Sforzando & Higher Sample rates?

Post your sforzando questions here

Moderators: eric_telemaque, davidv

jonat8han
Posts: 19
Joined: Mon Dec 15, 2014 11:43 pm

Sforzando & Higher Sample rates?

Postby jonat8han » Thu Jul 20, 2017 4:03 pm

Hi all,

I'm wondering if anyone else has this issue? I make a lot of instruments with higher sample rates (so I can pitch down & retain harmonics) but I'm noticing that Sforzando adds quite a bit of hiss when using samples higher than 48khz?

I've made an example here:

https://www.dropbox.com/s/zy17rs8jc8mri ... t.zip?dl=0

There are two very simple instruments here, each made with an identical sample - one at 192khz (the original), and one at 48khz (converted). The 192khz instrument plays back with a lot of added hiss, while the 48khz instrument sounds fine ... Ive included a bounce of the two instruments playing the same MIDI information back to back, first the 192khz, then the 48khz. This was made in a Logic session running at 48khz.

davidv
Site Admin
Posts: 1567
Joined: Tue Mar 02, 2004 7:23 pm
Contact:

Re: Sforzando & Higher Sample rates?

Postby davidv » Fri Jul 21, 2017 8:52 am

Hi

My hunch was right, the 192KHz file has lots of energy around 38KHz (and then more ultrasonic stuff gliding up to 96KHz), which is of course way higher than the Nyquist frequency of the target 48KHz samplerate (24KHz). Something the 48KHz wav files do not have since they were most probably downsampled correclty in a sound editor in a CPU intensive way.

Typical samplers like sforzando, Kontakt (last time I checked) do not do heavy brick wall downsampling/then interpolate to the pitch/sr you need but use much more cpu friendly 4 point interpolation or something similar because it has to play many many voices at once.

So essentially you are hearing aliasing from lack of proper downsampling. Not something we will change unfortunately.

EDIT: However, you can use a trick where you tell sforzando/ARIA to run the session at a higher internal samplerate.

Something like the following at the start of the SFZ file:
<control>
hint_min_samplerate=352800

We did that for chipsounds to support oversampling and better interpolation of some 96KHz waveforms,
David Viens,
Plogue Art et Technologie Inc. Montreal.
http://www.plogue.com

jonat8han
Posts: 19
Joined: Mon Dec 15, 2014 11:43 pm

Re: Sforzando & Higher Sample rates?

Postby jonat8han » Fri Jul 21, 2017 3:52 pm

amazing - thank you - that "hint_min_samplerate=352800" does indeed work like a charm. I think I'm blaming the high frequency noise on my Sennheiser mkh8040 microphones. I recorded a similar set of samples with a Sanken co-100k which does not have these problems.

But what is exactly going on there with the "hint_min_samplerate" opcode? Am I setting the samplerate of Aria to 352800? that seems higher than necessary? Why that number in particular?

seb@plogue
Site Admin
Posts: 9593
Joined: Tue Mar 02, 2004 7:23 pm
Location: Montreal
Contact:

Re: Sforzando & Higher Sample rates?

Postby seb@plogue » Mon Jul 24, 2017 10:45 am

But what is exactly going on there with the "hint_min_samplerate" opcode?


It triggers the engine into running at (at least) that sample rate internally which implies doing downsampling which implies applying filters before going to a lower sampling rate.

Why that number in particular?


That was pasted directly from an existing file in chipsounds.
David is off this week but I think that 352800 was selected for optimization reason given that the most common sample rate was 44.1 and
352800 is 8 times that.

jonat8han
Posts: 19
Joined: Mon Dec 15, 2014 11:43 pm

Re: Sforzando & Higher Sample rates?

Postby jonat8han » Mon Jul 24, 2017 4:28 pm

aha, gotcha - thank you!


Return to “sforzando”

Who is online

Users browsing this forum: No registered users and 2 guests