No your not. As I said in my first post, the noise reduction in Audacity 1.3.x is usually better, but not always.
I’ve found some clarification on what koz was saying about them both being based on the same code.
In the new Noise Removal in Audacity 1.3.3, there are now two additional sliders to give more control over the removal algorithm - one controlling the smoothness in the time domain via an attack/delay control, and the other controlling smoothness in the frequency domain. If you set both of these to zero, you’ll get something > very similar > to the old noise removal algorithm in Audacity 1.2.x
Similar, but not the same. I’ve not analysed the code (I wouldn’t know how to), but it seems to me that Audacity has fixed (but not zero) values for the smoothness parameters. I generally find that values of 150Hz and an Attack/Decay time of about 0.14 seconds to be about the optimum, though this can vary with different types of audio.
The crucial bit which explains the difficulty of reproducing the 1.2.6 type of effect with 1.3.x:
The main slider controlling the amount of noise reduction works differently now: instead of adjusting the threshold, it adjusts the gain applied to the noisy part of the signal - i.e. the amount by which the noise should be reduced in volume.
So if we want to have the same functionality of the 1.2.6 effect in 1.3.x, we need the “Threshold” slider.
Returning to the issue of my test samples - these are not very realistic test conditions. I deliberately created a sample that Audacity 1.2.6 would handle better, just to illustrate the point. The level of noise in that sample (around -40dB) is much louder than you should ever have in a recording, and if you do have that level of noise, you should go back and record it again.
Although it is not very evident in the listening test, the 1.2.6 noise reduction has done quite a lot of damage to the signal that I was trying to “restore” - particularly to the initial attack of the sound, which if you load the samples into Audacity you can see have been noticeably mangled. On the other hand, although there is still noise present in the 1.3.x version, (and it is quite an annoying “swooshing” sound), the audio signal that I was trying to “restore” is much more intact.
Having done some more experimentation, I have found a workaround that allows similar (in fact better) results using Audacity 1.3.x for this test sample;
The method is to make a duplicate of the “noise”, and amplify it before making the noise profile. This in effect changes the noise threshold value that we would be setting in Audacity 1.2.6
In this sample, I duplicated the “noise” and amplified it by 20dB, then used that for making the noise profile.
I then applied the noise reduction to the original sample with the following settings:
Noise reduction: 32 dB
This was sufficient to make the white noise virtually inaudible, but as low as possible to avoid damaging the original too much.
Frequency smoothing: 120 Hz
This was sufficient to prevent the resulting sound from “wobbling”, or gaining a hollow metallic sound. Raising this level too high would again start to damage the sound that want to keep, making it sound muffled.
Attack/Decay: 0.35 seconds (quite a lot higher than I usually use it, but necessary because the noise level is so high)
Setting this too low tended to clip off the natural decay of the note. Setting it too high and we get that “swooshing” sound as the noise fades in and out.
The result can be heard here: http://easyspacepro.com/audacity/examples/noise_removal/noise-removal-better-136.wav
I think that you will agree that this is better than either of the previous attempts.
The upshot of all this, is that it would be good to have the threshold slider back, but in addition to the refinements that we currently have in 1.3.x
If the developers think that this makes the effect too complicated, perhaps with the categorisation of the effects menu, there could be two versions, a simple, and an advanced interface.
This seems to have developed into a “feature request”, so I’m moving it to that section of the forum.
What do you think?