Recording engineers need a full-spectrum sonic palette. Sometimes, this means going against the ingrained instinct of “accuracy first.” Yes, there are times when transparently clean is the best and only choice. Other times, a little grunge helps bring a more aggressive “street” feel to overly sterile studio tracks, especially now that analog tape has become more a piece of outboard gear than a standard part of the recording process.
Just as television and print exaggerate the warmth of flesh tones (think distressed furniture, acid-washed jeans and a broken-in pair of sneakers), analog's artifacts saturate sonic colors to a level more vivid than reality. Designed to provide analog nuances when working in the digital domain, the first Crane Song HEDD (Harmonically Enhanced Digital Device) was previewed at AES five years ago, and it was an instant hit with producers, recording engineers and mastering studios.
Now, designer Dave Hill offers HEDD 192, the second generation of his brainchild, which now offers dither that's exclusively Crane Song's and, as its name suggests, 192kHz capability at 24-bit resolution.
However, more than just a stereo AD/DA converter, HEDD 192's built-in DSP includes three analog emulation controls (Triode, Pentode and Tape) with a common Bypass switch. The unit can operate as an effects device or as a separate AD/DA converter with the sound enhancement applied to either the A/D or D/A process. Just rotate the knobs clockwise and enjoy. It couldn't be easier. There are no menus, LCD screens or secret keystrokes.
HEDD 192 currently ships with 96kHz converters: The upgrade path is waiting for acceptable parts and communications standards, and its modular design will facilitate the transition. Each time a major setting, like sample rate, is changed, the converters recalibrate themselves. Outside, a front panel switch resets the meter's peak hold feature. Inside, two peak hold options can be selected via an internal jumper.
Among HEDD 192's front panel knobs are controls for selecting sample rate, bit depth (also inserts DSP in the correct signal path), AES or S/PDIF output, internal/external clock source, and DSP bypass. The rear panel has XLR balanced analog inputs and outputs, XLR AES and coaxial S/PDIF digital I/O, and wordclock in/out on BNCs.
The single-rackspace device lists for $3,495.
For the first test, the output of my Soundscape workstation was routed through HEDD to “warm up” a mix in progress. There's nothing subtle about HEDD processing, and everyone who heard the process was impressed with the results. Turn the Tape knob clockwise and the track gets larger without increasing “overs,” yet simultaneously adding richness to the bottom and mids.
I also used HEDD to emulate an Ampeg B-15 bass amp by routing an electric bass track through it, and cranked the Pentode knob to increase the “spectral content.” By adding a sweet bit o' distortion, a nice round bass guitar turned into a more robust version that could sit in the mix through verse and chorus without getting lost in the sauce. That's deep — with or without the pun.
From left to right on the front panel, each of the three controls — Triode, Pentode and Tape — become progressively more responsive. Triode generates the type of even-order (octave) harmonics associated with single-ended vacuum tube circuits. The effect is easier to hear when processing at higher sample rates. The emulation makes astounding visuals starting with Fig. 1, a family of sine waves from clean to mean. In Fig. 2, the arrow points to 1 kHz, and to the immediate right is the second harmonic, 2 kHz, one octave above. What is amazing about HEDD 192 is that the distortion is so controlled: There's no thin, shrill, hard clipping at all.
A completely different effect is available by combining the Pentode and Tape modes to generate odd harmonics, as the 3kHz and 5kHz spikes show in Fig. 3.
What is amazing about HEDD is the level of control that each knob has over its respective area of expertise. No analog product can deliver such controlled and desirable distortion. No digital product is as easy to use. If you've been putting off buying an outboard converter, then HEDD 192 may be the best reason to do so.
Recording was done at 88.2 kHz, via Alesis Masterlink, with the sample rate chosen to minimize the math for future comparison at 44.1 kHz. It should also be noted that the reason for using square waves is that they consist of all odd harmonics — essentially, sine waves ripped through a fuzzbox, clipped symmetrically top and bottom.
What you never see is the effect digitizing has on square waves; Fig. 4 shows just that. Via HEDD 192, notice how much more sedate the “ringing” is at higher sampling rates. Also note how tape emulation affects the wave. Of course, tape saturation is a dynamic process that cannot be depicted in print. Tape saturates at high frequencies because of the record EQ boost and at low frequencies due to head limitations. That's two different idiosyncrasies plus low-frequency head bumps, a complex bit of DSP made easy.
HEDD 192 is Crane Song's second-generation stereo digital converter, adding higher sample rates as well as tape emulation. (The original version featured only vacuum tube emulation.) Next to an LA-2A, HEDD is the simplest signal processor you'll ever use. Providing a remarkable level of sonic versatility with ease of use, HEDD 192 is a sonic crayon that can paint a whole rainbow.
Crane Song Ltd., 2117 East Fifth St., Superior, WI 54880; 715/398-3627; fax 715/398-3279; www.cranesong.com.