Re: [music-dsp] Precision issues when mixing a large number of signals

2012-12-10 Thread robert bristow-johnson
On 12/10/12 12:42 PM, Dave Gamble wrote: I dream of a time when TeX notation will be acceptable and universal in contexts like this. y=(1/N) \sum_{i=0}^N x_i doesn't stay ugly for very long, and is ultimately easier to read. And you can paste it into here: http://www.codecogs.com/latex/eqnedito

Re: [music-dsp] Precision issues when mixing a large number of signals

2012-12-10 Thread Bjorn Roche
On Dec 10, 2012, at 12:35 PM, robert bristow-johnson wrote: > On 12/10/12 11:18 AM, Bjorn Roche wrote: >> On Dec 10, 2012, at 4:41 AM, Alessandro Saccoia wrote: >> I don't think you have been clear about what you are trying to achieve. Are you trying to compute the sum of many si

Re: [music-dsp] Precision issues when mixing a large number of signals

2012-12-10 Thread Dave Gamble
I dream of a time when TeX notation will be acceptable and universal in contexts like this. y=(1/N) \sum_{i=0}^N x_i doesn't stay ugly for very long, and is ultimately easier to read. And you can paste it into here: http://www.codecogs.com/latex/eqneditor.php and then it's actually even MORE read

Re: [music-dsp] Precision issues when mixing a large number of signals

2012-12-10 Thread robert bristow-johnson
On 12/10/12 11:18 AM, Bjorn Roche wrote: On Dec 10, 2012, at 4:41 AM, Alessandro Saccoia wrote: I don't think you have been clear about what you are trying to achieve. Are you trying to compute the sum of many signals for each time point? Or are you trying to compute the running sum of a sing

Re: [music-dsp] Precision issues when mixing a large number ofsignals

2012-12-10 Thread Wen Xue
To only way to guarantee precision is to use enough bits for intermediate results. Given your running sum formulation, the worst-case quantization error for any N is 0.5*Pi + 0.25*Pm*(N+2)(N-1)/N where Pi is the precision of inputs (the summed signals) and Pm is that of the partial sum (notic

Re: [music-dsp] Precision issues when mixing a large number of signals

2012-12-10 Thread Bjorn Roche
On Dec 10, 2012, at 4:41 AM, Alessandro Saccoia wrote: >> >> I don't think you have been clear about what you are trying to achieve. >> >> Are you trying to compute the sum of many signals for each time point? Or >> are you trying to compute the running sum of a single signal over many time >

Re: [music-dsp] Precision issues when mixing a large number of signals

2012-12-10 Thread Alessandro Saccoia
> > I don't think you have been clear about what you are trying to achieve. > > Are you trying to compute the sum of many signals for each time point? Or are > you trying to compute the running sum of a single signal over many time > points? Hello, thanks for helping. I want to sum prerecorded