Reviewed by Richard Honeycutt
Virtos is a relatively new software company (founded in 1999) whose two divisions focus on software for digital media production and editing; and Internet, database, and E-commerce applications, respectively. Located in Karlsruhe, Germany, Virtos markets their products worldwide.
THE PRODUCT
The Virtos Noise Wizard is a DirectX compatible set of tools for removing clicks, crackle, hiss, hum, and other types of noise from old recordings. It requires a digital audio editor, such as Cool Edit or Sound Forge, to host its operation.
Noise Wizard consists of five plug-ins:
• The DeClicker/DeCrackler provides the function that some of us old timers remember in the Garrard click and pop machine of the early 1970s.
It removes short-duration impulsive noises such as those caused by vinyl (lacquer, on old 78s) surface imperfections.
• The DeNoiser removes broadband noise such as hiss or hum.
• The Filter Toolbox is a software implemented parametric filter.
• The Stereo Processor produces stereo recordings from mono sources by applying time offsets. It can also function as a vocal eliminator.
• The Band Extrapolator provides Aphex-exciter-like effects, as well as increasing apparent bass, by synthesizing high- or low-frequency harmonics.
OPERATION You can download the software from the Virtos site (see URL at the end of the article) and even run it in demo mode. You really don't want to do this for long, because a repetitive tone burst becomes inserted into whatever file you're working on in order to encourage you to purchase the product and register it. I can affirm that the tone bursts work as intended! In addition to the wave editor, sys tem requirements include a 350MHz or faster computer (but see my comment later) running Win95 or later, 64MB of memory, a hard drive with 2MB free for installation, plus a good bit of space for the operation of the wave editor, and, of course, a stereo sound card.
Installation proceeded without incident, except for some trouble getting the program to accept my registration.
The trouble may have been due to my using an old computer running Win95.
The folks at Virtos e-mailed me a solution which gave me enough info to register the program.
In the operational tests that follow, I used the default settings on each feature. Certainly, you can improve on the functionality of the soft ware by tweaking the parameters of each plug-in. Time considerations limited my knob-twiddling.
DE-CLICKING
The first project I chose was to re store a recording of Dobie Gray's "Drift Away." The LP was one of about a dozen I purchased in the late '70s since I routinely used that track in auditioning new speaker designs. Consequently, the track showed substantial wear, especially at the beginning, because it is the first track on the LP. Figure 1 shows the .wav file of that track as recorded from the LP. The serious pops are clearly visible.
The most convenient computer for me to use for the Noise Wizard evaluation was a 266MHz Win95 computer. The program works just fine on this old clunker, except that the preview function is understandably choppy, due to the slow processor. Thus de clicking the four-minute file took about ten minutes.
Please note that this computer runs about 15% slower than the stated mini mum speed for operating Noise Wizard, so for a computer meeting the mini mum system requirements, the functions would have been performed much more rapidly. Still, the various de noising functions require a good bit of analysis as well as subsequent data manipulation, so even on a fast machine, some time will be needed to complete an operation.
Figure 2 shows the .wav file after de clicking. You can easily see the reduction in pops and clicks by comparing Figs. 1 and 2. The audible difference was likewise impressive. Except for the first few bars of the music, which are also the first few grooves on the LP, click and crackle were gone, without any detectable change in the actual music.
FIGURE 1: Original
.Wav file.
FIGURE 2: .Wav file after de-clicking.
FIGURE 3: The trash that was removed by the de-clicker.
Another way to see the good results is to preview and/or record the residual noise--the stuff that was removed.
Figure 3 shows just how much trash the de-clicking process took out. I think you can imagine the improvement in sound!
DE-NOISING
To check out the de-noiser, I tried each of two files. The first was a lecture recording I had been asked to restore;
the second, a song with voice, guitar, and bass mastered on cassette. The lecture recording had about a 30dB signal to-noise ratio, which the de-noiser improved to about 50dB. However, it also produced a sort of warbling artifact that was more distracting than the noise had been. I think the additional distraction results from an almost-regular warble that draws your attention. Please note: first, this was not really the kind of test for which the software was de signed; and second, the artifact introduced by Cool Edit's de-noiser was considerably worse than that produced by the Virtos software.
The music recording originally had about a 50dB signal-to-noise ratio, and was essentially white noise. The de noiser removed it to inaudibility with no perceptible artifacts. This was a better test of the software, since it reflects the type of noise it was designed to handle. The bottom line is that the de-noiser works well, but you should be aware that some files are too far gone for it to improve, and they will result in the artifact I mentioned.
FILTER TOOLBOX
The filters are easy to use, if you under stand the use of parametric equalizers.
You can do any of the four basic filter types: high-pass, low-pass, bandpass, or notch. In fact, you can produce just about any filter response shape that you can draw. The versatility of this function is limited mainly by your experience in filter manipulation.
STEREO PROCESSOR
I used the stereo processor to synthesize a stereo version of a mono vocal/guitar recording. It provided a very pleasing result, although you must use discretion on which files you choose to process in this way. A folk singer with an 8' wide mouth is a frightening thing to contemplate.
BAND EXTRAPOLATOR
If you want that Aphex-exciter vocal cords-hanging-off-the-tip-of-the-tongue sound (read: female vocalist on pop radio), or if you want PHAT BOTTOM, the band extrapolator will give it to you. Those with taste can adjust the settings for just a bit of added sizzle or fattening at the low end. A very effective tool for specific jobs, if used cor rectly.
THE BOTTOM LINE
The Virtos Noise Wizard is an excellent ly conceived and executed piece of soft ware. It will add significant capabilities to your digital editing palette. If you're in the market for the functions it offers, you should buy it.
Virtos Noise Wizard -- $119 Media Technology Group, Virtos GmbH
Virtos GmbH
Kaiserstrasse 51 D-76131 Karlsruhe Germany
+49-(0)721-384 21-24
info@virtos-audio.com
Manufacturer's response:
We would like to bring forward some issues in regard of the content:
1. The license fee of Virtos Noise Wizard has recently been reduced to $89.25.
2.Virtos Noise Wizard is also available as separate plug-ins, e.g. DeClicker/ DeCrackler $51.75, DeNoiser $51.75.
3. Virtos' postal address has been changed to
Virtos GmbH PO Box 111544 D-76065 Karlsruhe Germany
Best regards,
Carl-Henrik Liljegren, Executive Director, Virtos GmbH
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Also see: OBITUARY -- PETER WALKER, 1916-2003