Raven Labs True Blue EQ Review

During the past three years, relative newcomer Raven Labs has designed and produced a respectable selection of direct boxes, preamps, and mixers for musicians

During the past three years, relative newcomer Raven Labs has designed and produced a respectable selection of direct boxes, preamps, and mixers for musicians and engineers alike. The latest addition to the fold is the True Blue EQ, a 5-band semiparametric equalizer that promises professional signal shaping at a reasonable price. This simple box is designed to allow some precision nip and tuck on signals as needed, whether you're tracking, mixing, or simply honing the sound of your instrument. If you're occasionally stymied by the relatively limited filters and equalizers often found in smaller mixers, the True Blue EQ could be a welcome alternative.


The True Blue EQ is a compact mono unit with a simple dark-blue two-piece chassis. The Raven Labs logo, the model name, and the control markings are emblazoned in white on the faceplate. Four rubber feet provide a bit of padding and grip for placing the unit on a flat surface. A threaded machine-screw stud at the center of the base provides the option of mounting the unit on a rack shelf. That's a nice touch, as an accumulation of free-floating pieces of outboard gear can clutter up a studio or become a hassle in a road rig.

The front panel is laid out simply, with two rows of juxtaposed pairs of potentiometers for five frequency ranges (see Fig. 1). Each band has two knobs: a level control that allows for as much as 15 dB of cut or boost, and a frequency-sweep control. On the top row, the first band is labeled Low and covers 30 to 100 Hz. The next band, labeled Low-Mid, ranges from 100 to 300 Hz. The third, labeled Mid, ranges from 300 Hz to 1 kHz. Positioned in the second row are bands labeled Treble (1 to 3 kHz) and Ultra Hi (3 to 10 kHz). An EQ In/Out button located in the lower-right corner allows for bypass and is accompanied by a red LED indicator. A Power on/off button with a green LED indicator completes the faceplate controls.

The neatly arranged rear panel of the True Blue EQ contains both balanced ¼-inch TRS and unbalanced ¼-inch TS input and output jacks (see Fig. 2). Two stereo minijacks are provided for power. A custom AC adapter provided with the unit supplies +9 and -9 VDC for the device's voltage rails. The second jack, labeled Out, lets you power several Raven Labs products from a single adapter by daisy-chaining them together. A dual-battery bay accommodates two 9V batteries. The True Blue can operate for as many as 100 hours on battery power. An internal mechanism automatically switches to battery power when the AC adapter is not connected; that's a useful backup if the wall wart is accidentally pulled from a socket while the device is in use.

According to Raven Labs, frequency-level adjustments are made by adding or subtracting the original signal to or from itself in a parallel circuit arrangement. That approach aims to avoid the pitfalls of active-series EQ circuit designs, namely muddiness and phase shifting. The equalizer sounds clean and quiet and doesn't exhibit the high-frequency phase-shifting problems characteristic of some less expensive equalizers.

By design, the True Blue offers fairly narrow bandwidths, apparently even more so in Cut mode — a characteristic that makes it behave much like a notch filter. Such an attribute allows surgical precision in shaping a sound but without negatively affecting the quality of the signal.

Standard sweepable equalizers on small to medium-size boards tend to have broader bandwidths, making, say, a 3 dB change quite noticeable. The effect is less radical with the True Blue. Although the level pots are labeled ±15 dB, the difference sounds more as if it's between 6 and 8 dB. A small issue I had with the test unit's level pots was the lack of center detents. Thankfully, current models feature pots with center detents.

Also, the EQ In/Out button is less than intuitive, because when the button is pressed in, the EQ is out, and when the button is out, the EQ is in. Granted, the illuminated red LED is an adequate clue; but even a simple bypass label would be easier to understand than the current arrangement. In addition, when the unit is in circuit, there is a slight drop in gain, even with all the level pots set to 0. The unit is not completely transparent sounding, though the overall effect is clean.


I put the True Blue EQ through many tests. Most notably, I used it while making a compilation demo CD for Bay Area cellist Samantha Black. It proved useful in doctoring a cassette recording, putting it more on par with digital source materials (CD and DAT) for the same project. I also brought the unit into a mixing session for disco-funk band Double Funk Crunch at Guerrilla Recording in Oakland, California. Here's what I discovered.

While making Black's compilation demo CD, I found the True Blue EQ to be a true friend. The hiss on the cassette was pretty bad, and the recording sounded rather roomy. With a couple of deep cuts in the high end and a little taming in the lows, I cleaned up the sound enough that it wasn't radically different from the digital recordings. It was still noisy, but far less so. I was sold on the usefulness of the True Blue in this application, especially compared with attempting the same precision cuts with the EQ on a compact mixer.

During the mixdown session at Guerrilla Recording, the True Blue made a positive contribution on a variety of sources. A slight boost at 80 Hz enhanced a kick drum without making it sound boomy, and a small boost in the high mids brought out the side-sticking on a snare drum while remaining true to the source sound. The unit also did a good job of rolling off the highs around 8.5 kHz on a perky keyboard part and putting a little body into the sound at 250 and 750 Hz.

Thin-sounding male vocals were pleasantly plumped up with modest boosts at 100 Hz and a few carefully chosen low-mid frequencies. On a slightly nasal-sounding female vocal track, boosting the low mids by about 2 dB subtly improved the sound. Thanks to its narrow bandwidth ranges, the True Blue EQ is an excellent diagnostic tool — it really allows you to hear where there's a bump in response. Similarly, it excels at enhancing signals while maintaining their original quality.


Raven Labs has a winner in the True Blue EQ. The unit has a neutral sound, and it lets you make surgically precise adjustments to signals without affecting their fundamental sonic characteristics. Although transparency diminishes slightly when the EQ is in circuit, the overall sound of the unit is clean and free of distortion. In addition, the True Blue offers more precision and tighter bandwidths than the semiparametric EQs found on most compact mixing boards.

Karen Stackpole,an independent engineer, operates Stray Dog Recording Services, based in Berkeley, California, and directs the studio maintenance course at Ex'pression Center for New Media in Emeryville, California. Special thanks to Myles Boisen.


Raven Labs
True Blue EQ semiparametric equalizer $349


PROS: Small, portable. Clean sounding. Narrow bandwidths useful for precisely shaping sounds without adversely affecting adjacent frequencies. Optional 9V-battery power. Power-out jack allows daisy chaining of multiple Raven Labs units. Three-year warranty.

CONS: Fixed bandwidths. Somewhat confusing EQ In/Out button. Slight drop in gain and transparency when unit is in circuit.


Raven Labs
tel. (818) 368-2400
e-mail raven-labs@aol.com
Web www.raven-labs.com

True Blue EQ Specifications

Frequency Bands(1) 30-100 Hz; (1) 100-300 Hz; (1) 300 Hz-1 kHz; (1) 1-3 kHz; (1) 3-10 kHzCut/Boost±15 dBInputs(1) balanced ¼" TRS; (1) unbalanced ¼" TSOutputs(1) balanced ¼" TRS; (1) unbalanced ¼" TSFrequency Response10 Hz-63 kHz (-3 dB)Noise-90 dBV (IHF unweighted)Distortion0.002% (@1 kHz)PowerAC adapter; (2) 9V batteriesDimensions6.70" (W) × 2.26" (H) × 6.00" (D)Weight3 lb.