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strokeanalysis:stroke_analysis [2013/02/21 09:19] – [Evaluation] devastrokeanalysis:stroke_analysis [2013/02/21 12:35] (current) deva
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 //However// ... the result of this mechanism is the playing of a sample at probably 44.1kHz or 48kHz and in order to avoid phasing problems when mixing with the analogue drum sound it should be considered to make the ADC samplerate 44.1kHz or 48kHz as well. //However// ... the result of this mechanism is the playing of a sample at probably 44.1kHz or 48kHz and in order to avoid phasing problems when mixing with the analogue drum sound it should be considered to make the ADC samplerate 44.1kHz or 48kHz as well.
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 ===Bit precision=== ===Bit precision===
 When considering bit precision it is the lowest angle velocity upon impact that are the worst case scenario. When considering bit precision it is the lowest angle velocity upon impact that are the worst case scenario.
-If we therefore look at the stroke sequence we can observe a 2.03 degrees between the last two frames, giving 0.447 degrees in the last millisecond. +If we therefore look at the stroke sequence we can observe a 2.03 degrees between the last two frames, giving 0.446 degrees in the last millisecond. 
-If we divide the entire 84 degree interval into 0.406 degree segments the result is a minimum of 207 steps.+If we divide the entire 84 degree interval into 0.446 degree segments the result is a minimum of 188 steps.
  
 Ergo: **A bit precision of 8 should be sufficient.** Ergo: **A bit precision of 8 should be sufficient.**
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 //However// ... since we cannot assume that we will work within the entirety of the bit span of the ADC it should be noted that the 8 bit precision is the //used// number of bits for the mallet swing and a substantial amount of headroom should be added in order to match different spring types and initial tensions. //However// ... since we cannot assume that we will work within the entirety of the bit span of the ADC it should be noted that the 8 bit precision is the //used// number of bits for the mallet swing and a substantial amount of headroom should be added in order to match different spring types and initial tensions.
 How much 'substantial' is in this case I am not able to evaluate in this article. How much 'substantial' is in this case I am not able to evaluate in this article.
 +
 ====Conclusion==== ====Conclusion====
 Since this experiment has not been performed by the fastest or hardest hitting drummer in the world, or the most latency sensitive one for that matter, we should increase both samplerate and bit precision in order to make sure all drummers are covered. Since this experiment has not been performed by the fastest or hardest hitting drummer in the world, or the most latency sensitive one for that matter, we should increase both samplerate and bit precision in order to make sure all drummers are covered.
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 If say the drummer hits twice as hard (double the angle velocity) and cannot accept latency at more than 0.5ms the calculations from above will be:\\ If say the drummer hits twice as hard (double the angle velocity) and cannot accept latency at more than 0.5ms the calculations from above will be:\\
  
-Samplerate: 2.06 * 2 degrees in 5ms = **8kHz sampling** (but still it should be considered to use 44.1kHz or 48kHz to avoid phasing problems)\\+Samplerate: 2 * 2.03 degrees in 4.55ms = **8kHz sampling** (but still it should be considered to use 44.1kHz or 48kHz to avoid phasing problems)\\
  
 A very slow stroke is the worst case scenario when considering the bit precision since we need more steps in the final steps of the swing. A very slow stroke is the worst case scenario when considering the bit precision since we need more steps in the final steps of the swing.
 If say the angle velocity is half of the measured one and the drummer is sensitive to latencies above 0.5ms the number of needed steps will go up by factor of 4: If say the angle velocity is half of the measured one and the drummer is sensitive to latencies above 0.5ms the number of needed steps will go up by factor of 4:
  
-Bit precision: 207 * 4 steps = **10 bit precision** + headroom.\\+Bit precision: 188 * 4 steps = **10 bit precision** + headroom.\\
strokeanalysis/stroke_analysis.1361434770.txt.gz · Last modified: by deva
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