How to end the snap, crackle and pop

PCs can put the power of an audio production system on your desktop. And for the average listener, there's no better illustration of that power than cleaning up pops, clicks and other electronic noise from analog sources, be they tape or record.

The process isn't perfect, and the results vary with the program you use and the skill with which you use it. Still, I've been astonished at how well I've succeeded in turning noisy LPs into MP3s of reasonable quality. The results are not quite up to the standards of today's CDs, but they're certainly better than the typical poorly done cassette tapes. In fact, in many cases, you may be able to make an old album sound better than the original by removing the tape hiss that's embedded in some recordings.

Last time we walked you through the equipment and procedures to follow to record music from analog sources. Now we'll look at software that cleans up the sound.

If you're not sure you want to get into this cumbersome process, the program I'd recommend that you try first is a nifty little $50 piece of shareware by Badgerbytes. You can download it from the company's home page at http://www3.bc.sympatico.ca/badgerbytes/groove/. Be sure to get version 2.3; there are a lot of earlier releases still floating around the Net.

It's the only de-noising program I've found that you can try, in its fully functional form, before you buy it. Although you still have to register your copy, others typically limit the functions of their trial copies to a few minutes of recording.

Groove Mechanic, first off, can function as a player and recording program, and take sound in directly from your turntable. It isn't the best tool for this purpose -- you may want to use the recorder that came with your sound card, but if you're just experimenting, it is light years ahead of the Windows sound editor and makes it simple to work on an entire album side at once.

You use two files with Groove Mechanic: You're prompted, when you start, to create an input file (the dirty one) and an output file (the clean one). At that point, you select the ''Analyze Clicks and Rumble'' option, and the program reads through the file.

It looks for clicks, sections where there is a sudden increase in high frequencies for a short period of time. It also analyses rumble, those low-frequency tones usually caused by your turntable. This can take 10 minutes or more, depending on the speed of your computer and the amount of noise in the album.

The next step: Remove the noise. The three filters that you can apply are click, rumble and hiss. The filters, in turn, have three settings: high, medium and low.

This is where things get tricky. The more noise you remove, the more music you will remove.

You'll have to listen to the output file carefully to see if you've gone too far. Most of the time, the medium setting works fine.

At that point, your computer will sit and stew; this is one of those increasingly rare instances where a faster computer means meaningfully faster performance. Groove Mechanic took more than an hour to process one side of a dirty album on my Midwest Micro PC, which has a 333 megahertz AMD K-6 2 processor. You will definitely get better performance on Pentium and Celeron systems, because both outshine the AMD in math-intensive operations.

This painfully slow performance means you should test a few minutes of each side before processing. In one instance, a high setting for noise removal simply destroyed the recording; conversely, on another album, the effects of low settings were barely noticeable.

Once you've cleaned up the file, Groove Mechanic has a nifty feature that simplifies converting individual tracks into individual files: You point and click to insert markers at the silences and number the track. At that point, another menu item lets you extract the track to a file, all set to be read in by your MP3 ripper. With many programs, this would require a manual cut-and-paste operation.

More expensive programs work in a similar fashion, but have the edge in speed and flexibility.

You're also more likely to get a good result without tweaking the various parameters and rerecording. Considered the industry standard is DART Pro 98, at $399 (see www.dartech.com), used not just to clean up records, but also for more esoteric material, such as wiretaps.

Also getting high marks is the Soundforge digital editor (www.soundforge.com) that comes with most Soundblaster Cards, which can be upgraded, for $399, with a noise removing plug-in. A unique feature, the company claims, helps compensate for ''clipping'' that occurs when your source material is poorly recorded.

I had a chance to work with a relative newcomer in high-end noise reduction, Sound Laundry ($249), from the German company Algorithmix (www.algorithmix.com). Advertised as the fastest noise reduction program available, it blasted through my dirtiest album sides in less than 30 minutes. The resulting output sounded a tad better than Groove Mechanic, too.

Noise removal software is evolving rapidly from a professional to a consumer product. Bear in mind that as few as five years ago, it cost thousands of dollars for specialized hardware that was the only way to clean up dirty recordings. In that context, $400 for a program isn't much.

Still, prices are falling on this type of software, as manufacturers adapt their wares to home computer users. DART, for example, has two less powerful versions of its software, one for $150, the other, just $50. Algorythmix, meanwhile, has its own consumer-grade $150 version.

The $50 DART product, CD-recorder 3.0 plus, is a pretty good indication of where this type of software is headed. It uses the same noise-reduction code as DART's more expensive products, it just doesn't give you as many options for adjusting it, and there's no graphical display like Groove Mechanic.

What it does do, however, is auto-detect silences in an album side, and split the side into individual files for each track. Once you've cleaned up the album, assuming you have a CD-R, you can burn it directly to CD, in effect handling automating the entire process of turning a record into a CD.

The highly regarded Adaptec Easy CD Creator Deluxe, also $50, takes a similar approach and also throws in useful functions like a disk label creator.

Distributed by the Los Angeles Times-Washington Post News Service