Crane Song Ibis Stereo Equalizer

Products built with George Massenburg's seminal parametric EQ design, and other gear built following the classic Pultec philosophy couldn't be more different in sound character -- and most well-heeled mastering labs own at least one from each group -- but where does this newcomer from Crane Song fit in?
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As an acoustic recording engineer always wanting to tweak an extra decibel or two from my recordings, I've been a user of high-end stereo equalizers for about thirty years. The original George Massenburg-designed I.T.I. Parametric MEP-230 (and its Sontec and, later, GML offspring) served me well from the early seventies until the nineties, when I began using the various Manley tube Pultec-inspired models. I eventually ended up purchasing Manley's Massive Passive in 1999 and recently upgraded it to the mastering version. Products built with George Massenburg's seminal parametric EQ design, and other gear built following the classic Pultec philosophy couldn't be more different in sound character -- and most well-heeled mastering labs own at least one from each group -- but where does this newcomer from Crane Song fit in?
Product PointsApplications: Recording, post production

Key features: Four overlapping EQ bands per channel; switch-selectable frequencies centered on and spanning musical major third intervals; adjustable "color" function can be applied globally, or to individual frequency bands

Price: $4,500; $8,000, for a fully-stepped mastering version

Contact: Crane Song at 715-398-3627,

Dave Hill, designed of the Ibis, claims that, for the first time, a "translation between musician-speak and engineer-jargon" has been produced. Well, I don't know about that, because I just equalize "by ear," but I do know that this box has the typical "extremely clear but, at the same time, very warm" Crane Song sound. With the EQ switched out -- or in, but set flat -- the sound is among the smoothest analog audio you're ever going to hear. But this is an equalizer, not a line amp, so let's see what those thirty knobs and seventeen switches can do to change the sound of audio flowing through it.

The front panel is arranged symmetrically, about the center axis, which simply sports two in/out toggle switches, a power switch, and a large green indicator lamp. To the left and right of this center column are the vertically arranged controls for each of the four overlapping frequency bands in each stereo channel. At the far left and far right is another column of controls, this time involving the low-cut filters and the special "color" circuit.

Each of the four EQ channels has 12 frequency choices, covering four musical octaves by intervals of a major third. Actually, make that 24 choices, because each band also sports a red pushbutton labeled "+1 step." As a former music theory professor, I'd have named it "+ whole tone," but you get the picture -- it increases any of the switch positions by two semitones. In other words, whereas the lowest frequency at the bottom position on the leftmost switch is 32.7 Hz "C" and the next position up is 41.2 Hz ('E'), with the red button pushed in, the lowest frequency is 36.7 Hz ('D') -- halfway between them. Thus, Dave Hill has filled in the spaces "between" the switch positions and, at the same time, has endowed a 12-position, four-octave rotary switch with 24 positions -- giving it resolution to the closest whole tone!

For the compulsive among us who might be curious about the semitones in between the whole tones, please be aware that the overlap in frequency choices between the lowest two EQ bands fills in a few of them, and the frequency overlap among the middle two bands -- coupled with that red pushbutton, of course -- gives one an almost complete chromatic scale over several of the most important midrange octaves. For a detailed look at all the frequencies available, simply go to, scroll to the bottom of the page, and click on "Ibis Frequency Chart." You'll download a PDF file showing 77 frequencies, along with color formatting to help identify which ones are adjustable in which EQ band, and where the overlaps are.

The cut/boost control is a smooth pot, as is the bandwidth knob, which ranges from a quarter octave to four octaves. The lowest and highest EQ bands can be switched to shelving (rather than peaking) functionality by pushing in a black pushbutton. The low cut filter circuitry -- found in the furthest leftmost and rightmost columns of knobs -- features 12 positions between 20 Hz and 150 Hz, with slopes of either 12 dB or 24 dB per octave, selected by a white pushbutton.

Like most other Crane Song products, the Ibis utilizes discrete Class A circuitry and also features a rather unique and adjustable "color" function; it can be applied to either the entire audio path or to any individual frequency band. Dave Hill tells me that the circuit produces varying amounts of extra second and third harmonics (i.e., distortion) while subtracting out some of the fundamental. In my own testing, with my typical delicate acoustic and classical music sources, I found its effect to be rather unsubtle and grungy -- nothing like the wonderful HEDD-based "fat" and "analog tape level" emulation circuitry on their Spider mixer (PAR 8/02), so I didn't use it very much. But many mastering engineers swear by it for giving a special aggressiveness to rock masters, so it's just a matter of taste. At any rate, it certainly gives the Ibis a different sound, and the subtlety of its effect can be easily varied over a large range

The rear panel features pairs of XLR jacks for inputs and outputs, as well as a pair of male and female DB15 connectors labeled "Side Chain." Since all the Ibis' filters are in parallel, between all thirty pins, one can access individual EQ bands and either switch them on/off separately, or send each to an external compressor. The circuit path is very short and the DB15 i/o is unbalanced (just like the sends in my Spider mixer), but it is definitely possible to hook up multiple compressors (such as Crane Song's STC-8 or Trakker units) to a single Ibis and end up with either an amazing high-end dynamic equalizer or an analog "audiophile multiband compressor" (if that's not an oxymoron in itself) -- depending on where the audio goes first!

In Use

Well, there's not much to say about using the Ibis! It works well and sounds great! Once I got used to the way that the controls were labeled, I found it as almost easy to use as a Massenburg-styled parametric equalizer. As someone with bad eyesight, I'd have preferred the Ibis to be larger -- say, three rack spaces high, instead of two. This would have made the multitude of engraved lettering choices on the front panel more legible, but I'm sure it would also have made the Ibis more expensive. At any rate, once I got my head around the way the unit's philosophy, I was able to operate it easily -- without looking at it at all.

The frequency choices are staggering and, since Crane Song also offers a mastering version with stepped controls for cut/boost and bandwidth, I'd say the Ibis will give its two competitors -- the GML 9500 and the Manley Massive Passive: Mastering Version -- quite a run for the money. I did not have a GML unit here with which to compare it, but from my experience with the GML 8200 back in the late 1980s, I'd go out on a limb and say the Ibis sounds at least as clean, and definitely warmer.

Even extreme amounts of EQ sound good, and the overall effect is one of "velvety-smoothness." It certainly does not have the sonic character or deliberate response "peculiarities" of the Manley unit (and, of course, was designed to a completely different sound ideal) but -- if I could afford both of them -- I would certainly put the Ibis near the top of my shopping list. Its high frequency EQ, in particular, is the smoothest and airiest I have ever heard, and is produced without any of the brittleness present in most other equalizers; in this respect, it's definitely on a par with the Massive Passive.


What's not to like? This is the most flexible and best-sounding solid-state stereo equalizer I've ever had the pleasure to use. If you don't already own a GML or a Massive Passive (and even if you do), this "new kid on the block" is definitely the one to audition.