Re: [chuck-users] Heavy distortion/clipping in Windows (Kassen)

Kas/others, It's even a little stranger than one might think. On Mac OSX, it's really hard to clip at all. For example, this code: SinOsc s => dac; 8.0 => s.gain; second => now; runs and sounds fine. You might need to turn your master system volume down so it doesn't blow out your headphones or speakers, but if you do that, you will hear a pretty pure sine wave. The proper gain for this should be 1.0 (the default), but it works ok up to pretty large numbers, but only on Macs. I haven't tried this in a VM Windoze on Mac, and I'm not sure how the audio is virtualized in this case. BUT This very same code would cause hideous distortion on a Windows/ Linux machine, because those audio subsystems have a hard limit on the amplitude that can be sent into the dacs. Mac seems to have figured out a how to deal with this in a very different (floating point) way. PRC

2. Re: Heavy distortion/clipping in Windows (Kassen)

Message: 2 Date: Thu, 19 Feb 2015 19:44:05 +0100 From: Kassen To: ChucK Users Mailing List Subject: Re: [chuck-users] Heavy distortion/clipping in Windows Message-ID: Content-Type: text/plain; charset="utf-8"

On 19 February 2015 at 18:59, Perry Cook wrote:

...

Ack! This is a common problem, and I thought I had caught all of the clipping/distortion cases on Windows/Linux with our last passes on checking the source code. I'll check it all again and put it in our Errata file for future ChucK/Mini releases, and future printings of the book.

Perry, now that you mention the OS's I'd like to share a thought. I wanted to postpone debating OS audio infrastructure because debates on OS features tends to lead to debates on OS preferences and the next step is likely to be total war and so I thought I'd try to figure out what was going on on my own. ;-)

Am I correct in understanding that you are saying the files could have been made on OSX with the system audio gain set to -say- 0.5? Then ChucK's output could reach peaks of -say-1.5 , it's get attunated and be at .75 when hitting the DAC; perfectly fine. In this case the audio reaching such amplitudes at ChucK's output might go unnoticed by the file's author. Under OS's with a audio infrastructure expressed in int's a output of 1.5 at the ChucK dac would clip at 1 at hitting the OS's audio rating and the final output (assuming identical system volume) would end up at a 0.5 amplitude while being heavily clipped. Is that correct?

Yours, Kas.