Topic: Q:Best free VST plugin for removing noise

[mmg_fan]

Hi
I'm a newcomer to the world of audio processing.
Just purchased an Edirol R09HR and would like to do a minimal amount of processing to clean up the audio, and possibly 'sweeten' the sound.
I use primarilly Amadeus Pro on the mac whic supports VST plugins.
There seems to be a HUGE number of options when it comes to plugins, can someone make a few recommednations?

[Brian Skalinder]

What, exactly do you mean by "removing noise" and "sweeten sound"?  The type of noise or sweetening will determine what plugin or function you employ to "clean up the sound" and "sweeten the sound".

Generally speaking, common functions used to enhance the quality of a master recording include:

• high pass filter
• parametric EQ
• compression
• specific sample rate conversion and dither / noise shaping algorithms

As for "removing noise", or more generally "fixing" noise, the types of functions often include:

• clip restoration
• limiting (doesn't really remove it, but can reduce its level significantly, e.g. clapping between songs)
• volume envelope (again, doesn't really remove it, but can reduce its level significantly, e.g. clapping between songs)
• de-click
• de-hum
• waveform re-drawing (with a "pencil"-like tool)

I'm not really sure the intent of your question, so these are just some general functions often used for this type of thing.  I think you'll find some of these functions already exist in the software you use, others are available as free plugins, and the more sophisticated require retail purchase.

And then there are those who take a purist approach to the recording - it is what it is, and they don't want to mess with it.

[mmg_fan]

Thanks Brian
Specifically, I want to remove the audible 'noise floor' present when using these solid state recorders, and also perhaps apply some modest equalization as well as normalize.

Is it best to normalize at the end of the processing chain when normalizing to say 95% peak value?

[Brian Skalinder]

The best way to address the noise floor issue is to minimize it up front by running levels high enough that you're approaching, but not hitting, 0 DBFS (i.e. good levels = lower noise floor).  Are you recording particularly quiet sources that make it difficult to achieve good levels?  Maybe you need a preamp?

As for noise reduction, some WAV editors support capturing a noise profile and then removing the noise profile from other sections of the recording.  Not sure if this will work for you, if your app even has the feature, or if you have a portion of audio that is only noise.  I'm not familiar with any free noise reduction plugins, as I've never really had a need for them.

MIQ responded to my search for a good, free parametric EQ here:  http://taperssection.com/index.php/topic,92354.msg1429578.html#msg1429578

I'm guessing your app already performs normalization and you don't need a plugin for it.  You may want to determine whether your app performs peak normalization or RMS normalization (or gives you an option of selecting which you want to use).  You probably want to use peak normalization, as it finds the highest actual peak, determines the difference between the highest actual peak and your desired peak, and then raises the level of the entire WAV by the same amount.  RMS normalization, on the other hand, sort of acts like compression, which you probably don't want to use.  And yes, I would apply peak normalization at the end of the processing chain, just before sample rate conversion and dither / noise shaping.