Dangerous Music: BAX EQ

Every once in a while, you run across a product that is seemingly simple, but offers so much more than its faceplate implies. The BAX EQ is one of them. After reading the review that Allen Farmelo submitted below, as well as the additional opinions printed here from Greg Calbi, Eric Broyhill, Dave Kutch, and our own LC, I bought one for myself. I’m absolutely loving it! Read on for all the reasons why everyone else loves it too. ($2529 MSRP; www.dangerousmusic.com) –AH

In 1950, Peter Baxandall entered a circuit design in an amateur competition sponsored by the British Sound Recording Association (later AES UK) and won a $25 wristwatch. That same design went on to grace hundreds of millions of home stereo systems as the commonplace bass and treble controls — probably the first EQ you ever used, and likely the only EQ many people will ever use. Baxandall never earned a royalty for his design, but he didn’t let that missed chance at fortune deter him from a long career in audio electronics or from contributing many significant papers to the AES Journal. Like many of us, he seems to have been driven by a life-long obsession with making records sound better.

Baxandall Curves are shelf EQs with exceptionally wide Q — so wide that, by the time the shelf levels off, they’re typically out of our hearing range, effectively creating a continuously rising or falling curve. The frequency at which the curve flattens into a shelf is usually called the shoulder frequency, but on the inside of that shoulder is a very smooth, gently sloping curve that pulls an enormous chunk of the spectrum up or down with it. So while you may be adjusting a curve with a 30 kHz shoulder frequency, you’re more gently boosting or cutting frequencies that can reach down as low as 3 kHz. The sonic result, as the BAX EQ manual puts it, is “subtle yet profound control of the frequency spectrum.”

Another key ingredient is the rather complex math Baxandall used to minimize the phase delay inherent in many shelving EQ designs. Phase delay can color the tonal character of a recording, but this color isn’t an inherently bad thing. We actually expect it from many EQs. The minimized phase delay of Baxandall’s design, however, allows us to make wide, sweeping changes to complex program material without really changing its sonic character. As a result, you can achieve a sweet and open sound that doesn’t impart its own character as much as it adjusts the character already inherent in the recording. Because of these seemingly neutral characteristics, Baxandall Curves are popular with mastering engineers as well as with mix engineers who use EQ on their stereo bus. The curves are also known for opening up the air on a vocal, for adding a subtle shimmer to acoustic guitars, or for putting some junk in the trunk on a drum subgroup.

To mimic Baxandall Curves, engineers have typically used the shelves on their best EQs and set the Q as wide as they can. While these can approximate the Baxandall Curve, it wasn’t until Dangerous Music developed their BAX EQ that we’ve had a professionally-designed analog EQ based solely and specifically around Baxandall’s design — and they nailed it! The BAX EQ is an instant classic, yet totally unique. I fell in love with it from the moment I patched it into my 2-bus chain while mixing, and I haven’t taken it out since. The transparency is rather astounding, and when I adjust this EQ, I get the feeling that I’m adjusting my mix and not the EQ itself. Nothing is ever harsh on top or boom on the bottom, and it’s simple to use and instantly satisfying.

All circuits in the BAX are based on Dangerous Music’s acclaimed mastering designs, using audiophile chips, selected stacked film caps and stepped attenuators — hand-wired using Mogami cable. Everything is DC-coupled, meaning no caps or transformers in the main audio path (of course, being an EQ, you run through whatever caps are in that selected frequency’s path). On the front panel are eight knobs to control the shelf frequencies (eight each for bass and treble) and boost/cut (5 dB max in 0.5 dB increments), as well as low and high–cut filters (12 dB/octave with selectable frequencies).

It’s important to keep in mind how wide these Baxandall curves are and how much of the frequency spectrum gets moved when you make adjustments. A 5 dB boost or cut may not seem like much, but remember that this unit is all about subtle yet profound changes, and with a Baxandall Curve, 5 dB is plenty. With the BAX EQ, the listed frequencies you see for the treble shelf actually correspond to what you’ll hear, rather than the exact shoulder frequency. (The frequency listed is roughly half the shoulder frequency.) So, what’s listed as 18 kHz, for example, is actually a curve with a shoulder frequency at 36 kHz. You’re moving 36 kHz, but you’re hearing the change pronounced around 18 kHz. On the low frequencies, however, the shoulder frequency is what’s listed, so you need to keep in mind that those are going to bring up a great deal of midrange due to the ultra-wide Q. While this may sound a little confusing, you don’t actually have to think about any of this while you’re using the BAX, and getting the curves to work for you couldn’t be easier.

The cut filters on either end of the spectrum are there to help you dial out unneeded frequencies that will be boosted at the far end of the shelves. On the low end, you can cut below 12 Hz, where headroom-eating, infrasonic rumble and DC-offset live. On the high end, you can dial out ultra-high frequencies like 70 kHz that can carry out-of-band noise that translates as harshness in many A/D converters (a somewhat hotly debated topic, but many believe to be inherent in digital systems).

These seemingly simple controls allow you to really shape these enormous curves to your needs, and you can easily play the shelves and cut filters off of each other as you might with a Pultec or other EQ with overlapping frequencies. Boost 74 Hz while cutting 54 Hz, and you get a nice, solid 60 Hz bump. A boost at 18 kHz with a cut at the same frequency opens up the air on a mix without over-emphasizing tape hiss. The combinations are virtually endless. Chris Muth at Dangerous Music is obviously a brilliant designer, and the way the different frequencies chosen for the BAX EQ work together might show off his skills better than any other piece of gear he’s designed. I can’t say enough about how musical and useful this EQ is while being totally intuitive and fun.

While mixing, I patched the BAX after my bus compressor and before my 2-track tape machine. I happened to have received the BAX on the same day I took in the new record by Brooklyn singer-songwriter Gray Reverend for mixing, and I was instantly comfortable printing mixes with the BAX engaged. Grey Reverend’s tracks are very intimate recordings of acoustic guitar, vocals, and strings — beautiful stuff that required a delicate hand. Mixing this record felt like a tightrope walk as the subtlest EQ and level adjustments would make enormous differences. The BAX proved to be my balance pole while out on the wire, allowing me to tilt the mix when it began to veer in one direction or another, without ever throwing it off. Looking at my recall sheets, there are a lot of 0.5 dB moves on shelves that cover multiple octaves, and I’m sure the mastering engineer is going to have less to do (famous last words!) because I was able to steer the overall frequency balance of each mix toward the central sound of the record.

On an entirely different mix project for the Brooklyn-based children’s artist Shelley Kay, the BAX’s high shelf helped me get a dreamy song about a silent, geothermal-powered, magnetic train to gently open up its inherent sense of wonder while the low-cut filter helped me dial out unneeded subsonic frequencies — so easy. On another tune, the BAX did something magical to clarify the whole mix when I boosted 1.6 kHz by a full dB. Then I remembered that the shoulder frequency here is going to be around 3.2 kHz, smack-dab in the middle of the articulation range — perfect for this mix.

I could go on and on, but you get the picture of how subtly, yet profoundly, I’m using the BAX as the last piece of gear my mixes see before going to tape. I’d even go so far as to say that the BAX reduces stress in my work life because I can so easily and so confidently bring the record closer to its finished state without changing the character of the overall sound I’ve worked so hard to achieve. The BAX EQ is a thoroughly serious and sophisticated piece of gear, but using it is as fun and satisfying as playing with Dad’s stereo when you were a kid.

–Allen Farmelo <www.farmelo.com>

After two months of working with the Dangerous BAX EQ, it has become an essential tool in my setup. Like any other piece of outboard gear, it is not a tool that you can use for everything (there is no such animal), but the BAX is a very unique equalizer and has some very powerful features.

Upper-midrange frequencies (labeled on the BAX as 3.4, 4.8, and 7.1 kHz) are usually problematic, but the BAX handles these better than any equalizer I have heard in 35 years of working on records. Adding in this area is oftentimes a minefield, as things usually get instantly too harsh or focused in a bad way. The BAX is extremely smooth in a usually-not-too-smooth area. I can add a certain musical presence to the mids without adding harshness, and this is extremely important, especially when mixes are done in-the-box and have a grating edge to begin with. On the other hand, the BAX rolls off harshness in these frequencies without killing the attack of those same mid frequencies. All in all, this is my favorite aspect of the BAX.

For some reason which only designer Chris Muth could probably explain, the bass frequencies of 74, 84, 98, 116, and 131 Hz are extremely subtle in adding a rich fundamental to electric bass; they are not very pointy and exact, but simply just rich and warm. The HPF is very good at filtering super-low (24 Hz) to just give bass drum and bass more clarity.

The BAX is not a tool to have as an only equalizer, nor is it designed that way. It is a great tool to supplement my Focusrite, Manley, API, and Curvebender, because it does something that is totally different than any of them. Don’t ask to borrow it; you can’t have it.

–Greg Calbi, www.sterling-sound.com

Initially, I ordered the BAX EQ because I really liked what Dangerous Music was trying to achieve — an overall, very-general tone control with a great quality EQ behind it. When mastering a song, sometimes I’m getting that song to feel just right but may have pulled things a little towards the low or high end. Making corrective EQ adjustments can change the way the compressors, limiters and everything else in the rest of the chain are working together. So, once I’ve corrected the tone, I may not be as excited about the vibe of the song. I felt that placing the BAX at (or near) the end of the chain could possibly be a great solution for my setup.

Once I got the BAX and started using it, I was way more impressed than anticipated. First off, the sound of the EQ was really amazing. More sheen than my Fred Forssell EQ but more refined in the high-frequency boost than my Manley Massive Passive — the BAX really gave me a nice option between the two. What also blew me away (and was really unexpected) was how good both the HP and LP filters sounded — very natural and focused, especially in the high end. On the LPF, Dangerous Music made some great choices with their frequency selection. There’s an 18 kHz position that I feel is perfect, giving me just enough to reel in some of that high-end graininess from certain mixes. In the low end, the BAX gives me a little more focus without changing the mix. Generally, I prefer (and have always been a fan of) the Weiss EQ1 (Tape Op #31) for its filters at the very ends of the spectrum. For that purpose, I’m not sure if I like the BAX better than the Weiss — but I’d say 50% of the time, it sounds better, and 50% of the time, I prefer the Weiss; so again, it’s nice to have an option.

–Eric Broyhill, www.monsterlabaudio.com

About ten months ago, I received an early prototype of the BAX EQ. No detents, no HP or LP filters, no frills, and no bypass. I test drove it on writer/producer Jack Splash’s solo album, and by the sixth song, I noticed I could not stop using the 84 Hz shelving. It gives a kick drum that great old school “foot” sound without getting muddy or sloppy. I commonly use an old Neumann PEQ for this frequency range, but it can get a little muddy on certain tracks; the BAX does not seem to have this problem. Jack Splash is a very critical listener, so when he approved the mastering on twelve out of the thirteen songs, I knew this new toy was special. The bottom end also sounds different than any of my other EQs, which is key for me. I do not need any new gear that’s not going to give a new color in my crayon box. Needless to say, I was addicted to this one frequency point of 84 Hz and begged Chris not to change, tweak, adjust, or fine-tune it on the final version. Leave it alone!

I stole the second prototype from Dangerous Music on the last day of the 2009 NYC AES show. I was just about to start mastering Alicia Keys’ The Element of Freedom album, and I needed that 84 Hz shelving like a meth-head needs a bath and new teeth. This new version, however, was a totally different beast. The addition of the HP and LP filters vastly broadens your sonic palette. The bottom end on Alicia’s latest single “Un-Thinkable (I’m Ready)” is all the BAX. The kick on that track is incredible, and it drives the song. I would boost 1 to 3 dB on the low shelving; turn on the HPF at 12, 18, or 24 Hz; and then sweep the frequencies on the low shelving until I hit the “sweet spot”. After that, it was just subtle adjustments to fine tune it.

I recently used the BAX on the new Roots (How I Got Over) and John Legend albums — though slightly differently. Questlove’s kick and snare sounds are his signature, and I don’t want to alter them. On the single “Dear God 2.0”, there’s this warm bass line that’s key to the mood of the song. I boosted the 74 Hz shelving on the BAX by 0.5 dB and then used a digital EQ somewhere between 60 and 85 Hz with a tight Q. This way, I brought out the “knock” in the kick drum independently while extending the “foot” of the kick and the warmth of the bass line.

I have not used the high shelving that much. As I stated before, I need new colors to start using something, and the BAX high end sounds very similar to my go-to EQs. I guess that’s a good thing if you do not already own any mastering EQs. I will, however, own and use a piece of gear solely for one frequency if it’s really special. I think by now you know which one that is on the BAX.

–Dave Kutch, www.themasteringpalace.com

I’m surprised anyone could create a piece of recording gear that I thought I had no need for, yet as soon as I used the BAX EQ, I wanted to own one. I generally never pop in any outboard gear on my mix bus, but this bastard won me over. On classical-type mixes (Portland Cello Project), it was absolutely a joy to add that soft, airy lift on the top end of a mix; I’d bypass it, and it felt like the mix was choking. It’s amazing on acoustic guitar tracks. If you normally think of EQ as “corrective” like I do, then think of this one as simply “sweetening” because that’s what it does. –LC