Audio Tools for Music Educators: Noise Cleaning Audio Enhancements

SBO Staff • May 2010Technology • May 19, 2010

We are all familiar with those dramatic “before and after” weight loss ads. Now just as dramatic results are available to everyday music educators with audio archives and performances we want to share via Internet blogs, podcasts, Web postings, CDs, and DVDs. While the recording industry has traditionally dealt with audio restoration, music educators have not because it was complicated and cost prohibitive. Fortunately, this is no longer the case.

“Audio restoration” is a generalized term for the process of removing imperfections (such as hiss, crackle, noise, and buzz) from sound recordings. It can also enhance the audio quality of the original recording. There are 19 before-and-after recording examples to listen to help illustrate this process for you at A list of recording challenges that new audio restoration software can correct include:

#149; Removing Broadband Noise from a concert recording.
#149; Using EQ and other tools with the spoken word.
#149; Restoring an Historical Speech making voice more intelligible.
#149; Removing clicks and pops from a concert on record.
#149; Cleaning up a phone interview clipping. (You can’t remove clipping, but you can use click/crackle repair to minimize it. At the URL above, check out the WWII recording of a heavily clipped recording that was salvaged.
#149; Removing guitar string squeaks.
#149; Filling an audio gap.
#149; Restoring old recordings removing unwanted noise.
#149; Putting analog tapes or vinyl onto CDs.

Before reviewing the audio restoration software applications, let’s look at some of the audio problems frequently found in recordings.

Hum and Buzz

Hum is usually the result of electrical noise somewhere in recorded signal chain heard as a low frequency tone based between 50Hz or 60Hz. It only takes a few harmonics to create a hum or buzz. Software can suppress some of the harmonics.

Hiss and Broadband Noise

Unlike hum and buzz, broadband noise is spread throughout the frequency spectrum and not concentrated at specific frequencies. Tape hiss and noise ventilation systems are good examples of broadband noise. Addition examples can be heating, ventilation, and air condition systems, as well as DV camera motor or needle hiss.

Clicks and Pops

Clicks and pops are common on recordings made from vinyl and can also be introduced by digital errors, including recording into a DAW with improper buffer settings. Most audio restoration products include both automatic and manual tools for removing clicks and pops.


Clipping is a common problem that occurs when a loud signal distorts on input to a sound card/converter, mixing console, field recorder or other piece of equipment. The result is overload distortion.

Intermittent Noises

Intermittent noises appear infrequently and may not be consistent in pitch or duration. Examples include coughs, sneezes, footsteps, car horns, cell phone rings, et cetera. Because noises like this are often unpredictable, they usually need to be removed manually.


Sometimes a recording may include short sections of missing or corrupted audio. Using information around the gap to fill in the missing information with patterns and advanced re-synthesis is the usual remedy.

Audio Restoration Products

I have found five products that remedy noise and audio problems while enhancing the audio recording by boosting high and low frequencies.

#149; Spin It Again by Acoustica, stand-alone for PC.
#149; Magix Audio Cleaning 15 by Magix, stand-alone for PC.
#149; SoundSoap 2 by BIAS-Inc., both plug-in and stand-alone for Mac and PC..
#149; SoundSoap 2 Pro by BIAS-Inc., for Mac and PC plug-in only.
#149; iZotope RX and RX Advanced by iZotope, for Mac and PC plugin and stand alone.

As noted, some of these are stand-alone products and some are plug-ins that interface seamlessly with audio applications through either VST hosting applications, Audio Units (supported by Apple computers) or RTAS/AudioSuite (Real Time AudioSuite) for ProTools hosts. Popular VST hosting programs include Peak, Audition, Cubase, Digital Performer, GarageBand,Live, ProTools, Premier, and SoundForge. For a complete list of plug-in products, along with a host of other supplemental information related to this article, including links and examples, go online to

A plug-in product lets you can run it seamlessly from inside of your familiar audio editing program using the editing program’s transport button, time-line, in-an-out markers and apply buttons. The advantage of a stand-alone application is that is it doesn’t require a compatible host program.

Primer Intermediate Levels

For PC users who want an easy-to-use product, Spin It Again by Acoustica does a superb job of basic noise reduction for tapes and records. It uses a wizard, which makes it very easy to achieve good results. I like how the product records vinyl LP or cassette to CD, dividing tracks, and also burns CDs. You can also record your LP collection and cassettes to your iPod or another portable MP3 player. There are 16 cleaning tools to get rid of clicks, pops, and crackles.

MAGIX Audio Cleaning Lab 15 Deluxe offers an amazingly clean interface. Simply click “Record” and the integrated recorder records everything that you hear via the sound card. Non-copy-protected audio CDs and MP3 files can be imported without any problems. With a single click, you can eliminate clipping, crackling vinyl, audio disturbances, noise, popping, and humming from any recording. The cleaning wizard automatically analyses the audio material, selects the appropriate effects and goes to work.

Fine tuning is also possible with the equalizer. There are numerous effects for producing a perfect, neutral stereo image. MAGIX Audio Cleaning Lab 15 Deluxe can also optimize the audio on your video recordings and even remove typical basic noise caused by nearly every camcorder. Exporting restored files to various audio file formats is both simple and powerful. The interface works seamlessly with loading files, making recordings, and ripping CDs, all within one application.

Another entry level application that works on both Mac and PC is the iZotope Music Speech Cleaner based on their more powerful RX program. For more details, go to the supplemental Web site previously cited. It doesn’t have the wizard like Spin It Again, but it does have settings specific to speech instead of just music.

SoundSoap by BIAS-Inc. is designed to be very easy to use, for the digital audio novices among us. The interface is set up to allow “one-click” noise reduction on pretty much any kind of unwanted background noise. SoundSoap is optimized for speech, but also works well with music. SoundSoap 2 dramatically reduces tape hiss, buzzing and hum, rumble and most other types of background noise. Just click the one-step “Learn Noise” button, and watch SoundSoap2 automatically clean your audio. This product can also fine-tune with its intuitive controls for even more professional results.

Users will like the Enhance slider, which boosts highs and lows, bringing old recordings back to life. SoundSoap 2 works on both PC and Mac and is a step up from Spin It Again with a few nice features such as: Preserve Voice, which removes anything that is outside of the range of the human voice, and Learn Noise, which finds the “noise” in your recording and removes it. The first few seconds of a recording will usually have silence before the music starts, so this is a good place for SoundSoap 2 to “learn the noise.” If you don’t have a full two seconds of silence, you can use the “Loop” command in a host app, or in the stand-alone edition of SoundSoap, in a shorter section.

SoundSoap 2 will work as a stand alone or as a plug-in within another audio editing program. SoundSoap is the most widely used crossplatform highquality noise reduction tool available in its price range. It is also used by law enforcement agencies for forensics because it is so easy and effective.

Professional Level

SoundSoap 2 Pro exposes dozens of parameters that are preset in the more basic version. For advanced users who understand the different controls, this is the powerful audio restoration/noise reduction tool of choice. SoundSoap 2 Pro is the professional version of SoundSoap 2 and adds a number of features for advanced noise reduction. You can even compare 4 different settings at the same time to make the best selection. It combines four advanced restoration tools: BroadBand, Click Crackle and Hum Rumble, as well as a “Noise Only” setting so users can listen to what the program plans to remove. SoundSoap 2 Pro is particularly efficient in respect to click and crackle removal.
Another powerful audio restoration software products is iZotope RX, which is basically a comprehensive toolbox for cleaning and repairing audio. RX removes hiss, buzz, eliminates clicks and crackles, and repairs distortion and even gaps in audio. It was designed for audio restoration and archiving, recording and mastering, broadcasting and podcasting, video production, and forensics. Key features include a denoiser, Spectral Repair, Declipper, hum removal, declicker, spectogram, and more.

In addition to the usual noise reduction tools, iZotope RX has some very powerful tools such as the “Declipper” which can rescue recordings that were too “hot” and distorted. The “Spectral Repair” can actually fill in drop-outs or remove intermittent noises. Despite advanced features like these, the program is actually fairly easy to use.

Closing Comments

While features themselves may seem important, educators really need to try the products to create an independent evaluation of how a particular product works. Contact manufacturers for a demo version or a 30-day money back option. And for those who are new to audio restoration and digital audio editing I suggest keeping it simple. If not used carefully, these unfamiliar controls and options could conspire to make the audio sound worse!

Dr. John Kuzmich Jr. is a veteran music educator, jazz educator and music technologist with more than 41 years of public school teaching experience. He is a TI:ME-certified training instructor and has a Ph.D. in comprehensive musicianship. As a freelance author, Dr. Kuzmich has more than 400 articles and five textbooks published. As a clinician, Dr. Kuzmich frequently participates in workshops throughout the U.S., Europe, Australia, and South America.
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