Michael, I think you were questioning JCarr's implication that a higher effective mass tonearm will produce more robust bass from your cartridge, even when the calculated resonant frequency is already within the generally accepted range of 8 to 12Hz (or lower than 8Hz, if you follow Kuzma's line of reasoning). Far be it from me to put words in JCarr's mouth, but I suspect the reasoning to back up his advice on increasing effective mass is related to the fact that the cartridge/tonearm/headshell are resonating at all frequencies in relation to the program material and that low bass frequencies induce the most energy and hence resonance into the upstream system. The equation we use is for the resonant peak, but there is resonance at higher frequencies, probably always inversely proportional in magnitude to the frequency. Hence bass frequencies produce more resonant energy than treble frequencies. Therefore, it may be that a higher effective mass than what is absolutely minimally necessary to place the peak below 12Hz helps the cartridge to control itself while trying to traverse grooves encoding low bass music. At least this makes perfect sense to me, and is in keeping with my own direct experience. Typically, the added effective mass will not be deleterious, i.e., will not drag the resonant peak down much below 8Hz so as to render the system sensitive to footfalls, or other environmental sources of disturbance.
