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Numbers and Clipping

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Author	Topic: Numbers and Clipping
tuscland Member	posted 09 January 2006 11:02 Hello, I was wondering under which condition the results of computation were "clipped". What I mean is if I put a sine wave with enveloppe of 1.0 into a Attenuator with a gain of +10 dB and then a Attenuator with a gain -10 dB, will I have my sine wave back or a distorted one? I tried the experience and found that I get the distorted one. Let me put this another way : I would like to know if the internal computations are done in 24 bits or a higher resolution (56 bits accumulator)? I guess the rule is : every number used in the DSP computation have their absolute value between 0 and 1. Is this true? Are there any exceptions? I am a bit confused about the range of values are handled in Kyma, and I want to make sure I fully understand the issue. Best wishes, Camille IP: Logged
SSC Administrator	posted 09 January 2006 14:26 "What I mean is if I put a sine wave with enveloppe of 1.0 into a Attenuator with a gain of +10 dB and then a Attenuator with a gain -10 dB, will I have my sine wave back or a distorted one? I tried the experience and found that I get the distorted one." Yes, a full amplitude sine wave is using all the bits of the sample word. When you put that through a Gain, the waveform is clipped. That information is lost so when you attenuate it again, it still has a square top. "Let me put this another way : I would like to know if the internal computations are done in 24 bits or a higher resolution (56 bits accumulator)?" There is a 56-bit accumulator. "I guess the rule is : every number used in the DSP computation have their absolute value between 0 and 1." Sound outputs are always in the range (-1, 1). (The generated value of a SoundToGlobalController can be any any number. However, this is true only of the hot value that it generates as a "side-effect". The actual audio output of the SoundToGlobalController when Silent is unchecked will be clipped to the range (-1,1). IP: Logged
tuscland Member	posted 09 January 2006 14:44 Does the 56 bit accumulator "accumulates" results all along the prototypes chain, or is it internally bounded to a single prototype? I would like to know if I can assume that the dynamic range is 56 bits from the input to output of a Sound. If yes, that leaves plenty of headroom with a dynamic of 337 dB !!! Apart from that, thanks, this all is very clear now. Cam IP: Logged
SSC Administrator	posted 10 January 2006 08:49 There is a 24-bit signal path between modules (144 dB). IP: Logged
tuscland Member	posted 10 January 2006 08:59 Right, that makes perfectly sense. That's good because there's still around 50 dB of headroom compared to 16 bit signals. I asked these questions because I read the explanation of the Kyma compressor and saw that the signal was attenuated of 10 dB. I wanted to know what 10 dB were meaning compared to the signal/ratio of the signal path. 10 dB in the 16 bits field mean a lot, but in the 24 bits field is fine. just my $0.02 IP: Logged

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