Audio file editing software/skills

[Marvin Humphrey]

On Jun 14, 2006, at 7:27 AM, James Mastros wrote:

> On Wed, Jun 14, 2006 at 02:34:17PM +0100, Jess Robinson wrote:
>>
>> Hi folks,
>>
>> I have a piece of self-recorded audio, (of a talk), that I'd like to
>> remove some clicks/crackles from.. Has anyone got any software
>> recommendations or appropriate advice?
>>
>> Jess
>>
>
> After taking a look at a few of the pops in Audacity, they appear  
> to be
> samples randomly changed to -1 or 1 (er, considering the audio as
> floating-point data).  I suspect normal analog filtering procedures  
> won't
> work very well to get rid of it.
>
> Really, the best way is probably to just write it myself.

Meaning, use the pencil tool?  For corrupted individual samples, that  
can be quite effective.

I'm a little confused here -- what's the relationship between Jess  
and James?  James, you seem to have access to the actual file, but I  
haven't seen a link posted.  So presumably there's a private  
connection, right?

> Of course, after that, it's still a muddy recording with lots of  
> background
> noise.

If the noise is constant, Audacity's Noise Removal tool might help  
some.  I haven't used it, but its functionality is plain from the  
interface: it generates an EQ filter based on a section of noise you  
select, dropping frequencies in proportion to their amplitude in the  
sample.  Doesn't work so well for broadband hiss, but it can be handy  
for stuff like 60 cycle hum.

The muddiness you can begin to address with simple EQ.  There are  
some other techniques, but they aren't easily explained and are  
appropriate only for specific cases.

Marvin Humphrey
Rectangular Research
http://www.rectangular.com/