Robdoorack,
Interesting stuff, but not necessarily conclusive of anything. Read the posts by Teres and Thom Mackris just above (well, some of Thom's anyway!). Depending on the time span over which "speed" is measured, the effects of stylus drag may produce no measured difference at all, yet may still be audible.
Consider this analogy:
A. You decide to time me running laps around a track, but the seat you chose to observe from can only see the start/finish line. It has no view of what's in between.
B. You observe that I pass the start/finish line precisely once each minute, so you conclude (correctly, from your perspective) that I'm travelling at a steady 4 minutes/mile clip (assuming a 1/4 mile track).
C. What you don't know, because your chosen vantage point doesn't let you see it, is that half the circumference of the track is actually a foot deep pool of water. This slows me down to 8 minutes/mile speed, but I make it up by blazing through the dry half of the circuit at 2 minutes/mile speed.
D. Your limited resolution of measurement (you can only see and measure in whole laps) leads you to the false conclusion that I'm running at a steady pace. The reality is that my speed is varying all over the place. Only the long term average is steady.
E. A turntable with a motor/drive system that allows deceleration due to drag, but then re-accelerates to faster than average speed when the drag is removed, could easily maintain a perfect AVERAGE speed of 33 1/3 rpm, while producing audible or even horrible sonic speed changes that a once-per-revolution measurement would never detect. A longer period of measurement would be proportionately less likely to detect them.
So, the experiment quoted was vaguely interesting, but proves virtually nothing. The human ear is vastly more capable of detecting short term speed changes than the crude experiment you described.
Doug
P.S. If anyone ever observes me running 4 minute miles, please let me know!
Interesting stuff, but not necessarily conclusive of anything. Read the posts by Teres and Thom Mackris just above (well, some of Thom's anyway!). Depending on the time span over which "speed" is measured, the effects of stylus drag may produce no measured difference at all, yet may still be audible.
Consider this analogy:
A. You decide to time me running laps around a track, but the seat you chose to observe from can only see the start/finish line. It has no view of what's in between.
B. You observe that I pass the start/finish line precisely once each minute, so you conclude (correctly, from your perspective) that I'm travelling at a steady 4 minutes/mile clip (assuming a 1/4 mile track).
C. What you don't know, because your chosen vantage point doesn't let you see it, is that half the circumference of the track is actually a foot deep pool of water. This slows me down to 8 minutes/mile speed, but I make it up by blazing through the dry half of the circuit at 2 minutes/mile speed.
D. Your limited resolution of measurement (you can only see and measure in whole laps) leads you to the false conclusion that I'm running at a steady pace. The reality is that my speed is varying all over the place. Only the long term average is steady.
E. A turntable with a motor/drive system that allows deceleration due to drag, but then re-accelerates to faster than average speed when the drag is removed, could easily maintain a perfect AVERAGE speed of 33 1/3 rpm, while producing audible or even horrible sonic speed changes that a once-per-revolution measurement would never detect. A longer period of measurement would be proportionately less likely to detect them.
So, the experiment quoted was vaguely interesting, but proves virtually nothing. The human ear is vastly more capable of detecting short term speed changes than the crude experiment you described.
Doug
P.S. If anyone ever observes me running 4 minute miles, please let me know!