Crane Song IBIS Stereo Discrete Class-A EQ

Crane Song has been busy making high-end equipment at their Wisconsin facility for more than a decade. Founder David Hill’s designs have a reputation for sonic excellence, first-class build-quality, and strange monikers (not to mention their ubiquitous teal control knobs). For most of the planet, an ibis is a medium-sized, long-legged, long-necked wading bird, but to Mr. Hill these stick-legged creatures stir dreams of frequency shaping. Thus, Crane Song’s IBIS is a stereo discrete class-A equalizer designed for recording and mastering applications.

Each channel has independent controls and is divided into three processing sections: a low-cut filter, four EQ bands, and a “color” feature. The controls flow left to right, creating a logical spectrum of frequency control. The low-cut filter is stepped in 12 positions that range from 20Hz to 150Hz. Its slope can be set at either 12 or 24dB via push-button. The equalizer bands, labeled 1 through 4, are fully parametric, with bands 1 and 4 able to do double duty as shelves. Sweepable Q values start at a narrow two-tenths of an octave and spread to 4 octaves. Users are given a generous boost or cut range of 12dB via smooth rotation knobs. Worried about setting a band to zero? Don’t. As long as the control is in a small area to the left or right of the zero point, the gain will be inactive. Finally, each channel has its own bypass switch, enabling users to avoid the signal chain altogether.

What’s most interesting about the IBIS is how it approaches the frequencies of each band. Instead of frequency values, Crane Song focuses on corresponding musical notes. Thus, the bands cover musical-step intervals from 32Hz C to 22.35kHz F. Its four overlapping bands are labeled with note names and (some) frequencies. According to the manufacturer, this creates a bridge “between musician-speak and engineer-jargon.” Each frequency band has a “+1 Step” button, which effectively shifts the affected frequency higher by one whole tone. Crane Song publishes a full-color reference chart showing the 77 frequencies covered by the IBIS. Visit for a link to this PDF download.

The color function can add or subtract second and third order harmonic distortion. This effect can be applied to either the entire audio path or to a single individual frequency band. Each channel has a color gain knob that controls the amount of this effect to be applied.

The rear panel features balanced inputs and outputs by way of XLR jacks. For added flexibility, a “Side Chain” port (via DB15 connectors) allows users to access individual bands, or send each to an external compressor. If you had the resources, an IBIS and four high-end stereo compressors could make an analog multi-band compressor that would put plug-ins to shame.

So far we know there’s a mad scientist freezing in Wisconsin and harboring a Miami Vice/Wild Kingdom fetish (the sad thing is, I don’t even know if this qualifies as “weird” by music industry standards). But the important thing about gear isn’t the mental state of its maker, but its real world performance.

I’ve used the IBIS in my mastering chain for quite a while and I still find it difficult to qualify the sound. In some respects, it has the transparency of a Weiss or Massenberg Design Works digital EQ, but it also harbors the musicality of a Manley. In particular, band 4 can add an airy quality that I’ve only heard from the very best hand-made equalizers. The low-cut filters are smooth, reducing low-end crud and rumble without undue phase shift issues. The four frequency bands are flexible and powerful. I have some EQs that are great for cutting, and some good for boosting, but the IBIS is at home doing either. (I don’t want to start a rumor about one-way EQs; it’s just my thing. Leave Eugene’s mailbox alone.) I’ve already mentioned the merits of band 4 on the high-end, but all of the bands can be used broad brush or surgical-style. I’ve had particular success playing seek and destroy with sibilant vocalists. For such precision operations, having the +1 Step feature is a real blessing. Conversely, I’ve been able to enhance the crack of a snare, the attack of a lead guitar solo, or the fundamental of a background vocal with small boosts of narrow areas.

With the standard IBIS, all knobs are full-range, with the low-cut filters, frequency selectors, and color band selectors being stepped. A mastering version, comprised of stepped controls for every function, can be special-ordered for a premium. Originally, I was interested in such a model since documentation and recall are much easier. However, I’ve come to appreciate the value of having full range gain and Q controls. There have been many times when I would close my eyes and just sweep a parameter until I found that “sweet spot.” That experience can be lost with stepped controls. Of course, this is ultimately a personal preference, but potential IBIS buyers should not feel compelled to order the mastering version without trying the standard configuration first.

Speaking of documentation, one of my only complaints about the IBIS is the frequency labeling. The note names are not unique per band. For example, band 1 has four E notes, band 2 has four Fs, band 3 has four Ds, and band 4 has four Bs. I often find myself jotting things down like “band 3, +1 @ D above A# 932. . . .” Maybe someday I’ll know the note frequency values by heart, but for now, I muddle through this exercise every time I use the IBIS.

Other than documentation, I have no objections to the note-centric frequency labels. Why? First, we should equalize with our ears. I really don’t care if the numbers say hamburger, lettuce, or pickle (but again, only one hamburger per band, please). Second, it has improved my ability to correlate frequency build up among instruments with song keys. And finally, it provides a lot of fun tongue-in-cheek fodder on the Web discussion groups (Brad Blackwood is rubbing off on me).

A little IBIS can go a long way in mastering. In fact, I’ve almost never used more than 2.5dB of gain or cut. However, the extended range can yield tremendous flexibility in a tracking situation. I’ve found that sculpting acoustic and electric guitar mid-range with the IBIS to be a new experience in control. Moreover, you can chain one channel into the other and do some radical comb filter techniques for beat and groove production. For urban and hip-hop, the color feature can bring life to stock beat loops, and the fine tuning of the frequency bands can really help to feather a kick in with a bass.

The color control seems to be a love it or leave it feature depending on the source material. Those wondering if this is a mere repeat of the “Triode,” “Pentode,” and “Tape,” enhancers found on Crane Song’s HEDD units should rest assured that the IBIS color is a different type of sound. I find that boosting color in very small (say less than 1.5) amounts can add a subtle thickness to a mix, while major color boosts (especially in mid bands) approaches API-land. Again, this is definitely not a control that you leave on for everything, but it’s an added tool for taking your client’s work to the next level when other methods fail.

The IBIS is a splendid unit. It’s well built, great sounding, and supported by the nearly 24 x 7 availability of the Crane Song staff (via phone or email). Mastering engineers will appreciate a tool that is transparent but not sterile. Mix and tracking engineers will benefit from the immense sculpting power of the four frequency bands.

I don’t like to prognosticate, but I’m willing to bet that Crane Song gear will be the classics of tomorrow. Just like the current rage over Fairchild, Neve, and Pultec, people will attribute mythical powers to these boxes. It’s clear that Dave Hill puts hours of thought and planning into these devices — let alone months of applied testing at his Inland Sea Recording studio. This combination of design and refinement is evident in every element of the IBIS. So, instead of waiting for the “vintage” Crane Song rush, grab a demo unit and hear what this stuff can do today.

Strengths: Exquisite sound that is both transparent and musical, build quality. The color feature can be the icing on the cake (in the right circumstances).

Limitations: Note/Frequency labeling can be difficult to document, no formal manual, priced beyond the budget of most project studios ($4,500; $8,000, for a fully-stepped mastering version).