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Subject:SpectraLayers for noise reduction=amazing!
Posted by: Doug_Marshall
Date:11/17/2013 11:54:27 PM

I record in pipe organ chambers. The enemy: motor noise and air leaks. Reducing that noise is essential, but what if you could eliminate it instead? With SpectraLayers, much of the time you can. Here, for example, is a high-pitched tone before noise extraction. The noise floor peaks as high as -8.5 dB:

https://dl.dropboxusercontent.com/u/3729273/Before%20SL.wav

The same file run through Spectralayers noise extraction process:

https://dl.dropboxusercontent.com/u/3729273/After%20SL.wav

The procedure itself could use streamlining - the required steps were not intuitive for me to learn, and I find them more time-consuming than I believe should be necessary* - yet, the RESULTS are amazing.

Here is what I did:

1. Select by frequency (shortcut F) everything below the fundamental frequency of the note, making sure the main layer is selected (highlighted red). Cut it (ctrl-x). This approach changes the original file. Alternatively, you can create a new layer and do a copy/paste and phase inversion instead (which is non-destructive) - but that is more steps.

2. Create a new layer (ctrl-shift-N), invert its phase and make sure it is selected (highlighted red) and stays that way.

3. Make a selection by time (shortcut T) in a clear area that has the noise you want to eliminate.

4. Select the extract noise tool in the tool bar on the left.

5. Adjust the properties across the top to adjust the frequency and time characteristics of the "paintbrush" you will use. In this case I selected a frequency range of 2.5 kHz, a time of 4.0 seconds, and a hardness of 100%.

6. Click the Register Noise button (it turns red) and start painting the entire area of your time selection. You may need to turn up the Level Multiplier slider at the top of the window (the middle one of the three sliders) in order to see your "painting" clearly. As you paint, the selection turns bluish. Be thorough.

7. When that's done, press the S key and click anywhere in the data window to deselect your freshly painted selection.

8. Now, reselect the Extract/Noise tool. Also check to be sure that the new layer you created on the right is still highlighted red. If not, select it again.

9. Click on the Register Noise button (which should still be highlighted red) to deselect it.

10. Return to the data window, drag your mouse around and watch everything turn bluish. When you let go of the mouse button, the blue areas will turn gold, indicating successful extraction of the noise.

11. When you're done painting all of the data, click in the layers area to deselect all the layers (they turn green).

12. Listen to your work. In this file, the results are particularly dramatic in the right channel. I brought the right channel up in volume considerably and the noise is still essentially gone.

*A lot of time could be saved if Sony would give us some "select all" commands. They really should get busy on that. Nevertheless, it goes faster as you become familiar with the process.

I hope this is helpful to someone.

Doug

Subject:RE: SpectraLayers for noise reduction=amazing!
Reply by: ChristoC
Date:11/18/2013 1:15:17 AM

Hey Doug thanks for taking the time to post story about your success :-) - yes the results are amazing; I use SL often for solving little problems and now clients are coming to expect that "magic" really exists!
Hopefully the developers of SL are listening.....

Subject:RE: SpectraLayers for noise reduction=amazing!
Reply by: ChristoC
Date:11/19/2013 10:28:25 PM

Doug, if using SLP2, you can do above more easily:

instead of Step 8, 9 & 10 above, just goto Process Menu and select Extract > Noise

now goto Step 11

Job done! Hope that helps...


Message last edited on11/19/2013 10:31:41 PM byChristoC.
Subject:RE: SpectraLayers for noise reduction=amazing!
Reply by: Doug_Marshall
Date:11/20/2013 5:23:58 PM

Go ChristoC!

Thanks for that! Now if we can just come up with a way to quickly select all the material in the selected area for steps 6 and 7 instead of having to "paint" it, we'll really be talking! :-)

Correct me if I'm wrong, but I don't think I saw that Process/Extract/Noise in the training videos...

Doug

Subject:RE: SpectraLayers for noise reduction=amazing!
Reply by: ChristoC
Date:11/20/2013 6:12:36 PM

Never seen the training videos; the Process Menu / Extract > Noise thingy is new in V2, and well documented in the Help pages - look for Extracting Spectral Data | Extracting Noise page and scroll down to "Extract noise for a layer" .... seems to be a bit simpler that way as I found you don't need to 'paint' so much when Registering Noise.


Message last edited on11/20/2013 6:51:43 PM byChristoC.
Subject:RE: SpectraLayers for noise reduction=amazing!
Reply by: Doug_Marshall
Date:11/20/2013 10:21:36 PM

Yes! Painting's bad - at least when you want to apply the noise reduction to everything. Glad they added that to v. 2.

Subject:RE: SpectraLayers for noise reduction=amazing!
Reply by: Bone Studio
Date:11/29/2013 8:53:09 PM

There's two ways of selecting without painting
1. Click at the start of what you want to remove,hold the Shift key and click at the end (it will draw a line of selection between those two points) good for selecting pop's from vinyl transferes
2. after setting the register noise go to the top bar process/extract/noise it will select all from the file .

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