missan wrote:Hi ld
Looking at Your latest plots of dry play, there is a certain level at, and around the res. freq. If this level was lower with another combination of stylus/cartridge/tonearm, one explanation would then be that the damping could be different, thus the lower level.
I´m not totally sure what I´m getting at, but one explanation could still be that the phenomina is some type of damping? I mean these very low stylus velocities that affects and lowering the noice, they could be lowered both by amplitude reduction and dampening microscopic vibrations?
sorry for rambling
Explaining what is going on is very interesting and challenging. Here's some of my own ramblings, missan !
I do not know either if there is any significant damping going on. Sometimes I think yes, because fluid drag would be velocity sensitive and have the correct form. Sometimes I think no, because the Q of the lf response seems to remain the same. I cannot think of another test other than the Q measurement.........?
I think Thomas_A has several good points:
Firstly reduced ticks and pops might provide less stimulus for resonant behaviour. Ticks/pops are impulses, and have wideband energy, including lf, but the reduction is very large......too large methinks for this alone to be the explanation perhaps ?
Secondly, significantly reduced friction might account for reduced noise floor energy. I previously measured a reduction of c 30% in friction coefficient IIRC, wet -v- dry. That is significant, and might be related to noise floor reduction i think. It also seems possible that the lf response is simply part of reduced noise floor through friction. Lastly, the pink noise plot shows the reduction in lf response persists in the presence of broadband signal level much higher than the noise floor, so that behaviour seems unrelated to audio band energy.