Kent,
First thing to do if you are going to try filtering is to save a copy
of your original recording, and only play around with filtering on a
COPY. For archiving, always save a copy of the ORIGINAL.
I am on a Mac and my next step would be to check the recording in the
live display window of apEQ from apulSoft - (now changed its name
from apEQ to apQualizr, about $80 US and a 3.2 MB download.
compatible with both Mac & Windows). If you have a hum in your
recording you can see exactly where the drones occur and you can
easily create your own series of notch filters. Or if there is
aircraft or traffic drone or whatever you can create a wider filter
from a range of filter types. You can see the effect the filter is
having on the visual display, as well as hear it with your ears.
Then after I have removed anything obvious in the way of hums or
noise, if the audio clip still needs some help, I would then use
Izotope RX which as Andrew has pointed out is a great program for
broadband noise reduction, plus the spectral repair function can
remove intermittent noise like the slam of a car door.
HOWEVER, unfiltered recordings are always best!!! You do need to be
very careful to avoid a 'filtered' sound in a recording, sometimes it
is preferable to keep the noise of passing traffic, and avoid the
dreaded artificial warbling sounds that you can get from broadband
filtering. I would much rather hear an unfiltered recording than a
poorly filtered one.
cheers,
Vicki
On 05/05/2011, at 5:02 AM, ndbdxr wrote:
> Thanks, Kent.
>
> Well, I checked all my small notebooks. As I said, it's not much -
> But, it's all I was ever able to find (after MANY Web searches, etc.).
> For Wildlife Sound recording enhancement, the recommendations I
> read were to use the following filters. As for the others, I've
> tried them, with mixed results. I've found that only 1 or 2 of
> these filters can be applied. More than that, and you lose most of
> your recording (you'll hardly hear anything). 80% of my recordings
> are ultrasonic - Of bats & insects; so I don't use these
> suggestions very much.
> Perhaps someone else on this Group, will be able to add some
> suggestions, etc., on the use of these Filters.
> In chronological order (for the most part):
>
> 50Hz Comb Filter - Now, I've even tried to find an audio editing
> program that offers a "Comb" Filter but, was unsuccessful, so...??
>
> 550Hz High Pass Filter -
>
> 2550Hz High Pass Filter -
>
> 150Hz High Pass Filter -
>
> 200Hz Low Pass Filter ?
>
> 300Hz Low Pass Filter -
>
> OK, I also just looked through my large notebook, and didn't find
> anything else. So, that's it. Very sparse info!
> But, again, I have a feeling that other Members here may be able to
> help us! : )
>
> Cheers,
> -Al
>
> --- In Kenton Brede <>
> wrote:
>>
>> On Wed, May 4, 2011 at 2:39 AM, ndbdxr <> wrote:
>>
>>>
>>>
>>> Dear Andrew,
>>>
>>> This is very interesting - I look forward to looking into these
>>> techniques.
>>> Especially since I've gone through the exact same process as Dan,
>>> the
>>> original poster: Looking all over the place, basically.
>>> I was only able to find very little info, re: good standard
>>> practices, when
>>> trying to clean up nature sound recordings.
>>> In fact, I will check one of my notebooks, and transcribe what
>>> little info
>>> I was able to glean. I will also try to post my sources (I
>>> believe I found
>>> the info on a Wildlife Sound Recording Society site).
>>> On my next post...
>>>
>> Al,
>> I'm looking forward to seeing your notes, they would be much
>> appreciated.
>> :)
>> Thanks,
>>
>> --
>>
>> Kent Brede
>> http://sandhillsnaps.com/
>> http://aphotoaday.sandhillsnaps.org/
>>
>>
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