SpecWeb 2.3 Beta 3

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zeerround

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Changes since Beta 1

Further improvements in artifact reduction (It sounds better). Tighter Drums, crisper snares, etc.

  • Transient detection / threshold is now in dB/ms with a 0.5 dB/ms default.
  • Upsample ratio now defaults to 4x
  • FFT size reduced to 8192

One download for both modern and older (Pre AVX instructions set) computers:

Edit: 12-19-2021 - Replaced with 2.3b4

  1. Download
  2. Unzip to a folder
  3. Click into install folder, for modern computers
  4. Click into "No AVX" folder for older computers
  5. Double click on Install_SpecWeb.bat
Can co-exist with other versions of SpecWeb.
 
Last edited:
So the last month or so were spent in deep research and experimentation into (Pre Machine Learning) transient detection, and a whole new upmix method for 7.1 and higher (immersive) channels. More on that in another thread, but I took the learnings on transient detection and the causes of audio artifacts in STFT to update SpecWeb 2.3 to Beta 3.

It turns out that part of the struggle with identifying a default value for transient detection (2.3 Beta 1) was because it needed to be measured on a dB, vs. linear, scale (DUH!). So now in this beta we are using Db/ms as a measure of spectral signal slope, to detect and separately process "transients" like drum hits.

As discussed in Beta 1, my ArcTan upmix method doesn't like drum hits. It "smears" the sound between multiple channels during the drum hit, so detecting those and processing them with a different method is one part of reducing drum artifacts.

Another is making the amount of time, represented by a spectral bin/frame, as short as possible. Given various trade offs in performance and other STFT parameters/effects, this beta further improves Drum sounds by changing the default upsample ratio from 2x to 4x. That makes the spectral bin/frame half as long time wise. The FFT size default was dropped from 16384 to 8192 to keep the performance in line with earlier versions, while not sacrificing any audible quality (early versions of SpecWeb and Spec also used an FFT size of 8192).

Of course all of these parameters are end user tweakable, on the command line or via the ini file, Should you have your own favorites or trade offs between processing speed and output quality.

Cheers,
Z
 
Heads up. After listening to more of my test regression tracks, I want to adjust the default Transient Threshold setting from 0.5 to 1.0 dB/ms:

In \Install\bin\SpecWeb.ini

;Starting with SpecWeb 2.3, arctan processes any "transient" sounds via slice, to eliminate artifacts​
;such as "swishy" drums/cymbals, etc.​
;The threshold to determine what is transient is set with the below transientthreshold value.​
;This is the slope of the sound change in volume at a given frequency and instant in time, so smaller values​
;will cause more of the sound to be treated as transient (fewer artifacts) and a larger value will cause less of the sound​
;to be treated as transient (more separation). The default value is 0.5 dB/ms​
transientthreshold=1.0
;​

That restores the front to back channel volumes to previous SpecWeb levels, while still having good sounding snare drums, etc.

So you can make that same change to your copy with a text editor. I will update the download and post, after further listening tests.

Cheers,
Z
 
In very critical listening I'm hearing some things (in this beta) I don't like and need to dig deeper. Sorry!:oops::(

Ultimately good things (and downstream bug fixes) should result, however.
 
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