Old 07-01-2020, 10:31 AM   #1
mikefloutier
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Default How much Polyphony is too much?

And how little polyphony is too little.

This is the issue I'm facing.

I'm running some fairly memory hungry sample packs in SampleTank4 as a plugin in my Reaper.

The one I like the most, The Berlin Piano, is the hungriest and I've found that when I play it layered with other instruments it starts to crack up; especially if I'm careless with my sustain pedal.

I thought it would help to mute the unwanted parts but, although it helped, it didn't totally solve the issue.

At first I thought it was a buffering issue and my CPU was overloading but this just wasn't happening.

It was only by chance that I realised it was running out of memory that was the issue. I had been reducing the size of my pagefile.sys file to save HDD space and this was when the memory issue stuck out like a sore thumb.

Anyway, to get down to my real question, I can obviously solve the memory overload issue by simply reducing the Polyphony limit, so, since I'm only concerned with playing live, "What would be a good Polyphony limit, would you say?"
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Old 07-01-2020, 10:43 AM   #2
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Errrrrrr.......10?
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Old 07-01-2020, 10:58 AM   #3
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Quote:
Originally Posted by mikefloutier View Post
"What would be a good Polyphony limit, would you say?"
Honestly, this is called an "N-1 problem" which translates to 1 less than how many knocks over your system.

Really, that isn't a joke, its the exactly the same thing in the enterprise server world because all systems and uses differ.
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Old 07-01-2020, 11:45 AM   #4
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First make sure the PC is optimised:

https://support.native-instruments.c...dio-Processing

For piano I suggest you would want at least 32. I run Pianoteq with 256 voices with no problems on an i7 CPU from 2012.

I haven't tried this latest Sampletank.
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Old 07-01-2020, 03:02 PM   #5
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Thanks guys, that's the sort of thing I was hoping to hear, good straight-forward advice.

I loved the n-1 thing; makes so much sense, just like sailing; rev it up until it stalls then back off a notch.

32 is also great, I tried 48 initially and that worked with just piano and strings loaded.

I'd really prefer to load up all the parts I'll be using in a set in order to get quick changes; hence I need to re-test in this mode to establish n-1. I can save on memory by loading each set of parts as and when they're needed BUT the time some of them take to spool up from the HDD rules that out somewhat; although it's generally not a deal-breaker.

I guess the remaining part of the question relates, not so much to the point at which breakdown occurs (ie. N), but rather, what is too small a number. Eg. Is 10 too small, in practice. I guess 10 comes from us having 10 fingers but, in practice, one might sustain a set of 10 notes in a chord, using a pedal and play a melody over that. Also, some piano playing styles do include pretty much continuous use of the sustain pedal; eg Erik Satie style.

My guess is that somewhere between 24 and n-1 would work well, depending on the style employed.

Obviously the other consideration is the addition of other layered parts.

Also, the size of the samples themselves is presumably a limiting factor.

Hence the n-1 formula should be the overarching guidance.

Thanks again!
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Old 07-03-2020, 12:19 AM   #6
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The polyphony figure I suggested was for piano alone. As far as I remember you can set polyphony per sound layer, at least you can in ST3. I imagine you can in ST4.
The most CPU hungry sounds in sample tank used their stretch technology, that was extremely CPU intensive even with a fairly powerful i7.
If you are layering sounds I suggest any stretch tracks are frozen in Reaper.
If you have a mere 10 voice budget you will hear very obvious voice stealing (sound of earlier played notes disappearing) as sustained notes continue to use some of those 10 voices.
This shouldn't need to be a consideration on modern computers with sample libraries!
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Old 07-03-2020, 12:36 AM   #7
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Many thanks SoftSynth, from a theoretical pov Iím still confused as Iíve noticed now that memory usage is still low when the glitching occurs so it presumably must be a cpu issue.

From a practical pov Iíll just keep reducing polyphony until I find an n-1 level that is acceptable from a playability standpoint.

Thanks for all the input; I know a lot more about the subject now.
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Old 07-03-2020, 12:59 AM   #8
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Quote:
Originally Posted by mikefloutier View Post
Many thanks SoftSynth, from a theoretical pov Iím still confused as Iíve noticed now that memory usage is still low when the glitching occurs so it presumably must be a cpu issue.

From a practical pov Iíll just keep reducing polyphony until I find an n-1 level that is acceptable from a playability standpoint.

Thanks for all the input; I know a lot more about the subject now.
Memory is unlikely to be a cause, unless you have a huge amount of tracks.


What CPU are you using?
How much memory do you have?
Is the computer optimised for DAW audio as per Native Instrument link provided earlier in the thread?
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Old 07-03-2020, 02:50 AM   #9
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Quote:
Originally Posted by Softsynth View Post
Memory is unlikely to be a cause, unless you have a huge amount of tracks.


What CPU are you using?
How much memory do you have?
Is the computer optimised for DAW audio as per Native Instrument link provided earlier in the thread?
Thanks so much SoftSynth, I'm about to go through the NI advice carefully, it looks awesome!

I have a late 2012 Mac Mini i5, 8Gb Ram, Intel HD graphics 4000, running Windows 7 sp1 64 bit (but < 5Gb HDD spare due to Bootcamp restrictions)

For Reaper I'm only using one track for live work with just Sampletank 4 running a max of 2 parts, although one of them is the Berlin piano who's .pak file is nearly 1Gb.

Will report back post-NI tweaks
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Old 07-03-2020, 03:10 AM   #10
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Given your project is using so little memory no way it's that.
Hopefully the NI advice should free up a few CPU cycles for you.
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Old 07-03-2020, 06:27 AM   #11
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Ok, well I tried everything in the NI tweaks nothing helped; I'm guessing my little old Mac mini just isn't really up to it.

Anyway, the NI tweaks certainly are pretty comprehensive.

I've ended up with a couple of workarounds that I can trade off against each other in different ways according to my circumstances:

1. I Increase my buffer size to 1024, which makes a big difference (confirming the issue as CPU). I like to play with a laid-back feel and the touch of extra latency induced at 1024 just seems to sooth me into the right feel, without actually making me slow down

2. I found that, for me (ie. my setup) N-1 = 18. Given my typical usage 18 is more than plenty so I am very happy.

Thanks so much for guiding me through this, as usual necessity is not only the mother of invention BUT also the mother of tutorials. A great focused way to learn; plus some new tools in NI tweaks and LatencyMon
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Old 07-03-2020, 07:17 AM   #12
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Well I'm glad you got somewhere satisfying with tweaking, especially Karbo's tip and buffer settings.
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Old 07-06-2020, 01:45 AM   #13
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oh sorry... I thought you said polygamy
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Old 07-08-2020, 06:18 PM   #14
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I thought you were talking about Bach's fugues!
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