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Page 2: Drawmer Masterflow DC2476

Mastering Processor By Paul White
Published October 1999

Effects And Patches

There are three types of patch available to the DC2476: User patches, Factory patches and patches stored on an optional S‑RAM card. There are 50 factory patches, 128 user patch locations and 128 further locations available on the optional card. To simplify patch creation, blocks may copied from any existing patch into the one being edited. Because you're unlikely to be loading and saving patches at the same rate as you might on a standard effects unit or a synth module, there are no dedicated save or load buttons. Instead, patches are handled from within a simple menu accessed via the Patch button. The Adjust knob is used to select the patch for loading, whereupon pressing the knob loads the selected patch. You do, however, have to make sure the cursor is over the Ready‑to‑Load message before trying to load in a patch, otherwise you simply toggle back and forth between the Factory and User bank. Saving patches is equally straightforward, except you get the opportunity to name your patch.

An interesting point here, and one which I feel could be important to a lot of users, is that when a new patch is loaded, the parameter settings within the individual blocks move smoothly to their new values, almost like morphing, so you don't get that glitch or silence that often occurs when new patches are loaded in conventional effects boxes. In theory, this means you could even get away with switching to a new patch during a mix, though of course you'd have to pick your point carefully.

Drawmer DC2476 Masterflow processor.

Using The DC2476

Navigating the DC2476 is straightforward — the control arrangement is fairly intuitive and all the processing blocks are arranged in a linear fashion. Because of the automatic gain management, you can't actually make the device clip, but it's still necessary to pay attention to the gain structure if you want the best results as overworked safety limiters aren't necessarily the kindest way to treat a master! Ideally, the input gain trim should be set up (via the I/P page) so that signal peaks come as close to 0dB DFS as possible but without setting off the limiters, but as there's no permanent display to show you when they are active, you have to check in the Input, DQ, EQ or Output pages to be quite sure. If the main three‑band limiter kicks in, the top red LED of the compression meters will let you know.

When the input gain has been set correctly, the safety limiters will step in if you add too much gain to the signal at any point. If your processing has increased the peak signal level, it must be brought back to normal at the end of the signal chain using the output level controls, otherwise the automatic gain management will jump on it.

If you're always wondering why professional material always sounds more 'produced' than the work you do at home, this box could help you discover the secret.

For typical mastering applications, I found that the subtle approach was best, because as with a good analogue EQ, just half a dB here and there makes a significant subjective difference. I compared some example settings with the excellent Drawmer 1961 tube equaliser and found the sound to be substantially the same, which surprised me. The dynamic equaliser also has a pretty hefty range, but even when I set it to produce less than 1.5dB of low‑end boost to bass sounds exceeding the threshold, then ran the master of my current album of 'lentil music' through it, I was rewarded by a very smooth, deep, expensive bass end. Similarly, you can apply a gentle, wide boost at around 15kHz and really add air to a recording.

One of the intriguing things about a multi‑band processor is the number of places in the signal chain at which you can make tonal changes. Obviously the EQ is going to change things, but altering the relative balance of the three bands in any of the multi‑band blocks also has the capacity to make a huge tonal difference. The Tube Drive stage was also surprising, in that I expected the signal to sound distorted when any significant amount of drive was applied; because of its smooth saturation characteristics, however, and because it is applied in three separate bands, you have to go quite a long way to make things sound rough. Applied moderately, the low band warms up the bass nicely, while the high band acts not unlike a harmonic enhancer. It's also interesting to combine conventional EQ with tube drive to see what can be achieved.

I was fortunate to have the unit available during a difficult Celtic acoustic‑plus‑vocals mastering project that had been recorded in a slightly boxy‑sounding room. Though the musicianship was exemplary and the recording quality was good, the finished mix lacked definition and the vocals were not really standing out properly. I found that careful use of EQ (a little cut at 180Hz plus a broad sheen at 15kHz), a hint of tube drive and an overall 1.1:1 compression transformed what was otherwise a pretty marginal mix into something very nice‑sounding indeed. The vocals took several paces forward, the high end shimmered (in that expensive, 'produced' kind of way) while remaining quite smooth, and I was able to tame the room's boxiness completely, all within minutes. Where small adjustments had to be made between different tracks on the album, the straightforward user interface allowed me to work almost as fast as I would using a conventional analogue processor — and you know how intolerant I am of unfriendly operating systems!

Those unused to mastering may find that using a factory preset as a starting point is easier than starting from a clean slate, though some of these are a little heavy‑handed because they're designed to impress! There are 50 factory patches designed to cover a number of real‑life situations, from music mastering to vocal treatments, and on the whole these are pretty effective once tamed a little. Drawmer's 'bootstrap' compressor control system is a little unusual, but it actually makes a lot of sense as it simplifies setting up the compressors — you're not constantly fiddling with the make‑up gain control level. The expander/gate operates conventionally, albeit in three frequency bands, the result of which is that the gating action is rather less obvious than with a full‑band gate or expander. Of course a lot depends on where you set the crossover frequencies, but I got the best overall results at around 90Hz and 5kHz, which keeps the mid‑band more or less intact.

I have to say that I like the EQ section a lot. It has a very classy, smooth sound and does what you'd expect an esoteric analogue EQ to do.

When compressing complete mixes, many people make the mistake of setting the compressor as they would for vocals or solo instruments, but as a rule, low compression ratios and low thresholds work best. The main three‑band limiter is always available to take care of signal peaks, so you don't need hard compression. To get the maximum loudness from a track without messing up the sound, it's OK to push the signal up against the limiters so as to produce a gain reduction of between 3 and 6dB.

I have to say that I like the EQ section a lot. It has a very classy, smooth sound and does what you'd expect an esoteric analogue EQ to do. Five bands is more than enough for most sensible applications anyway, but combined with the tube stage, the range is enormous.

Conclusions

Other than the lack of sample‑rate conversion, Drawmer haven't missed a trick, though I'd like to see a clearer means of showing when the automatic gain limiters are active and whereabouts in the chain the overload is taking place. The 2476 provides a superb set of relevant, well‑thought‑out mastering tools in a very easy‑to‑use format, and most importantly, it sounds really good. I particularly like having access to both multi‑band and single‑band compression at the same time, and the three‑band stereo width expansion adjustment capability is great news for anybody working on vinyl releases — though this feature has its creative uses in CD mastering too. Even the tube emulation surprised me with its smoothness and musicality, especially when combined with the EQ — it really does add that tube magic in a very controllable way.

And finally, yes, you can use the 2476 to make things sound very, very loud without making them sound over‑processed! If you do your own mastering, there's a lot to commend the Drawmer DC2476, not least that it probably costs no more than buying good software plug‑ins to do the same job. On top of that, the DC2476 is never going to tell you that your processor is already too busy and can't provide any more effects or processing! If you're one of those people who are always wondering why professional material always sounds more 'produced' than the work you do at home, this box could go a long way towards helping you discover the secret. During the period of this review, the 2476 got me out of a couple of 'impossible' mastering situations, so I'm definitely adding one to my rack.

Specifications

  • Dynamic Range (analogue): 112dB unweighted at 48kHz.
  • A‑D Conversion: 24‑bit.
  • Crosstalk: ‑80dB @ 10Hz to 20kHz.
  • THD: <0.008% unweighted.
  • Frequency Response: 7Hz to 20kHz (44.1kHz), 7Hz to 44kHz (96kHz), all ‑1dB.
  • Sample Rates: 32, 44.1, 48, 88.2 and 96kHz.
  • PC card Interface: Type 1 PCMCIA S‑RAM card (up to 256K).
  • Analogue I/O: Balanced XLRs switchable for +7 or 21dB peak levels.
  • Digital I/O: AES‑EBU In/Out (XLR); S/PDIF In/Out (Phono).
  • Word clock: In and Out (BNC).

I/O & Global Functions

Within the Global menu are the sections: Dig I/O, MIDI, Misc and Upgr, the latter of which looks after software upgrades. The operating software of the DC2476 is held in flash memory, so it will be possible for the software to be upgraded via MIDI at some time in the future (from v 1.03 onwards). Dig I/O allows the user to select either the analogue or digital input, though no output selection is available as both analogue and digital outputs are always active. The digital input format may be set to AES‑EBU or S/PDIF, with or without external word clock sync. The analogue inputs may be physically switched between +7 and +21dBu. This may seem strange, but remember that digital equipment cares about peaks, not average levels. These quoted figures are the levels at which the analogue circuitry will clip, not nominal operating levels, and in analogue terms, they correspond with ‑10 and +4dBu. The converters on the analogue inputs always run at 24 bits for maximum resolution. Output bit depths of 24, 20, 18 or 16 bits are available, and the input sample rate at which the A‑D converters operate is selectable beween 32, 44.1, 48, 88.2 and 96kHz. There are four different noise‑shaping curves to choose from when dithering to a lower bit depth.

Auto Gain Management

With any multi‑stage processor that involves the potential to change the signal level so radically, there is the possibility of clipping, so Drawmer have included a kind of electronic watchdog that limits the signal before clipping occurs. This is based on full‑band limiters, quite separate from the main three‑band limiter, and is intended mainly as a safety measure, though it may also be used creatively. As a rule, the user should endeavour to set the signal levels such that the safety limiters rarely if ever operate.

The gain‑management system monitors the input section, the output of the equaliser and the output section, with any gain reduction being registered via on‑screen meters on the relevant pages. I would have preferred a front‑panel warning LED, but in practice I didn't run into any problems when I used the unit in a 'real‑life' mastering situation. The main three‑band limiter causes the top red LED of the output level meters to flash whenever it is operating, and though its threshold is fixed, adjusting the compressor output gain allows the user to decide whether the signal will be limited or not.

Pros

  • Audio processes sound like the best analogue devices, but without the noise.
  • Gratifyingly easy to use.
  • Everything you need to fine‑tune a mix in a single box.
  • 24‑bit/96kHz‑compatible, with noise‑shaped dithering options for bit‑depth reduction.

Cons

  • No sample‑rate converter.

Summary

The Drawmer 2476 is a first‑rate mastering tool combining all the flexibility of digital audio processing with superb sound quality.

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