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Back in 2004 I was one of the very first reviewers to tackle the rather daunt-ing task of reviewing one of the first products available from Australian digital specialist DEQX: its PDC-2.6P processor. The unit was the companys flagship at the time and was a true Swiss Army knife of digital functionality featuring on-board crossovers, room correction, speaker correction, digital equalisation, digital-to-analogue conversion, and more. The review ended up being the most complex and lengthy Ive ever written and, when taking into account the multiple graphs and screen captures, it would not be

surprising if it was one of the longest ever published. Boy did I need some recovery time after that literary marathon. It may even have made the Guinness Book of Records just saying.

Nine years on, DEQX now offers prod-ucts with similar features (and more) to that earlier generation, but with a simplified operational approach that is profoundly more user-friendly. In fact, thanks to DEQXs splendid customer support and some computer, um, wizardry, very littleif anythingis required of owners in terms of computer skills while functionality can be

as hands-on or as passively inactive as that owners spirit of adventure.

Whats on DEQX?The PreMate is best described as an ana-logue preamplifier with built-in DAC that also features the DSP powers that have made DEQX world-famous. In fact it shares many of the features of the flagship HDP4. But what the brains behind DEQX wanted to achieve with the PreMate was a product that would easily fit into the context of established audio enthusiasts systems without upsetting traditionaland more

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conservativeconfigurations while also offering the more adventurous an avenue into the advanced wonders of digital manipulation.

So, in its basic guise, the PreMate can be used as a high-quality preamplifier with a 32-bit resolution DSP volume control. It can accept a digital signal from a CD transport or a computer while also taking a balanced and single-ended analogue input (all switchable via the remote control). The in-built high-quality PCM1795-based DACs then take over the signal, do the number crunching, and pass it on to analogue line outputs to connect to a power amplifier. Connection to an integrated amp would mean maxxing its volume control and riding levels with the PreMate (preferable due to its high-resolution volume control) or you could do it the other way around.

Now for the cream. For users with the spirit of Cortez, explorers and conquista-dors, the PreMate can be much more than a transparent preamp and a superb DAC.

A simple process allows for speaker response and room mode corrections to be applied which can be saved and accessed via the remote control. In my case, measure-ments were taken from the listening posi-tion and time domain room correction was applied below 200Hz to correct a minor room-related bass hump around 100Hz. As conducted by DEQXs Alan Langford, measuring took all of 10 minutes. The PreMate generates a number of tones for each channel and produces a graph with the measured frequency response plot. Corrections can be made in real time and/or stored.

A second level of digital wizardry can be applied to your speakers. Speaker correction can be used to compensate for group-delay errors so all frequencies are aligned in time. In the past Ive found the effect of such a correction to range from being subtlewith very expensive speakers using high-quality drivers and well-designed crossoversto sobering and jaw-droppingly dramatic sonic improvements with speakers at low- to mid-level price-points.

Thirdly, the PreMate can correct for impulse response timing errors for seamless subwoofer integration while adding the option of adjustable low-pass and high-pass filters.

So really, the point to stress in regards to this new DEQX product is that the PreMate can fit in to any system with as little or as much re-configuration, digital manipulation and user activity as the individual is willing to undertake.

on ya matE!The unit has been totally re-styled into a more conventional componentalbeit with a classy diamond-polished aluminium front panel (available in black or silver), a medium-gauge steel chassis and good quality connectors. As far as those are concerned, the PreMate features analogue inputs via RCA and XLR and a host of digital inputs. These include optical, SPDIF coaxial via BNC and RCA, AES/EBU XLR and USB. The USB inputwhich is a user-retrofittable option at an additional $495is PCM only, asynchronous from 1624/44.1kHz and 24/192kHz with direct I2S conversion. A BNC output rounds out the digital connec-tivity. RS-232 D-connector control options are also offered while theres an XLR micro-phone input used for the various correction features. As far as analogue outputs are concerned, the PreMate offers RCA and XLR main outs and two subwoofer outputs (also via RCA and XLR).

The front panel is sparsely populated with small buttons which, from left to right, operate the power and standby modes and volume up/down while finally youll find a row of three buttons for the Profile presets. These Profiles allow the storing of preset EQ curves to correct room issues, or to tailor the sound to suit listening tastes and/or for compensating for poor or col-oured recordings.

I briefly auditioned the PreMate in its guise as a preamplifier fed with a single-ended analogue signal from my reference AMR CD-77.1 CD player.

As such it performed very well with the clean, detailed, transparent sound that is expected from a competently designed solid-state preamplifier. The remainder of the time was spent feeding the PreMates wonderful onboard DAC with either a digi-tal SPDIF signal from the AMR CD player or via the USB input from a Mac laptop using BitPerfect player and AIFF music files.

My listening room is fortuitously reso-nance-free, so theres no need for the intru-sions and the spousal unfriendliness of bass traps and acoustic treatments. However, there is a medium amplitude-lowQ hump around the 100Hz region which manifests

DEQX PrEMatE Digital ProcEssor & PrEaMPlifiEr

Brand: DEQXModel: PreMatecategory: Digital Processor & PreamprrP: $4,495Warranty: Two YearsDistributor: DEQX Pty Ltdaddress: Unit 1/1 Roger Street Brookvale NSW 2100t: (02) 9905 6277E: sales@deqx.comW: www.deqx.com

Leading edge versatility and technologyClean, dynamic and detailed with stunning bassVery simple to use, but

Still requires basic computer skillsInterpreting the EQ graph

DEQX PrEMaTE DigiTal PrOcESSOr & PrEaMPlifiEr

LAB REPORT: Turn to page 84Test results apply to review sample only.

Call a DEQXpert!DEQX equipment is almost always completely installed and calibrated by a DEQX dealer or DEQX factory technician, but in situations where this is not possible for any reason, the company offers a DEQXpert service that provides remote measuring, correction and PreMate configuration via the Internet. All that is required is a low-cost test microphone, a computer running Windows, a USB port and broadband internet access. Help is also always available via phone, email or Skype should users prefer to set-up the PreMate themselves.

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as a tad of bass warmth in that region. Its not objectionable, and it can actually be some-what pleasing, even if its added weight takes away some low-end leading edge attack.

So, with the PreMate con-figured with a subtle fix around 100Hz on Profile 1 (P1) then, in addition, a minute smidgen of electronic tidying-up via parametric EQ around the 1kHz area on P2 and a total bypass on P0, I got on to the sonic evaluation.

Oh, at this point it should be mentioned that the EQ feature allows endless response error adjustments at any fre-quency (from 10Hz to 40kHz) to correct just about any deviation. Once youve reached the desired sound, store it as a Profile and use it as you please.

In our case, as much as I didnt mind the slight hump around 100Hz prior to DEQXing the system, the P1 Profile with the slight modification provided a surprising difference. DEQXed-out, the sonics became more dynamically exciting and much punchier in the low-end.

Switching between P1 and bypass (P0) clearly demonstrated the added punch the fix provided. Kick drum was felt far more profoundly via P1 and the overall bass region sounded far tighter and with enhanced rhythmic pace. This in turn pro-voked a change in the midrange reproduc-tion. It became more detailed with a clarity that stretched upwards towards the lower treble, taking the soundstage a tad more forward and very pleasingly so.

Switching to bypass (in order to audition via the regular familiar sound) and using the PreMates DAC showed some further skills. The DAC excels at presenting a detailed, powerful, full-bodied and dynamic sound; the kind of sonic energy that will instil a true sense of life and enthused pace into any system.

Before the Loudness Wars became the battleground of our sonic landscape The Red Hot Chilli Peppers Blood Sugar Sex Magic was one of the bet-

ter modern rock recordings. Hearing the ti-tle track even via the bypass mode provides bass hits that, speakers permitting, will really shake the room. Bring either of the corrected Profiles into play and things get even more bass-violent with the PreMate providing one of the most involving rock presentations my Wilson Audio Alexias have ever deliveredheard and felt. Expansive orchestral works fared equally well, with the PreMate preserving all that is important in classical music such as the sense of space and scale while also providing superb dif-ferentiation between the different orchestra sections. Violins sound like grouped individ-uals playing in unison rather than one large homogenised mass, and if the composition features a musical prominence in the bass, the corrected excellence of DEQX brings the detail and tone of those instruments to an arresting verisimilitude.

ConClusionThe design team at DEQX has aimed at an all-out assault on digital playback, determined to offer a DAC section in the PreMate to compete in the top tier. Based on the sound within my reference system, Id say theyve succeeded. Effectively, this is a very tricked-out preamp with a classy DAC on the surface, and that could be the end of it for many users. In that respect alone, such a customer would be happy with the ownership of a top-flight perform-er. But theres so much more to it than that. The DEQX proved to be a superb tool for the correction of the frequency response er-rors and deviations inevitable in all speaker/room interactions.

Sure, you could fit-out your room like a studio with massive and costly bass traps, acoustic foam and diffraction panels and you may approach the response your speak-ers were designed to deliver, but if you DEQX-out your system, youre guaranteed to respect the designers intentwhile pleasing your own sonic tastes via your customised stored correctionsand most likely saving yourself some hard-earned. Not only this butand I reiterateyoud also own a top-flight preamp and DAC combo into the bargain.

Preamp DAC room correction and more. Doesnt it start sounding like that Swiss Army knife again? Brilliant! Edgar Kramer

Preamp DAC room correction and more. Doesnt it start sounding like that Swiss Army knife again? Brilliant!

TEST RESULTS ON PAGE 84

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lab rEPOrT DEQX PrEMaTE DigiTal PrOcESSOr & PrEaMPlifiEr

laboratory tEst rEsultsAustralian Hi-Fi Test Labs looked first at the DEQX PreMATEs ability to correct the frequency response of a loudspeaker, in a room, using a nondescript speaker that is supplied as part of a complete electronics/speaker package by a major loudspeaker manufacturer. The lab first measured the response of the loudspeaker without the DEQX in circuit at all, then again with the DEQX in circuit, but switched to its bypass (P0) mode. The two frequency responses were identical, the only difference being a 3.2ms delay in bypass mode. The two re-sponses are shown as Graph 1, but because they were identical, they appear as only a single (red) trace. After running the DEQX PreMATEs correction software routine (a highly automated process that takes less

than ten minutes), the lab then re-measured the loudspeaker. The result is shown as the black trace in Graph 1.

As you can see, the difference is chalk and cheese. Whereas the frequency re-sponse of the speaker without DEQX was peaky and uneven, and extended from around 60Hz to 20kHz 7.5dB, the after response is incredibly flat, and extends from 45Hz to 20kHz 2.5dB. An incredible result! Note that even the DEQX has not been able to remove all of the speakers faults completely, such as the two response peaks at 5kHz and 7.2kHz, but it has totally ameliorated them. However, the huge peak between 550Hz and 1.6kHz is completely removed, as is the dip between 7.5kHz and 9.5kHz, and also the peak above 10kHz. In removing the peak above 10kHz, it appears the DEQX software has cleverly opted for a gentle roll-off out to 20kHz, rather than try-ing to run flat out to the tweeters practical upper limit at around 17kHz. One reason for this is that in the process of smoothing the test speakers response, theres a loss of efficiency (around 2dB for this correction) which means that in order to get the same

perceived volume level after correc-tion, youd need to apply around 2dB extra amplifier power. (Graph 2 is simply an expanded view of the graph that shows the effect on the high-frequency response in more detail.) The only other difference was an increase in latency up to around 10.2mS.

In addition to the automated correc-tion, the DEQX also allows you to tweak the low-frequency response of your speakers. The effect of this is shown in Graph 3, where the red trace shows the unequalised response of the loudspeaker, and the black trace the response with additional equalisation to flatten and extend the low-frequency response. Again, the difference is chalk and cheese, but the graph also shows you cant make a silk purse out of a sows ear, because the bass driver in the speakers used was simply too small, with insufficient excur-sion to allow bass extension further than around 50Hz. You can see however, that the DEQX allows a substantive improve-ment in bass response.

Distortion of the DEQX is extremely low, in either bypass or correction mode, with the overall THD+N coming in at around 0.0002%. The distortion spectrum in correction mode is shown in Graph 4, and you can see that all individual distortion components except for the third harmonic component (at 100dB, or 0.001%) are more than 110dB down. This is an excellent result. Note also that noise is incredibly low, even at low frequencies, so that the noise floor is virtually sitting at the 140dB limit of the test analyser. The overall wideband signal-to-noise ratio was measured at 101dB A-weighted.

The DEQXs intermodulation perfor-mance was also outstanding, as you can see in Graph 5, where the sidebands are more than 100dB down, and the regenerated 1kHz tone is at 110dB. Also excellent was the analog-analog frequency response, which was measured as extending from 4Hz to 46kHz 1.5dB.

Overall, my impression of the DEQX is that its an amazing instrument. It will improve the sound of any loudspeakers, in any room, without adding any noise or harmonic distortion to the signal in the process, and will do so for both digital and analogue music sources. Steve Holding

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Graph 1. Effect of DEQX calibration on frequency response. Red trace is unequalised response of small two-way loudspeaker. Black trace shows response after DEQX.

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Graph 5. CCIF Distortion (Twin-Tone Intermodulation) @ 1kHz @ 0dB using 19/20kHz in 1:1 ratio.

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Graph 3. Effect of DEQX calibration on frequency response. Red trace is unequalised response of small two-way loudspeaker. Black trace shows response of same loudspeaker after DEQX. Both traces have been smoothed to one-third octave via post-processing.

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Graph 4. THD @ 1kHz @ 1-volt output, using P3 filter settings intended for speaker correction. [DEQX]

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Graph 2. Effect of DEQX calibration on frequency response. Expanded trace showing high-frequency area in more detail. Red trace is unequalised response of small two-way loudspeaker. Black trace shows response of same loudspeaker after DEQX.

An amazing instrument that will improve the sound of any loudspeakers, in any room...

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