David Hill is based in the Superior, Wisconsin area and has been designing high-end audio hardware and software for quite some time.

Some of you may know him from his work with Summit or you may have bumped into him during an AES convention, Music Messe or NAMM show. Most of us know Dave from his amazing sounding EQs, compressors, mic pres and most importantly the A/D and D/A convertors.

So let’s have a closer look at the new and updated Crane Song HEDD Quantum.

HEDD stands for Harmonically Enhanced Digital Device and has been engineered to provide musically pleasing sound with the capability of generating tube/analogue sounds within the digital domain.

The key ingredient in HEDD Quantum is a new clocking crystal. It’s Crane Song’s fifth generation design just like the ones used in the Avocet IIA and Solaris and has less then 1pS jitter (1 trillionth of a second). The result is extremely accurate imaging, a very open 3D sound and detailed transient response.

I mentioned jitter and it’s one of those “black art”, hard to explain phenomena. The artefacts caused by jitter are blurred, harsh and unfocussed sound. It also results in a loss of image stability, depth and space.

Jitter, basically a time deviation in the clock timing, is caused by many factors. The main culprit being the frequency of the clock changing during the conversion process. The newly developed crystal clock within the HEDD Quantum has reduced this jitter to the, currently, lowest possible value, resulting in a well defined low end and clear top end. This will provide you with a much stabler image.

In addition to the new AD, DA, Clocking, I/O (Toslink Optical has been added) and extra WC outputs, HEDD Quantum still comes equipped with the same great DSP emulation of Triode, Pentode tubes and Tape emulation from the original model. The operational modes now allow the DAC and the ADC to be used simultaneously and at different sample rates.

The HEDD can operate as an effects device or as separate A/D and D/A convertor with the harmonic generation process applied to either convertor respectively. The signal processor performs up to 24 Bit Processing on digital or analogue sources. HEDD Quantum has transformerless balanced analogue inputs and outputs, transformer isolated digital inputs and outputs and uses separate power transformers and supplies for the analogue and digital sections.

The HEDD Quantum output now has a higher maximum output level +24.5 dBu and the maximum input range is adjustable from +16 dBu to +26 dBu for digital zero. The HEDD Quantum operates at sample rates from 44.1kHz to 192kHz.

The HEDD Quantum can be used for many different tasks. My first test was strapping it across the recording rig at the studio for a recording session. I bypassed the in-house clock and fed the convertors the Word Clock from the HEDD. The change in clarity and definition was instantly apparent.The low end in the bass and the kick drums was so much more detailed and punchy. Stereo imaging got a lot clearer as well, making panning and EQing much easier and faster.

This led to me installing the HEDD in my personal mix and mastering set up. The unit is the master clock, clocking all digital devices and also serves as my A/D converter and processor. The Triode, Pentode and Tape processes are as amazing as in the prior generation HEDD. In the MKI of the unit there used to be a little zipper noise when you cranked the Triode control and that is now no longer there.

Ever since running the HEDD as my master clock, the workflow has sped up considerably.

Because of the extreme low jitter, mixing and mastering do not only sound better, it’s made working more fun.

I performed listening tests with a client, where I had the same mix output feed my interface and the HEDD simultaneously. I had the client in the sweet spot and I kept switching between the interface and the HEDD. I started out by running both units separate from each other, so the HEDD’s crystal was not clocking the interface.

Once flipped to the HEDD the low-end information cleared up and the low mid mush you get from jitter vanished. The panning positions got a lot more precise and in general everything sounded a lot more robust.

Once we started clocking the interface from the HEDD’s word clock out, the interface’s performance improved dramatically as well. I was very pleased to see that the client, who doesn’t spend all his time geeking out of things like this, spotted the difference and was as impressed as I was.

Needless to say, this unit is staying in the rack and is now the centrepiece of the studio. Not only is it a wonderful sounding unit in its own right, it also improves the performance of everything that’s clocking from it.

Key Features

• High-quality 24-bit A/D and D/A Convertors
• 24-bit Processing
• Adjustable Triode, Pentode and Tape sounds
• Digital I/O, AES and S/PDIF

RRP: £3,800

Wes Maebe is a UK-based recording, mixing, mastering and live sound engineer.