Ett fåtal pickuper klarar det, och de uppvisar också en av de lägsta distorsionerna på normala testsignaler (ex DL103, AT OC9/II).
OM40 klarar inte + 18 dB spåret, inte heller V15VxMR. Osäkert om det är x-max som nås (enligt info ska det spåret vara 2 x uppgiven xmax hos pickupen, normalt mellan 80-90 um), eller om det är hastigheten som begränsar. Kopierar in ett svar från John till mig:
Hi Thomas,
I think you have the right idea about the relationship between groove amplitude and frequency given a constant groove velocity. By my calculations, the groove amplitude for a lateral velocity of 5-cm/s RMS (0-dB) at 1000-Hz is 11.25-µm. Since groove velocity is proportional to the product of amplitude and frequency, you can calculate a new groove amplitude for another frequency at the same velocity by the following equation:
(new groove amplitude) = 1000 × 11.25-µm ÷ (new frequency)
Using the above equation, the groove amplitude for 300-Hz at 5-cm/s RMS velocity is 37.51-µm. Now, there is also something called RIAA equalization that tends to reduce the groove velocity and amplitude by -5.48-dB at 300-Hz. So, when you factor in RIAA equalization, 0-dB groove amplitude at 300-Hz is actually 19.95-µm.
If you are interested in 80-µm amplitude at 300-Hz, it is approximately four times the 0-dB groove amplitude, or +12-dB. Therefore, if the HFNRR test record antiskating bands are actually based on a lateral 0-dB velocity of 5-cm/s RMS reduced by the RIAA equalization, these grooves have extremely high amplitudes. The following table lists what I believe to be the 300-Hz groove amplitudes of the HFNRR test record antiskating grooves.
Volume ..... Groove
Level ....... Amplitude
12-dB ...... 79.42µm
14-dB ...... 99.99µm
15-dB ..... 112.19µm
16-dB ..... 125.88µm
18-dB ..... 158.48µm
These amplitudes seem awfully high to me, but as far as I can tell the math is accurate. If I’ve made a mistake, I’d really like to know about it. Can anyone help?
Thanks,
John Elison
