I’ve started working with SpectraLayers 6 Pro some months ago and now upgraded to SL7 Pro. It’s a great tool for mixing, editing and restoration, with a very nice visual feedback of what you are doing.
While working with SL6, I encountered a strange problem, though. I often have to delete some parts of the spectrum (basically to high-pass or low-pass), and when I use the “Delete” function for this, there remains some clicks (or some other kind of artifact), especially when editing lower frequency areas. I’m pretty sure, that I encountered this problem also with other processes like Noise Reduction and Gain, and also with some transformations. I had some hopes, that these problems would have been solved in SL7, but they still occur.
I did some testings for this and found that these clicks occur periodically. It seems the setting for “Resolution” in the Display panel is responsible for the time between the clicks - the higher the resolution, the shorter the time between the clicks. The setting for “FFT Size” seems to affect the “width” of the click - the lower the FFT Size, the thinner the click (and so, more shifted into higher frequencies). I did not test any possible influence of “Refinement”, “FFT Window”, “Min./Max. Amplitude”, “Brightness Curve” or other settings, nor did I test any different sample rates other than 44100 Hz and 48000 Hz.
Attached is an image showing 1 source and 5 edited examples with different settings for Resolution (X1 to X4), each high-passed from 4 kHz to 20 kHz via “Delete” or “Silence”, with a FFT Size of 1024. You can clearly see the spikes in the waveform and in the spectrum. Interesting fact: If I use the Process > Generate > Silence function instead of just deleting the selected spectral areas, there are no clicks, the audio is clean.
These clicks are mostly not audible in the final mix, as they are overlayed by other low frequencies, but they are audible during more silent passages, or when there are not enough other low frequencies. Some extra work ist required to fix this.
Maybe this problem is already known to the devs. Either way, it would be great if this can be fixed. If not, an explanation would be interesting.