Stereo Tool

Hm, I'm not sure if I understand you correctly.

Basically, before clipping, I need to reduce the bass level (by clipping the bass) to make sure it doesn't punch holes in the mid/highs.

This is done as the last step before the actual clipper.

How far the bass needs to be clipped depends on the type and volume of non-bass frequencies:
- Single symmetrical tone: Doesn't matter much, will remain clean
- Asymmetrical tone: Bass needs to be lowered a lot; lots of artifacts can occur
- Hiss: Normally, lowering the bass to -1 or -2 dB suffices. In some cases (loud highs, loud lows, few mids) it may not - but then the new filter that I created should kick in.



BTW: I'm now restoring the protections from BETA091, it seems I don't really need all of them, but there are very many steps in it that reduce the bass level - usually without adding too many harmonics ('wood' sound as someone described it). The new filter that I wrote that protects highs against distorting might help to increase the bass level a bit. But at the moment it also causes some artifacts that I need to get rid of.

That's a static threshold bass clipper, actually. It clips what is coming from the 2 bass bands, and (in an HD core) sent to band 1 of the 2 band auto-summing final limiter. Only the L/R Clipper in the current BBP has an adaptive bass clipper for protection, and it's a neat innovative idea behind the control signal, but crude at best and it had some problems. Listen to the bass on "Madonna - Love Profusion" with New York preset, and tell me if that's what you're talking about. Leif's latest clipper has protection for bass and treble waveforms, but is implemented psycho-acoustically, so it shouldn't be audible in a bad way at "sane" settings.

=)

Are you sure? We've fed the same processed audio through the Stereo Tool and Omnia 9 clipper (including protection steps; in case of Stereo Tool it's the BETA093 version which is very simple) - the output is nearly identical (Stereo Tool had slightly less distortion in the treble, but the bass was dropping slightly more at the sound where the distortion was the worst). And here identical means bad: Some S sounds on top of loud bass were quite bad.

That's why I made the changes that led to BETA095, where that issue was solved almost completely (this time without dropping the bass, and only reducing the highs very slightly, less than 1 dB). Unfortunately BETA095 has some other issues which can make it sound really bad depending on what you feed it.

The only thing dynamic in BETA095 is that I increased the bass level if there were no or very little highs present at all.

BETA096:
Warning: Not indended for broadcasting!
There was a huge bug in BETA095 which caused things to sound pretty horrible.
I've re-enabled the clipping protection from BETA091 using default settings, besides the new (now fixed) one. You can turn on either or even both.

I'm not really sure yet which one is better: For very loud input the new protection works less well, but for not too loud input it retains punch better. And it even protects the highs if the bass clipping level is set to 100% (-0 dB)!

Note: In the new protection, the mid frequencies are still not protected - voice vibration protection is turned OFF!

Winamp DSP plugin: http://www.stereotool.com/download/dsp_ ... 20-096.exe
Stand alone version: http://www.stereotool.com/download/ster ... 20-096.exe
VST version: http://www.stereotool.com/download/vst_ ... 20-096.dll
VST version (No SSE2): http://www.stereotool.com/download/vst_ ... 20-096.dll
Command line version: http://www.stereotool.com/download/ster ... 20-096.exe
Linux command line version: http://www.stereotool.com/download/ster ... ETA620-096 NOT AVAILABLE
Linux GUI version: http://www.stereotool.com/download/ster ... ETA620-096 NOT AVAILABLE

Hans, you have protection working at 0-200Hz right ? can you make that adjustable?

Yeah, will look into it tomorrow (I have to change several things to make sure there are no drops in some frequencies). How's the audio now?

Can't test it ..my Graphic card died this morning

First things first - not sure if it's just me - but default settings for clipper at 0 sounds better than beta 89 clipper set at +10.
The other thing - all this while I had set the de-esser to 348240 (87060*4) to get max possible highs. Current default settings in beta 96 for the same filter proves that I am not insane!

So far I have liked the sound of this beta since beta 89.
Definitely I am not feeding super-compressed content and expecting hyper-compressed output. I am talking content with wide dynamic ranges.

Annexe: Beta96 is excellent. beta89 R.I.P!
On a side note, clipping for punched bass(Halo- Beyonce, Timbaland etc) needs to be better. Otherwise sound is very clean, transparent. Currently loudness set to 2.2.

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Hi Phoenix,

Just for my understanding:
By default settings, do you mean using the new clipping protection ('Advanced Bass Distortion Protection') enabled and the old one ('Old-style protections') disabled?

Did You try to change the supply electrolytic capacitors of the Graphic card ?
Or the chipset is out of the game. If current shock was presented ?