like a Sennheiser MD 421 with no bleed or an Electro-Voice RE20 with more detail in the top. We were able to adapt to any EQ needs simply by proximity or via the extremely useful high-pass filter. We'd switch it up a bunch on these live gigs, and from a Yamaha Maple Custom 6.5" x 14" snare drum (tuned low with a Remo Emperor drumhead) to a straight up piccolo snare, the KU5A didn't even flinch. It also allowed us to do some significant position and EQ adjustments via mic placement due to the tight polar pattern and the high-pass filter. Super impressive!

While the above are great examples of the KU5A's flexibility and prowess, vocal applications are where it shines brightest. The very first time I used the KU5A it was actually a prototype. In 2018, the wonderful folks from Splice Studio came through Detroit to capture sound and document the city sonically for their Movement 2018 Sample Pack. Detroit has been quite the focus of this type of branding, but I have to say that the Splice folks did it right. They captured sounds all over the city with artists Shigeto and Waajeed, and then brought on an all-star cast of Detroit's best to contribute. One of those contributors was the unstoppable Milan Ariel Atkins. She's an incredible artist, an unbelievably great singer in her own right, and a direct descendant of Detroit's Juan Atkins (credited as the originator of techno music). To say this lady has presence is a gross understatement, and her vibe is totally disarming. Her contribution to Splice's sample pack was putting the new iZotope VocalSynth 2 through its paces. Milan was immediately comfortable with theintense array of robot and otherworldly vocal sounds she was generating. I am aware this is not a typical use for a mic like the AEA, and may seem uninformative, but we did all of this live in the control room with the APS Aeon monitors [#116] turned up! No feedback issues. None. I also had a stereo Moog 500 Series delay running, and again no issues. This would 100% be my first choice for vocals on loud rock material going forward and has really opened up the option for tracking a quick vocal during final mix.

Next up I threw the KU5A on vocals for the Young Supply session a few months back. They are an acoustic trio with a nylon string guitar, a steel string guitar, and an upright bass, with both guitar players singing. They are both dynamic singers, and obviously the nylon guitar is a different animal than the steel string. I used the KU5A on Joey Del Re's vocals. The sound was present, immediate, and natural. It took compression well without increasing bleed or any perceptible noise floor. This mic is quiet! Also impressive was the tolerance to Joey's head movements. The KU5A seems to have an audio tractor beam emanating out of the front of the mic that draws sound to its ribbon. I know this may seem like hyperbole, but there some kind of magic happening here. Very useful. Super gratifying.

Over the past few months I have used this mic on nearly everything. After a while, I began to think "Is there anything this mic doesn't sound good on?" Seriously! Toms are unreal; acoustic guitar is freakishly good; screaming madman vocals (Marc Paffi on new Bars of Gold) are focused and dry as a bone; there's electric guitar through Sennheiser MD 421 vibes with more focus and no fizz; a smoother BK-5A with more bottom; and upright bass bridge mic – bonkers. The only thing I didn't love it on was piano. The piano here is, how shall we say, "vibey." It requires a wider snapshot as to not reveal its sonic blemishes. This is no fault of this mic, I just figured it was worth mentioning. It's a supercardioid mic, not an omni.

In short, the KU5A has all the qualities you've grown to love from AEA: magnificent sound, absurd price point versus performance, durability, and shockingly flexible. You know, the same as the old one, but totally different.The great folks at AEA have reinvented the wheel here with a beautiful ribbon sound, a gorgeous, natural high end, and insane rejection – it's less picky about preamps than other AEA mics as well. I love this microphone. It's rad to see a company like AEA isn't content resting on its laurels and is still offering something new and innovative that excels sonically, while addressing serious problems in both the studio and live worlds. As usual, the AEA folks have raised the bar yet again!