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Volume and Expression
Last post Mon, Aug 30 2021 by Helmholtz, 67 replies.
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Posted on Thu, Aug 26 2021 16:51
by Macker
Joined on Tue, Aug 21 2018, London, Posts 382

The vast majority of members here I'm sure don't need reminding of the differences between gain, attenuation and level, when dealing with audio; nor how these things have usually been dealt with for many many decades.

To confuse these things would be like, when dealing with money for a purchase, confusing added tax or discount deduction with the total amount to be paid. Pretty basic stuff, uh? lolol.

But ah well, there's always a few. I guess it's just another of the hazards these days when so many depend on Googling to cover for lack of basic knowledge, understanding, experience and skill in this or that field of interest.

Posted on Fri, Aug 27 2021 07:54
by Helmholtz
Joined on Fri, Aug 27 2021, London UK, Posts 15

Greetings to all,

I'm new to VSL, but been using other virtual instrument libraries for quite a few years, so not a complete noob. Having just bought several of the superb Vienna Synchron libraries, I've been learning to drive the excellent Vienna Synchron Player. Among other queries, I was wondering how most people here use the two sliders called Master Volume and Expression so I came to this forum to read up on the topic. Unfortunately I've found some confusing information here about how these sliders are supposed to work. If I may, I'd like to ask for help here so I can get a clear understanding. Specifically, I'm wondering how others get around the problem of not having any direct means of seeing gain changes as relative dB, and how to reconcile some of the advice given in this thread with results I'm getting from simple test runs with the Vienna Synchron Player.

 

My test-drive setup:- In my first very simple test runs with the standalone Synchron Player I've used the 02 Horns-12 - VelXF Preset and the 02 Horns-12 Classic Room-Mix Mixer Preset. I start with Master Volume, Expression, Vel XF (enabled) and Dynamic Range all at maximum, and Timbre Adjust disabled. With Articulation set at Long Notes and Type set at Regular.

My first test drive:- Playing and holding C4, the output level meter at the top reads about -6 dBFS. Then when setting Expression half way down so it indicates 64, the meter then reads about -18 dBFS. With Expression back at maximum and Master Volume set half way down at 64, the meter again reads about -18 dBFS. So far so good. Then I set both sliders half way down. So, totting up both their relative gain reductions of -12 dB gives -24 dB, then I looked for the meter to confirm the initial level of -6 dBFS is now reduced by 24 dB, giving -30 dBFS. And hey presto! That's what the meter indicated. All good.

 

That was an easy case just for test purposes. But knowing what gain reduction these two sliders give at any other settings is not obvious. The MIDI CC setting readouts on the sliders give no clue about their dB gain reduction. Also, like many others I'm used to working in dB up or down relative to a common working point set for mixing. Much closer to the final mix bus, dBFS levels become important. So on its own the Synchron Player's dBFS meter, though a welcome aid, is not what I'd usually find convenient for mixing. I'm also wondering if these two sliders are intended for mixing directly, rather than being buried in a host that would use other faders and with automation. Is the latter way how most people here generally use them? I'd guess so.

On the topic of dBFS, and the main source of my confusion, I see a post here by @Dewdman42 suggesting that we use his spreadsheet for calculating dBFS from MIDI CC setting. I've tried it but unfortunately it doesn't match up even approximately with the dBFS meter reading test I described above. That spreadsheet seems to use a very different scaling factor from the two faders in question - looks to me to be different by a factor of 2. Has anyone else tried to use the spreadsheet? Has the spreadsheet been verified, or even tested? Is the Synchron Player's output level meter out of whack? Or have I missed out something important in my test run? Something somewhere has to be very wrong.

Thanks in advance for any help on this knotty problem.

All the best,

Hermann

Posted on Fri, Aug 27 2021 14:32
by PaoloT
Joined on Tue, Dec 27 2016, Posts 1190

A practical answer to myself to get the same default 'natural' balance of the presets when lowering Expression from 127 to 110:

- Create two tracks in a DAW, and let them play a long note at maximum dynamics.

- Assign two VSL players to the tracks, one with an original VSL preset, the other with my custom one.

- Start playback in cycle, and along the level of the custom preset to the original one, by using the Master Control. Use the finest meter to balance them.

Paolo

Posted on Fri, Aug 27 2021 15:49
by Helmholtz
Joined on Fri, Aug 27 2021, London UK, Posts 15

Ok I've found good info in a thread called "A Graph of MIDI CC vs dB for Vol & Expr Faders" by @Macker.

That info agrees with my first test run. I've done some more test runs at different fader settings and they all agree too. So the spreadsheet is out of whack. Macker's formula is 40*log (ratio) but the spreadsheet's formula is 20*log (ratio) which doesn't match the fader scaling. Solved! Props to Macker!

I suppose the secret to mixing with Synchron Player is to ignore the MIDI CC settings on the Master Volume and Expression faders. When listening doesn't tell me enough I'll rely on the dBs shown in the DAW automation.

Slowly getting the hang of working with VSL's beautiful instruments. Just a matter of care, patience and knowing what's what and who's who - just like always 

Hermann

Posted on Fri, Aug 27 2021 18:49
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811
Originally Posted by: 170480 Go to Quoted Post
Ok I've found good info ina thread called "A Graph of MIDI CC vs dB for Vol &amp; Expr Faders" by @Macker.
That info agrees with my first test run. I've done some more test runs at different fader settings and they all agree too.So the spreadsheet is out of whack. Macker's formula is 40*log (ratio)but the spreadsheet's formula is 20*log (ratio) whichdoesn't match the fader scaling. Solved! Props to Macker!
Isuppose the secret tomixing with Synchron Player is to ignore the MIDI CC settings on the Master Volumeand Expression faders. When listeningdoesn't tell me enoughI'll rely on thedBs shownin the DAW automation.
Slowly getting the hang of working with VSL's beautiful instruments. Just a matter of care, patience andknowing what's what and who's who - just like always
Hermann


No the formula from macker is not correct. The formula I explained earlier is a well known formula. Macker derived his formula by looking at output readings in an external meter without taking into account the reference level.

If you apply attenuation with the cc controls, they are applied as a percentage of the amplitude. That percentage can be converted to dBFS using the well known formula of 20 * log10( amplitude percent), since we don’t generally know the reference level we assume it’s 0 Otherwise if we knew the reference level the amplitude percent would also involve the reference level as a ratio
Posted on Fri, Aug 27 2021 18:56
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811
To your second point I personally try to avoid using either cc7 or cc11, I prefer to use velXF for expression and daw faders or mirpro for orchestra balance.

However it’s all fine to use cc’s for either purpose and honestly it’s not that critical that
You get the exact gain back through some other means after synchron, if you want to bump the level back up equally across all your synchron instruments so that the orch balancing will be retained then send them all to a bus, add some gain back until it’s in the zone you want. Doesn’t have to be precise really. All this talk about DB’s has been a side show that complicates the matter more then it needs to
Posted on Fri, Aug 27 2021 19:42
by Helmholtz
Joined on Fri, Aug 27 2021, London UK, Posts 15

Dewdman42, I'm going to stand by empirical evidence. Empirically, I found that your solution does not work.

The simple tests I did on your solution produced a result that speaks for itself and can very easily be reproduced and inspected by others. If you would kindly address that result, I'd welcome your explanation of it.

Posted on Fri, Aug 27 2021 20:19
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811
What result did you want me to respond to?

As I said already, the discussion about DB’s on this thread is clouding the topic unnecessarily
Posted on Fri, Aug 27 2021 21:49
by Helmholtz
Joined on Fri, Aug 27 2021, London UK, Posts 15

With this extremely basic test, anyone still in any doubt can and should try this:-

With Master Volume set a max, start some sustained sound going forever. Pump up Synchron Player's output by any method until it's just tickling 0 dBFS on Synchron Player's output meter. Then drop Master Volume to half way, at CC level 64.

What do you read on the output meter? Is it about -6 dBFS,  as the spreadsheet says it should be? Or does it actually read about -12 dBFS, as predicted by Macker's figures? (Spoiler: it'll actually read about -12 dBFS)

It's ok Dewdman42, I don't need an answer from you because the empirical facts speak loudly and clearly without any help. Anyone can run this very simple test and see for themselves. It's really not rocket science.

Posted on Fri, Aug 27 2021 22:44
by Macker
Joined on Tue, Aug 21 2018, London, Posts 382

Paolo, so, we're back at the original problem - we haven't provided you with any real help. Shame on us, lol.

Yeah I can see the 'twin-track' method ought to work as your compensation trick, as long as your instrument presets all provide just enough room for raising your "natural balance' fader by the amount you require (about 2.5 dB, looking it up in my table). And I reckon it could be done just by comparing the two loudness levels carefully by ear, or by by whatever meters happen to be there - without any need for fancy metering. 

One thing I'm thinking is, wouldn't it eventually get a bit tedious for you? If so, would it be less hassle to insert a VSL gain plugin on all active channels in the Sy Player mixer, and raise them all by that 2.5 dB for your compensation? Up to you of course - whatever method you're most comfortable and confident with.

Posted on Fri, Aug 27 2021 23:02
by Macker
Joined on Tue, Aug 21 2018, London, Posts 382

Hello Hermann and welcome to the forum.

Looks like you prefer to dive into the deep end - great stuff! lol

Appreciate your testing and your kind comments about my tests and calculations. Totally agreed about empirical evidence being the ultimate arbiter. Heaven knows we need more of that!

The ultra simple test you describe is indeed a deal-breaker. No need for lengthy confabulations or endless faffing with these or those conditions for further tests. That one test will tell the truth clearly without fear or favour.

Good job! 

Posted on Fri, Aug 27 2021 23:24
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811

Originally Posted by: 170480 Go to Quoted Post

WWith Master Volume set a max, start some sustained sound going forever. Pump up Synchron Player's output by any method until it's just tickling 0 dBFS on Synchron Player's output meter. Then drop Master Volume to half way, at CC level 64.

Fine so far.  That is 50% amplitude reduction  (64/127 = .50)

Quote:

What do you read on the output meter? Is it about -6 dBFS,  as the spreadsheet says it should be? Or does it actually read about -12 dBFS, as predicted by Macker's figures? (Spoiler: it'll actually read about -12 dBFS)

You are unfortunately still missing the part about reference level.  Macker also appears to be missing this component.  The spreadsheet, as well as the other website I quoted, are referring to the amount of attenuation, not the predicted meter reading.  The source content you are using for a test has an unknown reference level.  

But it doesn't matter that you don't know this, the spreadsheet and the website tell you how much attenuation is being applied by Synchron..and you can then use the same amount of DB + gain to bring it back.

I am basing this on well understood mathematics bout dBFS and amplitude conversion, I'm not making it up.  Hey I'd like to know if this math works too...  I will try a test....

Posted on Fri, Aug 27 2021 23:26
by PaoloT
Joined on Tue, Dec 27 2016, Posts 1190

Originally Posted by: Macker Go to Quoted Post

Paolo, so, we're back at the original problem - we haven't provided you with any real help. Shame on us, lol.

Actually, it's a very interesting discussion, with some math that is useful to learn. But a clear answer (at least, not one I can grab) doesn't seem to be there, yet.

An empirical solution has the advantage of living in our main domain – the music/sound dimension. This one, we can easily understand!

Paolo

Posted on Fri, Aug 27 2021 23:29
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811

Originally Posted by: PaoloT Go to Quoted Post

Actually, it's a very interesting discussion, with some math that is useful to learn. But a clear answer (at least, not one I can grab) doesn't seem to be there, yet.

 

oh wait...I thought we figured that out already.  What is the open question exactly?

Posted on Sat, Aug 28 2021 00:29
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811

So I did a simple test.  

  1. measure a Synchron instrument with CC7/CC11/CC1 all set to max, write it down.

  2. set CC11 = 110, measure again.

  3. add a trim plugin after Synchron and fiddle with different gain settings until the measured result is the same as step#1 above.

A couple points.  Its hard to be precise with this test because we have to rely on a Synchron instrument as the test sound, which is applying unknown humanization to the sound which may or may not produce consistent results.  By playing at least a dozen notes at the same velocity and keeping track of the max peak during that time..might be ok enough.

I agree with Macker that the amount of gain needed to bring the level of step#3 back to the level of Step#1 required is around 2.5db 

which is not the same value as indicated by the 20*log10 formula, which comes up with -1.25db (note - the fact that its pretty much exactly 2x of the calculated value is interesting also)

So there is definitely something more to the story, but at the moment, I'm not sure what, I think its probably that none of us, including myself are calculating reference level into it properly while doing that math.  

VSL has already stated very clearly that the CC controls are a simple percentage of amplitude.   The formula I mentioned absolutely *IS* the correct formula for converting amplitude percentage to dBFS.  But it doesn't match the measured results, I agree.

Posted on Sat, Aug 28 2021 02:59
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811

I updated the spreadsheet I posted earlier to include a 2x fudge factor to make up for the discrepancy between what Synchron is outputting and the standard Amp->db calculation.  This is essentially the same as Macker's 40*log10() formula.  I don't know why this is necessary right now, but it does seem to be necessary.  

I also added a line for @PauloT to calculate a CC7 makeup value if you choose to increase CC7 in order to make up for setting CC11 to something lower to represent "unity".

https://docs.google.com/spreadsheets/d/19uQltWICdycednQbQRA0jNHSl75uzhIW7rsyi9OM0Ig/edit?usp=sharing

@PaoloT I think you solved your original problem by one of two ways, either make up the gain with CC7, using the calculation I gave you (or you can use the spreadsheet above if you want).  Or...use external gain plugin to make up the gain...which should be 2.5db to make up for cc11=110.

You can put a separate gain after every Synchron instrument, or you can send them all together through a bus and then just need a single gain plugin at +2.5db to bring them all back up as if you didn't lower CC11.  

However, note that with the gain plugin approach, you will want to be on the lookout for clipping mainly on the master bus whenever you raise CC11 over 110.

Was there something else unresolved?

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Posted on Sat, Aug 28 2021 09:50
by Macker
Joined on Tue, Aug 21 2018, London, Posts 382

The good news is, following an attempted insurrection by the crude forces of dogmatism, modern science has reasserted its long-term possession of certain territory in the field of audio engineering,

The bad news is that the attempted insurrection happened at all, and here in VSL's forum.

In the Mac's dictionary, "dogmatism" is defined as "the tendency to lay down principles as undeniably true, without consideration of evidence ..."

Over the past 5 centuries, modern science has shown the value that empiricism brings to the progress of human existence. Do we want to turn the clock back to pre-modern times, when often absurd dogmas ruled the roost pretty much across the board? I don't think so. Do we appreciate attempts to drag us back there? I don't think so.

So I'll just say this. Let's be careful who we listen to and believe, and let's make sure that the long-established value and reputation of empiricism in the disciplines of mathematics, science and engineering are protected and upheld against any who try to cast them aside imperiously as if mere trash. Also there are further offences to watch out for and guard against, such as bush-league sophistry and smearing tactics, as used since time immemorial to pave the way for, defend and promote dogmatism.

Over and out.

Posted on Sat, Aug 28 2021 12:35
by PaoloT
Joined on Tue, Dec 27 2016, Posts 1190

Originally Posted by: Dewdman42 Go to Quoted Post

oh wait...I thought we figured that out already.  What is the open question exactly?

It's still the one I asked in the first post. Many interesting ideas and solutions in this thread, but not yet one looking as effective as working with a vu-meter!

Paolo

Posted on Sat, Aug 28 2021 13:11
by PaoloT
Joined on Tue, Dec 27 2016, Posts 1190

Originally Posted by: PaoloT Go to Quoted Post

A practical answer to myself to get the same default 'natural' balance of the presets when lowering Expression from 127 to 110

I compared the original VSL presets and my custom ones, whose Master Volume was recalculated by multiplying the original value by 115.3%. It works! Probably just by chance, but the level are matching for all the presets.

Paolo

Posted on Sat, Aug 28 2021 17:05
by Dewdman42
Joined on Tue, Feb 27 2018, Posts 811
Originally Posted by: PaoloT Go to Quoted Post
Originally Posted by: PaoloT Go to Quoted Post

A practical answer to myself to get the same default 'natural' balance of the presets when lowering Expression from 127 to 110

I compared the original VSL presets and my custom ones, whose Master Volume was recalculated by multiplying the original value by 115.3%. It works! Probably just by chance, but the level are matching for all the presets.
Paolo


And the Vu meter approach has been mentioned several times in the thread as an additional solution. So it seems you are in fact resolved. What other solution could there be? What is left unresolved?

Using approximately 115% to compensate cc11=110 is right in line with the calculations I gave you earlier ( now on the spreadsheet ) . The cc11=110 is 86.61% of full. If you take 1/.8661 you get 1.15 which is 115%. Your Vu measurements confirm this. You can change cc11 to any other value instead of using 110 for home and use the calculation 1 / ( cc11 / 127 ) to obtain the needed compensation to use for cc7 fader as a percentage.

But when in doubt, using meters to get it where you want is also perfectly fine way to get it without trusting math
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