CEDAR is no stranger to audio restoration tools. The company isknown for its cutting-edge, PC-based systems and plug-ins forstudio workstations, as well as specialized rackmount units thatoffer near-real-time processing — declicking, decrackling,azimuth correction, etc. — of problematic source material.Now, CEDAR offers the DNS1000, a dynamic noise suppression devicefor cleaning vocal and dialog tracks.
Like other recent CEDAR hardware, the stereo DNS1000 has noanalog I/O, which keeps costs down and lets users choose theirpreferred converters — or simply stay within the digitaldomain. Between the rear panel's XLR AES/EBU and coaxial S/PDIFdigital I/Os are four LEDs that indicate input sample rate (32,44.1, 48 kHz) and whether the XLR or coax input is active. Althoughthese LEDs offer useful indications of status and the presence of astable signal, the rear panel location is inconvenient.
The DNS1000 has a deceptively simple interface — it'sabout the size of a console-top reverb controller — butthere's a lot happening under the hood. The digital I/Os are 24bits wide, and the unit is driven by dual 40-bit, floating-pointDSPs. The DNS1000 works by dividing the input signal into multiplebands. There are six faders on the control panel, but many moreanalysis and processing filters within the unit. A noise“Level Control” acts as a global threshold slider todetermine at what point the noise suppression action kicks in— or stays out — and the processing depends on theinteraction of the level control, the signal content and thealgorithm itself.
Just punch a button or two to select a filter frequency range:Low (20 to 400 Hz); Mid (200 to 6,000 Hz); High (4k to 18k Hz); Lowplus Mid (20 to 6k Hz); Mid plus High (200 to 18k Hz) and Fullrange(10 Hz to 18k Hz). Six “Band Gain” faders (+6/-24 dB)determine the maximum amount of processing in each band, and theircenter points vary, depending on the selected filter range. Forexample, the filters are narrow if the High range only is set andmuch broader when Fullrange is selected.
The remaining controls (Left/Right/Stereo, for applying theprocessing to each of those choices, and Bypass) are much simplerto grok, and all operations become clear within a few minutes.
I began testing the DNS1000 by feeding it an assortment ofdialog tracks with varying degrees of continuous noise problems.The key word here is continuous; the unit is not designedto remove transient noise sources, such as clicks, pops or burps,but steady-state noise problems, such as camera motors, rumble,rain, hiss, air conditioning, distant aircraft or traffic.
On a selection with excessive camera noise, a touch of midbandprocessing attenuated the offensive sound almost completely,turning an unusable take into a clean track. Similar results wereachieved on a vocal track with what sounded like hurricane-levelamounts of wind noise. Here, the DNS1000 did the trick, offeringdeep noise attenuation without destroying the source material. Ofcourse, it's possible to overdo the DNS1000 processing, resultingin a flat, lifeless recording, but the real-time controls makedetermining the right amount of filter action quick and simple.
One track that surprised me was some indoor dialog on which themic placement seemed like it was 10 feet away. The take was boomyand reverberant, with poor intelligibility and way too much roomtone. But, by selecting the Low and Mid filters, setting all thefaders to -24 dB and adjusting the level control, I was able to usethe DNS1000 to process the reverb tails on the end of each word,resulting in a clean track. I've never encountered a product thatcould do this — I'm impressed!
The DNS1000's ultrafast processing has a latency stated as lessthan 10 samples — about a quarter of a millisecond! So, forprocessing sync information (dialog tracks, etc.), latency isn't afactor; there's no need to slip tracks against timecode.
Priced at $5,895, the CEDAR DNS1000 is a fast, effective toolfor dealing with noise problems in dialog tracks. And with today'sskyrocketing production and talent costs, a product that minimizesthe need for pricey ADR sessions is very valuable indeed.
CEDAR Audio USA, 43 Deerfield Road, Portland, ME 04101;207/828-0024; fax 207/773-2422; www.cedaraudio.com.