Can Digital Distortion be caused by too many notes?

[lamboguy]

Hi Folks,

I'm really battling a THICK section of a piano piece that I'm orchestrating.

Piano alone is maybe a dozen tracks, many chords, etc, loud volume.

It plays fine (Ivory) but when I start to add orchestral instruments to it (via Kontakt) I start getting distortion. I'm monitoring the Mix carefully, and have the Master Fader down to -6 and am not getting any red overload or peak lights. (that's usually my problem)

But...when the piece gets really thick with notes like this, I start getting distortion (that sounds like overload or peak distortion)

Am I simply playing too many notes for DP5 on a Mac Mini to handle? And is that what is causing the distortion?

(I can go in and start pulling out notes -- that's not a problem. But I'd like to know what sort of boundary or boundaries I'm currently running up against)

Thanks!

Fred

[Frodo]

Check the I/O levels of any effects you are running. Quite often, the input gain can overload and distort even if the output gain might not show any signal overload.

The only other thing which comes to mind as just a guess is perhaps the more MIDI data there is, the harder the drive and its buss has to work to connect that MIDI data with the corresponding sample data. If you're using firewire, you're using a fairly narrow buss. Something like Ivory didn't fare so well for me on firewire, but I realize that there are limitations to the expandability of a MacMini.

I would try making temporary freezes of your various tracks and use fewer VIs at a time.

[FMiguelez]

Am I simply playing too many notes for DP5 on a Mac Mini to handle? And is that what is causing the distortion?

I think that's it.

That happens to me as well (G5).
And not only distortion. Then suddenly notes begin being dropped, etc.

If you REALLY don't want to get rid of notes, you will probably will have to start printing tracks and deleting VIs so your machines can recover.

I've mentioned this before, but one thing I like doing in these situations is:
- Finish and Freeze a busy track.
- Copy the VI and its MIDI track into a Clipping window in the same state after the freeze or print (with its buss assignments you used to print it)
- Delete the tracks.

So like this, you commit, but not entirely

This will liberate a LOT of CPU, and it will always be ready to be reintegrated into the project if you want to change anything afterwards. Just drag its icon from the Clipping window, and the tracks will appear instantly there ready to be messed with again
Then repeat procedure as necessary until you put your "finished" signature to the project.

[lamboguy]

Good advice guys, thanks.

When you said "printing" and "freezing" are you saying make/use soundbites? (of thick sections of the VI tracks)

Fred
(still learning a LOT about performer, even after 25 years with it)
(at least I don't have to cut the top off my mac for cooling anymore...)

[FMiguelez]

.

I meant it for either one, but for your case, for the VIs.

Every time you need to liberate CPU power (from very complex insert settings for audio tracks, or hungry VIs), freezing or printing them really helps (after you do the suggested Clipping workflow).
You can do it for only the busy sections, or for the full track.

[David Polich]

There is another aspect to this that hasn't been discussed. "Stacking sampled sounds on top of one another".

Let's start with any string ensemble patches that you are using. A string ensemble will usually use a waveform, or waveforms, consisting of samples of several players playing in unison. Let's say it is 14 violins playing the same note. When you play a four note chord, you now have 56 violins. That is
not what happens in the real world. But there is more - unlike a real analog synth, where the number of notes you play does not "stack up" oscillators on top of one another, sample playback instruments will always pile up more and more oscillators, and their respective filters, depending on the number of notes you play. The result is that, assuming your patches are all at high output levels, this stacking up of filters will lead to overload and distortion. This happens, by the way, with all sampled instruments, including Ivory.

The only way to reduce (not eliminate, but reduce) this effect is to lower
the outputs of your tracks. It's really like audio mixing - if you have a
mix with two guitars, bass, drums, and vocals, you have more headroom.
The more tracks you introduce, the less headroom is available, and you need
to then lower the faders on your tracks accordingly, or you overload the
mix buss.

[lamboguy]

I'm sorry, I'm not being clear...

What do Freeze and Print mean?

Thanks,

Fred

[philbrown]

- Finish and Freeze a busy track.
- Copy the VI and its MIDI track into a Clipping window in the same state after the freeze or print (with its buss assignments you used to print it)
- Delete the tracks.

Thanks for posting this. That's a great method utilizing the Clipping window- I have fear of total commitment.

[jlstcui]

Fred--

"Freezing" and "printing" are basically synonymous. You must select a MIDI track and its corresponding VI track (Ivory, in your case), and then choose the "Freeze tracks" command. What this does is to render the MIDI information as audio, hence "printing" it. Now you can disable or delete (or transform into a clipping) the initial MIDI track, and you will save CPU resources. That's the simple version, anyway.

--Jlstcui

[FMiguelez]

"Freezing" and "printing" are basically synonymous. You must select a MIDI track and its corresponding VI track (Ivory, in your case), and then choose the "Freeze tracks" command. What this does is to render the MIDI information as audio, hence "printing" it. Now you can disable or delete (or transform into a clipping) the initial MIDI track, and you will save CPU resources. That's the simple version, anyway.

Exactly.
Or you may prefer to record the track (print it) by assigning the VI's output to an audio track's input.
Freezing and recording like that will give you the exact same result.

Thanks for posting this. That's a great method utilizing the Clipping window- I have fear of total commitment.

I'm not very good at commitment either

Doing like I suggested is ALMOST as good as having a fast computer where you don't need to worry about these things.
Obviously I'd rather have a new Mac right now, but since that's not possible at the moment, that seems to be a not-so-bad compromise.

[lamboguy]

Holy Cow -- I had no idea!

Man, I am not worthy...

Ok guys, thanks for the tips. This is great stuff, I need to dig a bit and sort of take my performer chops to the next level, that's for sure!

Thanks,

Fred

[lamboguy]

Well this is really stupid -- but the distortion was caused by...failing batteries in my "Boostaroo" Headset Amplifier.

As the battery power tapers off, the distortion grows.

Anyway, I WILL run into these "overload" problems, so it's all good to know about.

I have to say, so far I'm very, very impressed by what a/the new mac mini can accomplish. I'm running a ton of plugin voices and it's really working well.

Thanks,

Fred

[Armageddon]

First thing to try when you hear weird distortion elements in a thick stack of notes like that is to Invert Phase. You'll have to go through each offending instrument, one by one and insert an Invert Phase plug (or a channel strip plug or EQ plug with an Invert Phase function) in its signal path. Once you figure out which instrument is the problem, you can automate the Invert Phase to become active (Bypass Off, if you will) only during that part, so you're not altering the rest of the mix or that individual instrument's tone, you're just affecting the part that isn't playing well with the others (beware of the "switching" sound that sometimes accompanies inverting the phase on an audio track; you can set up your automation to switch on and off when no audio is playing on that track).

Second thing, of course, is EQ. Most instruments don't need anything below 80 Hz, since they're addressing the lower midrange and up. Think of it this way: if your mix volumes are horizontal stacking, EQ is your vertical stacking (and reverb is your near/far stacking). Anything that doesn't require bass frequencies in the mix -- higher-register strings, mid-range brass, guitars, pianos, snares, vocals, overheads, hats, synths that aren't playing bass -- can probably stand to have 80 Hz cut from the low end (and in DP 7, this task is a lot easier with in-line Q!). I actually lop about 125 Hz from pianos, and between 125-150 Hz from guitars. This way, there's no bass buildup, and the instruments that do need those frequencies, like bass guitars, low-end strings, timps, kick drums and certain synths, don't need to be jacked up to be heard in the mix. I also perform a 30 Hz cut from the bottom of the entire mix during mastering.

Speaking of which, there's also the problems inherent in whatever mastering plugs you may be using. Sometimes, the analog-emulating comps and limiters (especially T-RackS, which I've had a decade-long battle with over "too much" and "just enough") will overly-hype the mid-range and cause distortion, even if your meters say you're well below 0 dB.

[lamboguy]

Very interesting, I will definitely give those a shot. Thank you!

Fred

[lamboguy]

Ok everybody on this thread -- tomorrow I start freezing and printing -- wish me luck!


Thanks,

Fred