Odd Routing/Math Issue with Xenon

[Daved]

This is more of a “watch your back” notice than useful bug report, as I’ve only noticed it once. Simply put: When I put an instance of PSP Xenon in the last Track effect slot, with no additional plugs in the Master Section, and it’s dither disabled, Xenon limited the signal as set, but the signal stayed at 24 bits! This indicates WL7 was processing the signal at some stage between my last plug (PSP Xenon) and my interface (which was feeding SpectraFoo).

I tried all possible dither settings, and verified via 8 bit that Xenon was in fact working properly and dumping bits - sound turned ugly and grainy at 8, opened back up at 24. Similarly I could tell it’s auto-black worked fine, turning on/off smoothly with signal. WL7, not Xenon, was doing some post-effect math.

To verify I wasn’t going insane, or just being sloppy, I opened an older project with the identical effects routing - it dutifully played back at 16 bits, as expected. I closed that, and created a new project, with the same audio files, and identical effects routing. It too played back 16 bits when dither was engaged. Only this one odd session had the issue. Something in the montage was changing gain or diddling bits post-VST plugs. I think this also verifies the problem isn’t in the master section - if the master section were diddling the signal, all 3 projects would have shown 24 bits.

I was measuring directly from my Metric Halo ULN8 in SpectraFoo, which had no effects or gain changes (and again they’d have shown up on ALL projects, not just one) happening, and is verifiably bit-clean at all depths. I tried restarting/reloading to see if this would clear the problem and it did not.

Attached below are some screen caps that show this in action… First the problem, with routing revealed:

Then simply moving Xenon to Master section with everything else identical, I get 16 bits as expected:

Finally, another project with Xenon only in the track effects - works great:

I would never have caught this, and possibly sent out a truncated master had I blindly trusted WL7 to properly do the math without verifying it’s integrity on every single job via scope. This issue is relatively subtle, and easily missed. So Ludwig’s Dictum applies in spades: Don’t turn your back on WL7! If you must trust, always verify.

[LutzR]

Dave, in your first example you have (maybe by mistake) made some track leveling (indicated by the blue and red colour of the track level faders).
As the track leveling is routed after track fx you have processing after the xenon which explains the 24bits in your bit meter.
Your last example shows that the track level faders are grey which means they are inactive and hence there is no further processing after the limiter.

[PG1]

Well seen Lutz.
Unless you’re an expert, there are always points where WaveLab could process audio (because of yoursettings). This is why dithering should always been done from the last Master Section slot. It’s a guarantee of safety.

[Daved]

Thanks Lutz! That’s it and it explains everything. Since there’s no manual or tutorial, I was unaware that they changed. Good catch!

As you guess that was absolutely an accident - I NEVER touch them intentionally because there didn’t seem to be a way to RESET them easily - no place to type in 0 if you touch them, and when you drag them they snap to strange spots (maybe bit-clean values for multipliers?). In checking this out I discovered command-clicking the track faders returns them to 0. It’s worth noting a good tutorial/manual would have hipped me to the fader-color change AND command-click to reset.

Phillipe - I hear you on this, and understand completely. I appreciate the dedicated “Dither” slot, and indeed have used it for some projects (I also appreciate having that extra gain stage at the track output!).

The problem is I don’t trust that my Master Section is reliably saved with my Montages. Likewise, I often work with 2 or more projects open, and each may have different limiter settings depending on the media target (I treat CDs, downloads and vinyl prep pre-masters differently) - I’m not sure the master section is capable of changing itself a you toggle around those windows. If not it would be very easy to render or deliver projects with the wrong settings.

OTOH if I put the limiter in the last stage of the Tracks, and leave all post-plug faders and slots untouched, everything is always saved perfectly and I can bounce between projects freely. Renders from such montages are always perfect whether or not I bypass the master section.

I suppose I could turn dither off in the limiter, or use TWO instance of the limiter, one in the master for dither, the other on the track for limiting. Seems like a hassle and waste of resources, plus it makes it pretty easy to mistakenly render a file undithered (since the default is to bypass master).

All that said, if there’s were a simple way to lash the master to a montage, and have it intelligently switch itself around as you bounce between projects, I’m happy to learn it. If not, well, bob’s your uncle.

Thanks again guys!

[Daved]

PS: While I am a frequent reporter/complainer, and have issues with Steinberg’s web support platform and lack of docs, I’ve found the people who handle that support, and the program’s creator amazingly helpful, pleasant and responsive. I report in detail to get things fixed, not to really complain (though in frustration I frequently fail).

Most of all, I want to note that since the mac version’s entirely new, and different from the ground up, I’m more impressed than annoyed by any of the issues I mention. The first revision came out relatively quickly and addressed the show stoppers, so we’re essentially running version 1.01. So while there’s good reason for PC users to be frustrated by blocks or changes, it’s hard for this mac user to get too upset. All of the competing mastering daws on the mac are well beyond version 2, and suffer as many or more defects. For a 1.0 launch, things are surprisingly solid.

Sure, I expect it to improve and bugs to be fixed. I still jones for a real manual. But in terms of the application itself, the mac version’s launch has been surprisingly solid. I thank Phillipe for his hard work and vision. And Steinberg support for their patience and help.

-d-