Stereo Tool

I have very specific settings in clipper, especially in deleyed clipping all that mean that i need to listen zillion tracks and check all settings again. Even without any listening i kinda guessed that. Clipper already had distortions from bass (depending on loudness level and other related settings), now when bass pass through more, it's obvious what can happen.

It's only clipper that literaly does not clip bass at final stage(s) rather somewhere erlier as a separate thing, it still has detection hole around 300-500Hz, (need to check that exactly) those are much bigger problems.

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control point
control point2

There are definitely more issues, but the most important one was that it was doing way too much, which was killing the bass. There are people who ran the clipper with ABDP disabled because they preferred the distortion over the loss in bass. That should be fixed now, but indeed, there are other things wrong that I need to look into at some point.

Are you saying that you hear more distortion now, without changing those settings? As I just wrote, I was surprised by how much effect that delayed clipping bug fix has, I didn't really expect any effect. So things may indeed be different now. I'll look at it in more detail tomorrow; I changed a few things because I noticed several issues, and maybe I can make it behave closer to how it was, just without the bug. Having said that, due to that bug there wasn't any type of control that really made sense when delayed clipping was used. I'm not 100% sure yet if the current control is what we want either.

I am just installing b18 and do quick check and more tomorrow, so didnt even listen it, kinda scared.
And that thing "without abdp" yes, that is true, only because bass clipper does not clip like it should. So it's really possible to have both. Look what bass do without abdp, abdp should do same (or sligtly better aka more soft clip) just ~2dB lower + delay clip = win.

bug: just hovering over soundcard buffer switches to that window.

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control point
control point2

Clipper update: I have done some tests with music with vocals with extremely loud bass, and compared the output side-by-side.

The highs aren't really impacted by any of the 3 changes. But the vocals are, surprisingly.

The "delayed clipping" fix doesn't appear to have much impact on the vocals; it only really affects the punchy bass sounds. The threshold changes however do. The effect that they had previously is probably by accident, the small (but not THAT small due to pre-emphasis) amount of highs is still pushing the bass down a bit, which ended up unintentionally protecting the vocals against intermodulation distortion.

The effect is of course bigger if the bass level going into the clipper are higher; at "sane" bass levels it's probably not very noticeable. And these changes might allow you to lower the bass levels going into the clipper, because they survive the clipper better. But it does makes things a bit more difficult than just "change these levels and everything is good".

Highs are sensitive to bass up to about 200 Hz, which is why the bass filters operate up to that frequency. The mids aren't that sensitive, so one possible option is to add a separate protection filter that protects vocals against very low bass frequencies. A purposely made filter instead of something that accidentally happens to works is probably better anyway. That actually exists, "Reduce bass for mids", but it doesn't appear to do anything... For now, I would suggest using somewhat lower values than what I suggested before, maybe 2.5% instead of 5%.

BETA019 is available. Some important notes about the clipper.

In BETA018 and in BETA019 we have made some changes that can have a large impact on the audio. By default, if you load BETA019, you'll get the same behavior as before BETA018. But a number of settings have been added allow much finer control over bass vs other sounds. Read the posts above for the threshold settings. Here are the changes specific for BETA019:

• One of the changes in BETA018, the delayed bass clipper behavior under Bass intermodulation distortion protection was changed. That change turns out to have much more effect than I expected, so I had to add a legacy mode setting, which is turned on by default.
  So if you want to have the new behavior from BETA018 (and you do), go to Bass intermodulation distortion protection -> Bass -> Delayed bass clipper settings popup -> open advanced settings -> Legacy mode. (Yes, it's hidden way too deep, we'll change that in future builds.)
• The new mids protection can be found under Bass intermodulation distortion protection -> Mids. Aside from reducing distortion in the mids, when extreme levels of bass were present (see my test setup below) that actually made everything sound really "thin", with more (but not too much) mids protection the sound became much fuller and nicer. But if you set it too high, the bass will disappear. I have found some settings that seem to be a good compromise between protection and bass, but I won't mention those yet. Please let me know which values you find.
• I've noticed that setting the protection for the highs higher, which has far less impact now than it did before due to the threshold that was added in BETA018, makes the highs much nicer: Cleaner, brighter, far less muffled as is common on FM. But of course at some point the original problems with the bass will return, so I'm curious what people find to be good numbers here as well. I also won't mention the value where I ended up at yet.

There are all kinds of strategies to find good values, here's what I did: I used a standard preset but boosted multiband band 1 by 6 dB. That causes a lot of IMD, and that allowed me to find values that nearly completely fix that IMD. Then I reduced MB band 1 back to its default setting, and with that I checked the effect on bass levels.

Bug in beta 019
Last row on Multiband Compressors isn't visible in Standalone 64.

Oh. Actually it is, but the frequency displays use more space than the sliders, so they aren't aligned properly. We'll look into it. Probably a remainder of the issue where all the sliders were too high until a few beta's ago.

BETA020 is posted.

@Wunjo: This GUI issue is fixed, but it will be in the next beta.

BETA021 is posted!

More clipper improvements:

• There's a new setting, "Ignore bass that affects total IMD less than". We now measure which exact bass frequencies are the cause of any IMD, and ignore others. This affects the bass protection, both for mids and highs (I had to put the slider somewhere, it's under "Bass" now; we might be able to find a good value and remove this setting completely in the end).
  
  While the effect depends on the type of bass, what we typically see if that bass frequencies between about 100 and 200 Hz are typically almost never reduced, because the lower bass is usually what causes any IMD. So the mid-bass comes out louder, making the sound warmer and punchier. With mids protection around 300%, the effect is very noticeable.
  
  The range of this slider goes from 0% (the old behavior) to 50%. At that setting, any bass frequency that has more than 6 dB less impact on IMD than the main cause is ignored. From the first tests it appears that 50% actually still works very well, let us know if you find otherwise.
• The behavior for "Highs Priority" is slightly changed. The intention of "Highs priority" is to reduce the bass when needed, but as it turns out it was also reducing the mids, slightly. This behavior has been changed; it seems to have very little impact on the highs, but the mids are more stable. At this point there's no "legacy" mode for this, but some presets have momentarily up to 0.5 dB (possibly more) mids than before, so maybe we need to add that. But it's probably always an improvement.

As a result of these settings, the bass and mids are punchier and louder, without adding extra distortion (as far as we've seen until now). It might also make it possible to set the mids and highs protection strengths higher than before, but I have not yet had time to check that.


The next step will be to check if we can give Highs Protection a similar filter to make it only reduce the bass frequencies that cause issues.

NO @hvz, it's under "Mids Protection".
Sounds good (50%)