US Coast Guard Radio Calls

[thdot44]

HI-


I am a communications watchstander with the US Coast Guard. My unit uses Goldwave to record distress radio communications. We never recieved any training on this program so over the last couple of years of 'playing' with it Ive gotten use to it. My question what you you use to best remove static and interference from and audio clip? Or what do you feel would be the best tool on this program to improve the quality of a sound file. I have a basic knowledge of this program but please exlpain to me how you would do it step by step.

Thank you very much for the help.

[DougDbug]

GoldWave has a couple of tools that might help, but first I'll warn you that noise reduction can be difficult, and sometimes it makes things worse... Professionals record in soundproof studios and they use low-noise equipment to prevent noise. Noise reduction works best when you have a constant low-level background noise, such as slight tape-hiss.... In other words, it works best when you don't really need it.

Note - All of GoldWave's effects and filters have a "preview" button so you can experiment before you apply the effect to the entire file. This kind of thing requires lots of trial-and-error.... Well... most audio editing requires lots of listening and trial-and-error.

For this type of noise, your best option is probably a noisegate. A noisegate works by killing all of the sound when the volume falls below a preset threshold. It doesn't affect the sound at all when the volume is above the threshold. It's similar to the squelch control that you might have on your communications-radio. In GoldWave, you can find some noisegate presets under Effect -> Compressor/Expander. (You can start with the presets, and then experiment with different threshold settings.)

GoldWave also has a noise reduction filter that tries to distinguish between the signal and the noise (Effect -> Filter -> Noise Reduction). The best way to use the noise reduction filter is usually to copy a section of noise-only into the clipboard (highlight the noise and click Copy), and then choose the Use Clipboard option. Again, that's a starting-point and you may need to experiment with the settings.

With the noisegate and noise reduction filter, you'll have to compromise between under-doing it, leaving some noise, and over-doing it, removing some "signal." Sometimes "the cure is worse than the disease", and you are better-off leaving it alone.

You can also do some frequency-filtering. You can start by experimenting with the equalizer (Effect -> Filter -> Equalizer). You can just experiment to see if you can reduce the noise and/or improve intelligibility. If you need "stronger" or more precise filtering, GoldWave has a parametric equalizer and a variety of other filters (high-pass, low-pass, band-pass, band-reject). The regular (graphic) equalizer can serve as a starting-point to help you decide what kind of filtering and what frequency range to use.

Good Luck!

[thdot44]

awesome thanks very much for the response.

[Mymilitary]

I just download goldwave and i'm trying to record a song but when I play it back I don't hear anything. How do I get it to record and playback what I just recorded.

MyMilitaryYears - Military communication Service, communication with friends and family, military messages, military news

[DewDude420]

i also want to tell you about the interpolate function.

basically what this does is let you select sample a and sample b and it will "interpolate" what audio should be between these two points.

this is MOSTLY used to fix small one or two sample imperfections in audio...like a pop/click or sometimes even corruption from a mis-read CD. you don't want to do it to more than a few samples because it's far from perfect and will yield bad results if overused.

it's the most common way people remove pops/clicks from vinyl audio..some dig through it manually and others use plugins...the auto pop/click remover in goldwave basically will seek out these pops and clicks and remove them for you.

but i'm going to tell you what i told someone else, you have to keep in mind that the audio is essentially "2-D", the program doesn't really know what's noise and what's not, all it has is a pile of samples that create audio...so if some of the interference and static blasts (say, from either lightning or atmospheric anolomies) sound like they're completely overpowering the underlying audio, then chances are you won't be able to remove it without damaging the intended audio.

basically if you can't hear it through the distortion just leave it.

Note - All of GoldWave's effects and filters have a "preview" button so you can experiment before you apply the effect to the entire file. This kind of thing requires lots of trial-and-error.... Well... most audio editing requires lots of listening and trial-and-error.

so true...i don't think i ever hit the point of not needed trial and error...espically with FFT based effects. [/quote]